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SDP 2011-917 Coral Mountain Apts (2)� / / \ \ J � .�_' . . �___�___ - � ' SC NNN ' / �_�___�_NNN _ �/ • • SDPA PIELIMIIVARY HYDROLOGY 024-PORT Located on the SE Corner of Highway 111 and Dune Palms.Rd Within a portion of the S.E. 1/4 of Section 29, Township 5 South, Range 7 East. S.B.M. City of La Quinta, California CORAL MO UNTAIN AFFORDABLE HO USING PARCEL 2 OF LLA 2010 -508 June 20, 2011 Prepared for: Shovlin Companies 46 -753 Adams Street La Quinta, Ca 92253 MSA Job Number: 1920 MSA CONSULTING, INC. PLAID MO ■ CM ]Won mo ■ .LAND Smviatwo 34200 Bos Hope DRm. E 'Rnmmo MmAoB. ■ CA 92270 41 D MUMMOns (760),320-9M • FAX (760) 323 -7893 • TABLE OF CONTENTS • • PROJECT DESCRIPTION .................................................................. ..............................1 EXISTING CONDITIONS .................................................................... ..............................1 FloodRate Map ............................................................................................. ..............................1 National Cooperative Soil Survey ............................................................... ..............................1 ExistingStorm Flows: ................................................................................................................ 1 PROPOSED FLOOD CONTROL REQUIREMENTS .......................... ..............................1 HYDROLOGY ANALYSIS DESIGN CRITERIA ................................. ..............................2 HydrologicSoil Group: .............................................................................................................. 2 Antecedent Moisture Condition: ............................................................................................... 2 Land Use Classifications and Runoff Index Numbers: .......................................................... 2 Precipitation Frequency Estimates: ......................................................................................... 2 SUMMARY of RCFCD RATIONAL METHOD PEAK FLOWS ........... ..............................3 ProposedConditions: ................................................................................................................ 3 STREET CAPACITY CALCULATIONS ............................................. ..............................5 CATCH BASINS AND STORM DRAIN SYSTEMS ...................:........ ..............................5 PRELIMINARY WQMP ANALYSIS .................................................... :.............................9 RESULTS AND CONCLUSIONS ....................................................... ..............................9 LIST OF APPENDICES: A. RIVERSIDE COUNTY TLMA VICINITY MAP B. NFIP FLOOD INSURANCE RATE MAP C. USDA NCSS HYDROLOGIC SOILS MAP D. NOAA ATLAS 14 & RCFCD REFERENCE PLATES E. RCFCD RATIONAL METHOD ANALYSIS COMPUTER RUNS F. STREET CAPACITY WORKSHEETS G. HYDRAULIC CALCULATIONS H. RCWQMP (White Water River Region) EXHIBIT C WORKSHEETS I. HYDROLOGY AND PRELIMINARY GRADING EXHIBITS SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing • PROJECT DESCRIPTION The Coral Mountain Affordable Housing project is a proposed 176 unit apartment complex located south of Highway 111, east of Dune Palms Road, north of Desert Sands Unified School District and west of the Costco shopping center. The site comprises approximately 10.3 acres and is designated as Parcel 2 of Lot Line Adjustment 2010 -508. The project is within a portion of the SE '/ of Section 29, Township 5 South, Range 7 East, San Bernardino Base and Meridian. Parcel 1 of LLA 2010 -508 (9.4 acres) located to the north of the project site; is proposed to be an auto -mall. A vicinity map obtained from Riverside County TLMA is included in Appendix A. EXISTING CONDITIONS Flood Rate Map The project area is covered by FIRM Panel Number 06065C2243G, revised August 28, 2008, which indicates the project area lies within Zone X (shaded and un- shaded). Zone X (shaded) indicates "areas of 0.2% annual chance flood; areas of 1% annual chance flood with average depths of less than 1 -foot or with drainage areas less than 1 square mile; and areas protected by levees from 1% annual chance flood ", while Zone X (un- shaded) indicates "areas determined to be outside the 0.2% annual chance floodplain" (see attached FEMA map — Appendix B). National Cooperative Soil Survey The existing soil is categorized primarily as hydrologic soil group A with some portions being hydrologic soil group B, as shown on the attached National Cooperative Soil Survey exhibits in Appendix C. For the purposes of this report, hydrologic soil group B will be assumed in hydrologic calculations. • Existing Storm Flows: The project site is relatively flat except for a hill, approximately 20 -feet high on the northwest side of the site, and generally slopes to the south and east. Storm runoff would be characterized as sheet flow, ponding in the various low points with overflow being directed to the southeast corner (see attached Preliminary Hydrology Map — Appendix 1). Off -site storm flow is negligible as the project is bounded to the north by Highway 111, on the west and east by commercial development and on the south by Desert Sands Unified School District (DSUSD). PROPOSED FLOOD CONTROL REQUIREMENTS Drainage requirements fall under the jurisdiction of the City of La Quinta. Storm flows are proposed to be directed to the La Quinta Evacuation Channel via a sub - surface storm drain system. The city requires that runoff from the 10 -year storm shall not overtop curbs and the 100 - year runoff shall be contained within the street right -of -way and /or public utility and drainage easements. Additionally, major and primary streets must have one driving lane clear in each direction in the 10 -year storm. SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing HYDROLOGY ANALYSIS DESIGN CRITERIA Peak storm flows for the 100 -year and 10 -year events were obtained utilizing the Rational Method, as described in the RCFC &WCD Hydrology Manual. The hydrologic data used for the calculations are as follows: Hydrologic Soil Group: As stated above the site is categorized primarily as Soil Group A with a small percentage of Soil Group B. The hydrologic calculations are based on the assumption that all the soil within the project area is Soil Group B which is defined by RCFCD as — `Those soils having moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission ". Antecedent Moisture Condition: AMC II — Moderate runoff potential, an intermediate condition. Per RCFC & WCD Hydrology Manual (Dated: April, 1978): "For the purposes of design hydrology using District methods, AMC II should normally be assumed for both the 10 year and 100 year frequency storm ". Land Use Classifications and Runoff Index Numbers: Runoff Index Numbers were obtained from RCFCD Plate D -5.5 and are summarized below: Proposed Conditions — Commercial Landscaping 56 Proposed open space areas as identified from the site plan were assumed to be 10% impervious. Precipitation Frequency Estimates: Precipitation depths were obtained from NOAA Atlas 14: 2 Year - 1 Hour Precipitation: 0.42 inches 100 Year — 1 Hour Precipitation: 2.02 inches Slope of Intensity Duration Curve: 0.59 See Appendix D for the NOAA Atlas 14 Point Precipitation Frequency Estimates and respective RCFCD Plates. SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing • SUMMARY of RCFCD RATIONAL METHOD PEAK FLOWS • .7 The rational method computer runs for the proposed conditions are included in Appendix E and are summarized below. Proposed Conditions: The drainage area was sub - divided into 3 (three) primary areas representing the proposed auto -mall (DA -A), the connecting street (DA -B) and the proposed multi - family complex (DA -C). Each of these areas was further subdivided into distinct areas corresponding to proposed inlet and catch basin locations (refer to the Preliminary Hydrology Map - Appendix 1). The total area under consideration is approximately 19.7 acres. Open space areas for the project site were determined from the proposed site plan and assigned a 10% impervious factor. Shown below is a summary of the proposed land use: DA Designation DA Total Area acres DA Open Space acres DA Open Space Adjusted acres DA Impervious Adjusted acres Area Impervious decimal Al 4.63 0.46 0.460 4.170 0.90 A2 4.44 0.44 0.450 3.990 0.90 DA Subtotal 9.07 0.90 0.910 8.160 0.90 131 0.19 0.04 0.036 0.154 0.81 B2 0.32 0.06 0.054 0.266 0.83 B3 0.19 0.04 0.036 0.154 0.81 B4 0.14 0.02 0.018 0.122 0.87 B5 0.24 0.05 0.045 0.195 0.81 B6 0.14 0.01 0.009 0.131 0.94 DA Subtotal 1.22 0.22 0.198 1.022 0.84 C1 0.99 0.27 0.243 0.747 0.75 C2 0.45 0.13 0.117 0.333 0.74 C3 3.06 0.90 0.810 2.250 0.74 C4 1.55 0.50 0.450 1.10 0.71 C5 0.67 0.12 0.108 0.562 0.84 C6 0.61 0.08 0.072 .0.538 0.88 C7 0.40 0.09 0.081 0.319 - 0.80 C8 0.55 0.16 0.144 0.406 0.74 C9 1.16 0.30 1 0.270 0.890 0.77 DA Subtotal 1 9.44 2.55 2.295 7.145 0.76 Total Area 1 19.73 3.68 1 3.312 16.418 0.83 3 SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing Summaries of the RCFCD Rational Runs for the 100 year and 10 year storm events are shown below: 100 Year Storm Event DA Designation Inlet Q100 cfs Tr min Intensity in /hr Area acres Al 117 22.55 10.98 5.50 4.63 A2 12 21.88 10.78 5.56 4.44 131 1.16 7.33 6.98 0.19 B2 1.89 7.85 6.70 0.32 Confluence 115/116 3.00 7.84 6.70 0.51 B3 1.16 7.33 6.98 0.19 B4 0.95 6.23 7.68 0.14 Confluence 13/14 2.03 7.33 6.98 0.33 B5 113/114 1.41 7.86 6.70 0.24 B6 VA 1.03 5.52 8.26 0.14 C1 110 6.09 7.19 7.06 0.99 C2 111 3.18 5.72 8.08 0.45 C3 112 15.17 10.22 5.74 3.06 C4 18 7.07 11.62 5.32 1.55 C5 19 4.85 5.59 8.19 0.67 C6 17 4.05 6.50 7.49 0.61 C7 16 2.68 6.32 7.62 0.40 C8 15 3.38 7.19 7.06 0.55 C9 11 6.36 8.74 6.30 1.16 10 Year Storm Event DA Designation Inlet Q100 cfs Tr min Intensity in /hr Area acres Al 117 11.91 10.98 2.94 4.63 A2 12 11.56 10.78 2.97 4.44 61 0.61 7.33 3.73 0.19 B2 0.99 7.85 3.58 0.32 Confluence 115/116 1.58 7.84 3.58 0.51 B3 0.61 7.33 3.73 0.19 B4 0.50 6.23 4.10 0.14 Confluence 13/14 1.07 7.33 3.73 0.33 B5 113/114 0.74 7.86 3.58 0.24 B6 VA 0.55 5.52 4.41 0.14 C 1 110 3.18 7.19 3.77 0.99 C2 111 1.66 5.72 4.31 0.45 C3 112 7.88 10.22 3.06 3.06 C4 18 3.65 11.62 2.84 1.55 C5 19 2.56 5.59 4.37 0.67 C6 17 2.14 6.50 4.00 0.61 C7 16 1.40 6.32 4.07 0.40 C8 15 1.76 7.19 3.77 0.55 C9 11 3.32 8.74 3.36 1.16 • SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing STREET CAPACITY CALCULATIONS Street capacities were analyzed utilizing Manning's equation for open channel flow. In accordance with City of La Quinta guidelines the 100 -year storm shall be contained within the right -of -way (public utility and /or drainage easement) and the 10 -year storm shall be contained within the curbs. The majority of the project consists of parking areas and drive aisles rather than public streets.- The proposed connecting street, "Street A" has a section width of 30 -feet (flowline to flowline). This section based on City of La Quinta guidelines precludes parking on either side of the street; therefore a Manning's 'n- value' of 0.015 was used in the calculations. The calculations were based on a minimum longitudinal slope of 0.55 %. Street Capacity (100 Year Storm): 27.43 cfs Street Capacity (10 Year Storm): 19.98 cfs The maximum 100 year runoff in Street 'A' is 3 cfs therefore the street provides sufficient capacity for both the 100 -year and 10 -year events. Street capacity worksheets are attached as Appendix F. CATCH BASINS AND STORM DRAIN SYSTEMS Catch basins and or drainage inlets and the associated "storm drain pipes were analyzed in accordance with Hydraulic Engineering Circular No. 22, utilizing Bentley Systems Inc. and StormCad software. A hydraulic grade line (HGL) elevation of 46 -feet was used in the calculations at the proposed storm drain outflow. This elevation was interpolated from Drawing • Number 10714- C-401, "Water Surface Profile ", prepared by Bechtel for the Coachella Valley Water District and is attached as Appendix G. • Storm drain pipes located within the public right -of -way are proposed to be RCP, Manning's n- value of 0.013 while all on -site storm drain pipe being HDPE (or approved equal), Manning's n- value of 0.012. Grated inlets were assumed to be utilized within the parking fields and have a clogging factor of 50% applied in the calculations. Curb inlet catch basins per City of La Quinta Standard 300 are proposed for Street 'A'. The StormCad calculations are presented as Appendix H. The software will only allow for a maximum of 10 inlets, therefore the analyses was divided into two separate files ( "A" and "B ") with Manhole 5 being the common point for the two analyses. The system flow, time of concentration and CA values from the drainage areas upstream of the manhole (from analysis "B ") were input into analysis "A" as additional external flow at inlet 1 -9 and the corresponding HGL was then used as the downstream starting HGL in analysis "B ". From Analysis "B ": Total System Flow: System Flow Time System Intensity: System CA: Input into Analysis "A 41.25 cfs 13.77 min 4.779 in /hr 8.564 acres " as Upstream System Flow From Analysis "A Manhole 5 HGL,N: 48.82 ft Input into Analysis "B" as beginning HGL. SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing Grated inlets were sized based on the orifice equation as prescribed by HEC22: Q = CoAg (2gd)0.5 f Where: Q = Intercepted Flow (cfs) Co = Orifice Constant (0.67) Ag = Gross Area of Grate (sf) g = Gravitational Constant (32.16 ft/s2) d = depth of water above grate (ft) f = clogging factor (50 %) Grate characteristics were obtained from Jensen Precast as follows: Grate Size Gross Area s 18x18 Grate 1.60 24x24 Grate 3.23 48x48 Grate 12.34 Curb inlet catch basins were sized utilizing FlowMaster Software in accordance with HEC22. A summary of the proposed inlets is shown below: Inlet No Inlet Type Total Intercepted Flow cfs Rim /FL Elevation ft HGL In ft HGL Out ft HW Depth Gutter Depth ft 11 24x24 Grate 6.36 53.86 50.38 50.21 0.51 12 Generic 21.88 56.00 51.17 51.05 -- 13 CLQ Std 300 1.02 54.53 50.91 50.91 0.23 14 CLQ Std 300 1.02 54.53 50.92 50.92 0.23 15 24x24 Grate 3.38 53.20 48.88 48.83 0.34 16 18x18 Grate 2.68 53.20 48.76 48.55 0.39 17 24x24 Grate 4.05 53.37 49.71 49.63 0.38 18 2424 Grate 7.07 54.80 50.21 50.17 0.59 19 24x24 Grate 4.85 53.46 48.90 48.80 0.43 110 24x24 Grate 6.09 53.68 49.56 49.40 0.50 111 24x24 Grate 3.17 53.92 50.07 49.93 0.33 112 48x48 Grate 15.17 53.40 51.11 51.05 0.59 113 CLQ Std 300 0.63 56.57 50.10 50.10 0.20 114 CLQ Std 300 0.63 56.54 50.25 50.25 0.20 115 CLQ Std 300 1.50 54.52 52.64 52.64 0.27 116 CLQ Std 300 1.50 54.52 53.01 52.76 0.25 117 Generic 22.54 55.50 53.22 53.09 -- It should be noted that all grated inlets shown within the parking field intercept 100% of the tributary run -off. It is highly likely that during the final precise grading phase of the project, area drains will be installed throughout the open space areas of each drainage area. These area drains will ultimately decrease the total flow intercepted by the parking field inlets. ' Assumed - Off -site area 2 Assumed - Off -site area SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing • Summaries of the backbone and lateral pipe characteristics are shown below: • • Pipe Summary Pipe No Pipe m in ) Material Total System Flow (cfs) Full Capacity (cfs) Length (ft Slope ft/ft Average Velocity (fps) P1.01 54 HDPE 71.23 116.68 127.40 0.0030 4.48 P1.02 54 HDPE 72.48 116.69 142.85 0.0030 4.56 P1.03 54 HDPE 73.33 116.68 97.97 0.0030 4.61 P1.04 54 HDPE 74.20 116.68 101.26 0.0030 4.67 P1.05 54 HDPE 74.31 116.59 12.52 0.0030 4.67 P1.06 54 HDPE 74.42 12.52 12.52 0.0030 4.68 P1.07 54 HDPE 74.52 116.55 12.36 0.0030 4.69 P1.08 54 HDPE 74.72 116.71 22.52 0.0030 4.70 131.09 54 HDPE 74.82 116.59 12.52 0.0030 4.70 131.10 54 HDPE 74.93 116.74 12.52 0.0030 4.71 P1.11 54 HDPE 75.02 123.55 10.91 0.0034 4.72 P2.01 30 HDPE 26.47 46.53 14.59 0.0110 5.39 P2.02 30 HDPE 26.55 47.65 20.00 0.0115 5.41 P2.03 30 HDPE 26.59 46.60 10.00 0.0110 5.42 P2.04 30 HDPE 27.58 47.03 253.54 0.0112 5.62 P2.05 30 HDPE 23.44 47.09 287.55 0.0112 4.78 P3.01 18 RCP 1.94 10.53 99.55 0.0100 1.10 P4.01 48 HDPE 52.19 125.64 7.67 0.0065 4.15 P4.02 48 HDPE 52.23 128.60 7.32 0.0068 4.16 P4.03 48 HDPE 52.48 1285.42 36.94 0.0065 4.18 P4.04 48 HDPE 49.06 125.43 35.40 0.0065 3.90 P4.05 48 HDPE 42.09 125.00 142.56 0.0065 3.35 P4.06 48 HDPE 41.27 125.78 169.88 0.0065 3.28 P5.01 36 HDPE 41.37 65.34 18.34 0.0082 5.85 P5.02 36 HDPE 37.38 81.06 23.04 0.0126 5.29 P5.03 36 HDPE 22.97 78.98 31.80 0.0119 3.25 P5.04 36 HDPE 23.06 71.67 14.23 0.0098 3.26 P5.05 36 HDPE 23.12 72.25 10.00 0.0100 3.27 P5.06 36 HDPE 23.18 72.25 10.00 0.0100 3.28 P5.07 36 HDPE 23.57 72.51 65.54 0.0101 3.33 P6.01 24 HDPE 16.74 24.54 117.70 0.0100 5.33 P6.02 24 HDPE 15.03 24.50 159.05 0.0100 4.78 P7.01 30 RCP 23.75 29.44 44.64 0.0052 4.84 P7.02 30 RCP 23.34 28.92 14.08 0.0050 4.75 P7.03 30 RCP 24.03 28.96 300.88 0.0050 4.90 P7.04 30 RCP 24.95 29.04 223.48 0.0050 5.08 SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing Lateral Summary Pipe No Pipe m in ) Material Total System Flow (cfs) Full Capacity (cfs) Length (ft Slope ft/ft Average Velocity (fps) 1-1.1 12 HDPE 6.36 24.85 11.29 0.4145 8.10 1-2.1 24 RCP 21.88 28.21 18.00 0.0156 6.96 1-3.1 18 RCP 1.02 1 60.45 19.05 0.3312 12.85 L4.1 18 RCP 1.02 54.67 19.60 0.2709 0.57 L5.1 12 HDPE 3.38 8.82 9.39 0.0522 4.30 L6.1 12 HDPE 5.84 38.59 7.52 1.0000 7.44 L7.1 12 HDPE 4.05 17.22 55.28 0.1990 17.92 1-8.1 18 HDPE 9.39 21.91 13.75 0.0371 5.31 L8.2 18 HDPE 6.84 21.84 119.20 0.0368 3.87 1-8.3 18 HDPE 7.02 21.86 128.71 0.0369 3.97 1-8.4 18 HDPE 7.05 21.84 17.91 0.0369 3.99 L8.5 18 HDPE 7.07 21.81 40.00 0.0367 11.02 1-9.1 12 HDPE 4.85 38.59 8.52 1.0000 6.18 L10.1 12 HDPE 6.09 9.04 11.31 0.0548 7.75 1-12.1 24 HDPE 15.17 82.28 49.05 0.1127 4.83 L13.1 18 RCP 0.63 44.93 21.59 0.1830 0.36 1-14.1 18 RCP 0.63 64.83 9.45 0.3810 0.36 L15.1 18 RCP 1.50 31.89 21.05 0.0922 0.85 L16.1 24 RCP 23.75 29.14 11.45 0.0166 7.56 L17.1 24 RCP 22.54 27.71 8.00 0.0150 7.18 Hydraulic calculations are provided as Appendix G. r SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing • PRELIMINARY WQMP ANALYSIS Preliminary design volume and flow for BMP measures were based on Worksheets 1 and 2 from the Riverside County - Whitewater River Region Water Quality Management Plan. Impervious areas for Drainage Areas 'B' and 'C' are derived from the proposed site plan. Drainage Area 'A' (future auto -mall site) is not included in the summary as this area is not a part of the affordable housing project other than for sizing of the proposed storm drain pipes. Once this area has been designed the site will be responsible for mitigation of its portion of the design volume. A summary of the design flow and volumes is presented below with the worksheets attached as Appendix H. Drainage Total Area Impervious Design Design Area Area Volume Flow acres acres cu -ft cfs DA -13 1.22 1.02 1,143 0.19 DA -C 9.44 7.15 7,553 1.34 Note: The impervious areas shown were determined by calculating the open space areas (as shown on the proposed site plan) and reducing the total pervious area by a factor of 10 %. Based on the above summaries, the project will provide 8,700 cubic feet of storage in underground retention facilities with a pre - filtration unit per City standards. It is proposed to utilize a Contech Detention System with 8 -foot diameter pipes and a Maxwell Plus Drywell (Interceptor) system to serve as the water quality BMP inlet. RESULTS AND CONCLUSIONS • As the above narrative and summaries confirm, the proposed project meets the hydrologic conditions as set forth by the City of La Quinta. • SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing Appendix A Riverside County TLMA Vicinity Map Riverside County GIS X ASHLEY WAY 4Q RPORATE CENTRE DR 11 f--AMT City of La Quinta RD HMO DR Z z W 0 Z D a Page I of I http: //www3.tlma.co.riverside.ca. 4 SEC ,49 z - " L OW ST 0 0 ui -j AGAVE ST z LIJ t0 o CASSUIST AVENUE48 a +u AVENUE 48 DE D try R A NMCC 14 Mverside County TLMA G1 S GOLOENGATEOR Selected parcel(s): 600-020-047 600-020-048 !to �makes *IMPORTANT* Maps and data are to be used for reference purposes only. Map features are approximate, and are not necessarily accurate u,.,,,., engineering standards. The County of Riverside no waranty or guarantee as to the content (the source is often third partj), accuracy, timeliness, or completeness of any of the data provided, and assumes no legal responsibility for the information contained on this map. Any use of this product with respect to accuracy and precision shall be the sole responsibility of the user. REPORT PRINTED ON VVed Mar 10 12:15: LATITUDE: 33.70 LONGITUDE: -11 http: //www3.tlma.co.riverside.ca. 0 SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing Appendix B NFIP Flood Insurance Rate Map Th,k iZ an oft,i copy On fu)Miln of "le IbOY-' rtWerse-" food M10 I' w--. extracted v.dng 9 MIT On UnQ, 7N% map 0oQ-1 not r0eC1 changes or amendments wNct) may have been made subsequent to the c6ate an the tiff. time, Pm tt-m * * mkxs,A NMI ld Mood Program food maps check the FEMA Rood MV.Ston: at ww&MSC fcma Q( • DEFINITIONS OF FEMA FLOOD ZONE DESIGNATIONS • Moderate to Low Risk Areas In communities that participate in the NFI'P, flood insurance is available to all property owners and renters in these zones: ZONE DESCRIPTION Areas of 0.2% annual chance flood; areas of 1% annual chance flood X (Shaded) with average depths of less than 1 foot or with drainage areas less than 1 square mile; and areas protected by levees from 1% annual chance flood. Insurance purchase is not required in these zones. (X) (Areas determined to be outside the 0.2% annual chance flood lain.) High Risk Areas In communities that participate in the NFIP, mandatory flood insurance purchase requirements apply to all of these zones: ZONE DESCRIPTION - Areas with a 1% annual chance of flooding and a 26% chance of A flooding over the life of a 30 -year mortgage. Because detailed analyses are not performed for such areas; no depths or base flood elevations are shown within these zones. Areas with a 1% annual chance of flooding and a 26% chance of AE flooding over the life of a 30 -year mortgage. In most instances, base flood elevations derived from detailed analyses are shown at selected intervals within these zones. Areas with a 1 % annual chance of shallow flooding, usually in the form of a pond, with an average depth ranging from 1 to 3 feet. These areas AH have a 26% chance of flooding over the life of a 30 -year mortgage. Base flood elevations derived from detailed analyses are shown at selected intervals within these zones. River or stream flood hazard areas, and areas with a 1% or greater chance of shallow flooding each year, usually in the form of sheet flow, AO with an average depth ranging from 1 to 3 feet. These areas have a 26% chance of flooding over the life of a 30 -year mortgage. Average flood depths derived from detailed analyses are shown within these zones. For areas of alluvial fan flooding, velocities are also determined'. Areas with a temporarily increased flood risk due to the building or restoration of a flood control system (such as a levee or a dam). AR Mandatory flood insurance purchase requirements will apply, but rates will not exceed the rates for unnumbered A zones if the structure is built or restored in compliance with Zone AR floodplain management regulations. Areas with a 1% annual chance of flooding that will be protected by a A99 Federal flood control system where construction has reached specified legal requirements. No depths or base flood elevations are shown within these zones. High Risk — Coastal Areas In communities that participate in the NFIP, mandatory flood insurance purchase requirements apply to all of these zones: ZONE DESCRIPTION Coastal areas with a 1 % or greater chance of flooding and an additional V hazard associated with storm waves. These areas have a 26% chance of flooding over the life of a 30 -year mortgage. No base flood elevations are shown within these zones. Coastal areas with a 1 % or greater chance of flooding and an additional hazard associated with storm waves. These areas have a 26% chance VE of flooding over the life of a 30 year mortgage. Base flood elevations derived from detailed analyses are shown at selected intervals within these zones. Undetermined Risk Areas ZONE DESCRIPTION Areas with possible but undetermined flood hazards. No flood hazard D analysis has been conducted. Flood insurance rates are commensurate with the uncertainty of the flood risk. SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing Appendix C USDA NCSS Hydrologic Soils Map 0 L ei 116'16'43" O >- D Z 0) y � o CD @ o w M = CD O o o p o (T O W rn O O O O Z � N O tl7 g O fD O Q 1a c) CD o @ = �U) D U) N O- D O CD CD d 0 y N O m o N x lD j. O N O N W Gomm W 0 11G °1G'1" O n) O A O A A O w w A '512V IU0 $ /G`SLUU 37 00 2e � A WN Of 116° 16'43" (n O n J n c �I N i C7 N > N 0 r O vc o O� C ' � 7 n N gj Sr J � J G J � CD CD i N J O 3 J N 0 116° 16' T' 00 373 200 w w A Hydrologic Soil Group— Riverside County, Coachella Valley Area, California (City of La Quinta) MAP LEGEND Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Units ppSoil Ratings 0 A A/D B 0 B/D 0 C C/D D Not rated or not available Political Features 0 Cities 0 PLSS Township and Range 0 PLSS Section Water Features NJ Oceans Streams and Canals Transportation +++ Rails Interstate Highways ru US Routes Major Roads Local Roads MAP INFORMATION Map Scale: 1:6,930 if printed on A size (8.5" x 11 ") sheet. The soil surveys that comprise your AOI were mapped at 1:24,000 Please rely on the bar scale on each map sheet for accurate map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: http : / /websoilsurvey.nres.usda.gov Coordinate System: UTM Zone 11 N NAD83 This product is generated from the USDA -NRCS certified data as of the version date(s) listed below. Soil Survey Area: Riverside County, Coachella Valley Area, California Survey Area Data: Version 4, Jan 3, 2008 Date(s) aerial images were photographed: 5/3112005 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. USDA Natural Resources . . . . i Soil Survey 3/'" - -- "_ �� Conservation Service Natic )perative Soil Survey Pag Hydrologic Soil Group — Riverside County, Coachella Valley Area, California 0 Hydrologic Soil Group City of La Quinta Hydrologic Soil Group— Summary by Map Unit — Riverside County, Coachella Valley Area, California Map unit symbol Map unit name Rating Acres in AOI Percent of AOI CpA Coachella fine sand, 0 to 2 percent slopes A 99.2 49.2% GbA Gilman fine sandy loam, 0 to 2 percent slopes B 0.1 0.0% MaB Myoma fine sand, 0 to 5 percent slopes A 5.9 2.9% MaD Myoma fine sand, 5 to 15 percent slopes A 96.6 47.8% Totals for Area of Interest 201.9 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long- duration storms. • The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B /D, and C /D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils. of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink -swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B /D, or C /D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. • USDA Natural Resources Web Soil Survey 3/18/2010 am Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Group — Riverside County, Coachella Valley Area, California Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff.- None Specified Tie -break Rule: Lower City of La Quinta Y Natural Resources Web Soil Survey 3/18/2010 � Conservation Service National Cooperative Soil Survey Page 4 of 4 SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing Appendix D NOAA Atlas 14 RCFCD Reference Plates 0 is Precipitation Frequency Data Server ' POINT PRECIPITATION FREQUENCY ESTIMATES • FROM NOAA ATLAS 14 QW-10, California 33.7053 N 116.2754 W 78 feet from "Precipitation- Frequency Atlas of the United States" NOAA Atlas 14, Volume 1, Version 4 G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley NOAA, National Weather Service, Silver Spring, Maryland, 2006 Extracted: Thu Mar IS 2010 Confidence Limits Seasonality Location Maps. l Othr er Info. GIS data ,Maps Dos Retum to Precipitation Frequency Estimates (inches) • • ' These precipitation frequency estimates are based on a partial duration series. ARI is the Average Recurrence Interval. Please refer to NOAA Atlas 14 Document for more information. NOTE: Formatting forces estimates near zero to appear as zero. * Upper bound of the 90% confidence interval Precipitation Frequency Estimates (inches) ARI ** 5 10 15 30 60 120 3 6 12 24 48 4 7 IOU 30 45 60 -1 (years) min min min min min min hr hr hr hr hr day day day day day day day Ol 0.12 0.19 0.23 0.31 0.39 0.52 0.60 0.79 0.97 1.01 1.02 1.07 1.17 - 1.40 1.55 1.75 1.86 =FO 0.11 ARI* ❑�n�� 5 10 15 30 60 Z'2ffj3�hrH 1.31 1.38 12 24 48 4 ❑❑ Z ❑❑ 20 30 ❑�❑ 45 60 0.41 0.51 0.69 0.86 mm min mm mm 2.09 2.11 hr hr hr day day � 10 0.36 d day 0.92 1.13 Ol 0.10 0.15 0.18 0.25 0.31 0.42 0.49 0.65 0.81 0.85 0.87 0.93 1.02 1.09 1.21 1.35 1.53 1.62 1.93 • • ' These precipitation frequency estimates are based on a partial duration series. ARI is the Average Recurrence Interval. Please refer to NOAA Atlas 14 Document for more information. NOTE: Formatting forces estimates near zero to appear as zero. * Upper bound of the 90% confidence interval Precipitation Frequency Estimates (inches) ARI ** 5 10 15 30 60 120 3 6 12 24 48 4 7 IOU 30 45 60 -1 (years) min min min min min min hr hr hr hr hr day day day day day day day Ol 0.12 0.19 0.23 0.31 0.39 0.52 0.60 0.79 0.97 1.01 1.02 1.07 1.17 1.27 1.40 1.55 1.75 1.86 =FO 0.11 0.26 0.32 0.44 0.54 OF717 0.81 1.07 1.31 1.38 1.39 1.47 1.59 1.73 1.91 2.12 j 2.42 2.56 =0.27 0.17 0.41 0.51 0.69 0.86 1.09 1.23 1.61 1.95 2.09 2.11 2.20 2.37 2.60 2.88 3.20 3.64 3.88 10 0.36 0.55 0.68 0.92 1.13 1.42 1.59 2.03 2.44 2.65 2.68 2.78 2.99 3.28 3.63 4.02 4.56 4.86 25 0.50 0.77 0.95 1.28 1.59 1.93 2.13 2.65 3.14 3.46 3.50 3.66 3.88 4.28 4.71 5.18 5.83 6.25 50 0.64 0.97 1.21 1.62 2.01 2.40 2.60 3.19 3.72 4.13 4.17 4.40 4.63 5.10 5.59 6.13 6.84 7.35 100 0.80 1.21 1.50 2.02 2.50 2.94 3.15 3.79 4.36 4.86 4.90 5.23 5.47 6.01 6.55 7.16 7.93 8.54 200 0.98 1.50 1.85 2.50 3.09 3.58 3.79 4.45 5.06 5.66 5.79 6.17 6.38 7.04 7.60 8.29 9.09 9.78 500 1.29 1.96 2.43 3.27 4.05. 4.61 4.79 5.47 6.08 6.85 7.13 7.59 7.74 8.53 9.14 9.89 10.73 11.55 1000 1.57 2.39 2.97 4.00 4.95 5.53 5.69 6.36 6.97 7.87 8.29 8.81 8.89 9.81 10.44 11.22 12.04 12.98 the upper bound of the confidence interval at 90% confidence level is the value which 5% of the simulated quantile values for a given frequency are greater than. " These precipitation frequency estimates are based on a partial duration series. ARI is the Average Recurrence Interval. Please refer to NOAA Atlas 14 Document for more information. NOTE: Formatting prevents estimates near zero to appear as zero. * Lower bound of the 90% confidence interval Precipitation Frequency Estimates (inches) ARI 5 10 15 30 [�1?2 120 3 6 12 24 48 4 7 ]0 20 30 45 60 (yers) min min min min hr hr hr hr hr day day day day day day day 11I0.08 0.12 0.15 0.20 0.25 0.34 0.41 0.54 0.67 0.71 0.75 0.80 0.88 0.94 1.04 1.18 1.32 1.41 0 0.11 0.17 0.20 0.28 0.34 0.47 0.55 0.73 0.91 0.97 1.02 1.09 1.19 1.29 1.43 1.61 1.82 1.93 =5 0.17 0.26 0.33 0.44 0.55 0.72 0.84 1.10 1.34 1.47 .52 ] 1.78 1.94 2.16 2.42 2.74 2.92 0 0.23 0.35 0.43 0.58 0.72 0.94 1.07 1.38 1.68 1.86 1.93 2.06 2.23 2.44 2.71 3.03 3.42 3.65 25 0.32 0.48 0.59 0.80 0.99 1.27 1.43 1.79 2.14 2.41 2.51 2.67 2.87 3.16 3.48 3.88 4.35 4.65 50 0.39 0.60 0.74 1.00 1.24 1.55 1.72 2.13 2.52 2.85 2.98 3.18 3.38 3.73 4.10 4.55 5.08 5.43 100 0.48 0.73 0.91 1.23 1.52 1.87 2.05 2.49 2.91 3.33 3.50 3.72 3.93 4.34 4.75 5.26 5.83 6.24 200 0.58 0.89 1.10 1.48 1.83 2.22 2.42 2.88 3.33 3.83 4.06 4.30 4.50 4.99 5.44 5.97 6.59 7.06 500 0.74 1.12 1.39 1.88 2.32 2.75 2.95 3.45 3.90 4.54 4.87 5.14 5.31 5.90 6.38 6.98 7.63 8.18 1000 0.87 1.33 1.65 2.22 2.74 3.21 3.39 3.92 4.37 5.10 5.53 5.83 5.96 6.65 7.13 7.77 8.41 9.06 I he lower bound of the confidence interval at 90% confidence level is the value which 5% of the simulated quantile values for a given frequency are less than. Page 1 of 3 http: // dipper. nws. noaa .gov /cgi- binlhdscibuildout.perl ?type =pf &units =us &series =pd &state... 3/18/2010 Precipitation Frequency Data Server " These precipitation frequency estimates are based on a partial duration maxima series. ARI is the Average Recurrence Interval. Please refer to NOAA Atlas 14 Document for more information. NOTE: Formatting prevents estimates near zero to appear as zero. WTLi7xt Lersion of,tables W ion C C E L L L L L L L 5 -min 120 -m 48 -hr. -x- 30 -day -x- 10 -min 34r -x1- 4 -day 45 -day 15 -min ± 6 -hr + 7 -day �- 60 -day 30 -min 12 -hr t 10 -day t M M 'a a 60 -min -x- 24 -hr --a- 20 -dau -� I 1 N Partial duration based Point Precipitation Frequency Estimates - Versions 4 33.7053 H 116.2754 W 78 ft 12 11 10 C g .0 8 Y Q d 7 A 0 6 M 5 Y Q 4 U L 3 o. 2 1 0 C C C C C C E L L L L L L L L L 31 M31 71 T T T 71 7 T E E E E I E E m S S 1 1 S S S S L 1 1 1 1 1 S L 1 1 M M M 'o a s M a M a M M 'a a N a W N .a a 1 1 1 1 I 1 N M? w m N m e .D W 1 1 1 1 1 I 1 1 1 1 N m N 0 ^ M 0 Q — 'o m -. N Duration M a M V In A 12 N m ^ N ax M VI ax a 'o Thu Mar 18 10:46:02 2010 Average Recurrence Interval (years) 1 -°- 2 100 — 5 + 200 + 10 --a- 500 + 25.-x- 100a --D- Maps - Page 2 of 3 http: / /dipper.nws.noaa. gov /cgi- binlhdscibuildout.perl ?type =pf &units =us &series =pd &state... 3/18/2010 Precipitation Frequency Data Server Page 3 of 3 _ • �1 \-Z i , a cation 1 - -- i r � r vo-w 11o"W loo «W qo «W do r «W 70 r "W . These maps_were produced using a direct map request from the - U. S. C ensus Bureau Mapping and Cartographic Resources Tiger Map Server. ' Please read disclaimer for more information. 1u e « LEGEND t — State — Connector -- — County Stream �.=1 Indian Resv Military Area �. Lake /Pond /Ocean National Park 4-- t — Street Other Park Expressway p City 74 86 — H I ghway 0 T_ County 6 8 mi Scale 1:228583 22 ',JO I *average- -true scale deventls.on monitor 8restion 11 F, -W 11 A 9 "61 11 fi .9 «W, • r Other Maps /Photographs - View USGS digital orthoahoto quadrangle (DOO) covering this location from TerraServer USGS Aerial Photograph may also be.available from this site. A DOQ is a computer - generated image of an aerial photograph in which image displacement caused by terrain relief and camera tilts has been removed. It combines the image characteristics of a photograph with the geometric qualities of a map. Visit the USGS for more information. Watershed /Stream Flow Information - Find the Watershed for this location using the U.S. Environmental Protection Agency's site. -Climate Data Sources. Precipitation frequency results are based on data from a variety of sources, but largely NCDC. The following links provide general information . about observing sites in the area, regardless of f f their data was used in this study. For detailed information about the stations used in this study, please refer to NOAH Atlas 14 Document. Using the National Climatic Data Center's (NCDC) station search engine, locate other climate stations within: + /730;minutes. . I ...OR... F + /-ldegree ;: ofthis location (33.7053/ - 116.2754). Digital ASCII data can be obtained directly from NCDC. Find Natural Resources Conservation Service (NRCS) SNOTEL (SNOwpack TELemetry) stations by visiting the Western Regional Climate Center's state - specific SNOTEL station maps. - Hydrometeorological Design Studies Center - DOC/NOAA/National Weather Service - - 1325 East -West Highway Silver Spring, MD 20910 (301) 713 -1669 . Questions ?: HDSC.Ouestions«7i noaa aov .Disclaimer http: / /dipper.riws.noaa. gov /cgi- bin /hdsc/buildout.perl ?type =pf &units =us &series =pd &state..: 3/18/2010 NOAA ATLAS 14 INTENSITY- DURATION WORKSHEET PROJECT NAME CITY OF LA QUINTA 22.1 PROJECT NUMBER 1920 MINUTES STORM EVENT 100 DATE: March 22, 2010 (in/hr) DATA FROM NOAA ATLAS 14 8.55 MINUTES RAINFALL RAINFALL 5.68 INTENSITY DEPTH 4.47 (in/hr) in 3.77 5 7.68 0.64 3.31 10 5.88 0.98 2.97 15 4.84 1.21 2.71 30 3.26 1.63 2.51 60 2.02 2.02 2.34 120 1.21 2.42 10.00 CONSTANT FROM GRAPH 22.1 EXPONENT FROM GRAPH -0.59 MINUTES RAINFALL RAINFALL INTENSITY DEPTH (in/hr) (in) 5 8.55 0.71 10 5.68 0.95 15 4.47 1.12 20 3.77 1.26 25 3.31 1.38 30 2.97 1.49 35 2.71 1.58 40 2.51 1.67 45 2.34 1.75 50 2.20 1.83 55 2.08 1.90 60 1.97 1.97 65 1.88 2.04 70 1.80 2.10 75 1.73 2.16 80 1.67 2.22 85 1.61 2.28 90 1.55 2.33 95 1.50 2.38 100 1.46 2.43 105 1.42 2.48 110 1.38 2.53 115 1.34 2.58 120 1.31 4.59 1.00 1 10 100 1000 INTENSITY VALUES FROM GRAPH CONSTANT FROM GRAPH 22.1 EXPONENT FROM GRAPH -0.59 MINUTES RAINFALL RAINFALL INTENSITY DEPTH (in/hr) (in) 5 8.55 0.71 10 5.68 0.95 15 4.47 1.12 20 3.77 1.26 25 3.31 1.38 30 2.97 1.49 35 2.71 1.58 40 2.51 1.67 45 2.34 1.75 50 2.20 1.83 55 2.08 1.90 60 1.97 1.97 65 1.88 2.04 70 1.80 2.10 75 1.73 2.16 80 1.67 2.22 85 1.61 2.28 90 1.55 2.33 95 1.50 2.38 100 1.46 2.43 105 1.42 2.48 110 1.38 2.53 115 1.34 2.58 120 1.31 2.62 NOAA ATLAS 14 INTENSITY - DURATION WORKSHEET PROJECT NAME CITY OF LA QUINTA RAINFALL PROJECT NUMBER 1920 DEPTH STORM EVENT 10 (in) DATE: [March 22, 2010 j 10 DATA FROM NOAA ATLAS 14 15 MINUTES RAINFALL RAINFALL 20 INTENSITY DEPTH 25 (in/hr) in 30 5 3.48 0.29 35 2.81 10 2.64 0.44 2.60 1.73 15 2.16 0.54 1.82 50 30 1.46 0.73 55 2.16 60 0.90 0.90 2.06 2.06 120 0.58 1.16 2.13 10.00 RAINFALL RAINFALL INTENSITY DEPTH (in/hr) (in) 5 8.69 0.72 10 5.81 c 15 4.59 1.15 20 3.89 1.30 25 3.42 1.42 30 3.07 1.54 35 2.81 1.64 40 2.60 1.73 45 2.43 1.82 50 2.29 1.90 55 2.16 1.98 60 2.06 2.06 65 1.96 2.13 70 1.88 2.19 75 1.81 2.26 80 1.74 2.32 85 1.68 2.38 90 1.63 2.44 95 1.58 2.49 100 1.53 2.55 105 1:49 2.60 110 1.45 2.65 115 1.41 2.70 120 1.38 2.75 1.00 0 0.10 INTENSITY VALUES FROM GRAPH CONSTANT FROM GRAPH 22.1 EXPONENT FROM GRAPH -0.58 MINUTES RAINFALL RAINFALL INTENSITY DEPTH (in/hr) (in) 5 8.69 0.72 10 5.81 0.97 15 4.59 1.15 20 3.89 1.30 25 3.42 1.42 30 3.07 1.54 35 2.81 1.64 40 2.60 1.73 45 2.43 1.82 50 2.29 1.90 55 2.16 1.98 60 2.06 2.06 65 1.96 2.13 70 1.88 2.19 75 1.81 2.26 80 1.74 2.32 85 1.68 2.38 90 1.63 2.44 95 1.58 2.49 100 1.53 2.55 105 1:49 2.60 110 1.45 2.65 115 1.41 2.70 120 1.38 2.75 SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing 0 Appendix E RCFCD Rational Method Analyses Computer Runs 0 • Riverside County Rational Hydrology Program CIVILCADD /CIVILDESIGN Engineering Software,(c) 1989 - 2005 Version 7.1 Rational Hydrology Study Date: 03/08/11 File:'1920cmahsdpal00yr.out ------------------------------------------------------------------------ CORAL MOUNTAIN AFFORDABLE HOUSING PRELIMINARY RATIONAL HYDROLOGY 100 YEAR STORM EVENT * * * * * * * ** Hydrology Study Control Information * * * * * * * * ** English (in -lb) Units used in input data file Program License Serial Number 6041 ------------------------------------------------------------------------ Rational Method Hydrology Program based on Riverside County Flood Control & Water Conservation District 1978 hydrology manual Storm event (year) = 100.00 Antecedent Moisture Condition = 2 2 year, 1 hour precipitation = 0.420(In.) 100 year, 1 hour precipitation = 2.020(In.) Storm event year = 100.0 Calculated rainfall intensity data: 1 hour intensity = 2.020(In /Hr) • Slope of intensity duration curve = 0.5900 +++++++++++++++++++++++++++++++++++++++ + ++ + + + + + + + + + + + + + + ++ + + + + + + + + + + ++ Process from Point /Station 100.000 to Point /Station 105.000 * * ** INITIAL AREA EVALUATION * * ** DA -A1 (Inlet I17) Initial area flow distance = 630.000(Ft.) Top (of initial area) elevation = 58.800(Ft.) Bottom (of initial area) elevation 55.000(Ft.) Difference in elevation = 3.800(Ft.) Slope = 0.00603 s(percent)= 0.60 TC = k(0.300) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 10.984 min. Rainfall intensity = 5.501(In /Hr) for a 100.0 year storm COMMERCIAL subarea type Runoff Coefficient = 0.886 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.100; Impervious fraction = 0.900 Initial subarea runoff = 22.554(CFS) Total initial stream area = 4.630(Ac.) Pervious area fraction = 0.100 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ Process from Point /Station 100.000 to Point /Station 110.000 * * ** INITIAL AREA EVALUATION * * ** DA -A2 (Inlet I2) Initial area flow distance = 605.000(Ft.) Top (of initial area) elevation = 58.800(Ft.) • Bottom (of initial area) elevation = 55.100(Ft.) Difference in elevation = 3.700(Ft.) Slope = 0.00612 s(percent)= 0.61 TC = k(0.300) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 10.778 min. Rainfall intensity = 5.562.(In /Hr) for a 100.0 year storm COMMERCIAL subarea type Runoff Coefficient = 0.886 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.100; Impervious fraction = 0.900 Initial subarea runoff = 21.875(CFS) Total initial stream area = 4.440(Ac.) Pervious area fraction = 0.100 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ Process from Point /Station 200.000 to Point /Station 210.000 * * ** INITIAL AREA EVALUATION * * ** DA -B1 Initial area flow distance = 190.000(Ft.) Top (of initial area) elevation = 56.000(Ft.) Bottom (of initial area) elevation = 54.900(Ft.) Difference in elevation = 1.100(Ft.) Slope = 0.00579 s(percent)= 0.58 TC = k(0.321) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 7.329 min. Rainfall intensity = 6.983(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.878 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.190; Impervious fraction = 0.810 Initial subarea runoff = 1.165(CFS) Total initial stream area = 0.190(Ac.) Pervious area fraction = 0.190 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + ++++ + + ++ + + + + + + + ++ Process from Point /Station 200.000 to Point /Station 210.000 * * ** CONFLUENCE OF MAIN STREAMS * * ** The following data inside Main Stream is listed: In Main Stream number: 1 Stream flow area = 0.190(Ac.) Runoff from this stream = 1.165(CFS) Time of concentration = 7.33 min. Rainfall intensity = 6.983(In /Hr) Program is now starting with Main Stream No. 2 +++++++++++++++++++++++++++++++++++++++ + +++++++ + + + + + + + + + + + + + ++ ++++++++ Process from Point /Station 205.000 to Point /Station 210.000 * * ** INITIAL AREA EVALUATION * * ** DA -B2 Initial area flow distance = 315.000(Ft.) Top (of initial area) elevation = 58.200(Ft.) Bottom (of initial area) elevation = 54.900(Ft.) Difference in elevation = 3.300(Ft.) Slope = 0.01048 s(percent)= 1.05 • TC = k (0.316) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 7.859 min. Rainfall intensity = 6.709(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.879 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.170; Impervious fraction = 0.830 Initial subarea runoff = 1.886(CFS) Total initial stream area = 0.320(Ac.) Pervious area fraction = 0.170 +++++++++++++++++++++++++++++++++++++++ + + + + + +++ + + + + + + + + + + + + + + + + + + + + + ++ Process from Point /Station 205.000 to Point /Station 210.000 * * ** CONFLUENCE OF MAIN STREAMS * * ** (Inlet I15 6 I16) The following data inside Main Stream is listed: In Main Stream number: 2 Stream flow area = 0.320(AC.) Runoff from this stream = 1.886(CFS) Time of concentration = 7.85 min. Rainfall intensity = 6.709(In /Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In /Hr) • 1 1.165 7.33 6.983 2 1.886 7.85 6.709 Largest stream flow has longer time of concentration Qp = 1.886 + sum of Qb Ia /Ib 1.165 * 0.960 = 1.118 Qp = 3.009 Total of 2 main streams to confluence: Flow rates before confluence point: 1.165 1.886 Area of streams before confluence: 0.190 0.320 Results of confluence: Total flow rate = 3.004(CFS) Time of concentration = 7.854 min. Effective stream area after confluence = 0.510(Ac.) +++++++++++++++++++++++++++++++++++++++ + +++++ + + + + + + + + ++ +++ + + + + + + + + ++ ++ Process from Point /Station 200.000 to Point /Station 220.000 * * ** INITIAL AREA EVALUATION * * ** DA -B3 Initial area flow distance = 190.000(Ft.) Top (of initial area) elevation = 56.000(Ft.) Bottom (of initial area) elevation = 59.900(Ft.) Difference in elevation = 1.100(Ft.) Slope = 0.00579 s(percent)= 0.58 TC = k (0.321) *[(length ^.3) /(elevation change)] ^0.2 Initial area time of concentration = 7.329 min. Rainfall intensity = 6.983(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.878 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.190; Impervious fraction = 0.810 Initial subarea runoff = 1.165(CFS) Total initial stream area = 0.190(Ac.) Pervious area fraction = 0.190 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ Process from Point /Station 200.000 to Point /Station 220.000 * * ** CONFLUENCE OF MAIN STREAMS * * ** The following data inside Main Stream is listed: In Main Stream number: 1 Stream flow area = 0.190(Ac.) Runoff from this stream = 1.165(CFS) Time of concentration = 7.33 min. Rainfall intensity = 6.983(In /Hr) Program is now starting with Main Stream No. 2 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ Process from Point /Station 215.000 to Point/ Station 220.000 * * ** INITIAL AREA EVALUATION * * ** DA -B4 Initial area flow distance = 165.000(Ft.) Top (of initial area) elevation = 56.200(Ft.) Bottom (of initial area) elevation = 54.900(Ft.) Difference in elevation = 1.300(Ft.) Slope = 0.00788 s(percent)= 0.79 TC = k(0.307) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 6.233 min. Rainfall intensity = 7.684(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.886 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.130; Impervious fraction = 0.870 Initial subarea runoff = 0.953(CFS) Total initial stream area = 0.140(Ac.) Pervious area fraction = 0.130 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ Process from Point /Station 215.000 to Point /Station 220.000 * * ** CONFLUENCE OF MAIN STREAMS * * ** (Inlet 13 6 I4) The following data inside Main Stream is listed: In Main Stream number: 2 Stream flow area = 0.140(Ac.) Runoff from this stream = 0.953(CFS) Time of concentration = 6.23 min. Rainfall intensity = 7.684(In /Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In /Hr) • 1 1.165 7.33 6.983 Bottom (of initial area) elevation = 57.000(Ft.) 2 0.953 6.23 7.684 Largest stream flow has longer time of concentration USER INPUT of soil data for subarea Qp = 1.165 + sum of Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Qb Ia /Ib Decimal fraction soil group D = 0.000 0.953 * 0.909 = 0.866 Qp = 2.031 Total initial stream area = 0.240(Ac.) Total of 2 main streams to confluence: Flow rates before confluence point: 1.165 0.953 Area of streams before confluence: 0.190 0.140 Results of confluence: Total flow rate = 2.031(CFS) Time of concentration = 7.329 min. Effective stream area after confluence = 0.330(Ac.) +++++++++++++++++++++++++++++++++++++++ + + + + + + + + ++ + + + + + + + + + + +++++ + + + + ++ Process from Point /Station 205.000 to Point /Station 225.000 * * ** INITIAL AREA EVALUATION * * ** DA -B5 (Inlet I13'& I14) +++++++++++++++++++++++++++++++++++++++ + + + + ++++ + + + + + + + + + +++++ + + + + + + +++ Process from Point /Station 225.000 to Point /Station 230.000 * * ** INITIAL AREA EVALUATION * * ** DA -B6 Initial area flow distance = 220.000(Ft.) Top (of initial area) elevation = 58.200(Ft.) Bottom (of initial area) elevation = 57.000(Ft.) Difference in elevation = 1.200(Ft.) Slope = 0.00545 s(percent)= 0.55 TC = k(0.321) *[(length ^3) /(elevation change)] ^0.2 • Initial area time of concentration = 7.865 min. Rainfall intensity = 6.699(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient' = 0.877 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 • Pervious area fraction = 0.190; Impervious fraction = 0.810 Initial subarea runoff = 1.410(CFS) Total initial stream area = 0.240(Ac.) Pervious area fraction = 0.190 +++++++++++++++++++++++++++++++++++++++ + + + + ++++ + + + + + + + + + +++++ + + + + + + +++ Process from Point /Station 225.000 to Point /Station 230.000 * * ** INITIAL AREA EVALUATION * * ** DA -B6 Initial area flow distance = 150.000(Ft.) Top (of initial area) elevation = 57.000(Ft.) Bottom (of initial area) elevation = 55.400(Ft.) Difference in elevation = 1.600(Ft.) Slope = 0.01067 s(percent)= 1.07 TC = k(0.300) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 5.520 min. Rainfall intensity = . 8.255(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.894 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 • RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.060; Impervious fraction = 0.940 Initial subarea runoff = 1.033(CFS) Total initial stream area 0.140(Ac.) Pervious area fraction = 0.060 Flows to VA portion of Street `A' +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ Process from Point /Station 300.000 to Point /Station 305.000 * * ** INITIAL AREA EVALUATION * * ** DA -C1 (Inlet I10) Initial area flow distance = 235.000(Ft.) Top (of initial area) elevation = 56.600(Ft.) Bottom (of initial area) elevation = 53.700(Ft.) Difference in elevation = 2.900(Ft.) Slope = 0.01234 s(percent)= 1.23 TC = k(0.336) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 7.186 min. Rainfall intensity = 7.065(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.871 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.250; Impervious fraction = 0.750 Initial subarea runoff = 6.092(CFS) Total initial stream area = 0.990(Ac.) Pervious area fraction = 0.250 +++++++++++++++++++++++++++++++++++++++ + + +++++ ++ + ++ ++ ++++++ +++ + + + ++ +++ Process from Point /Station 310.000 to Point /Station 315.000 * * ** INITIAL AREA EVALUATION * * ** DA -C2 (Inlet Ill) Initial area flow distance = 165.000(Ft.) Top (of initial area) elevation = 57.200(Ft.) Bottom (of initial area) elevation = 53.900(Ft.) Difference in elevation = 3.300(Ft.) Slope = 0.02000 s(percent)= 2.00 TC = k(0.339) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 5.721 min. Rainfall intensity = 8.082(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.873 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.260; Impervious fraction = 0.740 Initial subarea runoff = 3.176(CFS) Total initial stream area = 0.450(Ac.) Pervious area fraction = 0.260 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + ++ + + ++++ ++++ Process from Point /Station 320.000 to Point /Station 325.000 * * ** INITIAL AREA EVALUATION * * ** DA -C3 (Inlet I12) Initial area flow distance = 425.000(Ft.) Top (of initial area) elevation = 56.500(Ft.) Bottom (of initial area) elevation = 53.400(Ft Difference in elevation = 3.100(Ft.) Slope = 0.00729 s(percent)= 0.73 • TC = k(0.339) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 10.221 min. Rainfall intensity = 5.739(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.864 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.260; Impervious fraction = 0.740 Initial subarea runoff = 15.172(CFS) Total initial stream area = 3.060(Ac.). Pervious area fraction = 0.260 +++++++++++++++++++++++++++++++++++++++ ++ + + + + + + + + + + + + + + + + + + + + + ++ + + + + ++ Process from Point /Station 320.000 to Point /Station 330.000 * * ** INITIAL AREA EVALUATION * * ** DA -C4 (Inlet I8) Initial area flow distance = 410.000(Ft.) Top (of initial area) elevation = 56.500(Ft.) Bottom (of initial area) elevation = 54.800(Ft.) Difference in elevation = 1.700(Ft.) Slope = 0.00415 s(percent)= 0.41 TC = k(0.350) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 11.619 min. Rainfall intensity = 5.321(In /Hr) for a. 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.857 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 • Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.290; Impervious fraction = 0.710 Initial subarea runoff = 7.069(CFS) Total initial stream area = 1.550(Ac.) Pervious area fraction = 0.290 +++++++++++++++++++++++++++++++++++++++ +++ + + + + + + + + + + + + + ++++++ + + + + + + + ++ Process from Point /Station 335.000 to Point /Station 340.000 * * ** INITIAL AREA EVALUATION * * ** DA -05 (Inlet I9) Initial area flow distance = 165.000(Ft.) Top (of initial area) elevation = 56.000(Ft.) Bottom (of initial area) elevation = 53.500(Ft.) Difference in elevation = 2.500(Ft.) Slope = 0.01515 s(percent)= 1.52 TC = k(0.314) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 5.592 min. Rainfall intensity = 8.192(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.884 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.160; Impervious fraction.= 0.840 Initial subarea runoff = 4.850(CFS) Total initial stream area = 0.670(Ac.) Pervious area fraction = 0.160 • +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ Process from Point /Station 345.000 to Point /Station 350.000 * * ** INITIAL AREA EVALUATION * * ** DA -C6 (Inlet I7) Initial area flow distance = 220.000(Ft.) Top (of initial area) elevation = 55.800(Ft.) Bottom (of initial area) elevation = 53.400(Ft.) Difference in elevation = 2.400(Ft.) Slope = 0.01091 s(percent)= 1.09 TC = k(0.305) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 6.503 min. Rainfall intensity = 7.494(In /Hr) for a 100. USER INPUT of soil data for subarea Runoff Coefficient = 0.887 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.120; Impervious Initial subarea runoff = 4.054(CFS) Total initial stream area = 0.610(Ac Pervious area fraction = 0.120 0 year storm fraction = 0.880 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + ++ ++ + + + + + + + ++ Process from Point /Station 355.000 to Point /Station 360.000 * * ** INITIAL AREA EVALUATION * * ** DA -C7 (Inlet I6) Initial area flow distance = 185.000(Ft.) Top (of initial area) elevation = 55.400(Ft.) Bottom (of initial area) elevation = 53.200(Ft.) Difference in elevation = 2.200(Ft.) Slope = 0.01189 s(percent)= 1.19 TC = k(0.323) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 6.324 min. Rainfall intensity = 7.618(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.878 Decimal fraction soil group A = 0.000 . Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.200; Impervious fraction = 0.800 Initial subarea runoff = 2.676(CFS) Total initial stream area = 0.400(Ac.) Pervious area fraction = 0.200 Process from Point /Station 365.000 to Point /Station 370.000 * * ** INITIAL AREA EVALUATION * * ** DA -C8 (Inlet 15) Initial area flow distance = 220.000(Ft.) Top (of initial area) elevation = 55.700(Ft.) Bottom (of initial area) elevation = 53.200(Ft.) Difference in elevation = 2.500(Ft.) Slope = 0.01136 s(percent)= 1.14 TC = k(0.339) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 7.187 min. Rainfall intensity = 7.064(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.870 • Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.260; Impervious fraction = 0.740 Initial subarea runoff = 3.379(CFS) Total initial stream area = 0.550(Ac.) Pervious area fraction = 0.260 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + +++ + +++ Process from Point /Station 375.000 to Point /Station 380.000 * * ** INITIAL AREA EVALUATION * * ** DA -C9 (Inlet I1) Initial area flow distance = 300.000(Ft.) Top (of initial area) elevation = 56.000(Ft.) Bottom (of initial area) elevation = 53.900(Ft.) Difference in elevation = 2.100(Ft.) Slope = 0.00700 s(percent)= 0.70 TC = k(0.331) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 8.738 min. Rainfall intensity = 6.296(In /Hr) for a 100.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.870 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.230; Impervious fraction = 0.770 Initial subarea runoff = 6.357(CFS) • Total initial stream area = 1.160(Ac.) Pervious area fraction = 0.230 End of computations, total study area = 19.73 (Ac.) The following figures may be used for a unit hydrograph study of the same area. Area averaged pervious area fraction(Ap) = 0.172 Area averaged RI index number = 56.0 • . Riverside County Rational Hydrology Program CIVILCADD /CIVILDESIGN Engineering Software,(c).1989 - 2005 Version 7.1 Rational Hydrology Study Date: 03/08/11 File:1920cmahsdpalOyr.out ------------------------------------------------------------------------ CORAL MOUNTAIN AFFORDABLE HOUSING PRELIMINARY RATIONAL HYDROLOGY 10 YEAR STORM EVENT * * * * * * * ** Hydrology Study Control Information * * * * * * * * ** English (in -lb) Units used in input data file Program License Serial Number 6041 ------------------------------------------------------------------------ Rational Method Hydrology Program based on Riverside County Flood Control & Water Conservation District 1978 hydrology manual Storm event (year) = 10.00 Antecedent Moisture Condition = 2 2 year, 1 hour precipitation = 0.420(In.) 100 year, 1 hour precipitation = 2.020(In.) Storm event year = 10.0 Calculated rainfall intensity data: 1 hour intensity = 1.078(In /Hr) • Slope of intensity duration curve = 0.5900 +++++++++++++++++++++++++++++++++++++++ ++++++++++ + + + + + + + + + + + + + ++++ + + ++ Process from Point /Station 100.000 to Point /Station 105.000 * * ** INITIAL AREA EVALUATION * * ** DA -A1 (INLET I17) Initial area flow distance = 630.000(Ft.) Top (of initial area) elevation = 58.800(Ft.) Bottom (of initial area) elevation = 55.000(Ft.) Difference in elevation = 3.800(Ft.) Slope = 0.00603 s(percent)= , 0.60 TC = k(0.300) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 10.984 min. Rainfall intensity = 2.936(In /Hr) for a 10.0 year storm COMMERCIAL subarea type Runoff Coefficient = 0.876 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.100; Impervious fraction = 0.900 Initial subarea runoff = 11.913(CFS) Total initial stream area = 4.630(Ac.) Pervious area fraction = 0.100 +++++++++++++++++++++++++++++++++++++++ +++ + + + + + + + + + + + + + + + +++++ + + + + + + ++ Process from Point /Station 100.000 to Point /Station 110.000 * * ** INITIAL AREA EVALUATION * * ** DA -A2 (INLET I2) Initial area flow distance = 605.000(Ft.) Top (of initial area) elevation = 58.800(Ft.) • Bottom (of initial area) elevation = 55.100(Ft.) Difference in elevation = 3.700(Ft.) Slope = 0.00612 s(percent)= 0.61 TC = k(0.300) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 10.778 min. Rainfall intensity = 2.969(In /Hr) for a 10.0 year storm COMMERCIAL subarea type Runoff Coefficient = 0.877 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.100; Impervious fraction = 0.900 Initial subarea runoff = 11.555(CFS) Total initial stream area = 4.440(Ac.) Pervious area fraction = 0.100 +++++++++++++++++++++++++++++++++++++++ + + + + ++ + + + + + + + ++ + + + + + + + + + + + + + + ++ Process from Point /Station 200.000 to Point /Station 210.000 * * ** INITIAL AREA EVALUATION * * ** DA -B1 Initial area flow distance = 190.000(Ft.) Top (of initial area) elevation = 56.000(Ft.) Bottom (of initial area) elevation = 54.900(Ft.) Difference in elevation = 1.100(Ft.) Slope = 0.00579 s(percent)= 0.58 TC = k(0.321) *[(length ^3) /(elevation change)) ^0.2 Initial area time of concentration = 7.329 min. Rainfall intensity = 3.728(In /Hr) for a 10.0 year storm USER INPUT of soil data for.subarea Runoff Coefficient = 0.862 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.190; impervious fraction = 0.810 Initial subarea runoff = 0.611(CFS) Total initial stream area = 0.190(Ac.) Pervious area fraction = 0.190 +++++++++++++++++++++++++++++++++++++++ + ++ + ++ + + + ++ +++ + + ++ + ++ +++++ ++ + ++ Process from Point /Station 200.000 to Point /Station 210.000 * * ** CONFLUENCE OF MAIN STREAMS * * ** The following data inside Main Stream is listed: In Main Stream number: 1 Stream flow area = 0.190(Ac.) Runoff from this stream = 0.611(CFS) Time of concentration = 7.33 min. Rainfall intensity = 3.728(In /Hr) Program is now starting with Main Stream No. 2 Process from Point /Station 205.000 to Point /Station 210.000 * * ** INITIAL AREA EVALUATION * * ** DA -B2 Initial area flow distance = 315.000(Ft.) Top (of initial area) elevation = 58.200(Ft.) Bottom (of initial area) elevation = 54.900(Ft.) Difference in elevation = 3.300(Ft.) Slope = 0.01048 s(percent)= 1 1.05 TC = k(0.316) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 7.854 min. Rainfall intensity = 3.579(In /Hr) for a 10.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.865 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.170; Impervious fraction = 0.830 Initial subarea runoff = 0.991(CFS) Total initial stream area = 0.320(Ac.) Pervious area fraction = 0.170 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + ++ +++ + + + + + + + + + + + +++ Process from Point /Station 205.000 to Point /Station 210.000 * * ** CONFLUENCE OF MAIN STREAMS * * ** (INLET I15 & I16) The following data inside Main Stream is listed: In Main Stream number: 2 • Stream flow area = 0.320(AC.) Runoff from this stream = 0.991(CFS) Time of concentration = 7.85 min. Rainfall intensity = 3.579(In /Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In /Hr) 1 0.611 7.33 3.728 2 0.991 7.85 3.579 Largest stream flow has longer time of concentration Qp.= 0.991 + sum of Qb Ia /Ib 0.611 * 0.960 = 0.586 Qp = 1.577 Total of 2 main streams to confluence: Flow rates before confluence point: 0..611 0.991 Area of streams before confluence: 0.190 0.320 Results of confluence: Total flow rate = 1.577(CFS) Time of concentration = 7.854 min. Effective stream area after confluence = 0.510(Ac.) r� +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ Process.from Point /Station 200.000 to Point /Station 220.000 * * ** INITIAL AREA EVALUATION * * ** DA -B3 Initial area flow distance = 190.000(Ft.) Top (of initial area) elevation = 56.000(Ft.) Bottom (of initial area) elevation = 54.900(Ft.) Difference in elevation = 1.100(Ft.) Slope = 0.00579 s(percent)= 1 0.58 TC = k(0.321) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 7.329 min. Rainfall intensity = 3.728(In /Hr) for a 10.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.862 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.190; Impervious fraction = 0.810 Initial subarea runoff = 0.611(CFS) Total initial stream area = 0.190(Ac.) Pervious area fraction = 0.190 +++++++++++++++++++++++++++++++++++++++ + + + + + + ++ ++ + + ++ + + + + + + + + + + + + + + + ++ Process from Point /Station 200.000 to Point /Station 220.000 * * ** CONFLUENCE OF MAIN STREAMS * * ** The following data inside Main Stream is listed: In Main Stream number: 1 Stream flow area = 0.190(Ac.) Runoff from this stream = 0.611(CFS) Time of concentration = 7.33 min. Rainfall intensity = 3.728(In /Hr) Program is now starting with Main Stream No. 2 +++++++++++++++++++++++++++++++++++++++ + + ++ + ++ +++++ ++++++ + + + + + + + + + + + ++ Process from Point /Station 215.000 to Point /Station 220.000 * * ** INITIAL AREA EVALUATION * * ** DA -B4 Initial area flow distance = 165.000(Ft.) Top (of initial area) elevation = 56.200(Ft.) Bottom (of initial area) elevation = 54.900(Ft. Difference in elevation = 1.300(Ft.) Slope = 0.00788 s(percent)= 0.79 TC = k(0.307) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 6.233 min. Rainfall intensity = 4.102(In /Hr) for a 10 USER INPUT of soil data for subarea Runoff Coefficient = 0.876 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D =0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.130; Impervious Initial subarea runoff = 0.503(CFS) Total initial stream area = 0.140(Ac Pervious area fraction = 0.130 0 year storm fraction = 0.870 Process from Point /Station 215.000 to Point /Station 220.000 * * ** CONFLUENCE OF MAIN STREAMS * * ** (INLET I3 & I4) The following data inside Main Stream is listed: In Main Stream number: 2 Stream flow area = 0.140(Ac.) Runoff from this stream = 0.503(CFS) Time of concentration = 6.23 min. Rainfall intensity = 4.102(In /Hr) Summary of stream data: Stream Flow rate TC Rainfall Intensity No. (CFS) (min) (In /Hr) 1 0.611 7.33 3.728 2 0.503 6.23 4.102 Largest stream flow has longer time of concentration Qp = 0.611 + sum of Qb Ia /Ib 0.503 * 0.909 = 0.457 Qp = 1.068 Total of 2 main streams to confluence: Flow rates before confluence point: 0.611 0.503 Area of streams before confluence: 0.190 0.140 • Results of confluence: Total flow rate = 1.068(CFS) Time of concentration = 7.329 min. Effective stream area after confluence = 0.330(Ac.) +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ ++ Process from Point /Station 205.000 to Point /Station 225.000 * * ** INITIAL AREA EVALUATION * * ** DA -B5 (INLET I13 & I14) Initial area flow distance = 220.000(Ft.) Top (of initial area) elevation = 58.200(Ft.) Bottom (of initial area) elevation = 57.000(Ft.) Difference in elevation = 1.200(Ft.) Slope = 0.00545 s(percent)= 0.55 TC = k(0.321) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 7.865 min. Rainfall intensity = 3.576(In /Hr) for a 10.0 year storm USER INPUT.of soil data for subarea Runoff Coefficient = 0.861 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.190; Impervious fraction = 0.810 Initial subarea runoff = 0.739(CFS) Total initial stream area = 0.240(Ac.) Pervious area fraction = 0.190 • +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ Process from Point /Station 225.000 to Point /Station 230.000 * * ** INITIAL AREA EVALUATION * * ** DA -B6 Initial area flow distance = 150.000(Ft.) Top (of initial area) elevation = 57.000(Ft.) Bottom (of initial area) elevation = 55.400(Ft.) Difference in elevation = 1.600(Ft.) Slope = 0.01067 s(percent)= 1.07 TC = k(0.300) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 5.520 min. Rainfall intensity = 4.406(In /Hr) for a 10.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.890 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.060; Impervious fraction = 0.940 Initial subarea runoff = 0.549(CFS) Total initial stream area = 0.140(Ac.) Pervious area fraction = 0.060 Flows to VA portion of Street `A' +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ Process from Point /Station 300.000 to Point /Station 305.000 * * ** INITIAL AREA EVALUATION * * ** DA -C1 (INLET I10) Initial area flow distance = 235.000(Ft.) Top (of initial area) elevation = 56.600(Ft.) Bottom (of initial area) elevation = 53.700(Ft.) Difference in elevation = 2.900(Ft.) Slope = 0.01234 s(percent)= 1.23 TC = k(0.336) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 7.186 min. Rainfall intensity = 3.771(In /Hr) for a 10.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.851 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.250; Impervious fraction = 0.750 Initial subarea runoff = 3.178(CFS) Total initial stream area = 0.990(Ac.) Pervious area fraction = 0.250 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + ++++++++ ++ Process from Point /Station 310.000 to Point /Station 315.000 * * ** INITIAL AREA EVALUATION * * ** DA -C2 (INLET Ill) Initial area flow distance = 165.000(Ft.) Top (of initial area) elevation = 57.200(Ft.) Bottom (of initial area) elevation = 53.900(Ft.) Difference in elevation = 3.300(Ft.) Slope = 0.02000 s(percent)= 2.00 TC = k(0.339) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 5.721 min. Rainfall intensity = 4.314(In /Hr) for a 10.0 year storm • USER INPUT of soil data for subarea Runoff Coefficient = 0.854 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D'= 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.260; Impervious fraction = 0.740 Initial subarea runoff = 1.659(CFS) Total initial stream area = 0.450(Ac.) Pervious area fraction = 0.260 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +++ Process from Point /Station 320.000 to Point /Station 325.000 * * ** INITIAL AREA EVALUATION * * ** DA -C3 (INLET I12) Initial area flow distance = 425.000(Ft.) Top (of initial area) elevation = 56.500(Ft.) Bottom (of initial area) elevation = 53.400(Ft.) Difference in elevation = 3.100(Ft.) Slope = 0.00729 s(percent)= 0.73 TC = k(0.339) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 10.221 min. Rainfall intensity = 3.064(In /Hr) for a 10.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.840 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 • Pervious area fraction = 0.260; Impervious fraction = 0.740 Initial subarea runoff = 7.878(CFS) Total initial stream area = 3.060(Ac.) Pervious area fraction = 0.260 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ Process from Point /Station 320.000 to Point /Station 330.000 * * ** INITIAL AREA EVALUATION * * ** DA -C4 (INLET I8) Initial area flow distance = , 410.000(Ft.) Top (of initial area) elevation = 56.500(Ft.) Bottom (of initial area) elevation = 54.800(Ft.) Difference in elevation = 1.700(Ft.) Slope = 0.00415 s(percent)= 0.41 TC = k(0. 350) *[( length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 11.619 min. Rainfall intensity = 2.840(In /Hr) for a 10.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.830 Decimal fraction soil group A = 0:000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.290; Impervious fraction = 0.710 Initial subarea runoff = 3.653(CFS) Total initial stream area = 1.550(Ac.) Pervious area fraction = 0.290 1 +++++++++++++++++++++++++++++++++++++++ + +++ + + + + + + + + + + + + +++++++ ++ + + + + ++ Process from Point /Station 335.000 to Point /Station 340.000 * * ** INITIAL AREA EVALUATION * * ** DA -05 (INLET I9) • Initial area flow distance = 165.000(Ft.) Top (of initial area) elevation = 56.000(Ft.) Bottom (of initial area) elevation = 53.500(Ft.) Difference in elevation = 2.500(Ft.) Slope = 0.01515 s(percent)= 1.52 TC = k(0.314) *((length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 5.592 min. Rainfall intensity = 4.373(In /Hr) for a 10.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.872 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.160; Impervious fraction = 0.840 Initial subarea runoff = 2.555(CFS) Total initial stream area = 0.670(Ac.) Pervious area fraction = 0.160 +++++++++++++++++++++++++++++++++++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ++ Process from Point /Station 345.000 to Point /Station 350.000 * * ** INITIAL AREA EVALUATION * * ** DA -C6 (INLET I7) Initial area flow distance = 220.000(Ft.) Top (of initial area) elevation = 55.800(Ft.) Bottom (of initial area) elevation = 53.400(Ft.) Difference in elevation = 2.400(Ft.) Slope = 0.01091 s(percent)= 1.09 TC = k(0.305) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 6.503 min. Rainfall intensity = 4.000(In /Hr) for a 10.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.878 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.120; Impervious fraction = 0.880 Initial subarea runoff = 2.141(CFS) Total initial stream area = 0.610(Ac.) Pervious area fraction = 0.120 Process from Point /Station 355.000 to Point /Station 360.000 * * ** INITIAL AREA EVALUATION * * ** DA -C7 (INLET 16) Initial area flow distance = 185.000(Ft.) Top (of initial area) elevation = 55.400(Ft.) Bottom (of initial area) elevation = 53.200(Ft.) Difference in elevation = 2.200(Ft.) Slope = 0.01189 s(percent)= 1.19 TC = k(0.323) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 6.324 min. Rainfall intensity = 4.067(In /Hr) for a 10.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.863 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 • RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.200; Impervious fraction = 0.800 Initial subarea runoff = 1.404(CFS) Total initial stream area = 0.400(Ac.) Pervious area fraction = 0.200 ++++++++++++++++±++++++++++++++++++++++ + + + + + + + + + + + + + + + + + +++ ++ ++ + + + + + ++ Process from Point /Station 365.000 to Point /Station 370.000 * * ** INITIAL AREA EVALUATION * * ** DA -C8 (INLET I5) Initial area flow distance = 220.000(Ft.) Top (of initial area) elevation = 55.700(Ft.) Bottom (of initial area) elevation = 53.200(Ft.) Difference in elevation = 2.500(Ft.) Slope = 0.01136 s(percent)= 1.14 TC = k(0.339) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 7.187 min. Rainfall intensity = 3.771(In /Hr) for a 10.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.849 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.260; Impervious fraction = 0.740 Initial subarea runoff = 1.761(CFS) Total initial stream area = 0.550(Ac.) Pervious area fraction = 0.260 +++++++++++++++++++++++++++++++++++++++ ++ + + + + + + + + + + + + + + + ++++ + + + + + + + + ++ • Process from Point /Station 375.000 to Point /Station 380.000 * * ** INITIAL AREA EVALUATION * * ** DA -C9 (INLET I1) Initial area flow distance = 300.000(Ft.) Top (of initial area) elevation = 56.000(Ft.) Bottom (of initial area) elevation = 53.900(Ft.) Difference in elevation = 2.100(Ft.) Slope = 0.00700 s(percent)= 0.70 TC = k(0.331) *[(length ^3) /(elevation change)] ^0.2 Initial area time of concentration = 8.738 min. Rainfall intensity = 3.361(In /Hr) for a 10.0 year storm USER INPUT of soil data for subarea Runoff Coefficient = 0.851 Decimal fraction soil group A = 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C = 0.000 Decimal fraction soil group D = 0.000 RI index for soil(AMC 2) = 56.00 Pervious area fraction = 0.230; Impervious fraction = 0.770 Initial subarea runoff = 3.317(CFS) Total initial stream area = 1.160(Ac.) Pervious area fraction = 0.230 End of computations, total study area = 19.73 (AC.) The following figures may be used for a unit hydrograph study of the same area. Area averaged pervious area fraction(Ap) = 0.172 Area averaged RI index number = 56.0 • • 0 SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing Appendix F Street Capacity Worksheets r, • Worksheet for Street A (100 Year Storm) Project _Description Friction Method Manning Formula Solve For Discharge Input Data Channel Slope 0.00550 ft/ft Formal Depth 0.60 ft Section Definitions • j Station (ft) Elevation (ft) -20 +.000 -15 +.625 -15 +.125 -15 +.000 -13 +.000 0+.000 13 +.000 15 +.000 15 +.125 15 +.625 25 +.000 Roughness Segment Definitions 100.18 100.09 100.08 99.58 99.74 100.00 99.74 99.58 100.08 100.09 100.28 Start Station Ending Station Roughness Coefficient ( -20 +.000, 100.18) ( -15 +.625, 100.09) 0.025 ( -15 +.625, 100.09) (15+.625, 100.09) 0.015 (15 +.625, 100.09) (25 +.000, 100.28) 0.025 Results Discharge 27.43 ft3 /s Elevation Range 99.58 to 100.28 ft Flow Area 10.72 ft2 Wetted Perimeter 40.87 ft Top Width 40.07 ft Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.066.00] 3/1012011 12:01:03 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1- 203 - 755 -1666 Page 1 of 2 Worksheet for Street A (100 Year Storm) Results Normal Depth 0.60 ft Critical Depth 0.57 ft Critical Slope 0.00734 tuft Velocity 2.56 ft/s Velocity Head 0.10 ft Specific Energy 0.70 ft Froude Number 0.87 ft Flow Type Subcritical ft/ft GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 ,GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 0:60 ft Critical Depth 0.57 ft Channel Slope 0.00550 ft/ft Critical Slope 0.00734 ft/ft 7 Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.066.00] 3110/2011 12:01:03 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1- 203 - 755 -1666 Page 2 of 2 • Worksheet for Street A (10 Year Storm) Project Description Friction Method Manning Formula Solve For Discharge Input Data Channel Slope 0.00550 ft/ft Normal Depth 0.50 ft Section Definitions • • Station (ft) Elevation (ft) -20 +.000 100.18 -15 +.625 100.09 -15 +.125 100.08 -15 +.000 99.58 -13 +.000 99.74 0 +.000 100.00 13 +.000 99.74 15 +.000 99.58 15 +125 100.08 15 +.625 100.09 25 +.000 100.28 Roughness Segment Definitions Start Station Ending Station Roughness Coefficient ( -20 +.000, 100.18) ( -15 +.625, 100.09) 0.025 / ( -15 +.625, 100.09) (15 +.625, 100.09) 0.015 (15 +.625, 100.09) (25 +.000, 100.28) 0.025 Results Discharge 19.98 ft' /s Elevation Range 99.58 to 100.28 ft Flow Area 7.20 ftz Wetted Perimeter 31.05 ft Top Width 30.25 ft Bentley Systems, Inc. Haestad Methods Solution Center . Bentley FlowMaster [08.01.066.00] 3/10/2011 11:59:37 AM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1 -203- 755.1666 Page 1 of 2 Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 bVF Output Data Upstream Depth Worksheet for Street A (10 Year Storm) Results Profile Description Normal Depth 0.50 ft Critical Depth 0.50 ft Critical Slope 0.00548 ft/ft Velocity 2.77 ft/s Velocity Head 0.12 ft Specific Energy 0.62 ft Froude Number 1.00 Flow Type Supercritical GVF Input Data Channel Slope Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 bVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity fUs Upstream Velocity Infinity fUs Normal Depth 0.50 ft Critical Depth 0.50 ft Channel Slope 0.00550 ft/ft Critical Slope 0.00548 ft/ft 0 Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.066.00] 3/1012011 11:59:37 AM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1- 203 - 755 -1666 Page 2 'of 2 SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing Appendix G Hydraulic Calculations Bechtel "Water Surface Profile" StormCad Storm Drain Worksheets Inlet & Catch Basin Worksheets • --.! -I j'. Iti" r -i.l', ism:.. .. .��:. �.:: . +:_.., — _ �•_. TF _'�t'LV$tS L� i:'ij:e,tl -j.i. 'il�iii: .� •NI :�i i� i� �il• ` "'• _ " " "1 :' i7: .... .. ' i mow• •�u �•" .,. . 4 //I&AP7 AM" -oa At u Q► C` C �.. co 4t C1 O o . • • � .. _ • _' ... _ : , Zl CD- . . N ' . 2.7 j IZ ci wOW-7iogi. i-w IL l7s, 14 ' �:f4�}a�Cg °..:. �' off•: .. -=: •,..dmo NI W •PM MP W OUP wnooa BIWA [oe Aq POWW..e ao aw+e PM 'M POIM eW UI >peno peen »O •pNglgm 1 ' •pew0� =e+ 69 Iw lM &in Rq, $--Aft 2—fts 4 -000"q wo ao Pw P"" Ae+w+ W 4vLL -ULHM8 Io A+dud go on W" H Pw nINUP' IU W Q J o 5 V. CC CD W CC O I d am� a. 3a� -a W dCC 0 D =pC �= o ►$� � aU co 3 d W Y Q T G 7. vo v� Q v :o V 50 A� s O p O IN V CS4 \ o i N N L ` c { MA W co >, � a C o a 61,. u V W Q J o 5 V. CC CD W CC O I d am� a. 3a� -a W dCC 0 D =pC �= o ►$� � aU co 3 d W Y Q T G 7. vo v� Q v :o V 50 A� s O p O IN Title: Coral Mountain Affordable Housing - System A Project Engineer: DLS i:\bentiey\bentiey stormcad\1920 cmah system a.stm StormCAD v5.6 [05.06.012.00] 03/10/11 08:24:01 AM 0 Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1- 203 -755 -1666 Page 1 of 1 Calculation Results Summary ----------------------------------------------------------------- ----------------------------------------------------------------- Scenario: Base >>>> Info: Subsurface Network Rooted by: 0 -1 >>>> Info: Subsurface Analysis iterations: 3 >>>> Info: Convergence was achieved. CALCULATION SUMMARY FOR SURFACE NETWORKS Label Inlet Inlet Section Total Total Capture Gutter Gutter Grade Type Size Shape (ft) Intercepted Bypassed Efficiency Spread Depth Sections 0-1 - - - - -- 70.09 ----- - - - - -- 48.00 ----- - -- - -- 46.00 Flow Flow ( %) (ft) (ft) - - - - - -- --------- - - - - - -- ---- --- 46.52 (cfs) (cfs) (ft) (ft) P1.01 MH -5 - - - -- Generic Inlet ----------------- Generic Default - - - - -- 100% ------- - - - - -- 41.27 ---- - - - - -- 0.00 ------------- 100.0 - - - - - -- 0.00 --- - - - - -� 0.00 I9 Ditch Inlet Ditch Jensen DI 24x24 4.85 0.00 100.0 2.00 I 0.43 I8 Ditch Inlet Ditch Jensen DI 24x24 7.07 0.00 100.0 2.00 0.59 I7 Ditch Inlet Ditch Jensen DI 24x24 4.05 0.00 100.0 2.00 0.38 i6 Ditch Inlet Ditch Jensen DI 18x18 2.68 0.00 100.0 1.50 0.39 I5 Ditch Inlet Ditch Jensen DI 24x24 3.38 0.00 100.0 2.00 0.34 I1 Ditch Inlet Ditch Jensen DI 24x24 6.36 0.00 100.0 2.00 0.51 14 Curb Inlet Curb COR STD 300 -6CF 1.02 0.00 100.0 3.50 0.23 i3 Curb Inlet Curb COR STD 300 -6CF 1.02 0.00 100.0 3.50 0.23 I2 -------------------------------------------------------------------------- Generic Inlet Generic Default 100% 21.88 0.00 100.0 ------------------------- 0.00 0.00 - - - - -- CALCULATION SUMMARY FOR SUBSURFACE NETWORK WITH ROOT: 0 -1 Label .Number Section Section Length Total Average Hydraulic Hydraulic Grade of Size Shape (ft) System Velocity Grade Grade (ft) Sections 0-1 - - - - -- 70.09 ----- - - - - -- 48.00 ----- - -- - -- 46.00 Flow (ft /s) Upstream Downstream - - - - - -- ---- - - -- -- --- - - - - -- ---- --- 46.52 (cfs) HB1.02 (ft) (ft) P1.01 1 54 inch - -- Circular -- - - - - -- 127.40 -- - - - - -- 71.23 ---- - - - - -- 4.48 ----- - - - - -- 46.14 ------- - - - - -� 46.00 P1.02 1 54 inch Circular 1 142.85 72.48 4.56 46.42 46.26 P1.03 1 54 inch Circular 97.97 73.33 4.61 46.64 46.52 P1.04 1 54 inch Circular 101.26 74.20 4.67 46.87 46.75 P1.05 1 ( 54 inch Circular 12.52 74.31 4.67 47.01 I 47.00 P1.06 1 54 inch Circular 12.52 74.42 4.68 47.15 47.14 P1.07 1 54 inch Circular 12.36 74.52 4.69 47.30 47.28 P1.08 1 54 inch Circular 22.52 74.72 4.70 47.45 47.42 P1.09 l l 54 inch Circular 12.52 74.82 4.70 47.59 47.58 P1.10 1 54 inch Circular 12.52 74.93 4.71 47.74 47.72 P1.11 1 54 inch Circular 10.91 75.02 4.72 47.88 47.86 P4.01 1 �, 48 inch Circular 7.67 52.19 4.15 48.06 48.05 P2.01 1 30 inch Circular 14.59 I 26.47 5.39 48.10 48.05 P4.02 1 48 inch Circular 7.32 52.23 4.16 48.16 48.16 P2.02 1 30 inch Circular 1 20.00 26.55 1 5.41 1 48.32 48.24 P4.03 1 48 inch Circular 1 36.94 52.48 1 4.18 1 48.31 48.26 1 P2.03 1 1_30 inch I Circular 1 10.00 1 26.59 1 5.42 1 48.50 1 48.46 P4.04 1 48 inch Circular 1 35.40 1 49.06 1 3.90 1 48.42 1 48.38 L6.1 1 12 inch Circular 7.52 5.84 1 7.44 48.55 1 48.38 1 P2.04 1 30 inch Circular 253.54 27.58 5.62 49.62 1 48.64 P4.05 1 48 inch Circular 142.56 42.09 3.35 48.58 1 48.47 L8.1 1 18 inch Circular 13.75 9.39 5.31 48.57 48.47 L5.01 1 12 inch Circular 9.39 3.38 4.30 48.83 48.76 P2.05 1 30 inch Circular 287.55 23.44 4.78 50.70 49.90 L1.1 1 12 inch Circular 11.29 6.36 8.10 50.21 49.90 P4.06 1 48 inch Circular 169.88 41.27 3.28 48.79 48.67 L9.1 1 12 inch Circular 8.52 4.85 6.18 48.80 48.67 L8.2 1 18 inch Circular 119.20 6.84 3.87 49.09 48.66 L7.1 1 12 inch Circular 55.28 4.05 17.92 49.63 48.66 P3.01 1 18 inch Circular 99.55 1.94 1.10 1 50.91 50.88 L2.1 1 24 inch Circular 18.00 21.88 6.96 1 51.05 50.88 L8.3 1 18 inch Circular 128.71 7.02 3.97 1 49.71 49.22 L4.1 1 18 inch Circular 1 19.60 1 1.02 0.57 1 50.92 50.92 L3.1 1 18 inch Circular 1 19.05 1.02 12.85 1 50.91 I 50.92 L8.4 1 18 inch Circular 1 17.91 7.05 1 3.99 1 49.91 49.84 L8.5 ----------------------------------------------------------------------------------------- 1 18 inch Circular 1 40.00 7.07 1 • 11.02 1 50.17 50.04 - - - - -- Label Total Ground Hydraulic Hydraulic System Elevation Grade Grade Flow (ft) Line In Line Out ---------- (cfs) (ft) (ft) 0-1 - - - - -- 70.09 ----- - - - - -- 48.00 ----- - -- - -- 46.00 ------ - - - - -� 46.00 HB1.01 1 71.23 50.40 46.26 46.14 MH -1 1 72.48 50.00 46.52 46.42 HB1.02 73.33 51.00 46.75 46.64 HB1.03 74.20 52.40 47.00 46.87 HB1.04 74.31 53.00 47.14 47.01 HB1.05 74.42 53.00 47.28 47.15 HB1.06 74.52 53.00 ( 47.42 47.30 HB1.07 74.72 53.00 47.58 47.45 HB1.08 74.82 53.50 47.72 47.59 HB1.09 74.93 54.00 47.86 I 47.74 MH -2 75.02 54.26 48.05 47.88 HB4.01 52.19 54.07 48.16 48.06 HB2.01 26.47 54.17 48.24 48.10 HB4.02 52.23 53.96 48.26 48.16 HB2.02 26.55 1 54.06 48.46 48.32 Y4.1 52.48 1 53.79 48.38 48.31 HB2.03 26.59 1 54.07 48.64 48.50 Y4.2 49.06 53.79 48.47 48.42 I6 5.84 I 53.20 48.76 48.55 Y2.01 27.58 54.26 49.90 49.62 Y4.3 42.09 53.85 48.67 48.58 Y7.1 9.39 53.54 48.66 48.57 I5 3.38 53.20 48.88 I 48.83 MH -3 23.44 56.06 50.88 50.70 I1 6.36 53.86 50.38 50.21 MH -5 41.27 54.16 I 48.82 1 48.79 Title: Coral Mountain Affordable Housing - System A Project Engineer: DLS !: \bentley \bentley stormcad\1920 cmah system a.stm StormCAD v5.6 [05.06.012.00] 03/10/11 01:09:23 PM © Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1 -203- 755 -1666 Page 1 of 2 Calculation Results Summary I9 4.85 1 53.46 1 48.90 1 48.80 HB8.1 6.84 1 54.37 1 49.22 1 49.09 I7 4.05 1 53.37 1 49.71 1 49.63 MH -4 1.94 I 55.00 I 50.92 1 50.91 I2 21.88 1 56.00 I 51.17 1 51.05 H138.2 ( 7.02 1 55.60 1 49.84 1 49.71 I4 1.02 1 55.03 I 50.92 I 50.92 I3 1.02 55.03 1 50.91 1 50.91 HB8.3, 7.05 55.00 1 50.04 49.91 I8 ----------------------------- 7.07 54.80 --------------- 1 50.21 50.17 ----- - - - - -- Completed: 03/10/2011 01:08:27 PM Title: Coral Mountain Affordable Housing - System A Project Engineer: DLS I: \bentley\bentley stormcad\1920 cmah system a.stm StormCAD v5.6 [05.06.012.00] 03/10/11 01:09:23 PM *Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1- 203 - 755 -1666 Page 2 of 2 E-] • 1/1 I �J Scenario: Base Inlet Report No Additional Flow Label Inlet Clogging Factor (%) Headloss Method Rim Elev (ft) Sump Elev (ft) Structure Depth (ft) Area (acres) Tc (min) I (in/hr) Inlet C Rational Flow (cfs) HGL In (ft) HGL Out (ft) Gutter Ditch Depth (ft) Gutter Ditch Spread (ft) 11 Ditch Jensen DI 24x24 50.0 AASHTO 53.86 43.86 10.00 1.160 8.74 6.296 0.864 6.36 50.38 50.21 0.51 2.00 12 Generic Default 100% AASHTO 56.00 42.55 13.45 4.440 10.78 5.562 0.879 21.88 51.17 51.05 0.00 0.00 13 Curb COR STD 300 -6CF AASHTO 54.53 50.03 5.00 0.165 7.33 6.983 0.874 1.02 50.91 50.91 0.23 3.50 14 Curb COR STD 300 -6CF AASHTO 54.53 49.03 6.00 0.165 7.33 6.983 0.874 1.02 50.92 50.92 0.23 3.50 15 Ditch Jensen DI 24x24 50.0 AASHTO 53.20 44.80 8.40 0.550 7.19 7.064 0.863 3.38 48.88 48.83 0.34 2.00 16 Ditch Jensen DI 18x18 50.0 AASHTO 53.20 44.31 8.89 0.400 6.32 7.618 0.871 2.68 48.76 48.55 0.39 1.50 17 Ditch Jensen DI 24x24 50.0 AASHTO 53.37 48.78 4.59 0.610 6.50 7.494 0.880 4.05 49.71 49.63 0.38 2.00 18 Ditch Jensen DI 24x24 50.0 AASHTO 54.80 48.80 6.00 1.550 11.62 5.321 0.850 7.07 50.21 50.17 0.59 2.00 19 Ditch Jensen DI 24x24 50.0 AASHTO 53.46 46.46 7.00 0.670 5.59 8.192 0.877 4.85 48.90 48.80 0.43 2.00 MH -5 Generic Default 100% 1 1AASHTO1 54.161 37.55 16.61 9.880 13.77 1 4.780 1 0.867 41.27 48.82 48.79 0.00 0.00 Title: Coral Mountain Affordable Housing - System A i:\bentiey\bentley stormcad\1920 cmah system a.stm 03/10/11 01:28:26 PM 0 Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1- 203 - 755 -1666 Project Engineer: DLS StormCAD v5.6 [05.06.012.00) Page 1 of 1 • • Scenario: Base Pipe Report Label Material Mannings n Section Size Length (ft) Full Capacity (cfs) Total System Flow (cfs) Up Gmd Bev (ft) Down Gmd Elev (ft) Up Inv Elev (ft) Down Inv Elev (ft) Slope Oft) Avg Vel (ft/s) HGL In (ft) HGL out (ft) Flow Time (min) Profile Description L1.1 PVC 0.012 12 inch 11.29 24.85 6.36 53.86 54.26 44.47 39.79 0.4145 8.10 50.21 49.90 8.74 Pressure L2.1 Concrete 0.013 24 inch 18.00 28.21 21.88 56.00 56.06 42.55 42.27 0.0156 6.96 51.05 50.88 10.78 Pressure L3.1 Concrete 0.013 18 inch 19.05 60.45 1.02 55.03 55.00 50.03 43.72 0.3312 12.85 50.91 50.92 7.33 CompositePressure Prof ileSl L4.1 Concrete 0.013 18 inch 19.60 54.67 1.02 55.03 55.00 49.03 43.72 0.2709 0.57 50.92 50.92 7.33 Pressure L5.01 PVC 0.012 12 inch 9.39 8.82 3.38 53.20 53.20 44.80 44.31 0.0522 4.30 48.83 46.76 7.19 Pressure L6.1 PVC 0.012 12 inch 7.52 38.59 5.84 53.20 53.79 44.31 36.79 1.0000 7.44 48.55 48.38 7.23 Pressure L7.1 PVC 0.012 12 inch 55.28 17.22 4.05 53.37 53.54 48.78 37.78 0.1990 17.92 49.63 48.66 6.50 Composite Pressure S1 S2 1-8.1 PVC 0.012 18 inch .13.75 21.91 9.39 53.54 53.79 37.53 37.02 0.0371 5.31 48.57 48.47 12.81 Pressure 1-8.2 PVC 0.012 18 inch 119.20 21.84 6.84 54.37 53.54 .41.92 --37.53 0.0368 3.87 49.09 48.66 12.30 Pressure 1-8.3 PVC 0.012 18 inch 128.71 21.86 7.02 55.60 54.37 46.67 41.92 0.0369 3.97 49.71 49.22 11.76 Pressure 1-8.4 PVC 0.012 18 inch 17.91 21.84 7.05 55.00 55.60 47.33 46.67 0.0369 3.99 49.91 49.84 11.68 Pressure 1-8.5 PVC 0.012 18 inch 40.00 21.81 7.07 54.80 55.00 48.80 47.33 0.0367 11.02 50.17 50.04 11.62 CompositePressure Prof ileSl L9.1 PVC 0.012 12 inch 8.52 38.59 4.85 53.46 53.85 46.46 37.94 1.0000 6.18 48.80 48.67 5.59 Pressure P1.01 PVC 0.012 54 inch .127.40 116.68 71.23 50.40 48.00 33.38 33.00 0.0030 4.48 46.14 46.00 17.28 Pressure P1.02 PVC 0.012 54 inch 142.85 116.69 72.48 50.00 50.40 33.81 33.38 0.0030 4.56 46.42 46.26 16.76 Pressure P1.03 PVC 0.012 54 inch 97.97 116.68 73.33 51.00 50.00 34.10 33.81 0.0030 4.61 46.64 46.52 16.40 Pressure P1.04 PVC 0.012 54 inch 101.26 116.68 74.20 52.40 51.00 34.41 34.10 0.0030 4.67 46.87 46.75 16.04 Pressure P1.05 PVC 0.012 541nch 12.52 116.59 74.31 53.00 52.40 34.45 34.41 0.0030 4.67 47.01 47.00 16.00 Pressure P1.06 PVC 0.012 54 inch 12.52 116.74 74.42 53.00 53.00 34.48 34.45 0.0030 4.68 47.15 47.14 15.95 Pressure P1.07 PVC 0.012 54 inch 12.36 116.55 74.52 53.00 53.00 34.52 34.48 0.0030 4.69 47.30 47.28 15.91 Pressure P1.08 PVC 0.012 54 inch 22.52 116.71 74.72 53.00 53.00 34.59 34.52 0.0030 4.70 47.45 47.42 15.83 Pressure P1.09 PVC 0.012 54 inch 12.52 116.59 74,82 53.50 53.00 34.63 34.59 0.0030 4.70 47.59 47.58 15.78 Pressure P1.10 PVC 0.012 54 inch 12.52 116.74 74.93 54.00 53.50 34.66 34.63 0.0030 4.71 47.74 47.72 15.74 Pressure P1.11 PVC 0.012 54 inch 10.91 123.55 75.02 54.26 54.00 34.70 34.66 0.0034 4.72 47.88 47.86 15.70 Pressure P2.01 PVC 0.012 30 inch 14.59 46.53 26.47 54.17 54.26 35.86 35.70 0.0110 5.39 48.10 48.05 12.67 Pressure P2.02 PVC 0.012 30 inch 20.00 47.65 26.55 54.06 54.17 36.09 35.86 0.0115 5.41 48.32 48.24 12.61 Pressure P2.03 PVC 0.012 30 inch 10.00 46.60 26.59 54.07 54.06 36.20 36.09 0.0110 5.42 48.50 48.46 12.58 Pressure P2.04 PVC 0.012 30 inch 253.54 47.03 27.58 54.26 54.07 39.04 36.20 0.0112 5.62 49.62 48.64 11.83 Pressure P2.05 PVC 0.012 30 inch 287.55 47.09 23.44 56.06 54.26 42.27 39.04 0.0112 4.78 50.70 49.90 10.82 Pressure P3.01 Concrete 0.013 18 inch 99.55 10.53 1.94 55.00 56.06 43.62 42.62 0.0100 1.10 50.91 50.88 7.90 Pressure P4.01 PVC 0.012 48 inch 7.67 125.64 52.19 54.07 54.26 35.00 34.95 0.0065 4.15 48.06 48.05 15.67 Pressure P4.02 PVC 0.012 48 inch 7.32 128.60 52.23 53.96 54.07 35.05 35.00 0.0068 4.16 48.16 48.16 15.64 Pressure P4.03 PVC 0.012 48 inch 36.94 125.42 52.46 53.79 53.96 35.29 35.05 0.0065 4.18 48.31 48.26 15.49 Pressure P4.04 PVC 0.012 48 inch 35.40 125.43 49.06 53.79 53.79 35.52 35.29 0.0065 3.90 48.42 48.38 15.34 Pressure P4.05 PVC 0.012 48 inch 142.56 125.00 42.09 53.85 53.79 36.44 35.52 0.0065 3.35 48.58 48.47 14.63 Pressure P4.06 I PVC 0.012 48 inch 1 169.88 1 125.78 1 41.27 1 54.161 53.85 37.55 36.44 0.0065 3.28 46.79 48.67 13.77 Pressure Title: Coral Mountain Affordable Housing - System A !: \bentley \bentley stormcad\1920 cmah system a.stm 03/10/11 08:24:20 AM © Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1- 203 - 755 -1666 Project Engineer: DLS StormCAD v5.6 [05.06.012.00] Page 1 of 1 114 Scenario: Base 117 MH -5 Title: Coral Mountain Affordable Housing - System B i:\bentley \bentley stormcad \1920 cmah system b.stm 03/10/11 08:30:00 AM © Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1 -203- 755 -1666 112 Project Engineer: DLS StormCAD v5.6 (05.06.012.00) Page 1 of 1 Calculation Results Summary Scenario: Base >>>> Info: I14 No bypass target specified. Bypass is assumed to travel to MH -5. >>>> Info: I13 No bypass target specified. Bypass is assumed to travel to MH -5. >>>> Info: Subsurface Network Rooted by: MH -5 >>>> Info: Subsurface Analysis iterations: 3 >>>> Info: Convergence was achieved. CALCULATION SUMMARY FOR SURFACE NETWORKS Label Inlet Inlet Total Total I Capture I Gutter I Gutter Hydraulic Type of Intercepted Bypassed I Efficiency I Spread I Depth Grade Grade I (ft) Flow Flow (k) (ft) I (ft) Flow (ft /s) Upstream (cfs) (cfs) I 1 48.88 1 I I I -------- I I --- - - - - -I - - - - - -- I15 --------------- Curb Inlet I ---------- - - - - -- -- - - - - -� Curb COR STD 300 -6CF I------- - - - - -- 1.50 ---------- I 0.00 ------------ 1 100.0 1 3.72 1 0.27 I17 Generic Inlet Generic Default 100% 22.54 0.00 1 100.0 0.00 0.00 I16 Curb Inlet Curb COR STD 300 -6CF 1.50 0.00 1 100.0 3.79 0.25 ISO Ditch Inlet Ditch Jensen DI 24x24 6.09 0.00 1 100.0 2.00 0.50 I12 Ditch Inlet Ditch Jensen DI 48x48 15.17 0.00 1 100.0 4.00 0.59 Ill Ditch Inlet Ditch Jensen DI 24x24 3.17 0.00 1 100.0 2.00 0.33 I14 Curb Inlet Curb COR STD 300 -6CF 0.63 0.07 1 89.9 4.39 0.20 I13 ------------------------------------------------------------------------------------------ Curb Inlet Curb COR STD 300 -6CF 0.63 0.08 1 88.8 4.24 -------- 0.20 - - - - - -- CALCULATION SUMMARY FOR SUBSURFACE NETWORK WITH ROOT: MH -5 Label Number Section Section Length Total Average Hydraulic Hydraulic Grade of Size Shape .(ft) System Velocity Grade Grade I (ft) Sections - ------- MH -5 I-------- 1 41.25 I I 54.16 I ----------- 1 48.82 Flow (ft /s) Upstream Downstream 1 49.12 1 48.88 1 Y5.2 37.37 1 53.85 1 49.38 (cfs) I10 (ft) - - - - -- (ft) ------- - - - - -� - - - - - -- P5.01 ---- - - - - -- l --- - l 36 - - - -- inch ---- - - - - -- Circular -- - - - - -- 18.34 -- - - - - -- 41.36 ---- - - - - -- 5.85 ----- 48.88 48.82 P5.02 1 36 inch Circular 23.04 37.37 5.29 49.18 49.12 L10.1 1 12 inch Circular 11.31 6.09 7.75 49.40 49.12 P6:01 1 24 inch Circular 117.70 16.74 ( 5.33 49.93 49.38 P5.03 1 36 inch Circular 31.80 22.96 3.25 49.41 ( 49.38 P6.02 1 24 inch Circular 159.05 15.03 4.78 50.67 50.07 P5.04 l l 36 inch Circular 14.23 23.05 3.26 49.48 49.47 L12.1 1 24 inch Circular 49.05 15.17 4.83 51.05 50.86 P5.05 1 36 inch Circular 10.00 23.11 3.27 49.56 49.55 P5.06 1 36 inch Circular 10.00 23.17 3.28 49.63 49.62 P5.07 1 36 inch Circular 65.54 23.56 3.33 49.76 49.69 P7.01 1 30 inch Circular 44.64 23.75 4.841 49.99 1 49.84 L13.1 1 18 inch Circular �. 21.59 0.63 0.35 1 50.10 1 50.10 P7.02 1 30 inch Circular 14.08 23.34 4.75 1 50.15 1 50.10 1,14.1 1 18 inch Circular 9.45 0.63 0.36 1 50.25 1 50.25 P7.03 1 30 inch I Circular 1 300.88 1 24.03 1 4.90 1 51.28 1 50.25 P7.04 1 1 30 inch I Circular 223.48 24.95 5.08 52.22 51.39 L16.1 I 1 24 inch I Circular I 11.45 23.75 7.56 52.76 52.63 L15.1 1 1 l 18 inch I Circular 21.05 1.50 0.85 52.64 52.63 1,17.1 --------------------------------------------------------------------------------- 1 1 24 inch I Circular 8.00 22.54 7.18 53.09 53.01 -------- - - - --- Label Total Ground Hydraulic Hydraulic System Elevation Grade Grade ( Flow (ft) Line In Line Out I (cfs) I ------------ I (ft) I (ft) I ------ - - - - - I - ------- MH -5 I-------- 1 41.25 I I 54.16 I ----------- 1 48.82 1 48.82 Y5.1 1 41.36 1 53.78 1 49.12 1 48.88 1 Y5.2 37.37 1 53.85 1 49.38 1 49.18 1 I10 6.09 1 53.68 1 49.56 1. 49.40 Ill 16.74 1 53.92 50.07 49.93 1 HB5.01 22.96 1 54.35 49.47 49.41 Y6.1 15.03 1 54.44 50.86 50.67 HB5.02 23.05 1 54.58 49.55 49.48 I12 15.17 1 53.40 51.11 51.05 HB5.03 23.11 1 54.74 49.62 49.56 HB5.04 23.17 1 54.91 49.69 1 49.63 MH -6 23.56 56.58 49.84 1 49.76 J7.1 23.75 56.91 50.10 1 49.99 I13 0.63 57.07 50.10 1 50.10 J7.2 23.34 56.90 50.25 50.15 I14 0.63 57.04 50.25 50.25 MH7 24.03 57.16 51.39 51.28 MH8 24.95 1 54.83 52.63 52.22 I16 I 23.75 1 55.02 I 53.01 I 52.76 I15 1.50 1 55.02 52.64 52.64 I17 ------------------------------------ 22.54 1 55.50 53.22 ------------- 53.09 -- - - -- Completed: 03/10/2011 01:02:59 PM Title: Coral Mountain Affordable Housing - System B Project Engineer: DLS i:\bentley\bentley stormcad\1920 cmah system b.stm StormCAD v5.6 (05.06.012.00] 03/10/11 01:05:30 PM 0 Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1- 203 - 755 -1666 Page 1 of 1 • • Scenario: Base Inlet Report No Additional Flow Label Inlet Clogging Factor (°/,) Headloss Method Rim Elev (ft) Sump Elev (ft) Structure Depth (ft) Area (acres) Tc (min) I (in/hr) Inlet C Rational Flow (cfs) HGL In (ft) HGL Out (ft) Gutter Ditch Depth (ft) Gutter Ditch Spread (ft) 110 Ditch Jensen DI 24x24 50.0 AASHTO 53.68 39.82 13.86 0.990 7.19 7.064 0.864- 6.09 49.56 49.40 0.50 2.00 111 Ditch Jensen DI 2024 50.0 AASHTO 53.92 40.18 13.74 0.450 5.72 8.082 0.866 3.17 50.07 49.93 0.33 2.00 112 Ditch Jensen DI 48x48 50.0 AASHTO 53.40 47.40 6.00 3.060 10.22 5.739 0.857 15.17 51.11 51.05 0.59 4.00 113 Curb COR STD 300 -6CF AASHTO 56.57 48.57 8.50 0.120 7.87 6.699 0.870 0.63 50.10 50.10 0.20 4.24 114 Curb COR STD 300 -6CF AASHTO 56.54 48.54 8.50 0.120 7.87 6.699 0.870 0.63 50.25 50.25 0.20 4.39 115 Curb COR STD 300 -6CF AASHTO 54.52 49.02 6.00 0.255 7.85 6.704 0.872 1.50 52.64 52.64 0.27 3.72 116 Curb COR STD 300 -6CF AASHTO 54.52 47.02 8.00 0.255 7.85 6.704 0.872 1.50 53.01 52.76 0.25 3.79 117 1 Generic Default 100% 1AASHTO1 55.501 47.241 8.261 4.6301 10.981 5.5011 0.8781 22.541 53.221 53.091 0.001 0.00 Title: Coral Mountain Affordable Housing - System B is \bentley\bentley storrncad\1920 cmah system b.stm 03/10/11 01:23:10 PM 0 0 Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1- 203 -755 -1666 0 Project Engineer: DLS StormCAD v5.6 [05.06.012.00] Page 1 of 1 • • Scenario: Base Pipe Report Label Material Mannings n Section Size Length (ft) 'Full Capacity (cfs) Total System Flow (cfs) Up Gmd Elev (ft) Down Gmd Elev (ft) Up Inv Elev (ft) Down Inv Elev (ft) Slope (ft/ft) Avg - Vel (fVs) HGL In (ft) HGL Out (ft) Flow Time (min) Profile Description 1-10.1 PVC 0.012 12 inch 11.31 9.04 6.09 53.68 53.78 39.82 39.20 0.0548 7.75 49.40 49.12 7.19 Pressure L12.1 PVC 0.012 24 inch 49.05 82.28 15.17 53.40 54.44 47.40 41.87 0.1127 4.83 51.05 50.86 10.22 Pressure L13.1 Concrete 0.013 18 inch 21.59 44.93 0.63 57.07 56.91 48.57 44.62 0.1830 0.36 50.10 50.10 7.87 Pressure 1-14.1 Concrete 0.013 18 inch 9.45 64.83 0.63 57.04 56.90 48.54 44.94 0.3810 0.36 50.25 50.25 7.87 Pressure L15.1 Concrete 0.013 18 inch 21.05 31.89 1.50 55.02 54.83 49.02 47.08 0.0922 0.85 52.64 52.64 7.85 Pressure L16.1 Concrete 0.013 24 inch 11.45 29.14 23.75 55.02 54.83 47.02 46.83 0.0166 7.56 52.76 52.64 11.00 Pressure L17.1 Concrete 0.013 24 inch 8.00 27.71 22.54 55.50 55.02 47.24 47.12 0.0150 7.18 53.09 53.01 10.98 Pressure P5.61 PVC 0.012 36 inch 18.34 65.34 41.37 53.78 54.16 38.20 38.05 0.0082 5.85 48.88 48.82 13.72 Pressure P5.02 PVC 0.012 36 inch 23.04 81.06 37.38 53.85 53.78 38.49 38.20 0.0126 5.29 49.19 49.12 13.65 Pressure P5.03 PVC 0.012 36 inch 31.80 78.98 22.97 54.35 53.85 38.87 38.49 0.0119 3.25 49.41 49.38 13.49 Pressure P5.04 PVC 0.012 36 inch 14.23 71.67 23.06 54.58 54.35 39.01 38.87 0.0098 3.26 49.48 49.47 13.41 Pressure P5.05 PVC 0.012 36 inch 10.00 72.25 23.12 54.74 54.58 39.11 39.01 0.0100 3.27 49.56 49.55 13.36 Pressure P5.06 PVC 0.012 36 inch 10.00 72.25 23.18 54.91 54.74 39.21 39.11 0.0100 3.28 49.63 49.62 13.31 Pressure P5.07 PVC 0.012 36 inch 65.54 72.51 23.57 56.58 54.91 39.87 39.21 0.0101 3.33 49.76 49.69 12.98 Pressure P6.01 PVC 0.012 24 inch 117.70 24.54 16.74 53.92 53.85 40.18 39.00 0.0100 5.33 49.93 49.38 10.94 Pressure P6.02 PVC 0.012 241nch 159.05 24.50 15.03 54.44 53.92 41.77 40.18 0.0100 4.78 50.67 50.07 10.39 Pressure P7.01 Concrete 0.013 30 inch 44.64 29.44 23.75 56.91 56.58 43.89 43.66 0.0052 4.84 49.99 49.84 12.83 Pressure P7.02 Concrete 0.013 30 inch 14.08 28.92 23.34 56.90 56.91 43.96 43.89 .0.0050 4.75 50.15 50.10 12.78 Pressure P7.03 Concrete 0.013 30 inch 300.88 28.96 24.03 57.16 56.90 45.46 43.96 0.0050 4.90 51.28 50.25 11.76 Pressure P7.04 Concrete 0.013 130 inch 1 223.48 1 29.041 24.951 54.83 1 57.16 1 46.58 45.46 1 0.0050 5.08 52.22 51.39 11.02 Pressure Title: Coral Mountain Affordable Housing - System B is \bentley\bentley stormcad\1920 cmah system b.stm 03110/11 08:30:32 AM © Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA +1- 203 - 755 -1666 Project Engineer: DLS StormCAD v5.6 [05.06.012.00] Page 1 of 1 SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing Appendix H RCWQMP Exhibit C Worksheets • Riverside County - Whitewater River Region Water Quality Management Plan Exbibit C Worksheet 1 • 40 Design Procedure for BMP Design Volume Designer: DLS Company: MSA Consulting Inc. Date: June 15, 2011 Project: Coral Mountain Affordable Housing Drainage Area: DA A - Offsite Commercial Site 1. Determine the Tributary Area to the BMP (Ahb) Amb= 9.07 acres 1 2. Determine the impervious area ratio (i) a. Determine the impervious area within kb Amp 8.16 acres (2) b. Calculate I = amdAtfb = (2)1(1) i= 0.90 3 3. Determine Runoff Coefficient C C= 0.858 *i3 - 0.78 *i2 +0.774 *i +0.04 C= 0.73 (4) C= 0.858 *(3 )3- 0.78 *(3 )2+0.774 *(3) +0.04 4. Determine Unit Storage Volume (V„) V„= 0.40 *C = 0.40 *(4) V„= 0.29 acre -in /acre 5 5. Determine Design Storage Volume e VBMP = Vu * ^Irib = (5) *(1) VBMP= 2.65 acre -in (6) VBMP = (6)/12 VBMP= 0.22 acre -ft (7) VBMP = (7) *43560 VBMP= 9,611 cubic ft 8 Notes: IMPERVIOUS AREA ASSUMED TO BE 90% (NO SITE PLAN TO DETERMINE ACTUAL AREAS) Riverside County - Whitewater River Region Water Quality Management Plan Exbibit C Worksheet 1 Design Procedure for BMP Design Volume Designer: DLS Company: MSA Consulting Inc. Date: June 15, 2011 Project: Coral Mountain Affordable Housing Drainage Area: DA B - Offsite Street'A' 1. Determine the Tributary Area to the BMP (A,,;b) kb= 1.22 acres 1 2. Determine the impervious area ratio (i) a. Determine the impervious area within Airib A;mp 1.02 acres (2) b. Calculate I = A;mp/Auib = (2)/(1) i= 0.84 3 3. Determine Runoff Coefficient C C= 0.858 *i3 - 0.78 *i2 +0.774 *i +0.04 C= 0.65 (4) C =0. 858 *(3)3 - 0.78 *(3)2 +0.774 *(3) +0.04 4. Determine Unit Storage Volume (V„) V„= 0.40 *C = 0.40 *(4) V„= 0.26 acre -in /acre 5 5. Determine Design Storage Volume A Vamp = V. * Aft = (5) *(1) VBMp= 0.31 acre -in (6) Vamp = (6)/12 VBMp= 0.03 acre -ft (7) Vamp = (7) *43560 vamp= 1,143 cubic ft $ Notes: PERVIOUS AREAS (CALCULATED FROM THE SITE PLAN) WERE REDUCED BY A FACTOR OF 10 %. THIS ADJUSTED PERVIOUS AREA WAS SUBTRACTED FROM THE TOTAL AREA TO DETERMINE THE IMPERVIOUS AREA USED IN THESE CALCULATIONS. • Riverside County - Whitewater River Region Water Quality Management Plan Exbibit C Worksheet 1 • • Design Procedure for BMP Design Volume Designer: DLS Company: MSA Consulting Inc. Date: June 15, 2011 Project: Coral Mountain Affordable Housing Drainage Area: DA C 1. Determine the Tributary Area to the BMP ([rib) Atdb= 9.44 acres 2. Determine the impervious area ratio (i) a. Determine the impervious area within Afib Amp 7.15 acres (2) b. Calculate I = Aimp Atrib = (2)/(1) i= 0.76 3 3. Determine Runoff Coefficient C C= 0.858 *i3 - 0.78 *i2 +0.774 *i +0.04 C= 0.55 (4) C =0. 858 *(3)3 - 0.78 *(3)2 +0.774 *(3) +0.04 4. Determine Unit Storage Volume (V„) V„= 0.40 *C = 0.40 *(4) V„= 0.22 acre -in /acre 5 5. Determine Design Storage Volume y VBMP = Uu * Atrib = (5) *(1) VBMP= 2.08 acre -in (6) VBMp =(6)/12 VBMP= 0.17 acre -ft (7) VBMp = (7) *43560 VBMP= 7,553 cubic ft 8 Notes: PERVIOUS AREAS (CALCULATED FROM THE SITE PLAN) WERE REDUCED BY A FACTOR OF 10 %. THIS ADJUSTED PERVIOUS AREA WAS SUBTRACTED FROM THE TOTAL AREA TO DETERMINE THE IMPERVIOUS AREA USED IN THESE CALCULATIONS. F J • Riverside County - Whitewater River Region Water Quality Management Plan Exbibit C Worksheet 2 • • Design Procedure for BMP Design Flow Uniform Intensity Design Flow Designer: DLS Company: MSA Consulting Inc. Date: June 15, 2011 Project: Coral Mountain Affordable Housing Drainage Area: Drainage Area A - Offsite Commercial Site 1. Determine the Tributary Area to the BMP (Anb) AWb= 9.07 acres (1) 2. Determine the impervious area ratio (i) a. Determine the impervious area within Anb A,P 8.16 acres b. Calculate I = AmdAtib (Note: Rounded to nearest 5 %) i= 90 % (2) 3. Determine Runoff Coefficient C Use Table 4 and impervious % (2) A Soil Runoff Coefficient Ca 0.82 (3) B Soil Runoff Coefficient Cb= 0.82 (4) C Soil Runoff Coefficient Cc= 0.83 (5) 0 Soil Runoff Coefficient Cd= 0.84 (6) 4. Determine the Area Decimal Fraction of Each Soil Type A. Area of Soil Type 'A' / (1) 0.00 acres Aa 0.00 (7) A. Area of Soil Type 'B ' / (1) 9.07 acres Ab= 1.00 (8) A. Area of Soil Type'C'/ (1) 0.00 acres Ac= 0.00 (9) A. Area of Soil Type 'D' / (1) 0.00 acres Ad= 0.00 (10) . 5. Determine Runoff Coefficient C = (3)x(7) + (4)x(8) + (5)x(9) + (6)x(10) = C= 0.82 (11) 6. Determine BMP Design Flow QBMP = C'I`A = (11) x 0.2 x (1) - QBMP= 1.49 cfs (12) Notes: IMPERVIOUS AREA ASSUMED TO BE 90% (NO SITE PLAN TO DETERMINE ACTUAL AREAS) FLOW BASED BMP NOT USED Riverside County - Whitewater River Region Water Quality Management Plan Exbibit C Worksheet 2 Design Procedure for BMP Design Flow Uniform Intensity Design Flow Designer: DLS Company: MSA Consulting Inc. Date: June 15, 2011 Project: Coral Mountain Affordable Housing Drainage Area: Drainage Area B - Offsite Street 'A' 1. Determine the Tributary Area to the BMP (q,;b) Atdb= 1.22 acres (1) 2. Determine the impervious area ratio (i) a. Determine the impervious area within Anb AmP 1.02 acres b. Calculate I = A1mP/Abib (Note: Rounded to nearest 5 %) i= 85% (2) . 3. Determine Runoff Coefficient C Use Table 4 and impervious % (2) A Soil Runoff Coefficient Ca= 0.77 (3) B Soil Runoff Coefficient Cb= 0.79 (4) C Soil Runoff Coefficient Cc= 0.80 (5). D Soil Runoff Coefficient Cd= 0.81 (6) 4. Determine the Area Decimal Fraction of Each Soil Type A. Area of Soil Type 'A' / (1) 0.00 acres Aa= 0.00 (7) A. Area of Soil Type 'B ' / (1) 1.22 acres Ab= 1.00 (8) A. Area of Soil Type 'C' / (1) 0.00 acres Ac= 0.00 (9) A. Area of Soil Type'D' / (1) 0.00 acres Ad= 0.00 (10) 5. Determine Runoff Coefficient C = (3)x(7) + (4)x(8) + (5)x(9) + (6)x(10) = C= 0.79 (11) 6. Determine BMP Design Flow QBMP = C'I'A = (11) x 0.2 x (1) QBMP= 0.19 cfs (12) Notes: PERVIOUS AREAS (CALCULATED FROM THE SITE PLAN) WERE REDUCED BY A FACTOR OF 10 %. THIS ADJUSTED PERVIOUS AREA WAS SUBTRACTED FROM THE TOTAL AREA TO DETERMINE THE IMPERVIOUS AREA USED IN THESE CALCULATIONS. FLOW BASED BMP NOT USED • Riverside County - Whitewater River Region Water Quality Management Plan Exbibit C Worksheet 2 • • Design Procedure for BMP Design Flow Uniform Intensity Design Flow Designer: DLS Company: MSA Consulting Inc. Date: June 15, 2011 Project: Coral Mountain Affordable Housing Drainage Area: Drainage Area C 1. Determine the Tributary Area to the BMP (inb) AWb= 9.44 acres (1) 2. Determine the impervious area ratio (i) a. Determine the impervious area within AM Amp 7.15 acres b. Calculate I = AmdAthb (Note: Rounded to nearest 5 %) i= 75% (2) 3. Determine Runoff Coefficient C Use Table 4 and impervious % (2) A Soil Runoff Coefficient Ca= 0.69 (3) B Soil Runoff Coefficient Cb= 0.71 (4) C.Soil Runoff Coefficient Cc= 0.73 (5) D Soil Runoff Coefficient Cd= 0.74 (6) 4. Determine the Area Decimal Fraction of Each Soil Type A. Area of Soil Type'A' / (1) 0.00 acres Aa= 0.00 (7) A. Area of Soil Type 'B ' / (1) 9.44 acres Ab= 1.00 (8) A. Area of Soil Type'C'/ (1) 0.00 acres Ac= 0.00 (9) A. Area of Soil Type 'D' / (1) 0.00 acres Ad= 0.00 (10) 5. Determine Runoff Coefficient C = (3)x(7) + (4)x(8) + (5)x(9) + (6)x(10) = C= 0.71 (11) 6. Determine BMP Design Flow QBMp = C'I'A = (11) x 0.2 x (1) QBMp= 1.34 cfs (12) Notes: PERVIOUS AREAS (CALCULATED FROM THE SITE PLAN) WERE REDUCED BY A FACTOR OF 10 %. THIS ADJUSTED PERVIOUS AREA WAS SUBTRACTED FROM THE TOTAL AREA TO DETERMINE THE IMPERVIOUS AREA USED IN THESE CALCULATIONS. FLOW BASED BMP NOT USED Riverside County - Whitewater River Region Water Quality Management Plan Exhibit C Table 4 Runoff Coefficients for an Intensity = 0.2 in /hr for Urban Soil Types Impervious % 0 (Natural) 5 10 15 20 (1 -Acre) 25 30 35 40 (1/2 -Acre) 45 50 (1/4 -Acre) 55 60 65 (Condominiums) 70 75 (Mobilehomes) 80 (Apartments) 85 90 (Commercial) 95 100 A Soil B Soil C Soil D Soil RI =32 RI =56 RI =69 RI =75 0.06 0.14 0.23 0.28 0.10 0.18 0.23 0.31 0.14 0.22 0.29 0.34 0.19 0.26 0.33 0.37 0.23 0.30 0.36 0.40 0.27 0.33 0.39 0.43 0.31 0.37 0.43 0.47 0.35 0.41 0.46 0.50 0.40 0.45 0.50 0.53 0.44 0.48 0.53 0.56 0.48 0.52 0.56 0.59 0.52 0.56 0.60 0.62 0.56 0.60 0.63 0.65 0.61 0.64 0.66 0.68 0.65 0.67 0.70 0.71 0.69 0.71 0.73 0.74 0.73 0.75 0.77 0.78 0.77 0.79 0.80 0.81 0.82 0.82 0.83 0.84 0.86 0.86 0.87 0.87 0.90 0.90 0.90. 0.90 • • C, D Y O D 5 TM Design Your Own Detention System .._mil _._.�_ _..R.O ��Q1Fg ir�� CMP DETENTION SYSTEMS r.,, ^� =_ ele A�I��TCAV• ��_ i `Wn and For design assistance, drawings, pricing send completed worksheet to: 4ea - ' CONSTRUCTION PRODUCTS INC. dyods @contech - cpi.com '- �- Project Summary Dat 6/15/2011 Project Name: Coral Mountain Affordable Housing La Quinta City / County: State: Pavement Finished Grade Elevation CA Designed By: Company: Telephone: Enter Information in Blue Cells DLS �! > ^` oeoii ro Grade "tip E .^ m v MSA Consulting " Corrugated Metal Pipe Calculator Storage Volume Required (co: 8,700 Limiting Width (ft): Invert Depth Below Asphalt (ft): Solid or Perforated Pipe: Shape Or Diameter (in): Number Of Headers: 50.27 ft` Pipe Area Spacing ' =1 Diameter Spacing m ° u w 45.00 24.00 Perforated 96 { 1 Spacing between Barrels (ft): 3.00 Stone Width Around Perimeter of System (ft): Depth A: Porous Stone Above Pipe (in): Depth C: Porous Stone Below Pipe (in): Stone Porosity 0 to 40%): X 2r 24 24 40 S stem Sizing' Pipe Storage: 5,278 cf System Layout Porous Stone Storage: 3,937 cf Total Storage Provided: 9,215 cf 105.9% Of Required Storage Barrel 12 Number of Barrels: 4 barrels Barrel 11 Length per Barrel: 16.0 ft Barrel 10 Length Per Header: 41.0 ft Barrel 9 Rectangular Footprint W x L: 45. ft x 28. ft Barrel 8 Barrel 7 Barrel 6 CONTECH Materials Total CMP Footage: 105 ft Approximate Total Pieces: 6 PCs Barrel 5 Approximate Coupling Bands: 5 bands Barrel 4 Approximate Truckloads: 3 trucks Barrel 3 Barrel 2 Barrel 1 Construction Quantities " Total Excavation: 1120 cy Porous Stone Backfill For Storage: 365 cy stone Barrel Footage (w /o headers) Backfill to Grade Excluding Stone: 560 cy fill — Construction quantities are approximate and should be verified upon -final desigl © 2007 CONTECH Stormwater Solutions LJ 0 Ij C7 SDPA Preliminary Hydrology Report Coral Mountain Affordable Housing Appendix Hydrology Exhibits Preliminary Grading Exhibit i i W d OV.:J --.__- 1-- -._ � a .-.._ - _. -_..- _ -. _ .�v. -� --._ - - - -- _� -__- / JO.J -�,.- ,J x x � � '�� x57.6 �`` .____ _.._. 1_111.._._ - - 55.9 55.8 -____ V---'' ---°'" - - - --- - -_ _ - -` - ---- -- -- „�.. 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PIPE NO. PIPE 0 (in) MATERIAL LENGTH (ft) SYSTEM FLOW (cfs) SLOPE (ft /ft) AVERAGE VELOCITY (ft /s) 1.01 54 HDPE 127.40 71.23 0.0030 4.48 1.02 54 HDPE 142.85 72.48 0.0030 4.56 1.03 54 HDPE 1 97.97 73.33 0.0030 4.61 1.04 54 HDPE 101.26 74.20 0.0030 4.67 1.05 54 HDPE 12.52 74.31 0.0030 4.67 1.06 54 HDPE 12.52 74.42 0.0030 4.68 1.07 54 HDPE 12.36 74.52 0.0030 4.69 1.08 54 HDPE 22.52 74.72 0.0030 4.70 1.09 54 HDPE 12.52 74.82 0.0030 4.70 1.10 54 HDPE 12.52 74.93 0.0030 4.71 1.11 54 HDPE 10.91 75.02 0.0030 4.72 2.01 30 HDPE 14.59 26.47 0.0110 5.39 2.02 I 30 HDPE 1 20.00 26.55 0.0115 5.41 2.03 .30 HDPE 10.00 26.59 0.0110 5.42 2.04 30 HDPE 253.54 27.58 0.0112 5.62 2.05 30 HDPE 287.55 23.44 0.0112 4.78 3.01 18 RCP 99.55 1.94 0.0100 1.10 4.01 48 HDPE 7.67 52.19 0.0065 4.15 4.02 48 HDPE 7.32 52.23 0.0068 4.16 4.03 48 HDPE 36.94 52.48 0.0065 4.18 4.04 48 HDPE 35.40 49.06 0.0065 3.90 4.05 48 HDPE 142.56 42.09 0.0065 3.35 4.06 48 HDPE 125.78 41.27 0.0065 3.28 5.01 36 HDPE 18.34 41.37 0.0082 5.85 5.02 36 HDPE 23.04 37.38 0.0126 5.29 5.03 36 HDPE 31.80 22.97 0.0119 3.25 5.04 36 HDPE 14.23 23.06 0.0098 3.26 5.05 36 HDPE 10.00 23.12 0.0100 3.27 5.06 36 HDPE 10.00 23.18 0.0100 3.28 5.07 1 36 HDPE 1 65.54 23.57 0.0100 3.33 6.01 24 HDPE 117.70 16.74 0.0100 5.33 6.02 24 HDPE 159.05 15.03 0.0100 4.78 7.01 30 RCP 44.64 23.75 0.0052 4.84 7.02 30 RCP 14.08 23.34 0.0050 4.75 7.03 1 30 RCP 300.88 24.03 0.0050 1 4.90 7.04 1 30 RCP 1 223.481 0.0050 5.08 56.1 x 56.1 �-- -... � ---- � - - - - - - P4 02 0 � s L6.1 1 x 55`1 F=__ \ 50.3 L10.1 W W W v P1.11 �- - TO G° .g P4.0 L81 P4.04 P4.03-/ . �v P1.1o' j� I PROPOSED LATERAL SUMMARY I, L DG r�i W - 4. 8 ® ® P . 01A PROP. MAXWFLL I" j' 56.4 rs \ �FF 56.1 a - _. _ , - _.. _ _ _. - - -- P1.(9 r==DME IN IN ERC PTOR) PE 55. II I __ 1 - - PROP. CONT €CH �x \ ) t - l > t �. � \ � n (8.700 CF o 0 BL�D C P1.08 55.W � � �4� , _ � � \ --'�� BLUG- --rBr --�� r r -+°v I � x UNDERGROUND x // l l (- \ P1.07 5s 1 \ WQMP STORAGE o i� \ a FF 56.00 FF"5S.90 FACILITY-----_- - -- t PE 55.5 -- -- PE 55.4 - - -- s4.9 _ __4-- r 54 9 --�.P 1-86- �----- 1- �--�.- � _ s.-Y1 � �7 t (} x 5 54.3 - - -� - ` x 54-2_ 54.3 54.4 _ x 54.2 - - x 54.2 -_ x 54.2 54.9 54.4 54.5 x 53.6 5 .5 _ _ 52 6 _- -- S- - - - - - - - �- x41 x53.8 x53.5 / �� _ I ^45.2 x 45.4 .sv� _ J � x -�--- 54_.5`_.= x 53.6 - -- - - _ __. - 53.7 x - _ 53.6 - ` .0 - ( �!( �. f L - - -- J - a -- - 53.8 x / , -. 53.6 x _4 x 53.6 x 53.6 � - \ 3T /44.9 _ - _ _ _ \ \ 53.5 � - \ � -- 11 ( I 1 _ x -° \)_ \ \ h5 .5 51.6 51.1 x x 14.8 �1� 44.9 -- 54.9 53.3 �-. � ""° 1 --"_- - � \ , \ x L 5 .4 x 53.3 x \ x 52. x 7 \ \\ x 5�.6 x ..._ x 53.7 51.6 ( 52 4 52 5 x � .._.,• ""°' -° i LAT NO. PIPE 0 (in) MATERIAL LENGTH (ft) SYSTEM FLOW (cfs) SLOPE (ft /ft) AVERAGE VELOCITY (ft /s) 1.1 12 HDPE 11.29 6.36 0.4145 8.10 2.1 24 RCP 18.00 21.88 0.0156 6.96 3.1 18 RCP 19.05 1.02 0.3312 12.85 4.1 18 RCP 19.60 1.02 0.2709 0.57 5.1 12 HDPE 9.39 3.38 0.0522 4.30 6.1 12 HDPE 7.52 5.84 1.0000 7.44 7.1 12 HDPE 55.28 4.05 0.1990 17.92 8.1 18 HDPE 13.75 9.39 0.0371 5.31 8.2 18 HDPE 119.20 6.84 0.0368 3.87 8.3 18 HDPE 128.71 7.02 0.0369 3.97 8.4 18 HDPE 17.91 7.05 0.0369 3.99 8.5 18 HDPE 40.00 7.07 0.0367 11.02 9.1 12 HDPE 8.52 4.85 1.0000 6.18 10.1 12 HDPE 11.31 6.09 0.0548 7.75 12.1 24 HDPE 49.05 15.17 0.1127 4.83 13.1 18 RCP 21.59 0.63 0.1830 0.36 14.1 18 RCP 9.45 0.63 0.3810 0.36 15.1 18 RCP 21.05 1.50 0.0922 0.85 16.1 24 RCP 11.45 23.75 0.0166 7.56 17.1 24 RCP 8.00 22.54 0.0150 7.18 1 x \ J - 43 8 55.3 I / 1 52.6 -( - x - - - - - - "'-•- -- - 51.3 -' Y lJ NOTE: MANNING S n- VALUES A„ x % 44.1 ` HDPE = 0.012 51.7 51.6 <51.6 J/ 50.6 50.5 \ % x49.8 4 44.2 ` • RCP = 0.013 54.4 � I / _.. -."" 'J - _ - -.__ ---- -- 5r- X °�i2.4 � � 51.8 1\ � \ \ � � \ `0.6 �x �� x I .Q� � 51.6 �' ".�� 'r �-�' x x x {9 Io 1 7 ° ° � ° °° \ \ J\ -\ \ \ x \ \ 51. ` DOWNSTREAM HGL (46.00 FT) IN EVACUATION CHANNEL - r 50.A \ x 44.9 OBTAINED FROM BECHTEL WATER SURFACE PROFILE, 51 7 51 8 ° , s1.5 x �� \ \ \ \� \ I �1' x DRAWING NUMBER 10714 -C -401 (CVWD DWG N0. 36205) 51.5 x \ �., 4.6 x x ° x \j�\�\j \ ti\ 43.91 / _zz q 54F 8 '�'-� 5 9 - �I �1-- 50.6 - �.. , Y` "'"'" 43.8 x I / x 10 rJ � \1 � '- - 51.8 4 50.4\ � `. 50.3 l,� �� >� � 44.9 [ \ x\ - ---- -' ---+ - 5 50.9 _ ��1_ �� 0' `1 \ 49.8 \ 6 � � { 53.9 x 52.6- 52.6 _ _ _ _ _ - �� X49.2 49.6 46 x44.5 a 52I I I _ _ _L�} -- - { �� I- V , ~- - - - ~. - 111 &��' � 5.5 x 51.4 I __ \ - x "" �` - -- \ 51. x 50.4 .1t i 56.6 56.9 51.4 x ` 44.8 / 53.7 III x 56.8 x I I�I - _- _ I °.w - 50.4 ` -� 49.8 \ x _ x (I 11 I II f III =_ _ �- - �- x ( `~� acs, , -- - ° C III x 52.7 ( III y 52.6 57 6 r 50.4 \ `\ \\ \ x 45.� 53.4 I III x� II 51111) "`\52.7 o x III j x - _.._- -_ q y ° ° ° 50.4 \ x 50.6 312 III 56.4 \ �\ \. 49.9 x 11 56.5 56.5 x I I III 51.7 50.5 50.2 II x �\ 1 v ° x^ IIII III x I III ° -- a.. % / 52.5 �\ v 51.1 a 49.8 / / / / I = r �52 o 7�p -� x I� �I �I p c III �1 I l ` .... °° , x �- -- - - -- f= - -1 L III ► i III /%�` _ .7 -7 < f - I 455 DES Rt\ \SAN - S I, r _�P G UNIFIED SCHgyjpL DISTRICT I �oo °O �� °Otlo /?% 111 I P / PROPOSED INLET SUMMARY INLET NO. INLET TYPE TRIBUTARY AREA Q100 (cfs) INTERCEPTED FLOW (cfs) BY- PASSED FLOW (cfs) RIM / FL ELEVATION (ft) HEADWATER DEPTH (ft) GUTTER DEPTH (ft) HGL IN (ft) HGL OUT (ft) 1 -1 24x24 GRATE C9 6.4 6.4 -0- 53.86 0.53 -N A- 50.38 50.21 1 -2 VIRTUAL A2 21.9 21.9 -0- 56.00 -N A- -N A- 51.17 51.05 1 -3 CLQ STD 300 - SAG B3 B4 1.0 1.0 -0- 54.53 -N A- 0.23 50.91 50.91 1 -4 CLQ STD 300 - SAG B3 B4 1.0 1.0 -0- 54.53 -N A- 0.23 50.92 50.92 1 -5 24x24 GRATE C8 3.4 3.4 -0- 53.20 0.34 -N A- 48.88 48.83 1 -6 18x18 GRATE C7 2.7 2.7 -0- 53.20 0.39 -N A- 48.76 48.55 1 -7 24x24 GRATE C6 4.1 4.1 -0- 53.37 0.38 -N A- 49.71 49.63 1 -8 24x24 GRATE C4 7.1 7.1 -0- 54.80 0.66 -N A- 50.21 50.17 1 -9 24x24 GRATE C5 4.9 4.9 -0- 53.46 0.43 -N A- 48.90 48.80 1 -10 24x24 GRATE C1 6.1 6.1 -0- 53.68 0.50 -N A- 49.56 49.40 1 -11 24x24 GRATE C2 3.2 3.2 -0- 53.92 0.33 -N A- 50.07 49.93 1 -12 48x48 GRATE C3 15.2 15.2 -0- 53.40 0.59 -N A- 51.11 51.05 1 -13 CLQ STD 300 - GRADE B5 0.7 0.66 0.04 56.57 -N A- 0.20 50.10 50.10 1 -14 CLQ STD 300 - GRADE B5 0.7 0.66 0.04 56.54 -N A- 0.20 50.25 50.25 1 -15 CLQ STD 300 - SAG B1 B2 1.5 1.5 -0- 54.52 -N A- 0.27 52.64 52.64 I -16 CLQ STD 300 - SAG B1 B2 1.5 1.5 -0- 54.52 -N A- 0.25 53.01 52.76 I -17 VIRTUAL Al 22.6 22.6 -0- 55.50 -N A- -N A- 53.22 53.09 NOTE: HEADWATER ELEVATION IS BASED ON THE ORIFACE EQUATION FOR GRATED INLETS ASSUMING A 50% CLOGGING FACTOR. CLEAR OPENING AREAS OF GRATES: 18x18 GRATE - 1.60 SF 24x24 GRATE - 3.23 SF 48x48 GRATE - 12.34 SF GRATES CHARACTERISTICS WERE OBTAINED FROM JENSEN PRECAST. R 0' 50' 100' 150' 200' SCALE 1 " =50' JUNE 20, 2011 U C Cb } 0 U Q D a Q M O 46 N M N 0 3 u) 0 V) E .FD _ Q U 0 N o� i Z a c E a 0 i T m 0 0 T _ c a `o U 0 N 0 0 0 U Q i N O� -j U, � l � X "�,° � � ,\ `` � \ I 56.4 I� - _ ` \\ \ \. 1 56.6 ( x 57.3 0 603 \ \ ' _ 7`' \ -- ` 1 7.1 x x I I x � 57.5 I \ N Y X l `\ �\ ~°` ti _ \ \ \ - (5.5)'\ ) ' ( x 56.3 o c� - - - - - - - - - - - - - �\ _ \ , �` 50.7 �~ \ \ FUTURE COMMERCIAL SITE ASP5 56.9 - `°- -r- `-- - r--�.- � r__ I I� l �~ 1 �' `° -... °-� -` ' \ P&RVEL t,/- L L& 20 100 °60 0 \ 58.1 I ------ - - - --- ;`� - - -,JL� / ` % `� `�. ° coo-020-063 cJrC J�7 X 57.4 58.2 V') f- _ _ _ I , ��. j Qp[N] \ 54.4 x _ v I y 56.4 ` ✓� 1' \ \ `\ \ °~ i J-- fC 55.47 c"' TC 55.96 .� x TC 55.13 TC 55.06 - /I 0 2 \\- Ld \�9 5 \ f / .� \ �� FL 54.97 - - �) - - FL 55.46 ,' _ _ 1 - - - - FL 54.63 - 56.� 54.56 /� 551 -� I � I ( - - - - x I x �.I�. I - -- - - -.. - - - - - - -- - - - - -- - - - - -- _� _. -- - -- - -X - Te -- �, 5415 wn I 56.8 (57.4)t \ , 57.6 ` \ 5.. / -c 50' VC w SS % t i __ �. � � I` "_ .• � 56.5 � � _ . i .,._._._ �. •2g xI � I �` x 5539 \ 55.95 ) 1 55.05 TC NO TP \55. PVI -HP N'< 00'00 "' E 264.78'- _ -TP , -,0.55% iPVi8LP w FC sss.pp I I TW 57.5 f \ ~ Yr '' - 56.4 x \ , - 1 65 V rk (57.4)t - x 0.55% �, A =18 °025 - P 6 0 n ._ 0 I �I 56.5 \ %--� �- i I `� ,�I 55.4 S " = 300 �X TIC 56.46 NG [c \ L/ 54.2 1 xp ` 50 / �S �� _ ._ _ .. _ '_---i T 5 . 6 _ . -_ . / _ _ - - - - r - - C 55 1 / 16 / °Og'�7 6s� T p 56.21 T I FL 56. 4_. -5W / _ - - - \ `TC X5.96 T 5-+ -T� 55 p6�/\��R =30p• _TP -GB I-_ 54.97 ~� FL 55.46 x FL 54.63 x FL 54.56 ...- 5 '4 0 I L- 657'.60% T 57.7 �� FC 5,9 \ _. I 0.37% ��I TO 56.36_ -P -� / X , ` x1 S�p�• QJ "� i \ �_ - - - / -- ^ -- - - - -- -- - - - - - - - 5 55.29 TC 5 \ ° 57.6 f /� � V - �' ! - J (S -_ X / \FC 5 S0 O ' - F ROP. BLOCK WlX�L S) / ✓ 0 w ui w l // / ' ` Cy r TC 56.10 / - ° 55.5 X000 /• i / - I \ °�° 1 TP 55.68 I / L _ NG X \ /� h0 5•,7. \ ° _ \ - J \ (55) - - - -- / TP 55.50 �5 PROP. BUILDING \ f / w w FS , o 58.2 / ` SETBACK LINE o ROPE UILDING 56.47 ` �� ° 54.8 o r� / x I TW 61.6 �-- / \ x \ SETBACK" INE FS `LO� x n �n TC 55.8 TF 5 .3 \ /p, 6.5 \ 5 .8 >- o Tf� 55.33 � J 56. X 54.8 \ N z U 54.8 I t 1 1 / .,,\58.3 x L r r 5 1 U - -- -- -, 56.40 ` 56.90 LDG G o w ___ - --\ 1. 0 r rk-� -� �56.1j f / x P x � Q 56.47 \ 1 �--:- �o x ti �. FF= 57,.00 \ cr - FS _r _ _ �0 - - - - ` \ \ Fs 57.4 ( Fs PE =56: w _ - o --- \ 54.3 \) ° E =� x j 56.50 P_i ° 56-:47 _ -- - TP 57.8 f �� \ \ I FS E- o "'� FS 0 r / A56.40 `> - - _ - �.7 56.90 Off° - �- X 1.8 �� . FS / FS s- 6 y 53.3 A I co Ln 56.47 � \ 1 {; L/ J �x � x \ / �6 ry uj 58.1 ` 1 / N 56.00 \ \ 50 �°�, x b� 5- 1 l\ 56.00 \ rn1 �C 56.10 cD `L% �, 56.00 p`/ L -/ 1 �0 0 55.8 I n - � \ � .__.` -`T � 55.60 I �. 2 %' o , TC 55..70 / / 5f , o FS �5 .4 FS �g FD5 .50 p :ri 0 - Of f-- j / ,. �� 3.1 o I 56.1 f J �� rMr V�)).° TP 55.0 "" x .. 0.50% � x ' � PE= 6.0 �"� �n �n � � - 57.00 �� { - �, \ FF= -- -. - - -- - -- -.. -_. _ J.g ... \ 55.95 � 5(.6 , w I -L 58.1 f E= L56..0 F89T _ % g ° y� 6.95 . - i - FS X x - 1.8 x N 1 o 55 32 TC 55.3 ,n� \! - FS 56.47 56.47 \ � I ``� ' 53. i TC 56.15 55 .18 16% J ' �y TP 54.8. v� 2 A X54 82 ® K ` 4.8 -- - - -- TP 55.65 x\ r I '� ` t\FS b� co m L j MITT rr / ` n m ao r� cD co 5523 X 1.50% 56 2 L--4 � -H y b� PROP. 1 WAT�� , � � " � I +i -- --- ----, I - - - - 56.40 I X1.5% x :n :n FS �� 56.00- 56.00 0 �:n 54 53 I I o I W S T 55.71 - W ( FS FS - - - - 58.2 f A 2'88% o. _ L tt II 2.3'0% TF'^55�1 i 53.8 \ \ i 56.47 - I - 2.00% � J �.,� �--- . G 1 �►- 1 FS 2.48% - 15w 9 x Z �? 55.857` 56.47 FS ~ 1.85_% - _ F m N 8 50'26 E 1.0 F-- F-x Q 58.3 oo I I - x , irr 3 53.5 - TC 55.31 / 51. FS ° �o I w - _ - - -_' uJ r Q 1.18 N 1.50 TP 55.23 TP 54.81 _. - x x o x 58.3 f ' i 1.69 O`1� , - ❑ ` I I \ -*_ �� <_. TO 54.39 \ 53.4 1 PROP P ' YGR ND I t N I 0 I TC 56.0 x Z 0 r I 56.00 , C X55. 3 t: 54.41 TP 55.54' Ui :n I, I r1====:) cD co - - � r � � \ I� a, ° ® P �4. 3 __ - - - -- FL 53.89 1fC 55 3� � FL TC- 5��1 -i � TC 55.8 � ��L% i ,� � � > i� � � �. � LO :n 51. r-r-i _ Z_ NO o0 9 I ) J 4.2 ' :, \ © �1�99% P 54 1 TP 55.31 f- F- ®51.x.88% 540 2.0�% I C5 a. Q 1: 1 % TP 55.48 ti U -� r - - - - - -{ W Op r- cD I :n :n x ) ° +o TC 55.25 1.5= 55,80 / ° FL o `I I a 0 a I ` } , 1 1 I I \ ® P 54.76 ® ` / \ �° Q © v ` I -- . - . _. -- - F3.76 54.4 ` 89% y \� L i Z �- �` TC .55.73\ u)1% 52.6 I / wa " ( c� I B TR 55.23 w 7. 1 x 1 I = O U I °Z 2° V �, i x - 56.27 x 56.27 Ia -' I 56.5 )f 58.5 f ° i -' �O w� �° 1.52 %TC 55.57 :� ° 1.93% 0 I ( I I I 1 F5� \ FSx° NO - - o A / N I A m 56.0 �/ �? �/ o \` 5.5 TP 55.07 . 42�' _ 55.80 TP 55.169 cn I - V X I 4 ( I 0 m S �r � ` � o �` 4 � `rr rnr �� FS � � � w 1 55.8 � W a f i I � Of TC 55.04 Q- M 54.18 / w�l� 2.30% °1 5 5 w TP 54.54 1.50% FIL 55 X/ A ° x Q o �I- _.:_. -..��, ' I - \ 5 2.42% 9% .70 AX N � � _ 1 7Ti i 54.3 / 6 FS 2 J x wi' �', ° x TC 54.95 �g 56.27 2.2 LOI w � TP`.55.05 55.80 / 56.27 � 56.2 �° ° 52.8w �..., ,nl I N 0 58.7 t ` r ! l I TP 54.45 1.69% FS FS 11111 a NG -HP >N z ! _ __ ° 55.80 H v I ¢ S �TC 55.71 FS FS ° o c� I R- 55, 21 / - s 5.00 a \- 58.7 x o 58.5 f i i' 000 5; I v FS ° 5� 6 ' , - �(°x� BLD �r(-1 =r i �(`� 4 i NG I V� � 9.,2 x �\ a o 0 %� O° O S =5 0 x -` n \ b� c ,�of 4j �. 53.3 o `I co (i ` I o 0 I I m ' C i x 53.40 'O �Q j ~ \OFF _ I y f / o w 53.6 3I w D N /�J 1.91.% F LP P- 5..8 �. _ 56.27 X �- O r- I ' / n A \� x o of o A 56.27 0 1-� I h V % FS i w - - 5 L- ao r; T I w I� ° TO 55. -49 V .65% ,�G ��i 56.27 / FS o :n :n � G � h • ,n o n T 54.99 0 ° Q 52.8 L 55.80 PROP. HOPE S © I �G `o i� R> I �: 85.0 52.9 ��9 / ° i �Q / �� ` 55.80 "' FG -LP x\ TC 55.43w FL� LP =� { o 1 4.8 i �: 54 FS 56.27 �' -- . TP 54. 3 . 6 ,° I r ti TC 4.43 / I / \� � � LDG L , ini � 1.$5� � w� x � ��° ;� � � . FS � �w TP 53 93 - / I - - - FF= 56�30� 2 .6 vmi ° _.�., - �`L V -c7 -(55)- 56.27 2 7 �9 / I ��N o p / r �- I 2. -0% f 0 °� �• O`T; 4.�. 0� 1 FS �' PE =55.8 AX w ° h r r I m Fs � GCE ti, , 59. I a ' TO ° : G h`O / r �c 55.88 ° I I �J• � I � 5 F o �� Q' �' /� 56.27 Z: ( 56.20 ° z TP 54.11 �' �� O G / �- F L- 58.3 f I 5 �.4 i x FS - I �� 5 2 ��q .. / FP =55.8 FS ° tZ I / 53.� NO b� o � I V o T 4 2 \ \"7 �� % 56.27 x2 00D x I �' ( I T 4. o `p°�°� '\ / FS �� SOg TC 55.43 16 O 55.30 / �� 5 .80 3.3 1 ! /� f T 54.6 a�° g 1 55.80 FS - t .6 TC 54.30 5 , 6 ° , n T .1 53. \ x \ / FS Z1�` 55.88 8 cO 1. 18% I� 53 0 NO I /15! X O' / �� / 0� r %\ '�,. 55.77 f. , /� 1 55.70 2..� x 2, - FS ►_ `I I �T- I!I�I I LEGEND ABBREVIATIONS MATCHLINE _ SEE SHEET C1.02 xx.x EXISTING SPOT ELEVATIONS PROP. ELEC SWITCH PAD AC ASPHALT CONCRETE MIN. MINIMUM EXISTING CONTOURS C/L CENTERLINE NO NATURAL GROUND EXISTING BOUNDARY PROP. Ill 3 PHASE TRANSFORMER PAD C &G CURB AND GUTTER N.T.S. NOT TO SCALE C.B. CATCH BASIN P/L PROPERTY LINE DRAINAGE NOTE: EXISTING LOT LINE DWG. DRAWING PE PAD ELEVATION - - - - - - - - - - - EXISTING EASEMENT /BUILDING SETBACK m PROP. IID MEDIUM PULL -BOX EA. EACH PROP. PROPOSED DRAINAGE AROUND BUILDINGS, INCLUDING SWALES, AREA DRAINS, ETC. R/w EXISTING RIGHT OF WAY EC ELEVATIONURVE S.F. SQUARE FEET (BERMS) WILL BE DESIGNED ALONG WITH FINAL LANDSCAPE FEATURES BERMS - -E EXISTING ELECTRIC \ PROP. Ill SINGLE PHASE TRANSFORMER PAD EX EXISTING S/W SIDEWALK AND SHOWN ON THE PRECISE GRADING PLANS. THE BACKBONE STORM DRAIN SYSTEM HAS BEEN DESIGNED TO ACCOMMODATE THE - -c EXISTING GAS - T EXISTING TELEPHONE s EXISTING SEWER - -w EXISTING WATER FL PROPOSED ADA PATH OF TRAVEL - PROPOSED AND EXISTING CENTER LINE FS PROPOSED CURB TC 00.00 PROPOSED ELEVATIONS FL 00.00 GRADE BREAK - - PROPOSED RIGHT OF WAY S PROPOSED SEWER SD PROPOSED STORM DRAIN W PROPOSED WATER © PROPOSED WATER METER -- PROPOSED FIRE HYDRANT -� PROPOSED DETECTOR CHECK /FDC & PIV FF FINISHED FLOOR TC TOP OF CURB FG FINISHED GRADE TF TOP OF FOOTING ENTIRETY OF THE 100 YEAR STORM EVENT (SEE SDPA PRELIMINARY FL FLOWLINE TOG TOP OF GRATE HYDROLOGY AND HYDRAULICS REPORT). FS FINISHED SURFACE TP TOP OF PAVEMENT GB GRADE BREAK TRW TOP OF RETAINING WALL HP HIGH POINT TW TOP OF WALL L.F. LINEAL FEET TYP. TYPICAL LP LOW POINT UG UNDERGROUND MAX. MAXIMUM CORAL MOUNTAIN APARTMENTS AFFORDABLE HOUSING PROJECT LA QUINTA, CA APN 600- 020 -054 (PARCEL 2 OF LLA 2010 -508) do �� 0' 30' 60' 90' 120' SCALE 1"=,30' MSA CONSULTING, INC. PLANNING ■ CIVIL ENGINEERING ■ LAND SURVEYING 34200 BOB HOPE DRIVE ■ RANCHO MIRAGE ■ CA 92270 TELEPHONE (760) 320 -9811 ■ FAx (760) 323 -7893 JULIAN A. DE LA TORRE PE C43880 PRELIMINARY PRECISE GRADING PLAN PREST • VUKSIC ARCHITECT S SDP PACKAGE APRIL 5,2011 v c C5 c c 0 U N N U Q N Q �o 0 co N d 3 a 0 U Z ry 0 C7 J W CL CL 0 a i 0 c 0 a► 0 `0 T HLI SHEET 01.01 — ---� —_ N G --r 2 \X _.52�' ''`\ �• 50.3 � x \ t 56.4 \\ 56.1 l-•-� VV �. _- 55 �� - IV VJ TV LL Y VVL. IT J'*.V �- "^- ..,,,� �= 54-3 - - - - - - - - - - - - -54.3 — -SC4.97 x - TE�9 - 54 „9 r+ 4 54.:87 5,4.93 - 5� ,5.00 54.94 54.2 54.95 TC4.21 � s — s — __ — s — — — 5 — - _ _ C XTC TC\ - — �- S —L� . 2 — s — T� — 5 _ _ - �C— -� 5 — _ -5.3.6 ___ - -_ — 54.4 54.5 - DESERT SANDS U IFIE SCHOOL "DISTICT x - -.._._ - - - - - - - - - - - - - - - - - - - - - - - - - - - PROP. BLOCK y 54. 3.8 53. .— � x 5 C4.01 54.05 53.99 53.745 / J - - ” IX 53.6 T TC 53.7 x TC x TC 1 r x l ( 54.5 ry _ x _ — _ __ __ _ __ -- _ _ — - — __..._ .�._ 53.6 — � -- 1 - _ - - - - _, -- - - �� - ° �� 53.8 x 53.6 x x 53.6 x 53.6 LEGEND CORAL MOUNTAIN APARTMENTS AFFORDABLE HOUSING PROJECT - LA QUINTA, CA APN 600 -020 -054 (PARCEL 2 Of LLA 2010 -508) 'I'owxx R ol 30' .• •• • MSA CONSULTING, INC. PLANNING ■ CIVIL ENGINEERING ■ LAND SURVEYING 34200 BOB HOPE DRIVE ■ RANCHO MIRAGE ■ CA 92270 TELEPHONE (760) 320 -9811 ■ FAx (760) 323 -7893 JULIAN A. DE LA TORRE PE C43880 P , z.67 EMERY - - -O Vj=- PRELIMINARY PRECISE GRADING PLAN PREST • VUKSIC A R C H I T E SDP PACKAGE C T S APRIL 5, 2011 N 0 r U xx.x EXISTING SPOT ELEVATIONS ABBREVIATIONS EXISTING CONTOURS EXISTING BOUNDARY - - EXISTING LOT LINE - - - - - - - - - - - EXISTING EASEMENT /BUILDING SETBACK R/W EXISTING RIGHT OF WAY — _E EXISTING ELECTRIC — . —c EXISTING GAS — r EXISTING TELEPHONE — s EXISTING SEWER — —W EXISTING WATER a IID 3 PHASE TRANSFORMER PAD PROPOSED ADA PATH OF TRAVEL - P/L PROPOSED AND EXISTING CENTER LINE PROPOSED CURB TC 00.00 DWG. PROPOSED ELEVATIONS FL 00.00 PAD ELEVATION DRAINAGE AROUND BUILDINGS, INCLUDING SWALES, AREA DRAINS, ETC. - - PROP. PROPOSED RIGHT OF WAY S EACH END OF CURVE PROPOSED SEWER SD ALONG WITH FINAL LANDSCAPE FEATURES (BERMS) WILL BE DESIGNED PROPOSED STORM DRAIN W PROPOSED WATER m S.F. PROPOSED WATER METER AND SHOWN ON THE PRECISE GRADING PLANS. THE BACKBONE PROPOSED FIRE HYDRANT IID SINGLE PHASE TRANSFORMER PAD EX PROPOSED DETECTOR CHECK /FDC & PIV CORAL MOUNTAIN APARTMENTS AFFORDABLE HOUSING PROJECT - LA QUINTA, CA APN 600 -020 -054 (PARCEL 2 Of LLA 2010 -508) 'I'owxx R ol 30' .• •• • MSA CONSULTING, INC. PLANNING ■ CIVIL ENGINEERING ■ LAND SURVEYING 34200 BOB HOPE DRIVE ■ RANCHO MIRAGE ■ CA 92270 TELEPHONE (760) 320 -9811 ■ FAx (760) 323 -7893 JULIAN A. DE LA TORRE PE C43880 P , z.67 EMERY - - -O Vj=- PRELIMINARY PRECISE GRADING PLAN PREST • VUKSIC A R C H I T E SDP PACKAGE C T S APRIL 5, 2011 N 0 r U ABBREVIATIONS �❑ PROP. ELEC SWITCH PAD AC ASPHALT CONCRETE MIN. MINIMUM C/L CENTERLINE NG NATURAL GROUND DRAINAGE NOTE: C &G CURB AND GUTTER N.T.S. NOT TO SCALE PROP. IID 3 PHASE TRANSFORMER PAD C.B. CATCH BASIN P/L PROPERTY LINE DWG. DRAWING PE PAD ELEVATION DRAINAGE AROUND BUILDINGS, INCLUDING SWALES, AREA DRAINS, ETC. i- W PROP. IID MEDIUM PULL -BOX EA. EC EACH END OF CURVE PROP. R/W PROPOSED RIGHT OF WAY ALONG WITH FINAL LANDSCAPE FEATURES (BERMS) WILL BE DESIGNED ELEV ELEVATION S.F. SQUARE FEET AND SHOWN ON THE PRECISE GRADING PLANS. THE BACKBONE PROP. IID SINGLE PHASE TRANSFORMER PAD EX EXISTING S/W SIDEWALK STORM DRAIN SYSTEM HAS BEEN DESIGNED TO ACCOMMODATE THE FF FINISHED FLOOR TC TOP OF CURB ENTIRETY OF THE 100 YEAR STORM EVENT (SEE SDPA PRELIMINARY FG FINISHED GRADE TF TOP OF FOOTING HYDROLOGY AND HYDRAULICS REPORT). FL FLOWLINE TOG TOP OF GRATE FS FINISHED SURFACE TP TOP OF PAVEMENT GB GRADE BREAK TRW TOP OF RETAINING WALL HP HIGH POINT TW TOP OF WALL L.F. LINEAL FEET TYP. TYPICAL LP LOW POINT UG UNDERGROUND MAX. MAXIMUM CORAL MOUNTAIN APARTMENTS AFFORDABLE HOUSING PROJECT - LA QUINTA, CA APN 600 -020 -054 (PARCEL 2 Of LLA 2010 -508) 'I'owxx R ol 30' .• •• • MSA CONSULTING, INC. PLANNING ■ CIVIL ENGINEERING ■ LAND SURVEYING 34200 BOB HOPE DRIVE ■ RANCHO MIRAGE ■ CA 92270 TELEPHONE (760) 320 -9811 ■ FAx (760) 323 -7893 JULIAN A. DE LA TORRE PE C43880 P , z.67 EMERY - - -O Vj=- PRELIMINARY PRECISE GRADING PLAN PREST • VUKSIC A R C H I T E SDP PACKAGE C T S APRIL 5, 2011 N 0 r U EX. PL 6.18' 15' cn I- 21 ZI w �I 01 V) Wj yl2.5' ~— 2.00% PROP. CL PROP. ROW PROP. BUILDING SETBACK 15' 10' I 20 _ VARIES I I I PROP. C &G PROP. BLOCKI PER CITY STD 201 I WALL I 2.00% 2% MAX MqX = 1 0% rT1rl 2;0 TrTT1 �I f-IT1- Tf1 =�� I - =1 -I MIN 6'f I ROP. SIDEWALK PER CITY STD 240 PROP. ROUGH CUT 7' BELOW FL /TP PROP. HDPE STORM DRAIN SECTION A -A SCALE HORZ: 1"=10' VERT: 1 " =5' 100 2 c� z 0 J_ D m i� 83' 45' 19' 45' SECTION D -D SCALE HORZ: 1"=10' VERT: 1 " =5' .�I 2.5' PROP. CURB ESTIMATED EARTHWORK QUANTITIES 2% MAX MAX PROP. CURB VARIES PROP. VALLEY GUTTER VARIES CUT CY FILL CY _ VARIES PROP. VALLEY GUTTER VARIES 6" PCC /4" AB 1% MIN TO 4% MAX �— — ( ) ( ) 1% MIN TO 4% MAX 6" P, VARIES AB 1 % MIN TO 4% MAX 1% MIN TO 4% MAX ° I =_ =1 .: ��_ � � .vN�.n ,. >, u x . — — — =I �' RAW QUANTITIES 1 II- I- I------ - - - - -- ,�:� .,. u... ,.,r �.x,r...,, ,..�.... _ -;_,r. - - -- - ITS ..,x 3.r a _ .: :, , , , ,. , � ..... _ _ _ — — — — — — — — — — — — — _ _ — — _ — — — — — — — — _ =1 I 1 =� � i— iii —� � �— � � ,_ t t III III .I I I_I i -1 I_I I_I I- _ _I - _ -, - _ _ m „A ti _ � —_ — ...�.... — -I - III = I- -� �— — — — — — — — = � -III h —III ,� I = — III_ —III III SUBSIDENCE 878 18 25 _ 1 �'_' -' �_� t =1 t 1 =111 = II I -1 ( =1 -1 11 =1 1 =1 1 =1 11 =1 -1 =1 =_ -I _ -= 1 =_= 1 =1 1 =1 1 =1 1 =1 1= i I 1 =1 1 =1 i t =� �' -' '' -- =1 i 1 =I 1 =1 I -1 1 =1 11 =1 1 =1 t I_ 18 793 0 644 " — "' —" — iii —i =1 t I— III — III —III III —III III —III —I I= —' —' PROP. ROUGH CUT 11, 26 RAW ADJUSTED 9,766 20,111 7' BELOW FL /TP SHRINKAGE 4,266 PROP. 12" DIP WATER MAIN PROP. 12" DIP WATER MAIN — OVER —EX 27,835 27,835 OVER —EX SHRINKAGE 5,904 SUBTOTAL 37,601 58,117 PROP. 8" VCP SEWER PROP. 8" VCP SEWER-0 IMPORT 20,516 TOTAL EARTHWORK 58,117 58,117 SECTION B -B EARTHWORK FACTORS: SCALE THE FOLLOWING FACTORS WERE USED IN THE PREPARATION HORZ: 1"=10' OF THE EARTHWORK ANALYSIS: VERT: 1 " =5' SHRINKAGE: 17.5% (AVERAGED VALUE) SUBSIDENCE: 0.15' (AVERAGED VALUE) OVEREXCAVATION BASED ON 5 —FOOT DEPTH ALL OF THE FACTORS WERE OBTAINED FROM GEOTECHNICAL REPORT FILE No. 09354 -02 PREPARED BY EARTH SYSTEMS SOUTHWEST, DATED JULY 10, 2010. EXISTING TOPOGRAPHY WAS PROVIDED BY THE CITY OF LA QUINTA AND VERIFIED BY MSA CONSULTING. SECTION C -C SCALE HORZ: 1"=10' VERT: 1 " =5' CORAL MOUNTAIN APARTMENTS AFFORDABLE HOUSING PROJECT - LA QUINTA, CA APN 600 -020 -054 (PARCEL 2 OF LLA 2010 -508) PARKING CALCULATIONS REQUIRED PARKING 2 SPACES AS NEGOTIATED WITH THE CITY OF LA QUINTA 176 UNITS X 2 SPACES = 352 PARKING SPACES REQUIRED 352 PARKING SPACES PROVIDED COVERED PARKING OF THE 352 SPACES PROVIDED 176 SPACES ARE COVERED ADA ACCESSIBLE PARKING REQUIRED 5% OF UNASSIGNED PARKING TO BE ADA ACCESSIBLE 352 X 0.05 = 17.6 ADA PARKING SPACES REQUIRED 18 ADA PARKING SPACES PROVIDED 2 VAN ACCESSIBLE SPACES REQUIRED 2 VAN ACCESSIBLE SPACES PROVIDED MSA CONSULTING, INC. PLANNING ■ CIVIL ENGINEERING ■ LAND SURVEYING B34,200 BOB HOPE DRIVE ■ RANCHO MIRAGE ■ CA 92270 TELEPHONE (760) 320 -9811 ■ FAx (760) 323 -7893 JULIAN A. DE LA TORRE PE C43880 SECTIONS /NOTES /EARTHWORK QUANTITIES PREST ARC H SDP PACKAGE C BLOCK WALL • VUKSIC I T E C T APRIL 5,2011 Rl �J DISCLAIMER- ADA PATH OF ACCESS THE PRELIMINARY ADA PATHS OF ACCESS ROUTES DEPICTED ON THIS PLAN ARE IN SUBSTANTIAL CONFORMANCE TO ADA COMPLIANCE STANDARDS. UPON COMPLETION OF THE PRECISE GRADING AND DS UNIFIED PAVING PLANS THE FINAL DESIGN AND LOCATION OF THE ADA ACCESS ROUTES WILL BE DEPICTED IN MORE DETAIL AND SHALL CONFORM TO DISTRICT THE REQUIRED ADA COMPLIANCE STANDARDS. FEMA- THIS PROJECT IS COVERED BY FIRM PANEL NUMBER 06065C2243G CURB EFFECTIVE AUGUST 28, 2008. THESE MAPS INDICATE THAT THE PAVEMENT PROJECT AREA IS DESIGNATED AS ZONE X (SHADED & UNSHADED). ZONE X (SHADED) INDICATES AREAS OF 0.2% ANNUAL CHANCE FLOOD; AREAS OF 1% ANNUAL CHANCE FLOOD WITH AVERAGE DEPTHS OF LESS THAN 1 —FOOT OR WITH DRAINAGE AREAS LESS THAN 1 SQUARE MILE; AND AREAS PROTECTED BY LEVEES FROM THE 1% ANNUAL CHANCE FLOOD WHILE ZONE X (UN— SHADED) INDICATES AREAS DETERMINED TO BE OUTSIDE THE 0.2% ANNUAL CHANCE FLOODPLAIN. PARKING CALCULATIONS REQUIRED PARKING 2 SPACES AS NEGOTIATED WITH THE CITY OF LA QUINTA 176 UNITS X 2 SPACES = 352 PARKING SPACES REQUIRED 352 PARKING SPACES PROVIDED COVERED PARKING OF THE 352 SPACES PROVIDED 176 SPACES ARE COVERED ADA ACCESSIBLE PARKING REQUIRED 5% OF UNASSIGNED PARKING TO BE ADA ACCESSIBLE 352 X 0.05 = 17.6 ADA PARKING SPACES REQUIRED 18 ADA PARKING SPACES PROVIDED 2 VAN ACCESSIBLE SPACES REQUIRED 2 VAN ACCESSIBLE SPACES PROVIDED MSA CONSULTING, INC. PLANNING ■ CIVIL ENGINEERING ■ LAND SURVEYING B34,200 BOB HOPE DRIVE ■ RANCHO MIRAGE ■ CA 92270 TELEPHONE (760) 320 -9811 ■ FAx (760) 323 -7893 JULIAN A. DE LA TORRE PE C43880 SECTIONS /NOTES /EARTHWORK QUANTITIES PREST ARC H SDP PACKAGE C BLOCK WALL • VUKSIC I T E C T APRIL 5,2011 Rl �J � 0 • • Whitewater River Region WQMP Project Specific Preliminary Water Quality Management Plan For: CORAL MOUNTAIN APARTMENTS South of Highway 111. and east of Dune Palms Road in the City of La Quinta, CA 92253 DEVELOPMENT NO. APNS 600- 020 -012; -047; - 048 DESIGN REVIEW NO. TO BE DETERMINED Prepared for: Shovlin Companies 46 -753 Adams Street La Quinta, CA 92253 Telephone: (760) 771 -3345 Prepared by: Julian De La Torre, Principal Engineer MSA Consulting, Inc. 34200 Bob Hope Drive Rancho Mirage, CA 92270 Telephone: (760)320 -9811 WQMP Preparation/Revision:Date: June 20, 2011 Whitewater River Region WQMP Coral Mountain Apartments OWNER'S CERTIFICATION This project - specific Water Quality Management Plan (WQMP) has been prepared for: Shovlin Companies by MSA Consulting, Inc. for the project known as Coral Mountain Apartments in the City of La Quinta, CA 92253. This WQMP is intended to comply with the requirements of La Quinta for APN 600 - 020 -012; -047; - 048, which includes the preparation and implementation of a project - specific WQMP. The undersigned, while owning the property/project described in the preceding paragraph, shall be responsible for the implementation of this WQMP and will ensure that this WQMP is amended as appropriate to reflect up -to -date conditions on the site. This WQMP will be reviewed with the facility operator, facility supervisors, employees, tenants, maintenance and service contractors, or any other party (or parties) having responsibility for implementing portions of this WQMP. At least one copy of this WQMP will be maintained at the project site or project office in perpetuity. The undersigned is authorized to certify and to approve implementation of this WQMP. The undersigned is aware that implementation of this WQMP is enforceable under City of La Quinta Water Quality Ordinance (La Quinta Municipal Code Municipal Code — Title 13 § 13.24.120). If the undersigned transfers its interest in the subject property/project, the undersigned shall notify the successor in interest of its responsibility to implement this WQMP. "I, the undersigned, certify under penalty of law that I am the owner of the property that is the subject of this WQMP, and that the provisions of this WQMP have been reviewed and accepted and that the WQMP will be transferred to future successors in interest." Owner's Signature Owner's Printed Name Owner's Title /Position Date 43 -753 Adams Street La Quinta, CA 92253 ATTEST Notary Signature Printed Name Title /Position Date THIS FORM SHALL BE NOTARIZED BEFORE ACCEPTANCE OF THE FINAL PROJECT SPECIFIC WQMP JUNE 20, 2011 • • Whitewater River Region WQMP Coral Mountain Apartments Contents SECTION PAGE I. Project Description ........................................................................................ ..............................1 It. Site Characterization .............................................................:....................... ..............................6 III. Pollutants of Concern .................................................................................... ..............................8 IV. Hydrologic Conditions of Concern .............................................................. ...............'.............12 V. Best Management Practices ......................................................................... .............................14 V.1 SITE DESIGN AND TREATMENT CONTROL BMPS .............................. ............................... 14 V. 1.A SITE DESIGN BMPS ..................................:................................. .............................16 V. 1.13 TREATMENT CONTROL BMPS ................................................... .............................22 V. LC MEASUREABLE GOAL SUMMARY .............................................. .............................24 V.2 SOURCE CONTROL BMPS .................................................................. ............................... 25 V.3 EQUIVALENT TREATMENT CONTROL ALTERNATIVES ....................... ............................... 27 VA REGIONALLY -BASED TREATMENT CONTROL BMPS ......................... ............................... 27 VI. Operation and Maintenance Responsibility for BMPs ............................ .............................28 VII. Funding ...........................................................................:.............................. .............................30 TABLES TABLE 1. POLLUTANT OF CONCERN SUMMARY TABLE 2. BMP SELECTION MATRIX BASED UPON POLLUTANT REMOVAL EFFICIENCY (�) TABLE 3. IMPLEMENTATION OF SITE DESIGN CONCEPTS TABLE 4. SITE DESIGN BMPS MEETING THE MEASUREABLE GOAL IN WQMP SECTION 3.5.1.1 TABLE 5: TREATMENT CONTROL BMP SUMMARY TABLE 6: MEASUREABLE GOAL SUMMARY TABLE 7. SOURCE CONTROL BMPS APPENDICES A. CONDITIONS OF APPROVAL B. VICINITY MAP, WQMP SITE PLAN, AND RECEIVING WATERS MAP C. SUPPORTING DETAIL RELATED TO HYDRAULIC CONDITIONS OF CONCERN (IF APPLICABLE) 8 15 17 21 23 24 25 D. EDUCATIONAL MATERIALS E. SOILS REPORT F. SITE DESIGN AND TREATMENT CONTROL BMP SIZING ;CALCULATIONS AND DESIGN DETAILS G. AGREEMENTS - CC &RS, COVENANT AND AGREEMENTS AND /OR OTHER MECHANISMS FOR ENSURING ONGOING OPERATION, MAINTENANCE, FUNDING AND TRANSFER OF REQUIREMENTS FOR THIS PROJECT- SPECIFIC WQMP H. PHASE I AND PHASE II ENVIRONMENTAL SITE ASSESSMENT 1. PROJECT- SPECIFIC WQMP SUMMARY DATA FORM June 20, 2011 Whitewater River Region WOMP Coral Mountain Apartments I. Project Description Project Owner: Shovlin Companies 46 -753 Adams Street La Quinta, CA 92253 Telephone: (760) 771 -3345 WQMP Preparer: Julian De LaTorre, Principal Engineer 34200 Bob Hope Drive Project Site Address: Planning Area/ Community Name/ Development Name: APN Number(s): Thomas Bros. Map: Project Watershed: Sub - watershed: Project Site Size Rancho Mirage, CA 92270 Telephone: (760) 320 -9811 9500 Block of Highway 111 La Quinta, CA 92253 La Quinta /Coachella Valley Planning Area 600 - 020 -038; - 039 Page 849, grid 33 (2007 Riverside County Edition) Whitewater River Whitewater Evacuation Channel, Coachella Valley Sto.-m Channel 10.66 acres Standard Industrial Classification (SIC) Code: Proposed Project Uses: 6513 Apartment Buildings Formation of Home Owners' Association (HOA) or Property Owners Association (POA): Existing Surrounding Uses: 4225 General Warehousing and Storage 5399 Miscellaneous General Merchandise.Stores 5541 Gasoline Service Station 9411 Administration of Educational Programs 4151 Operation of School Buses 7521 Automobile Parking ■ /1 June 20, 2011 1 Whitewater River Region WQMP Coral Mountain Apartments • Additional Permits /Approvals required for the Project: q J AGENCY Permit required State Department of Fish and Game, 1601 Streambed Y ® No Alteration Agreement State Water Resources Control Board, Clean Water Act Y ® N❑ (CWA) Section 401 Water Quality Certification US Army Corps of Engineers, CWA Section 404 permit Y ® N❑ US Fish and Wildlife, Endangered Species Act Section 7 Y ❑ N® biological opinion ** Other City of La Quinta Grading Permit Y ® N❑ City of La Quinta Building Permit Y ® N❑ SWRCB General Construction Permit Y ® N❑ Parcel Merger Permit Approval Y ® N❑ • * Consultation with the U.S. Army Corps of Engineers is presently taking place regarding the permit requirements for this project. Additional documentation will be provided in the Final WQMP. • ** The proposed project site is not recognized as a habitat of an endangered species nor does it form part of a Conservation Area of the Coachella Valley Multiple Species Habitat Conservation Plan. James W. Cornett — Ecological Consultants, conducted a biological evaluation of the site in which it was concluded that due to the inability to detect any sensitive plant or animal species or a riparian or any other rare plant community, the modifications associated with the proposed project will not have a significant adverse impact upon any species or community. No further mitigation is recommended in the evaluation (See Appendix B for the entire report). Based on the findings provided in the project - specific biological evaluation, a U.S. Fish and Wildlife, Endangered Species Act Section 7 biological opinion is not deemed required for this project. June 20, 2011 Whitewater River Region WQMP Coral Mountain Apartments Project Location and Existing Conditions The proposed project comprises a multi - family residential complex with up to 176 dwelling units on a 10.66 -acre site situated south of Highway 111 and east of Dune Palms Road. The project property is located near the southeast comer of Highway 111 and Dune Palms Road in the City of La Quinta, Riverside County, California. The project property is assigned Assessor's Parcel Numbers 600 -020- 012; 600 - 020 -047; and 600 - 020 -048. The location of the site can also be described as a central portion of Section 29, Township 5 South, Range 7 East, San Bernardino Base and Meridian. The subject property (currently vacant) is bounded by Highway 111 to the north; a large commercial plaza to the east; a Desert Sands Unified School District facility to the south; and a self storage facility and commercial plaza to the west. Additionally, the La Quinta Evacuation Channel is found to the southeast. Proposed Automotive Dealership — Tributary Area A The proposed future automotive dealership will occupy 9.07 acres corresponding to the northern portion of the project site. This development encompasses the site previously occupied by a 3 -acre mobile home park. The dealership will likely include a sales /office area, a multiple vehicle garage and an automotive service area. This future development is not a part of Coral Mountain Apartments. The water quality management plan practices and measures for this future project will be determined by the project applicant Street A — Onsite Tributary Area B Tributary area `B" comprises 1.22 acres primarily corresponding to Street A. Multi- Family Residential Development — Onsite Tributary Area C The residential project, composed of on -site tributary area B, will occupy 9.44 acres. The complex will comprise up to 176 dwelling units, including 40 one - bedroom units, 82 two - bedroom units and 53 three - bedroom units. Building "K" is proposed as a clubhouse facility with laundry, and maintenance /storage facilities. A swimming pool and recreational areas are also proposed. The project will be served by 352 parking spaces, 176 of which will be covered stalls. This residential development does not occupy the former 3 -acre mobile home park. Location of Facilities: The proposed development is configured to accommodate multiple residential buildings as well as parking areas, open space, a community center (clubhouse) and a swimming pool. As shown in the site plan (Appendix B), the roughly rectangular- shaped complex will have gated entries situated near the southwest and northeast property corners respectively. The site will contain two primary parking areas: one parking lot generally occupying the northwest portion of the site and a second parking area following the easterly and southern boundary. The site's open space and landscaped areas are also distributed to serve as buffer space between residential buildings. The project's clubhouse and nearby swimming pool are proposed for the southwestern portion of the site, near one of the vehicular access points. June 20, 2011 3 Whitewater River Region WQMP Coral Mountain Apartments • Storm Drain and BMP Facilities: To provide clarification for the Coral Mountain Apartments Preliminary Water Quality Management Plan in relation to the corresponding SDPA Preliminary Hydrology Report, we present the following explanation: The City of La Quinta (City) and the Coachella Valley Water District (CVWD) have allowed the project to discharge storm runoff into the La Quinta Evacuation Channel and the City will not require the project to retain the 100 -year storm on -site. However, the project will retain the first - flush volume (a much smaller volume compared to the 100 -year storm) per MS4 requirements. Therefore, the function of the proposed storm drain and structural BMP improvements will be to retain the first -flush volume on -site and convey the 100 -year storm flows to the La Quinta Evacuation Channel. To achieve this, the project will employ one Maxwell IV Drainage System (drywell) in conjunction with a Contech underground infiltration system. The Maxwell IV Drainage System will serve as a pre - filtration system in conformance with the City of La Quinta Engineering Bulletin #06 -15. Nuisance and first -flush flows will first be conveyed to a settling chamber, where vegetation debris, sediments and other particulates will be retained. Additional nuisance and first -flush flows will be conveyed to an overflow and drainage pipe after passing through an integrated hydrophobic petrochemical sponge and a debris shield. This pre- treatment function will prevent the accumulation, decay and possible gas formation from vegetation debris and other potential pollutants in the subsequent infiltration ( Contech) system. As described herein and illustrated in Appendix B (Site Plan), the Maxwell IV Drainage System has • the function of a water quality inlet and a filtration system in reference to Table 2 (BMP Selection Matrix on page 14). The Water Quality Inlet function of the proposed system includes the trapping catch basin (settling chamber) to promote sedimentation of coarse materials. The hydrophobic petrochemical sponge in conjunction with the PurefloTM debris shield serve as the media filters characteristic of a Filtration System. As a result, pollutant removal efficiency for the Maxwell IV Drainage System is deemed equal to both a Water Quality Inlet and a Filtration System. • Pre - treated nuisance and first -flush flows will then enter the Contech infiltration system, which is composed of 8 -foot diameter perforated pipes with a storage capacity in excess of the required volume of 8,700 cubic feet (BMP design volume). Percolation of the BMP design volume (first -flush) will occur within the regulatory 72 -hour period utilizing both the Maxwell IV Drainage System and the Contech infiltration system. A conservative calculation indicates that the Maxwell IV Drainage System can solely dissipate the first flush volume (8,700 cf) at a rate of 0.034 c.f.s. for the 72 -hour period (8,700 c.f. /72 hours/ 60 minutes / 60 seconds = 0.0335). The percolation rate of 0.034 c.f.s. is well within the anticipated percolated rates of the Maxwell IV drywell. Runoff volume in excess of the first -flush will be conveyed via an underground storm drain system to the La Quinta Evacuation Channel. June 20, 2011 4 Whitewater River Region WQMP Coral Mountain Apartments Location of Activities: The proposed project will accommodate typical residential activities. The pedestrian activity is expected to occur in a distributed manner, not in a concentrated area of.the complex. Residents will have access to the site on multiple points along the northern and western complex boundaries. Pedestrians will utilize walkways and sidewalks throughout the complex to access residences as well as the lawn and recreation amenities. Residents and invited visitors are expected to widely employ the outdoor facilities, which include the shaded and recreational spaces. Furthermore, it is anticipated that some residents will utilize bicycles as an alternate form of transportation or for recreational purposes. The complex will have five enclosed areas with covered waste bins, which will be accessed by waste management trucks two times a week. Due to the site's adjacency to the Costco commercial plaza parking lot to the east and the Desert Sands Unified School District bus parking area to the south, no pedestrian or vehicular access to the site is expected to along the easterly and southerly boundaries. Waste Generation: The proposed project is expected to generate non - hazardous waste typical of most residential land uses. The project will have at least five enclosed areas where trash containers can be stored. Additionally, trash and recyclable material receptacles will be situated in the common areas, such as the community center. The potential pollutants of concern associated with this project include bacteria/virus; nutrients; pesticides; organic compounds; sediments; trash and debris; oxygen demanding substances; and oil and grease. The site can potentially produce pathogens, a pollutant category identified as an impairment to the Coachella Valley Stormwater Channel Application of pesticides, herbicides and related chemicals may occur on the site as needed. However, industry regulations stipulate the correct application quantities and practices in residential areas to reduce any runoff from being considered a hazardous waste. Moreover, the proposed water - efficient landscape irrigation system will help reduce the potential distribution of this waste. An education program, supported by existing City recycling campaigns, will be implemented to promote waste reduction, pollution prevention and recycling practices. Materials Storage and Delivery Areas: The project's residential uses will not require a designated delivery area. Materials storage facilities will be provided on -site. June 20, 2011 5 Whitewater River Region WQMP Coral Mountain Apartments 0 II. Site Characterization is • Land Use Designation or Zoning: Commercial Park (CP) Current Property Use: Vacant Proposed Property Use: Residential Availability of Soils Report: Y ® N ❑ Note: A soils report is required if infiltration BMps are utilized. Attach report in Appendix E. Phase 1 Site Assessment: Y ® N ❑ Note: If prepared, attached remediation summary and use restrictions in Appendix H. June 20, 2011 6 Whitewater River Region WQMP Coral Mountain Apartments Receiving Waters for Urban Runoff from Site Receiving 303(d) List Designated Beneficial Uses Proximity to RARE Waters Impairments Beneficial Use Coachella Valley Storm Pathogens, FRSH, REC I b, REC II b, WARM, Approximately 2 miles Water Channel Toxaphene, WILD, RARE c Abbreviations: I — Intermittent Beneficial Use FRSH — Freshwater Replenishment REC I — Water Contact Recreation REC II — Non - Contact Water Recreation WARM — Warm Freshwater Habitat WILD — Wildlife Habitat RARE — Preservation of Rare, Threatened, or Endangered Species a. Section of perennial flow from approximately Indio to the Salton Sea. b. Unauthorized use. c. Rare, endangered, or threatened wildlife exists in or utilizes some of this waterway. d. Includes the section of flow fi•om the headwaters in the San Gorgonio Mountains to (and including) the Whitewater Recharge Basins near Indian Avenue crossing in the City of Palm Springs. e. Applies only to tributaries to the Salton Sea. f. This beneficial use, if any, to be determined on a case -by -case basis. X n June 20, 2011 • • • Whitewater River Region WQMP Coral Mountain Apartments III. Pollutants of Concern 719.40 Coachella Hydrologic Subunit — Impaired for: Pathogens, Toxaphene Coachella Valley Storm Channel HUB No. 719.40 Impaired for: Pathogens, Toxaphene Table 1. Pollutant of Concern Summary Pollutant Category Potential for Project Causing Receiving Water Impairment BacteriaNirus (Pathogens) Yes (Pathogens) Heavy Metals Yes Nutrients Yes Pesticides Yes Organic Compounds (Toxaphene) Yes (Toxaphene) Sediments Yes Trash & Debris Yes Oxygen Demanding Substances Yes Oil & Grease Yes Other (specify pollutant): The Coachella Valley Stormwater Channel is impaired by pathogens and toxaphene. • The proposed development is not anticipated to produce toxaphene because the use of this substance has been illegal since 1990; therefore, it will not be used or form part of the proposed development. The project has the potential to generate small amounts of pathogens. These pollutants are generally associated with various human activities, but pathogens are also present in natural environments. Moreover, pathogens can be associated with wild and domesticated animal waste. Source control of this potential pollutant is discussed in the following sections. The pollutant categories causing receiving water impairments are bacteria /virus (pathogens) and organic compounds (toxaphene). June 20, 2011 Whitewater River Region WQMP Coral Mountain Apartments In reference to Exhibit B of the Riverside County Water Quality Management Plan for Urban Runoff, the proposed project comprises the following types of development and associated potential pollutant categories. Type of Oxygen Bacteria Oil Development Sediment/ Organic Trash Demanding & & (Land Use) Turbidity Nutrients Compounds & Substances Viruses Grease Pesticides Metals Debris Attached P P N P PM P P(Z) P N Residential Development Parking P(1) P(1) P(4) P P(1) P(6) P P(1) P Lots Streets P P(1) P(4) P P(1) P(6) P P(1) P Abbreviations: P = Potential N = Not potential Notes: (1) A potential pollutant if landscaping or open area exists on the Project site. (2) A potential pollutant if the project includes uncovered parking areas. (3) A potential pollutant if land use involves animal waste. (4) Specifically, petroleum hydrocarbons. (5) Specifically, solvents. (6) Bacterial indicators are routinely detected in pavement runoff. The project's attached residential development, associated parking lot and street improvements have the generalized potential to produce sediment/tubidity; nutrients; organic compounds; oxygen - demanding substances; bacteria and viruses; oil and grease; pesticides and metals. The receiving waters of the project include the Whitewater Evacuation Channel and the Coachella Valley Storm Water Channel. The 2006 CWA Section 303 List of Impaired Water Bodies identifies the eastern segment of the Coachella Valley Storm Water Channel as being impaired by pathogens and toxaphene, but the sources of these pollutants are unknown. A General Description of Potential Urban Runoff Pollutants, provided in the following page, presents background information for the categories of potential project pollutants. Potential Project Pollutants: Sediments /turbidity; nutrients; organic compounds; trash and debris; oxygen demanding substances; bacteria and viruses; oil and grease; pesticides; and metals. Based on the project's listed land use categories in Exhibit 2 in the Whitewater Region Water Quality Management Plan. Legacy Pollutants: According to a Phase I Environmental Site Assessment conducted by Earth Systems Southwest (ESSW) in 2006, a northern portion of the project site served for agricultural operations between 1949 and 1955 approximately. This previous use results in the potential for residues of DDT and other organochlorine pesticides. At the time of the investigation, a trailer park with associated storage areas, a pool and a well site, occupied approximately 3 acres of the 19 +/- acre site. Traces of DDT and organochlorine pesticides were found in the mobile home park areas and former agricultural fields. A Phase II Site Investigation, also conducted by ESSW, revealed that the detected pesticide traces did not surpass the acceptable threshold. The property's historic agricultural uses and trailer park have resulted in residual pesticide levels that could be considered legacy pollutants. June 20, 2011 9 Whitewater River Region WQMP Coral Mountain Apartments • However, the findings reached after two site and soil investigations conclude that the mentioned traces do not appear to represent a significant issue to future development. Pollutants of Concern: The pollutants of concern associated with the proposed project include bacteria /virus and organic compounds. General Description of Potential Urban Runoff Pollutants • Pathogens — Pathogens (bacteria and viruses) are ubiquitous microorganisms that thrive under certain environmental conditions. Their proliferation is typically caused by the transport of animal or human fecal wastes from the watershed. Water, containing excessive bacteria and viruses can alter, the aquatic habitat and create a harmful environment for humans and aquatic life. Also, the decomposition of excess organic waste causes increased growth of undesirable organisms in the water. • Metals — The primary source of metal pollution in Urban Runoff is typically commercially available metals and metal products. Metals of concern include cadmium, chromium, copper, lead, mercury, and zinc. Lead and chromium have been used as corrosion inhibitors in primer coatings and cooling tower systems. Metals are also raw material components in non -metal products such as fuels, adhesives, paints, and other coatings. At low concentrations naturally occurring in soil, metals may not be toxic. However, at higher concentrations, certain metals can be toxic to aquatic life. Humans can be impacted from contaminated groundwater resources, and bioaccumulation of metals in fish and shellfish. Environmental concerns, regarding the potential for release of metals to the environment, have already led to restricted metal usage in certain applications. ■ Nutrients — Nutrients are inorganic substances, such as nitrogen and phosphorus. They commonly exist in the form of mineral salts that are either dissolved or suspended in water. Primary sources of nutrients in Urban Runoff are fertilizers and eroded soils. Excessive discharge of nutrients to water bodies and streams can cause excessive • aquatic algae and plant growth. Such excessive production, referred to as cultural eutrophication, may lead to excessive decay of organic matter in the water body, loss of oxygen in the water, release of toxins in sediment, and the eventual death of aquatic organisms. ■ Pesticides — Pesticides (including herbicides) are chemical compounds commonly used to control nuisance growth or prevalence of organisms. Excessive or improper application of a pesticide may result in runoff containing toxic levels of its active ingredient. ■ Organic Compounds — Organic compounds are carbon - based. Commercially available or naturally occurring organic compounds are found in pesticides, solvents, and hydrocarbons. Organic compounds can, at certain concentrations, indirectly or directly constitute a hazard to life or health. When rinsing off objects, toxic levels of solvents and cleaning compounds can be discharged to the MS4. Dirt, grease, and grime retained in the cleaning fluid or rinse water may also adsorb levels of organic compounds that are harmful or hazardous to aquatic life. ■ Sediments — Sediments are soils or other surficial materials eroded and then transported or deposited by the action of wind, water, ice, or gravity. Sediments can increase turbidity, clog fish gills, reduce spawning habitat, lower young aquatic organisms survival rates, smother bottom dwelling organisms, and suppress aquatic vegetation growth. ■ Trash and Debris — Trash (such as paper, plastic, polystyrene packing foam, and aluminum materials) and biodegradable organic matter (such as leaves, grass cuttings, and food waste) are general waste products on the landscape. The presence of trash and debris may have a significant impact on the recreational value of a water body and aquatic habitat. Excess organic matter can create a high biochemical oxygen demand in a stream and thereby lower its water quality. In addition, in areas where stagnant water exists, the presence of excess organic matter can promote septic conditions resulting in the growth of undesirable organisms and the release of odorous and hazardous compounds such as hydrogen sulfide. ■ Oxygen- Demanding Substances — This category includes biodegradable organic material as well as chemicals that react with dissolved oxygen in water to form other compounds. Proteins, carbohydrates, and fats are examples of biodegradable organic compounds. Compounds such as ammonia and hydrogen sulfide are examples of • oxygen- demanding compounds. The oxygen demand of a substance can lead to depletion of dissolved oxygen in a water body and possibly the development of septic conditions. June 20, 2011 10 Whitewater River Region WQMP Coral Mountain Apartments ■ Oil and Grease — Oil and grease are characterized as high - molecular weight organic compounds. Primary sources of oil and grease are petroleum hydrocarbon products, motor products from leaking vehicles, esters, oils, fats, waxes, and high molecular- weight fatty acids. Introduction of these pollutants to the water bodies are very possible due to the wide uses and applications of some of these products in municipal, residential, commercial, industrial, and construction areas. Elevated oil and grease content can decrease the aesthetic value of the water body, as well as the water quality. June 20, 2011 11 • • is Whitewater River Region WQMP Coral Mountain Apartments IV. Hydrologic Conditions of Concern Local Jurisdiction Requires On -Site Retention of Urban Runoff: Yes ❑ The project will be required to retain urban runoff onsite in conformance with local ordinance (See Table 6, Permittees Requiring Onsite Retention of Stormwater, of the Whitewater River Region WQMP). This section does not need to be completed. No ® This section must be completed. This Project meets the following condition: ® Condition A: Runoff from the Project is discharged directly to a publicly- owned, operated and maintained MS4; the discharge is in full compliance with Permittee requirements for connections and discharges to the MS4 (including both quality and quantity requirements); the discharge would not significantly impact stream habitat in proximate Receiving Waters; and the discharge is authorized by the Permittee. * ❑ Condition B: The project disturbs less than 1 acre and is not part of a larger common plan of development that exceeds 1 acre of disturbance. The disturbed area calculation must include all disturbances associated with larger plans of development. ❑ Condition C: The project's runoff flow rate, volume, velocity and duration for the post- development condition do not exceed the pre - development condition for the 2 -year, 24 -hour and 10 -year 24 -hour rainfall events. This condition can be achieved by minimizing impervious area on a site and incorporating other site - design concepts that mimic pre - development conditions. This condition must be substantiated by hydrologic modeling methods acceptable to the Permittee. ❑ None Refer to Section 3.4 of the Whitewater River Region WQMP for additional requirements. * Note: The function of the proposed storm drain and structural BMP improvements will be to retain the first -flush volume on -site and convey the 100 -year storm flows to the La Quinta Evacuation Channel. The City of La Quinta (City) and the Coachella Valley Water District (CVWD) have allowed the project to discharge storm runoff into the La Quinta Evacuation Channel and the City will not require the project to retain the 100 -year storm on -site. The project will retain the first -flush volume per MS4 requirements. June 20, 2011 12 Whitewater River Region WQMP Coral Mountain Apartments Table 6 - Permittees Requiring Onsite Retention of Stormwater Acquired from Appendix H of the Whitewater River Region Water Quality Management Plan Permittee Ordinance Requirement Cathedral City Municipal Code — Title 8 § A. Except as noted below, development of all land within the city must include 8.24.070 provisions for the management of stormwater runoff from the property which is to be developed. This management shall consist of constructing stormwater storage ' facilities, which includes detention basins. As a minimum, all development will make provisions to store runoff from rainfall events up to and including the one- hundred- year, three -hour duration event. If a suitable outlet for a detention basin is not available, or if engineering analysis indicates that available outlet systems would be overtaxed by detention basin outflow, a retention basin shall be constructed in lieu of a detention basin. B. The requirement for construction of a detention basin or a retention basin may be waived in the following cases: 1. The runoff has been included in a storage facility at another location. This may include storage facilities proposed as part of the Cathedral City Storm Drain Master Plan; 2. An application for a building permit to construct a single - family residential structure; 3. Development which will drain directly into a floodway or watercourse drainage channel which has been determined by the project review manager, using engineering analyses provided by the development, to have the capacity and be constructed to handle the additional runoff flow without increasing the potential for flood damage on any other downstream property. 4. Development of a parcel under one -half acre in an area where it can be demonstrated by engineering analyses that no significant increase in the potential for flood damage will be created by the development. Indio Code of Ordinances — Title Properties of one acre or greater in size shall be designed to retain the 100 -year, 24- XV: Land Usage, §162.140 hour, duration storm on site. Such properties shall retain this duration storm on site or provide a drainage system to convey the drainage to an acceptable retention site as determined by the Director of Public Works. Such a drainage system shall include a provision to fully address disposal of nuisance water to the satisfaction of the Director of Public Works. La Quinta Municipal Code — Title D. Stormwater runoff produced over the peak twenty -four- 13 §13.24.120 hour period of a one - hundred -year storm shall be retained on site unless waived by the city engineer. Engineering Bulletin #06 -16 sets Hydrology and Hydraulic Report Criteria for Storm Drainage Systems. Palm Desert Municipal Code — Title 26 § Developments of ten gross acres or more shall provide sufficient on -site stormwater 26.49.060 retention and /or retardation so as to limit peak runoff during a storm having twenty- five -year intensity to a rate no greater than that which would have otherwise occurred under undeveloped conditions. Palm Springs Municipal Code 9.60.030 (18) (18)The subdivider shall install storm sewer conduits, structures, and appurtenances & (19) (A) when required, in accordance with the master plan of flood control and drainage or by city council direction. (19)(A) The design of lots shall be in accordance with the zoning ordinance, adopted general plans, specific plans and with city policy. Rancho Mirage Municipal Code — Title 15 Properties of one acre or greater in size located northerly of the Whitewater River §15.64.140 Channel shall be designed to retain the one - hundred -year, twenty- four -hour, duration storm on site. Other properties shall retain this duration storm on site or provide a drainage system to convey the drainage to an acceptable disposal site as determined by the city engineer. June 20, 2011 13 Whitewater River Region WQMP Coral Mountain Apartments 0 . V. Best - Management Practices This project implements Best Management Practices (BMPs) to address the Pollutants of Concern that may potentially be generated from the use of the project site. These BMPs have been selected and implemented to comply with the Section 3.5 of the WQMP and consist of Site Design, Source Control and, if /where necessary, Treatment Control BMPs as described herein. V.1 SITE DESIGN AND TREATMENT CONTROL BMPs Local Jurisdiction Requires On -Site Retention of Urban Runoff: Yes ❑ The project will be required to retain urban runoff onsite in conformance with local ordinance (See Table 6, Permittees Requiring Onsite Retention of Stormwater, of the Whitewater River Region WQMP). Section VA does not need to be completed. No ® Section V.1 must be completed. This section of the Project - Specific WQMP documents the Site Design BMPs and, if /where • necessary the Treatment Control BMPs that will be implemented on the Project to meet the requirements within Section 3.5.1 of the WQMP. Section 3.5.1, includes requirements to implement Site Design Concepts and BMPs, and includes requirements to address the project's Pollutants of Concern with BMPs. Further sub - section 3.5.1.1 specifically requires that the projects Pollutants of Concern be addressed with Site Design BMPs to the extent feasible. This project incorporates Site Design BMPs to fully address the Pollutants of Concern where and to the extent feasible. If and where it has been acceptably demonstrated to the Permittee that it is infeasible to fully meet this requirement with Site Design BMPs, this section includes a description of the conventional Treatment Control BMPs that will be substituted to meet the same requirements. • In addressing pollutants of concern, BMPs are selected using Table 2 on the following page. June 20, 2011 14 Whitewater River Region WQMP Coral Mountain Apartments Table 2. BMP Selection Matrix Based Upon Pollutant Removal Efficiency (Excerpted, with minor revision, from the Orange County Water Quality Management Plan dated September 26, 2003 and the San Bernardino Water Quality Management Plan dated April 14, 2004) June 20, 2011 15 Wet Water Hydrodynamic . Manufactured Detention Infiltration Ponds Filtration Quality Separator or Proprietary Pollutant of Biofilters Basins (3) BMPs (4) or Systems (6) Inlets Systems (1) Devices (8) Concern (2) Wetlands (5) Sediment/Turbidity HIM M HIM HIM HIM L HIM U (L for Turbidity) Nutrients L M HIM HIM UM L L U Organic U U U U HIM L L U Compounds Trash & Debris L M U U HIM M HIM U Oxygen L M HIM HIM HIM L L U Demanding Substances Bacteria & Viruses U U HIM U HIM L L U Oil & Grease HIM M U U HIM M LIM U Pesticides U U U U U L L U (non -soil bound) Metals HIM M H H H L L U Note: The Maxwell IV Drainage System functions as both a water quality inlet and a filtration system. The Water Quality Inlet function of the proposed system includes the trapping catch basin (settling chamber) to promote sedimentation of coarse materials. The hydrophobic petrochemical sponge in conjunction with the PurefloT11 debris shield serve as the media filters characteristic of a Filtration System. As a result, pollutant removal efficiency for the Maxwell IV Drainage System is deemed equal to both a Water Quality Inlet and a Filtration System in the table above. Abbreviations: L: Low removal efficiency HIM: High or medium removal efficiency U: Unknown removal efficiency Notes: (1) Periodic performance assessment and updating of the guidance provided by this table may be necessary. (2) Includes grass swales, grass strips, wetland vegetation swales, and bioretention. (3) Includes extended /dry detention basins with grass lining and extended /dry detention basins with impervious lining. Effectiveness based upon minimum 36A8 -hour drawdown time. (4) Includes infiltration basins, infiltration trenches, and porous pavements. (5) Includes permanent pool wet ponds and constructed wetlands. (6) Includes sand filters and media filters. (7) Also known as hydrodynamic devices, baffle boxes, swirl concentrators, or cyclone separators. (8) Includes proprietary stormwater treatment devices as listed in the CASQA Stormwater Best Management Practices Handbooks, other stormwater treatment BMPs not specifically listed in the WQMP, or newly developed /emerging stormwater treatment technologies. June 20, 2011 15 Whitewater River Region WQMP Coral Mountain Apartments • V.1.A SITE DESIGN BMPS The project will employ one Maxwell IV Drainage System (drywell) in conjunction with a Contech underground infiltration system. The Maxwell IV Drainage System will serve as a pre - filtration system in conformance with the City of La Quinta Engineering Bulletin #06 -15. Nuisance and first -flush flows from the entire project will first be conveyed to a settling chamber, where vegetation debris, sediments and other particulates will be retained. Additional nuisance and first -flush flows will be conveyed to an overflow and drainage pipe after passing through an integrated hydrophobic petrochemical sponge and a debris shield. This pre- treatment function will prevent the accumulation, decay and possible gas formation from vegetation debris and other potential pollutants in the subsequent infiltration ( Contech) system. The Maxwell IV Drainage System functions as both a water quality inlet and a filtration system in reference to Table 2 (BMP Selection Matrix on page 14). The Water Quality Inlet function of the proposed system includes the trapping catch basin (settling chamber) to promote sedimentation of coarse materials. The hydrophobic petrochemical sponge in conjunction with the PurefloTM debris shield serve as the media filters characteristic of Filtration System. As a result, pollutant removal efficiency for the Maxwell IV Drainage System is deemed equal to both a Water Quality Inlet and a Filtration System in Table 2 of this report. Pre - treated flows will then enter the Contech infiltration system, which is composed of 8 -foot diameter perforated pipes with a storage capacity in excess of the required volume of 8,700 cubic feet (BMP design volume). Infiltration BMP Structure • Based on Table 2, found in page 13, infiltration BMP structures have high removal efficiency (H) for metals. These structures are also found to have high or medium (H /M) removal efficiency for sediment/turbidity; nutrients; oxygen demanding substances; and bacteria and viruses. Furthermore, infiltration BMPs have unknown (U) removal efficiency for organic compounds; trash and debris; oil and grease; and non -soil bound pesticides. C Water Quality Inlet/Filtration System Based on Table 2 the Water Quality Inlet function of the Maxwell IV Drainage System has a medium (M), removal efficiency for trash and debris and for oils and grease. The removal efficiency for sediment/turbidity; nutrients; organic compounds; oxygen demanding substances; and bacteria and viruses; pesticides; and metals is determined to be low (L). The Filtration System component of the Maxwell IV Drainage System has a high /medium (M /H) removal efficiency for sediment/turbidity; organic compounds; trash and debris; oxygen demanding substances; bacteria and virus; oil and grease. The removal efficiency determined at low /medium (L /M) for nutrients; at undetermined (U) for pesticides; and at high (H) for metals. June 20, 2011 16 Whitewater River Region WQMP Coral Mountain Apartments Table 3. Implementation of Site Design Concepts June 20, 2011 17 Included Brief Reason for BMPs Design Concept Technique Specific BMP Yes No N/A Indicated as No or N/A Conserve natural areas by concentrating or cluster development on the lease environmentally sensitive portions ❑ ❑ ® The entire project site will be developed. of a site while leaving the remaining land in a natural, undisturbed condition. Conserve natural areas by incorporating the goals of the Multi- Species Habitat Conservation Plan or other natural ❑ ❑ ® The entire project site will be developed. resource plans. Preserve natural drainage features and natural depressional ® ❑ ❑ The BMP structures will be placed in the natural storage areas on the site. low points of the project area. Maximize canopy interception and water conservation by preserving existing native trees and shrubs, and planting ❑ ® ❑ Existing vegetation is minimal. �► additional native or drought tolerant trees and large shrubs. 4 Minimize Urban The project site is surrounded by existing v Runoff, Minimize development to the north, east, south and west. Impervious Use natural drainage systems. ❑ ® ❑ The site is partially disturbed as a result of V Footprint, and previous development and does not contain a C Conserve Natural demarcated natural drainage system to be Areas disturbed. .9 d Increase the building floor area ratio (i.e., number of stories ® ❑ ❑ O (See WQMP above or below ground). Section 3.5.1.3) Construct streets, sidewalks and parking lot aisles to W minimum widths necessary, provided that public safety and a ® ❑ ❑ walkable environment for pedestrians is not compromised. Reduce widths of streets where off - street parking is ® ❑ ❑ available. Design driveways with shared access, flared (single lane at ❑ ❑ ® Not a part of the proposed project. street), or wheel strips (paving only under the tires). Minimize the use of impervious surfaces, such as decorative ® ❑ ❑ concrete, in the landscape design. Other comparable and equally effective Site Design BMP (or BMPs) as approved by the Permittee (Note: Additional ❑ 11 narrative required to describe BMP and how it addresses site design concept). June 20, 2011 17 June 20, 2011 18 Whitewater River Region WQMP Coral Mountain Apartments Table 3. Site Design BMPs (continued) Included Design Brief Reason for Each BMP Concept Technique Specific BMP Yes No N/A Indicated as No or N/A Residential and commercial sites must be designed to contain and infiltrate roof runoff, or direct roof runoff to vegetative swales or buffer ❑ ❑ ® To be determined in the Final Design. areas. Drain impervious sidewalks, walkways, trails, and patios into adjacent • landscaping. ® ❑ ❑ Incorporate landscaped buffer areas between sidewalks and streets. ® ❑ ❑ Uncovered temporary or guest parking on residential lots paved with a permeable surface, or designed to drain into landscaping. ❑ ❑ ® Not part of the proposed project design. Rural swale system: street sheet flows to vegetated swale or gravel shoulder, curbs used at street corners, and culverts used under ❑ ❑ ® Not part of the proposed project design. N driveways and street crossings. Urban curb /swale system: street slopes to curb; periodic swale inlets drain to vegetated swale or biofilter. E] ❑ ® Not part of the proposed project design. 4 O V C 0 Minimize Directly Connected Impervious Area (See WQMP Section 3.5.1.4) Dual drainage system: first flush captured in street catch basins and discharged to a proposed underground retentions stem. ® ❑ ❑ Maximize the permeable area by constructing walkways, trails, patios, overflow parking, alleys, driveways, low- traffic streets, and other low - traffic areas with open - jointed paving materials or permeable surfaces such as pervious concrete, porous asphalt, unit pavers, and granular materials. ❑ ® ❑ Not part of the proposed project design. Use vegetated drainage swales in lieu of underground piping or imperviously lined swales. ® ❑ ❑ CO) Incorporate parking area landscaping into the drainage design. ® ❑ ❑ Where soil conditions are suitable, use perforated pipe or gravel filtration pits for low flow infiltration. ❑ ❑ ® Not part of the proposed project design. Construct onsite infiltration BMPs such as dry wells, infiltration trenches, and infiltration basins consistent with vector control ® ❑ ❑ objectives. Construct onsite ponding areas or detention facilities to increase opportunities for infiltration consistent with vector control objectives. ® ❑ ❑ June 20, 2011 18 Whitewater River Region WQMP Coral Mountain Apartments Included Brief Reason for Each BMP Design Concept Technique Specific BMP Yes No N/A Indicated as No or N/A The Coachella Valley's historic annual rainfall is not significant enough to generate sufficient roof runoff to sustain the adequate collection in cisterns or barrels. According to the National Oceanic and Atmospheric N Direct roof runoff into cisterns or rain barrels for reuse. ❑ ® ❑ Administration, the average total precipitation for this portion of the valley is a Q Minimize Directly 3.28 inches per year. This low amount of 1Z Connected annual rainfall would cause a prospective (j a Impervious roof runoff collection system to become C Area underutilized. The mentioned collection system is not feasible for this project. to Q_ (See WQMP O Section 3.5.1.4) Use vegetated drainage swales in lieu of underground piping or ❑ ❑ ® Not part of the proposed project design. w; imperviously lined swales. y Incorporate tree well filters, flow- through planters, and /or bioretention E] E] ® The proposed water quality inlet/filtration system does not incorporate trees or tree areas into landscaping and drainage plans. well filters. Other comparable and equally effective Site Design BMP (or BMPs) as by the Permittee Additional El No additional Site Design BMPs are used in approved (Note: narrative required this project. describing BMP and how it addresses site design concept). June 20, 2011 19 • Project Site Design BMPs: • Whitewater River Region WQMP Coral Mountain Apartments See Appendix B for site design BMP placement and volume capacity details. June 20, 2011 20 Whitewater River Region WQMP Coral Mountain Apartments Table 4. Site Design BMPs Meeting the Measureable Goal in WQMP Section 3.5.1.1 (1) (2) (3) (4) (5) (6) DRAINAGE SITE DESIGN POLLUTANTS WITHIN SUBAREA RELATIVE EFFECTIVENESS BMP MEETS BMP SUBAREA BMP TYPE * 'CAUSING RECEIVING WATER OF BMP (COLUMN 2) AT WHICH DESIGN TRIBUTARY ID OR NO. IMPAIRMENTS ADDRESSING IDENTIFIED CRITERIA? AREA POLLUTANTS (COLUMN 3) (See Table 2) (refer to Table 1) (U, L, M, HIM, H; see Table 2) (identify as VBMP OR QBMP) (nearest 0.1 acre) B— PRE - FILTRATION BACTERIANIRUS: H/M — HIGH OR MEDIUM 8,700 CU. FT. (Vamp) STREET A AND INFILTRATION ORGANIC COMPOUNDS: REMOVAL EFFICIENCY 1.22 C_ PRE - FILTRATION BACTERIANIRUS: HIM — HIGH OR MEDIUM 8,700 CU. FT. (Vamp) MULTI - FAMILY AND INFILTRATION ORGANIC COMPOUNDS: REMOVAL EFFICIENCY 9.44 RESIDENTIAL TOTAL AREA TREATED WITH SITE DESIGN BMPS NEAREST 0.1 ACRE)" 10.66 Note: All project first -flush runoff (8,700) is directed to a single location containing the proposed Maxwell IV Drainage System (pre - filtration) and Contech infiltration system. * Site Design 13MPs included in this table are those that completely address the Treatment Requirements for their tributary area. June 20, 2011 21 Whitewater River Region WQMP Coral Mountain Apartments • Justircation of infeasibility for sub -areas not addressed with effective Site Design BMPs in Table 4: • C, V.1.13 TREATMENT CONTROL BMPs Conventional Treatment Control BMPs shall be implemented to address the project's Pollutants of Concern as required in WQMP Section 3.5.1 where, and to the extent that, Section VA.A has demonstrated that it is infeasible to meet these requirements through implementation of Site Design BMPs. ® The Site Design BMPs described in Section VA.A of this project - specific WQMP completely address the Pollutants of Concern for the entire project site as required in Section 3.5.1.1 of the WQMP. Supporting documentation for the sizing of these Site Design BMPs is included in Appendix F. *Section V.1.6 need not be completed. ❑ The Site Design BMPs described in Section V.1.A of this project - specific WQMP do NOT completely address the Pollutants of Concern for the entire project site as required in Section 3.5.1.1 of the WQMP. *Section V.1.6 must be completed. The Treatment Control BMPs identified in this section are selected, sized and implemented to address the Pollutants of Concern for all project sub -areas where these pollutants were not fully addressed with Site Design BMPs. Supporting documentation for the sizing of these Treatment Control BMPs is included in Appendix F. June 20, 2011 22 Whitewater River Region WQMP Coral Mountain Apartments Table 5: Treatment Control BMP Summary (1) (2) (3) (4) (5) (6) DRAINAGE TREATMENT POLLUTANTS POTENTIALLY RELATIVE EFFECTIVENESS BMP MEETS BMP SUBAREA CONTROL GENERATED WITHIN SUBAREA OF BMP (COLUMN 2) AT WHICH DESIGN TRIBUTARY ID OR NO. BMP TYPE CAUSING RECEIVING WATER ADDRESSING IDENTIFIED CRITERIA? AREA IMPAIRMENTS* POLLUTANTS (COLUMN 3) (IDENTIFY AS VBMP OR (NEAREST 0.1 (SEE TABLE 2) (REFER TO TABLE 1) (U, L, M, H /M, H; SEE TABLE 2) QBMP) ACRE) • WATER HIM - HIGH OR MEDIUM QUALITY INLET/ BACTERIANIRUS: REMOVAL EFFICIENCY B— FILTRATION 8,700 CU. FT. (VBMP) 1.22 STREET A SYSTEM ORGANIC COMPOUNDS: • INFILTRATION SYSTEM • WATER HIM - HIGH OR MEDIUM C QUALITY INLET/ N BACTERIAIRUS: REMOVAL EFFICIENCY FILTRATION 8,700 CU. FT. ( VBMP ) 9.44 MULTI - FAMILY SYSTEM ORGANIC COMPOUNDS: RESIDENTIAL • NFILTRATION SYSTEM TOTAL AREA TREATED WITH TREATMENT CONTROL BMPS NEAREST 0.1 ACRE ** 10.66 Note: All project first -flush runoff (8,700) is directed to a single location containing the proposed Maxwell IV Drainage System (pre - filtration) and Contech infiltration system. June 20, 2011 23 • Whitewater River Region WQMP Coral Mountain Apartments V.1.0 MEASUREABLE GOAL SUMMARY This section documents the extent to which this project meets the measureable goal described in WQMP Section 3.5.1.1 of addressing all of the projects Treatment Requirements with Site Design BMPs. Table 6: Measureable Goal Summary Instructions: Column (1) Enter the sum of the BMP Tributary Areas from Table 4 Column (2) Enter the sum of the BMP Tributary Areas from Table S Column (3) Calculate the %-of the Treatment Requirement that was addressed with 0 BMPs. Site Design (3) _ (1) * 100 1(1)+(2) • 66) Site Design BMP's. (3) _ (10. * 100 =50% 1(10.66)+(10.66)] June 20, 2011 24 F (2) (3) % of Treatment Total Area Treated with Total Area Treated with Requirement addressed Site Design BMPs Treatment Control BMPs with Site Design BMPs 10.66 10.66 50 Instructions: Column (1) Enter the sum of the BMP Tributary Areas from Table 4 Column (2) Enter the sum of the BMP Tributary Areas from Table S Column (3) Calculate the %-of the Treatment Requirement that was addressed with 0 BMPs. Site Design (3) _ (1) * 100 1(1)+(2) • 66) Site Design BMP's. (3) _ (10. * 100 =50% 1(10.66)+(10.66)] June 20, 2011 24 F Whitewater River Region WQMP Coral Mountain Apartments V.2 SOURCE CONTROL BMPs This section identifies and describes the Source Control BMPs; applicable and implemented on this project. Table 7. Source Control BMPs BMP Name Check One If not applicable, state brief reason Included App licable Non - Structural Source Control BMPs Education for Property Owners, Operators, Tenants, Occupants, or Employees ® ❑ Activity Restrictions ® ❑ Irrigation System and Landscape Maintenance ® ❑ Common Area Litter Control ® ❑ Street Sweeping Private Streets and Parking Lots ® ❑ Drainage Facility Inspection and Maintenance ® ❑ Structural Source Control BMPs MS4 Stenciling and Si na e ® ❑ Landscape and Irrigation System Design ® ❑ Protect Slopes and Channels ® ❑ Provide Community Car Wash Racks ❑_ ® Not part of the proposed project uses. Properly Design*: _ Fueling Areas El ® Not part of the proposed project uses. Air/Water Supply Area Drainage ❑ ® Not part of the proposed project uses. Trash Storage Areas ® ❑ Loading Docks ❑ ® Not part of the proposed project uses. Maintenance Bays ❑ ® Not part of the proposed project uses. Vehicle and Equipment Wash Areas ❑ ® Not part of the proposed project uses. Outdoor Material Storage Areas ❑ ® Not part of the proposed project uses. Outdoor Work Areas or Processing Areas ® ❑ Provide Wash Water Controls for Food Preparation Areas ❑ ® Not part of the proposed project uses. *Details demonstrating proper design must be included in Appendix F. June 20, 2011 25 Whitewater River Region WQMP Coral Mountain Apartments Non - Structural Source Control BMPs Education Program: The primary non - structural source control BMP for the proposed project will involve an education program. Residents will be informed on topics related to stormwater pollution and prevention through various means, which can include the distribution of printed materials or public posting of rules or activity restrictions. A series of guidelines should be formulated and promoted to communicate beneficial habits and restricting harmful activities. For example, pet waste clean -up shall be required and littering prohibited. Appendix D includes samples of the educational materials that can be used in implementing this project - specific WQMP. Activity Restrictions: Activity restriction shall include requiring pet waste clean -up. Littering shall be prohibited. All discharge and waste dumping shall. be prohibited. Nuisance water flows from irrigation shall be prohibited. Furthermore, blowing, sweeping or hosing debris into streets will not be permitted. Irrigation System and Landscape Maintenance: Operation and Maintenance responsibilities and scheduling will be adhered to throughout the life of the project. Issues such as broken irrigation equipment shall be repaired immediately. Continued irrigation and landscape maintenance will increase the effectively of these systems. Runoff and any associated effects, including erosion and pesticide /fertilizer conveyance, will be minimized through the employment of proper maintenance. Common Area Litter Control • Landscaping maintenance staff shall be instructed to follow proposed schedule of common area maintenance. Littering will be prohibited throughout the development. Street Sweeping of Private Streets and Parking Lots Landscaping maintenance staff shall be instructed to sweep streets or conduct the specific measures called out in the maintenance schedule. Drainage Facility Inspection and Maintenance Employees will immediately repair malfunctioning facilities. Inspection and Maintenance of facilities will maintain the effectiveness of the BMP's. Structural Source Control BMPs MS4 Stenciling and Signage Storm drain signage will be placed in appropriate locations to prohibit discharge and waste dumping into storm water inlets and storm channels in the project area. The signage may include a written expression that explicitly prohibits the discharge or dumping. Landscape and Irrigation System Design The site's structural source control BMP involves an efficient landscape irrigation design, which will be consistent with the City of La Quinta Irrigation Water Efficient and Irrigation System Design (Chapter 8.13). The project will employ the following water consumption reduction methods • • Drought tolerant landscaping June 20, 2011 26 Whitewater River Region WQMP Coral Mountain Apartments • Drip landscape irrigation The drought tolerant landscaping, in combination with the proposed .drip landscape irrigation, will minimize the potential for runoff of excess irrigation water (nuisance water) into the stormwater conveyance system. It will also work to reduce soil amendments and irrigation frequency. Furthermore, the system will minimize the conveyance of landscape related chemicals, including fertilizers and pesticides. Trash Storage Area The project will incorporate the proper design of trash storage areas to prevent spills, leakage and contamination of runoff or soils. For example, trash containers will be leak -proof with attached lids. The project will have five trash storage locations distributed throughout the apartment complex. V.3 EQUIVALENT TREATMENT CONTROL ALTERNATIVES Not applicable V.4 REGIONALLY -BASED TREATMENT CONTROL BMPS Not applicable June 20, 2011 27 • C Whitewater River Region WQMP Coral Mountain Apartments VI. Operation and Maintenance Responsibility for BMPs Operations and maintenance requirements for all structural Source Control and Treatment Control BMPs shall be identified in the final project - specific WQMP Report. TABLE 8 - OPERATIONS AND MAINTENANCE BMP Requiring Party Inspection Implementation Maintenance Maintenance Maintenance Responsibility Frequency Period Frequency Requirements Landscaped As necessary based on Areas To be determined observations made in the Final Twice monthly Post - Construction during inspection or (See following WQMP per approved page) landscaping maintenance plan Irrigation As necessary based on Systems To be determined observations made (See following in the Final Twice monthly Post - Construction during inspection or Page) WQMP. per approved irrigation plans Trash Storage To be determined Based on trash- (See following Areas in the Final pick -up intervals Post- Construction Twice monthly page) WQMP. Storm Drain To be determined Quarterly and As necessary based on (See following in the Final After storm events Post - Construction observations made Page) WQMP during inspection Maxwell IV As necessary based on Drainage System To be determined According to the observations made According to the in the Final manufacturer's Post - Construction during inspection or as manufacturer's WQMP. specifications specified by specifications manufacturer Contech As necessary based on Underground To be determined According to the observations made According to the Infiltration in the Final manufacturer's Post - Construction during inspection or as manufacturer's System WQMP. specifications specified by specifications manufacturer June 20, 2011 28 Whitewater River Region WQMP Coral Mountain Apartments Description of Maintenance Requirements: Landscaped Areas: All trimming, pruning, and removal of fallen organic material from plants, shrubs, and trees is to be collected twice monthly, stored in an appropriate location and transported to an approved green -waste collection facility approved by the City of La Quinta and the County of Riverside. The planting materials are to remain as indicated on the approved set of landscape planting plans. These approved plant species require very limited to no use of fertilizer, herbicide and pesticide. Irrigation Systems: Water conservation is to be maintained at all times per approved irrigation plans. Monitoring of the irrigation system is to be provided twice monthly to ensure that appropriate watering levels are maintained as well as to verify that no piping, or irrigation heads are leaking. Debris /sediment/mineral deposits are to be removed from the irrigation system at regular intervals -to provide consistent watering levels. Trash Storage Areas: Each area is to be cleaned twice monthly. All trash is to be placed in the approved trash bins. No trash is allowed to be stored at the base of the bins. Pick -up intervals are to be determined so that the dumpsters are not overfilled. Only approved materials and chemicals are to be allowed to be placed in the dumpsters. Storm Drain: Inlets, outlets, basins, cleanouts, manholes, and pipelines are to be inspected quarterly and after each storm event. All parts of the system are to be periodically cleaned to ensure that the system works properly during any storm event. Maxwell IV Drainage System: All maintenance operations shall be performed according to the manufacturer's guidelines or specifications. Maintenance procedures will be provided in the Final WQMP. Contech Underground Infiltration System: All maintenance operations shall be performed according to the manufacturer's guidelines or specifications. Maintenance procedures will be provided in the Final WQMP. June 20, 2011 29 0 VII. Funding • Whitewater River Region WQMP Coral Mountain Apartments To be provided as part of the Final Water Quality Management Plan June 20, 2011 30 I• a �.0 : Whitewater River Region WQMP Coral Mountain Apartments Appendix A Conditions of Approval Planning Commission Resolution Dated Whitewater River Region WQMP Coral Mountain. Apartments Appendix B Vicinity Map, WQMP Site Plan, and Receiving Waters Map • �tra PI r - -.- - COACHELL.i "ORMWATER ( COACHELLA \� ME 21, MSA CONSULnNG, INC. Pi.AMa ■ CrM B11004MIM ■ L"D &reeaxM 34200 Ba Elm Deus ■ RAmm himum • CA 91270 05/17/2011 1z,mmmCM 320M - PAZ (MO) 323 -7M 9. aw t MSA CONSULnNG, INC. Pi.AMa ■ CrM B11004MIM ■ L"D &reeaxM 34200 Ba Elm Deus ■ RAmm himum • CA 91270 05/17/2011 1z,mmmCM 320M - PAZ (MO) 323 -7M James W. Cornett — Ecological Consultants June 4, 2011 Ms. Michelle Witherspoon Director of Planning and Environmental Services MSA Consulting, Inc. 4200 Bob Hope Drive Rancho Mirage, California 92270 Subject: Coral Mountain Affordable Housing Proposed Storm Drain Site Biological Evaluation Dear Ms. Witherspoon: On June 1, 2, and 3, 2011, I conducted biological surveys to determine the presence of sensitive plant or animal species and the existence of a riparian or other rare plant community within a portion of the La Quinta Evacuation Channel (LQEC) located in the city of La Quinta, Riverside County, California. In addition, I determined the extent or existence of a high water line within • the channel. Description of Study Area The entire study area is approximately 5 acres (see Figure 1 attached to this document). The primary area of possible disturbance lies within the LQEC, a manmade earthen channel. The channel sides and bottom consist of fine sand and silt. The channel evacuates storm runoff from lands to the south including runoff from streets, yards and commercial properties. The entire channel, both above (northeast) and below (southwest) of the study site area, has been recently graded. As a result there is very little plant biomass within the boundaries of the project site. No surface water occupies any area of the site. Elevation is approximately 60 feet above sea level. The site is surrounded by development. A Costco store lies immediately to the north. A residential development is located to the east. The district offices of Desert Sands Unified School District form the western boundary. A golf course is situated south of the project site. Methods Both the primary and secondary project areas (see Figure 1 attached to this document) were surveyed on foot by walking transects parallel with the direction of the channel. Trsects were spaced at 10 meter intervals. • High Water Line The entire channel, both above (northeast) and below (southwest) the study area, has been graded recently. Therefore, there are no vegetational indicators of any category of water presence. In addition, the recent grading has eliminated geomorphologic evidence of the existence of water — there are no discernable areas of silt deposition, cut banks or stream courses. Plant Life In spite of the recent grading, a number of plant species were detected within the site boundaries. All of these may be considered pioneer species that have the ability to rapidly colonize disturbed areas such as the graded project site. No plant species considered sensitive by any agency were discovered and none are expected. In addition, there was no evidence of any riparian plant community or any other rare plant association. The plant survey was conducted in late spring when most plant species would be in evidence. A complete list of plant species encountered can be found in Table 1 attached to this document. Animal Life Animal surveys were done simultaneously with plant surveys. A special effort was made to detect the presence of the burrowing owl, a sensitive species. Although the habitat was considered suitable no owls were observed and there was no evidence of their presence. No other sensitive animal species were observed or detected. The animal surveys were conducted in late spring when all resident vertebrate species would be active and detectable. A complete list of every vertebrate species observed or detected can be found in Table 2 of this document. Conclusions The inability to detect any sensitive plant or animal species or a riparian or any other rare plant community resulted in the conclusion that modification of the project site will not have a significant adverse impact upon any species or community. Therefore, there are no recommendations for mitigation. Sincerely, ��4 James W. Cornett " Red Box 846 Palm Springs CA 92263 760 - 320 -8135 �� y � ipih�l urw � 4i' r, il, II IIII ��li i" x PLANT SPECIES RECORDED CORAL MOUNTAIN AFFORDABLE HOUSING In.. PROPOSED STORM DRAIN SITE A. ANGIOSPERMAE - DICOTYLEDONES AMARANTHACEAE - AMARANTH FAMILY a Amaranthus palmeri — Palmer Amaranthus Tidestromia oblongifolia — Honeysweet AST CEAE - SUNFLOWER FAMILY Conyza canadensis - Horseweed Dicoria canescens - Desert Dicoria Helianthus annuus — Common Sunflower Palafoxia arida - Spanish Needle Sonchus oleraceus — Sow - thistle - f .ra p BORAGINACEAE - BORAGE FAMILY Cryptantha angusti folia - Narrow - leafed Forget -me -not g Heliotropium curassavicum — Alkali Heliotrope BRASSICACEAE - MUSTARD FAMILY Brassica tournefortii - Sahara Mustard Sisymbrium irio — London Rocket HENOPODIACEAE - GOOSEFOOT FAMILY Atriplex canescens - Wingscale Chenopodium sp. - Goosefoot Salsola tragus - Russian Thistle EUPHORBIACEAE - SPURGE FAMILY Croton californicus - Desert Croton Chamaesvice polycarpa - Sand -mat Ir FABACEAE -PEA FAMILY Psorothamnus emoryi - Emory Dalea GERANIACEAE - GERANIUM FAMILY MIhmErodium cicutarium - Filaree • TABLE 1 (Continued) NYCTAGINACEAE - FOUR-O'CLOCK FAMILY Abronia villosd — Sand Verbena . .: Allionia incarnata — Windmills . PLANTAGINACEAE - PLANTAIN FAMILY Plantago insularis - Plantain SOLANACEAE - NIGHTSHADE FAMILY Datura metdloides - Jimson Weed . TAMARICACEAE - TAMARISK FAMILY Tamdrix ramosissima —.Shrub Tamarisk ZYGOPHYLLACEAE - CALTROP FAMILY Tribulus terrestris - Puncture Vine • ANGIOSPERMAE MONOCOTYLEDONES POACEAE - GRASS FAMILY Avena fatua — Wild Oat Bromus Madritensis - Foxtail Grass Cynodon dactylon - Bermuda Grass . Polypogon monspehensis - Rabbitfoot Polypogon Schismus barbatus - Abu- niashi • TABLE 2 EXPECTED BREEDING OR OBSERVED VERTEBRATES CORAL MOUNTAIN AFFORDABLE HOUSING PROPOSED STORM DRAIN SITE REPTILES GEKKONIDAE - GECKOS Coleonyz variegatus - Western Banded Gecko ? IGUANIDAE — IGUANIDS Dipsosaurus dorsalis - Desert Iguana PHRYNOSOMATIDAE — HORNED, SPINY, EARLESS LIZARDS Uta stansburiana - Side - Blotched Lizard * TEIIDAE - WHIPTAILS Cnemidophorus tigris - Western Whiptail LEPTOTYPHLOPIDAE - BLIND SNAKES Leptotyphlops humilis - Western Blind Snake ? COLUBRIDAE - COLUBRIDS Chionactis occipitalis - Western Shovel -nosed Snake ? FALCONIDAE - FALCONS Falco sparverius - American Kestrel PHASIANIDAE - QUAIL Callipepla gambelii - Gambel's Quail COLUMBIDAE - PIGEONS AND DOVES Columba livia - Rock Dove * Zenaida macroura - Mourning Dove • CUCULIDAE - CUCKOOS Geococcyx californianus - Greater Roadrunner CAPRIMULGIDAE - NIGHTJARS Chordeiles acutipennis - Lesser Nighthawk TROCHILIDAE — HUMMINGBIRDS Calypte costae - Costa's Hummingbird * TYRANNIDAE - TYRANT FLYCATCHERS Sayornis saya - Say's Phoebe Tyrannus verticalis — Western Kingbird CORVIDAE - CROWS AND JAYS Corvus brachyrhynchos — American Crow Corvus corax = Common Raven MIMIDAE - MOCKINGBIRDS AND THRASHERS Mimus polyglottos - Northern Mockingbird. EMBERIZIDAE - WOOD WARBLERS, TANAGERS, SPARROWS • Euphagus cyanocephalus — Brewer's Blackbird Quiscalus mexicanus — Great - tailed Grackle PLOCEIDAE WEAVER FINCHES Passer domesticus - House Sparrow FRINGILLIDAE - FINCHES Carpodacus mexicanus - House Finch MAMMALS VESPERTILIONIDAE - EVENING BATS Pipistrellus hesperus - Western Pipistrelle MOLOSSIDAE - FREE- TAILED BATS Tadarida brasiliensis - Brazilian Free- tailed Bat • LEPORIDAE - HARES AND RABBITS Lepus californicus — Black- tailed Jackrabbit Sylvilagus audubonii - Audubon Cottontail SCIURIDAE - SQUIRRELS Spermophilus beecheyi - Beechey Ground Squirrel ? Spermophilus tereticaudus chlorus — Coachella Valley Ground Squirrel ? GEOMYIDAE — POCKET GOPHERS, POCKET MICE, KANGAROO RATS Thomomys bottae - Botta's Pocket Gopher MURIDAE — RATS, MICE, VOLES Mus musculus — House Mouse Peromyscus maniculatus - Deer Mouse:* CANIDAE - FOXES, WOLVES, AND COYOTES Canis latrans - Coyote MUSTELIDAE - WEASELS AND SKUNKS Mephitis mephitis — Striped Skunk * = Sign or individual observed on or near site during field surveys. ? = Possible occurrence on or near site; not detected during survey. 57.5 (1� \ Y x 6 \3 -------- - - - - -- 1 x - X9.5 x 57.6 NO (5 4)t 56.5 x 0 0 I I 1- 0 57.6 f ( X51 ° L _ NO 55.5 00' l 54.3 NO 56.40 58.1 � x� 5 r DG r M � I OI 1/ x ` \ FFT '5� f .56,.0 G 153. / 15 / 5 5. 2 sJ I .132 , 1 56.40 1 ' FS NG 2x-307. 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I PE =55.8 a_ 1 5 ' 656.20 l x z 58.3 f NG ,n 0 I 58.2 NO LEGEND LEGEND CONTINUED xx.x EXISTING SPOT ELEVATIONS = = = -=(�/ -7 = = -_-= EXISTING CONTOURS 206 NODE NUMBER EXISTING BOUNDARY 64.5 ELEVATION EXISTING LOT LINE - - - - - - - - - - - EXISTING EASEMENT /BUILDING SETBACK PROPOSED MAXWELL IV / R/w EXISTING RIGHT OF WAY WATER QUALITY INLET FILTRATION SYSTEM - -E EXISTING ELECTRIC (SEE SHEET 2 OF 2) _G- EXISTING GAS T EXISTING TELEPHONE s EXISTING SEWER PROPOSED CONTECH - -w EXISTING WATER RETENTION SYSTEM A (SEE SHEET 2 OF 2) m m PROPOSED ADA PATH OF TRAVEL - PROPOSED AND EXISTING CENTER LINE MINIMUM PROPOSED CURB TC 00.00 FL 00.00 PROPOSED ELEVATIONS - - PROPOSED RIGHT OF WAY S PROPOSED SEWER SD PROPOSED STORM DRAIN ❑❑ PROPOSED CATCH BASIN ❑ PROPOSED STORM DRAIN INLET O PROPOSED STORM DRAIN INLET OPROPOSED FINISHED FLOOR STORM DRAIN MANHOLE W PROPOSED WATER TOP OF FOOTING PROPOSED WATER METER TOP OF GRATE PROPOSED FIRE HYDRANT a PROPOSED DETECTOR CHECK /FDC & PIV TOP OF RETAINING WALL TRIBUTARY DRAINAGE AREA BOUNDARY B10 DRAINAGE SUB -AREA ID L °207 FLOW TRAVEL LENGTH (FT) Am0.9 AREA (AC) X. MAXIMUM PROPOSED TYPICAL TRASH ENCLOSURE PROPOSED TYPICAL APARTMENT BUILDING / UNIT _11 1 56.6 56.6 1 56.4 1� 57.3 57.1 x x x 1 x � x 56.3 Q100= 21.88cfs 110 1 ��o 50 -7 JW - r FUTURE 6OMMERCIAL SITE ASP 5 Qto= 11.56cfs 66.1 ` 9 I I� `� , 105 Qtoo= 2�.55cfs 1 ss. Q10= 1,1.91cfs ' __ �� pQR��L� t/- L�LQ 200 X O-00 0 A56. 37 58.1 I I /� �n I� � 1� TW 37.� f LIJ \ 54.4 Aplm 000 °020_09 Qtoo= 2.03cfs 220 x x 57.4 k 58.2 FG 56. f- 5\4.1 r;_ \ 200 56.4 Q1o= 1.07cfs 64.9 /210 "- Qto0= 3.00cfs ` l -' fV TC 5596 PROP -. ATC-H- BASIN- 64.9 _ Qto= 1,58cfs TC 55.47 56.0 r` _ TC 55.13 LIJ x, r, . FL 54.97 J FL 55.46 / FO 5� 06 551 J �1 M L ! 56.4 � FL 54 63 56.3 - - -- �._ _ ------ f - - - _.r.. x - S6 /_ TO` -- L wt� 1 56.8 216 - _ - - -_ x l J 55 39 I ~" p 55.95C) 56.5 - W 55.05 50 VC` 5S 29 x+ �\ 58.2 4.85 TC A TP - p1 - 177 5.1PVI -HP N�90 °00'00•• E 264.78 - 3 - _TP ,- I X0.55%/ PVI -�� ry F� S 600 1 I TW 57.5 \ - I m190 - 5•Sp 1 \ TF 54.0 /J L 190 =1 ' 0.55 %�- 54 2Amd.19 � ' 55.4 �' 2'S � =3p�-X B 5 1 C 56.46 \ x Am019 S Sg / TP 56.06 - - \ _... a rz Mn � s€, I w0l a aj a 1 a U A s IM W3 l A m am £u'A � xa rim sm _ 4 wo ,was � ua�t �� a a � � �� _ / 92 \ a ._ _ ° • , 4' 16. Tp 5 0 56.21 W TC 55.47 - `TC .55.96 x TC 5 1 p9�R =app TP -GB x FL 54.97 �� FL 55.46 x / Ls 4 1.60% 0.3790 I jr, 56.36 \ �- - - =� 5 SS.2g TC 56 - -- - - - - - - -- FL Op -- _- �ROP. BLOCK WA L - % ass I - - 820 - / \ �s.sp L6 L \� LO w TC 56.10 TO 56.0 _ 55.68 1 I x �x > �\ /' PROP\BUIL[51NG \ w �� 55.08 TP 55.50 o 1 �� / j - 58.2 V /` SETBACK LINE PROP. UILDING 56.47 �° u� 1 / A �v o` 54.8 o r0 x TW 61.6 - -� x \ � SETBAC INE FS x ° . n TO 55.8 TF 5 .3 t T \ 56. :� 54.8 \ Z w 54.8 Tf' 55.3 1__ x L ^�+ rGr 5 w o \ \ Q \ ri --r-i �6.1j f Ln 56.40 - - 56.90 FF= 57.00 \ S75 \ !, 1.50% o% N _- s FS = 57.4 \ FS x t 56.50 �_, PE =56:5 w / 68.0 _ �--G) li ao ao a -56-.47- - ' - TP 55681.E ,n ui ! / l.._ - - 1 s \ u - L - cvj '� 1.8 ,�,, v a +I FS vti�" \ b\ / ~ _✓ / l / `L� ��J� 56.47 `x 53.3 �° n x _- - - / 56.00 ti `� 56.00 \ y0 �° FS �! 6 t, ° w ` L,. FS T� 55.60 001 ti�� y 56.00 , \ - �/ �x co co ,°n1 55.8 I TO 55.70 J `5 of 56.50 FS \ / 2 °d 01 7 �9 TP 55.20 , _ _ �� J i � � ' FS �5 .4 . 3.1 LDG_ rFr r n � j 56.1 t l� �- aa -:� r , r as 0.50% ! 57.00 FF x56.50 ��- - o NG - - - --� 55.95 PE =56.0 (��'' 5(.6 I 1L .89 � `�. % 9 b� � ,� / 6.95 t ,- _....•` FS ---- -- r --' � ° 1 Iw I o,T 55 32 TO 55.3 _ `� /� r FS x x �' ry 1.8 b\ x TP 54.8f �� ' TC 56.15 X6.47 56.4�� c� ` T 54 82 ® 55. 8 �xFS 2.16% o v� \1-. PROP. 51523 WAT�(Z 1.50% 4 55.65 :.� I 56.2 ,. 9 / I +1 --- -� - ... 4.8 ` 1 rriTT m ,' / 4n m rr ° x ` 1 / FS 56.00- W _ _ - TO 55.71 W �' { 2.48% FS FS ' 1 m30 54 53 2.0.0% N o r:::. - - 1 53.8 r _ - - -` - - - l� 0 , ' -`- 56.47 fL�8% ,p --- C° TC 55 3 ` 5Si.85� 56.47 FS �Am1.1 LL Z L TP 55.23 53.5 1 y TC 55.31 j 51.7 FS .85 ° I-- " -x w LU �- 1.50 / , ; --i 1.69 ol - TP 54.81 _ _ __ x x -w �✓ TC 56.V4 1 x 5�8 �n,n 56+ 53 4 / PROP PLAYGR ND i { r` cv -- ti' x TC 54.39 54 41 TP 55.54 52. b; ` - FL 53.89 9 TC- Pi4. 3 1fC 5.3f ° FL - ` I �� ' nn Z Cam] _ I _ 1: 1 % TC 55.98 ___. 51. r-r-i 1.99% TP 54:8'1 TP 55.31 � �. `-�v .� :o -+; - TP 55.48 ❑ 88% ® � \® , / 55.80 I 51.E FL o o _;� (L o TC 55.26 1.50% ��R ° FS u, 0 _ -- 54.4 0 T,C \55.73\ i° TP 55.23 `52`6 (Lm425- J.7. ° �J- x 1 1 _� ` 2 q 11.2, �.._ y If J; x x� _ 2: \ 1'A x.06 �w� _�� , �° 1.52 %TC 55.57 5 2 56.27 _ _ �� _ Q 0 5.5 TP 5 07 1 /42% ` ° & 1.93% ° NG t FS� FSi TC 55.69 ° ° \ 55.80 �- TP 55.19 - mmT ) `nTrrrT 55.8 �� j Q q r TO 55.04 m 54.18 Q / 52.7 3 Of w F5_ �' x � I w TP 54.54 1.509 FL '-�� ,wsls� x / 2�' °1 \ 555 �. 55.70 x Q o Qyoo= 15.17cf I 54.3 s 9 2.42% / .49% < 1 = Qpo= 188cfs �', c� T f _.6 FS x TO 54.95 TR 55.05 55.80 56 7 �9 56.27 2.2 �` b` o I V 7 I TP 54.45 FS ° FS ° 52.8w L �° N o �� TC 55.71 > F - � TR 55,21 . 25 I 2.00% / 4 _._.._ LDG rH ( 55.80 �� w ° I �\ +i-+1 a { --_. ° �', 3.4 0 - -r ro F =56.30 ` FS�°° .� 9' 5 6 I w o �° <0 �� l _ d cv �� .z� �� of o ��, h s� / E =55.8 1 x s3.3 _ C, �o o � \ _ I 53.40 o `Q g / I y o � I \53.6 q 1.91.% % 53.8 / O w ' \ A \ - FI�LF / r?� v �� 56.27 w I c '_ f- �C O / - 56.27 FS TC 55.49 1.65% ro ``�`0h / �� z 0 TP 54.99 G ° } h��o � h / FS.27 \ I 52. / FSr r- 9 L 8 BLDG E 2) • PROP. HDPE © � � G h �?� x � O o �-�� ' ro � � / i ,9 55.80 I � `' � 55.0 TC 55.43 x x53`•.86 1 �. �- e � � � FF =56.30 52.9 � �.- � 4.8 c 54 , C G\ ' 56.27 / TP 54.3 I FL -LP $,O, I - too- 6.36cf 7 FS E =55. �, � , �2. s , : 6 0 1.65. �� x °' ; / 56.27 63. I to= 3:32cfs TP 53:9 FS `L F, -(55)- FS 410- �9 / °co I r - - - -- x 5 x�� y 5� 2'17 55 3 \ r` N n a2- -w Tc -54.6; ° _' G `� �,•o� ,art, FS m1.55 \ , `� u�i u� A i 01 I or I I v, A T 4. 2 ~ °I° , �� / `) 56.27 a I x :�� ..�© ° 5570 /• 3 80 3 TO ,55.43 5 � .. 56.27 `6 I I I � �1% �' T 54.6 ' T 1 .6 TC 54 30 �°�° 60 • x / 55.80 FS mm o U) x 53.r� o; - V / FS e �� 55.88 1.9'8 - c� 55.77 1%, ,. /� { 55.70 2� �° _� -� x 2•p1% FS `' 1 3 ' M T HLINE -- SEE SHEET 2 Off' BBREVIATIONS ASPHALT CONCRETE MIN. MINIMUM L CENTERLINE NO NATURAL GROUND :G CURB AND GUTTER N.T.S. NOT TO SCALE 3. CATCH BASIN P/L PROPERTY LINE fG. DRAWING PE PAD ELEVATION EACH PROP. PROPOSED END OF CURVE R/W RIGHT OF WAY EV ELEVATION S. F. SQUARE FEET EXISTING S/W SIDEWALK FINISHED FLOOR TC TOP OF CURB FINISHED GRADE TF TOP OF FOOTING FLOWLINE TOG TOP OF GRATE FINISHED SURFACE TP TOP OF PAVEMENT GRADE BREAK TRW TOP OF RETAINING WALL HIGH POINT TW TOP OF WALL LINEAL FEET TYP. TYPICAL LOW POINT UG UNDERGROUND X. MAXIMUM 0.13 0.14 PROPOSED LAND USE SUMMARY DA LAND USE PERVIOUS AREA (acre) IMPERVIOUS AREA (acre) TOTAL AREA (acre) Ap DECIMAL Ai DECIMAL INLET / FILTRATION SYSTEM AND CONTECH UNDERGROUND DA -B 1.22 1.00 1,143 B1 MULTIFAMILY 0.04 0.15 0.19 0.19 0.81 B2 MULTIFAMILY 0.06 0.26 0.32 0.17 0.83 B3 MULTIFAMILY 0.04 0.16 0.19 0.19 0.81 B4 MULTIFAMILY 0.02 0.12 0.14 0.13 0.87 B5 MULTIFAMILY 0.05 0.19 0.24 0.19 0.81 B6 MULTIFAMILY 0.01 0.13 0.14 0.06 0.94 Cl MULTIFAMILY 0.27 0.72 0.99 0.25 0.75 C2 MULTIFAMILY 0.13 0.32 0.45 0.26 0.74 C3 MULTIFAMILY 0.90 2.16 3.06 0.26 0.74 C4 MULTIFAMILY 0.50 1.05 1.55 0.29 0.71 C5 MULTIFAMILY 0.12 0.55 0.67 0.16 0.84 C6 MULTIFAMILY 0.08 0.53 0.61 0.12 0.88 C7 MULTIFAMILY 0.09 0.31 0.40 0.20 0.80 C8 MULTIFAMILY 0.16 0.39 0.55 0.26 0.74 C9 MULTIFAMILY 0.30 0.86 1.16 0.23 0.77 TOTAL 2.771 7.891 10,661 0.23 0.77 NOTE: MULTIFAMILY FOR OPEN SPACE AREA ASSUMED TO BE 10% IMPERVIOUS PRELIMINARY WQMP SUMMARY DRAINAGE AREA TOTAL AREA (acres) IMPERVIOUS AREA (acres) DESIGN VOLUME (cu -ft) DESIGN FLOW (cfs) PROP. MAXWELL IV WATER QUALITY INLET / FILTRATION SYSTEM AND CONTECH UNDERGROUND DA -B 1.22 1.00 1,143 0.19 6A -C 9.44 6.89 7,553 1.34 DRAINAGE NOTE: DRAINAGE AROUND BUILDINGS, INCLUDING SWALES, AREA DRAINS, ETC. ALONG WITH FINAL LANDSCAPE FEATURES (BERMS) WILL BE DESIGNED AND SHOWN ON THE PRECISE GRADING PLANS. THE BACKBONE STORM DRAIN SYSTEM HAS BEEN DESIGNED TO ACCOMMODATE THE ENTIRETY OF THE 100 YEAR STORM EVENT (SEE SDPA PRELIMINARY HYDROLOGY AND HYDRAULICS REPORT). SEE SHEET 2 OF 2 FOR BMP LOCATION AND DETAILS BEST MANAGEMENT PRACTICES FOR TREATMENT CONTROLS BMP LABEL ON PLAN CONTROL DESCRIPTION BMP PROP. MAXWELL IV WATER QUALITY INLET / FILTRATION SYSTEM AND CONTECH UNDERGROUND RETENTION / INFILTRATION SYSTEM R 0' 30' 60' 90' 120' SCALE 1 " =30' U c m c 0 U rn a� 3 a 0 i ¢ v i2 a 0 N C0 cv m 3 0 0 N o� a_ a CL a CL i d i m 2 0 i 0 ¢ U i 0 N d' The MaxWeIITM IV Drainage System Detail And Specifications (Modified Detail) W z W 0.. a_ W J z �x � � 1 H INLET /OUTLET PIPE TO = CONTECH DETENTION SYSTEM 0- W re W m Q 2 U C7 Z J W U 15\ FOR TREATMENT CO NTROLS BMP LABEL ON PLAN M&Well "'M BMP PROP. MAXWELL IV WATER QUALITY Date: ProjectName: INLET / FILTRATION SYSTEM AND EXISTING BOUNDARY CONTECH UNDERGROUND - Manufactured and Installed by' Enter' Information in ., Blue 'Cells Fnrshed brad® Pavement- �Elevativn La QOF15 5 T"5 CA, x t ' {r " °; ; °7, #::` €� r s TORRENT RESOURCES DWG. i Y. �pacrng t An evolution of McGuckin Drilling 14 www•torrentresources.com .,. ..- .•;. ....., .., ,.T v„ r„ 'eri .!., e,Galc I,atvr ��_N,}.��., «./ Storage Volume Required (co: 9 q Limiting Width (ft): Invert Depth Below Asphalt (ft): Solid or Perforated Pipe- p Shape Or Diameter (in): Number Of Headers: Spacing between Barrels (ft): Stone Width Around Perimeter of System (ft): De p t A: Po rous Stone Above Pi pe (in): Depth G Porous Stone Below Pipe (in): 0 Stone Porosity (0 to -40 /e): EXISTING TELEPHONE ARIZONA 602/268 -0785 45 0 QA� 3� - NEVADA 702/366 -1234 13 1 CALIFORNIA 661/947 -9836 AZ Lie. R00070465 A, R00047067 B4, ADWR363 CA Lie. 528080, G42, HAZ. NV Lie. 0035350 A - NM Lie. 90504 GF04 U.S. Patent No. 4,923,330 - o" Trademark 1974, 1990, 2004 O MaxWell IV ITEM NUMBERS 1, MANHOLE CONE - MODIFIED FLAT BOTTOM. 2. MOISTURE MEMBRANE - 6 MIL. PLASTIC. PLACE SECURELY AGAINST ECCENTRIC CONE AND HOLE SIDEWALL. 3. BOLTED RING & GRATE - DIAMETER AS SHOWN. CLEAN CAST IRON WITH WORDING "STORM WATER ONLY" IN RAISED LETTERS. BOLTED IN 2 LOCATIONS AND SECURED TO CONE WITH MORTAR. RIM ELEVATION ±0.02' OF PLANS. 4. GRADED BASIN OR PAVING (BY OTHERS). 5. COMPACTED BASE MATERIAL (BY OTHERS). 6. PUREFLOTM DEBRIS SHIELD - ROLLED 16 GA. STEEL X 24" LENGTH WITH VENTED ANTI - SIPHON AND INTERNAL .265" MAX. SWO FLATTENED EXPANDED STEEL SCREEN X 12" LENGTH. FUSION BONDED EPDXY COATED. 7. PRE -CAST LINER - 4000 PSI CONCRETE 48" ID. X 54" OD. CENTER IN HOLE AND ALIGN SECTIONS TO MAXIMIZE BEARING SURFACE. 8. MIN. 6' o DRILLED SHAFT. 9. SUPPORT BRACKET - FORMED 12 GA. STEEL. FUSION BONDED EPDXY COATED. 10.OVERFLOW PIPE - SCH. 40 PVC MATED TO DRAINAGE PIPE AT BASE SEAL. 11. DRAINAGE PIPE - ADS HIGHWAY GRADE WITH TRI -A COUPLER. SUSPEND PIPE DURING BACKFILL OPERATIONS TO PREVENT BUCKLING OR BREAKAGE. DIAMETER AS NOTED. 12. BASE SEAL - GEOTEXTILE, POLY LINER OR CONCRETE SLURRY. 13. ROCK - CLEAN AND WASHED, SIZED BETWEEN 3/8" AND 1 -1/2" TO BEST COMPLEMENT SOIL CONDITIONS. 14. FLOFASTTM DRAINAGE SCREEN - SCH. 40 PVC 0.120" SLOTTED WELL SCREEN WITH 32 SLOTS PER ROW /FT. 96" OVERALL LENGTH WITH TRI -B COUPLER. 15. MIN. 4' o SHAFT - DRILLED TO MAINTAIN PERMEABILITY OF DRAINAGE SOILS. 16. FABRIC SEAL - U.V. RESISTANT GEOTEXTILE - TO BE REMOVED BY CUSTOMER AT PROJECT COMPLETION. 17.ABSORBENT - HYDROPHOBIC PETROCHEMICAL SPONGE. MIN. 128 OZ. CAPACITY. 18. FREEBOARD DEPTH VARIES WITH INLET PIPE ELEVATION. INCREASE SETTLING CHAMBER DEPTH AS NEEDED TO MAINTAIN ALL INLET PIPE ELEVATIONS ABOVE OVERFLOW PIPE INLET. 19.OPTIONAL INLET PIPE (MAXIMUM 4 ", BY OTHERS). EXTEND MOISTURE MEMBRANE AND COMPACTED BASE MATERIAL OR 1 SACK SLURRY BACKFILL BELOW PIPE INVERT, BEST MANAGEMENT ENT PRAC TICES FOR TREATMENT CO NTROLS BMP LABEL ON PLAN CONTROL DESCRIPTION BMP PROP. MAXWELL IV WATER QUALITY Date: ProjectName: INLET / FILTRATION SYSTEM AND EXISTING BOUNDARY CONTECH UNDERGROUND - RETENTION / INFILTRATION SYSTEM iNU ? ,52i �� 51 ----------------- ~Q?] 50.3 \ Qto�0.55c�§ qi, 56.4 \� X ti 56.1 X S- -�_ 54.4 54.5 7- X -- _.... ._ -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ------ - - - - - - - - - = = r - - - -- ---- - - - - -- - - - - - - -- 54. F as >- --�-- ®- X - 1 x`54.5 r- w°. \ x 53.8 __-- TM II ®® 91110 0 �i�l+�9 .o-- on .. Design Your Own Detention System CIVIP DETENTION SYSTEMS Access Riser B r eis Header For design assistance, drawings, V. and pricing send completed worksheet to: GON &TRtlGiiANPRt31)UCTSlNC: dyods a�contech- cpi.com ,t $, f , en . Bands , ect . +.a,.�w S ........gym .r..,.. -e.�k. Pro =i p..,..�r,3 �:.,; rs ..::- ......c. , r .;. .. ,• ='c.., -..e+. ,r :... ... ,.' -�_, . ;�y s:;.: .1+�; r:.a.•.. A. k,,aiur+ �. I,c1 w.:r*'Y,+`iS?s ., -: x: �: ..'S<3".....:@ `i �r7'r !lir:i .' •• � � :� _,� �. �t f � � � �� .� - � s ;„ .,.> �:. ;, Date: ProjectName: NATURAL GROUND EXISTING BOUNDARY Coral;M e HQusing w - City / County: State; Designed By: Company; e hone' Enter' Information in ., Blue 'Cells Fnrshed brad® Pavement- �Elevativn La QOF15 5 T"5 CA, x t ' {r " °; ; °7, #::` €� r s R/W DWG. i Y. �pacrng ,-� Bacrrnlr to Grade f pp[ l-' t- �.1�:�e , <.,:;•- ,� C �t ,,.ff r :��.. �t+fi z tl *.'Y. , -*. �:.. . ,. l,.t,. :"s..�:.l.uc`..: ! ��t -rr..,.. f ' � J 1 , .; � I : .S 'I ' ' ,{ . Diameter 7 �Spacin� N -i , - U - -- MSA:Gctps-ultin ;� My t - x wTel .. ..:.,...... �, ...: ..� .. Corru ated °Metalgt?i ... S, .,. ..- .•;. ....., .., ,.T v„ r„ 'eri .!., e,Galc I,atvr ��_N,}.��., «./ Storage Volume Required (co: 9 q Limiting Width (ft): Invert Depth Below Asphalt (ft): Solid or Perforated Pipe- p Shape Or Diameter (in): Number Of Headers: Spacing between Barrels (ft): Stone Width Around Perimeter of System (ft): De p t A: Po rous Stone Above Pi pe (in): Depth G Porous Stone Below Pipe (in): 0 Stone Porosity (0 to -40 /e): EXISTING TELEPHONE 50.27 ft` Pipe Area 45 0 QA� 3� F?en`orated„ 06 = �`t;; h,r:,r. cY , �r;x EXISTING 1 3 00' 2,� 1r ;7 : FINISHED FLOOR 2 r TOP OF CURB .,c µ,a, ,� .y Y {¢4 S `�: 1l"'• # tii :1'?`O3-,s*A 1 4^' } 'd $ )t Pipe Storage: 5,278 cf 'x� Porous Stone Storage: 3,937 cf Total Storage Provided: 9,215 cf 105:9% Of Required Storage Number of Barrels: 4 barrels Length per Barrel: 16.0 ft 9 p Length Per Header: 41.0 ft .. Rectan ular "Foot rtnt W x L: 45. ft x 28. ft .: r� v ;, L „_: �e C .r r . .,, . ... _xt .. i.. a . t... ._. . ... r.h,f ... x,,, ..3z .s .,. .. d i _.. . r....i 4fi, .. . <. . .. .E' s , u.... 3 ., .... , rr ... L. { -& , ,s , r ,., 5 . „ 1, , Y.F. 7 i ,- _ iT a u.. .w .... 1fl 3. 4 .,.., �1r3. }..r{ ., . .. ... N.� � .ji. . -_ 4.T� .. , c >x, , . ,. .. COIVT.E Et,.M r s. , �bP .,,.��a > 7' x.�,�, ..,=r s � a . ,.,.� .�.,.....��...,.� t t..:� :G a e gat_ six r -r #'_ , r �r', ° }',t System LauoY r;� �,,71 -„3 *aL, ''RGr Fp- ';�YsF'� „x ;rd�5 �t :Y.Nkk A"t . -T+,�i iii � I.STw`�5i Barr I „1Zr, ��r� a k x yfYg .d.O 21 � { kczb@ S 2ki.� ,p",. x` 't s^k �.�� r4 .3+ s xt L fb ^WS 4f +G' S 43 Ba ei ,1 f � t , - r,. J< }µKS k��o-Tt i FiNrfir ?i�ry6 #?uas s raa 0art'e xe a �s a P {ru x kr r fi is t i Br I < "' •are,; 1 sa �tt1 r rat f 0 �a °tt, xs I r IA �i rta °• W 5 ,asA ,: €• .:<° , s r %,f. '.Jt 5,7. ` <., .'et'a t._... m.i�. i.•b'ES.," 4•::.d a.,l.. .r.; "t... ir;.*;... t; •n ;S b,t.., gs�i }�. «. £i,3's�0 7r i i.. .} _b _U. 3 {. r„ k.v s kA.4 : -... t k , ,.,.£ # N, ., t 3. ,x x. �. � 7: ... SS. n ... ..s.., ,. ...a .. .a?,, m .. .. .... e. ,. :, ....,r •U x#' Y.. Bar 7 f .. 5^ { � , . , :fk-i � Barbel 5,. s..<at- Barrel4 t , r aT* Bare 3 1 l�� k 3�'�$ y r y ,ar�el 2��,� �� Barre1 i1 "��'r`r j'jf d Bafjel Foo`ge 4v /o'k)eadersj `t,, a � � '; -.. Total CMP' Footage: 105 ft g App roximate Total Pieces: 6 cs p Approximate Coupling Bands: 5 bands Approxirriate`Truckloads: 3 trucks ,.. tl � r1 � , _ . � 2.� . •., ,�.�.r�, .�.fi��.. r F$t�r".r�a,,.,. t1 r.. ,aft: �� >��, . �. �.,� �,a 6� Total Excavation: 1120 cy Porous Stone Backfill For Storage: 365 c 7 stone Backfillto Grade Excluding Stone: 560 ay fill "Construction Construetton quantities are approximate and should be venfled upon final design O 2007 CONTECH Stormwater Solutions AT LI I - SEE SHEET 1 OF 2 ULbLH I SANUS UNIIFILL) bUHUOL UISTRIGT - - - 54.05 TC 53.6 x 53.6 LEGEND -W PROPOSED WATER PROPOSED WATER METER �- PROPOSED FIRE HYDRANT LI`^� PROPOSED DETECTOR CHECK /FDC & PIV TRIBUTARY DRAINAGE AREA BOUNDARY B10 DRAINAGE SUB -AREA ID L -207 FLOW TRAVEL LENGTH (FT) Am0.9 AREA (AC) 53.99 53.7 x TC 53.6 W��RVrtvu1.4U "T104 IINf UT- RATION- :TNAA fn, 7ntll f-c C� 1 - x X -------------- - - - - -- -PROP. BLOCK WALL --- x -2 -6 -- - - -- X - - -- 53.74 / 52.67 EMERGENCY X 53.6 _ _ TC TC -_ - - Q-VJE-RFLLOV1�`sa ( -- ABBREVIATIONS LEGEND CONTINUED 2O5 NODE NUMBER 54.5 ELEVATION /1. PROPOSED MAXWELL IV WATER QUALITY INLET / FILTRATION SYSTEM (SEE SHEET 2 OF 2) PROPOSED CONTECH RETENTION SYSTEM (SEE SHEET 2 OF 2) PROPOSED TYPICAL TRASH ENCLOSURE PROPOSED TYPICAL APARTMENT BUILDING / UNIT AC xx.x EXISTING SPOT ELEVATIONS MINIMUM C/L EXISTING CONTOURS NG NATURAL GROUND EXISTING BOUNDARY - - EXISTING LOT LINE - - - - - - - - - - - EXISTING EASEMENT /BUILDING SETBACK R/W DWG. EXISTING RIGHT OF WAY - -E- EXISTING ELECTRIC - - _c- EXISTING GAS EC r EXISTING TELEPHONE - s EXISTING SEWER - SQUARE FEET EXISTING WATER EXISTING S/W PROPOSED ADA PATH OF TRAVEL - FINISHED FLOOR PROPOSED AND EXISTING CENTER LINE TOP OF CURB FG PROPOSED CURB TC 00.00 TOP OF FOOTING R O PROPOSED ELEVATIONS FL 00.00 TOG TOP OF GRATE - - FINISHED SURFACE PROPOSED RIGHT OF WAY S GB PROPOSED SEWER SD TOP OF RETAINING WALL 0' 30' 60' 90' 120' PROPOSED STORM DRAIN ■-1 TW PROPOSED CATCH BASIN ❑ LINEAL FEET PROPOSED STORM DRAIN INLET O LP PROPOSED STORM DRAIN INLET OPROPOSED UNDERGROUND SCALE 1"=30' STORM DRAIN MANHOLE -W PROPOSED WATER PROPOSED WATER METER �- PROPOSED FIRE HYDRANT LI`^� PROPOSED DETECTOR CHECK /FDC & PIV TRIBUTARY DRAINAGE AREA BOUNDARY B10 DRAINAGE SUB -AREA ID L -207 FLOW TRAVEL LENGTH (FT) Am0.9 AREA (AC) 53.99 53.7 x TC 53.6 W��RVrtvu1.4U "T104 IINf UT- RATION- :TNAA fn, 7ntll f-c C� 1 - x X -------------- - - - - -- -PROP. BLOCK WALL --- x -2 -6 -- - - -- X - - -- 53.74 / 52.67 EMERGENCY X 53.6 _ _ TC TC -_ - - Q-VJE-RFLLOV1�`sa ( -- ABBREVIATIONS LEGEND CONTINUED 2O5 NODE NUMBER 54.5 ELEVATION /1. PROPOSED MAXWELL IV WATER QUALITY INLET / FILTRATION SYSTEM (SEE SHEET 2 OF 2) PROPOSED CONTECH RETENTION SYSTEM (SEE SHEET 2 OF 2) PROPOSED TYPICAL TRASH ENCLOSURE PROPOSED TYPICAL APARTMENT BUILDING / UNIT AC ASPHALT CONCRETE MIN. MINIMUM C/L CENTERLINE NG NATURAL GROUND C &G CURB AND GUTTER N.T.S. NOT TO SCALE C. B. CATCH BASIN P/L PROPERTY LINE DWG. DRAWING PE PAD ELEVATION EA. EACH PROP. PROPOSED EC END OF CURVE R/W RIGHT OF WAY ELEV ELEVATION S.F. SQUARE FEET EX EXISTING S/W SIDEWALK itiohill* FF FINISHED FLOOR TC TOP OF CURB FG FINISHED GRADE TF TOP OF FOOTING R O FL FLOWLINE TOG TOP OF GRATE FS FINISHED SURFACE TP TOP OF PAVEMENT GB GRADE BREAK TRW TOP OF RETAINING WALL 0' 30' 60' 90' 120' HP HIGH POINT TW TOP OF WALL L.F. LINEAL FEET TYP. TYPICAL LP LOW POINT UG UNDERGROUND SCALE 1"=30' MAX. MAXIMUM Whitewater River Region WQMP Coral Mountain Apartments Appendix C Supporting Detail Related to Hydraulic Conditions of Concern (Note: Please refer to the Coral Mountain Affordable Housing SDPA Preliminary Hydrology Report (June 20, 2011), submitted in conjunction with this Preliminary WQMP report.) Or t: .0 Whitewater River Region WQMP Coral Mountain Apartments Appendix D Educational Materials Did you know that disposing .of pollutants into the street, gutter, storm drain or nearest body of water is PROHIBITED by law and can bring about stiff penalties. Best Management Practices Waste wash water from Mechanics, Plumbers, Window /Power-Washers, Carpet Cleaners, Car Washing and Mobile Detailing activities may contain significant quantities of motor oil, grease, chemicals, dirt, detergents, brake pad dust, litter and other materials. Best Management Practices, or BMPs as they are known, are guides to prevent pollutants from entering the storm drains. Each of us can do our part to keep storm water clean by using the suggested BMPs below: Simple solutions for both light and heavy duty jobs: Do ... consider dry cleaning methods first such as a mop, broom, rag or wire brush. Always keep a spill response kit on site. Do ... prepare the work area before power cleaning by using sand bags, rubber mats, vacuum booms, containment pads or temporary berms to keep wash water away from the gutters and storm drains. Do ... use vacuums or other machines to remove and collect loose. debris or litter before applying water. Do ... obtain the property owner's permission to dispose small amounts of power washing waste water to landscaped, gravel or unpaved surfaces. Do ... check with your local sanitary sewer agency's policies on wash water disposal regulations. (See list on reverse side). DO....be aware that if discharging to landscape areas, soapy wash water may damage landscaping. Residual wash water may remain on paved surfaces to evaporate. Sweep up solid residuals and dispose of . properly. Vacuum booms are another option for capturing and collecting wash water. DO not let ... wash or waste water from sidewalk, plaza or building cleaning go into a street or storm drain. Report illegal storm drain disposal, Call Toll Free 1- 800 - 506 -2555 Using Cleaning Agents Try using biodegradable /phosphate -free products. They are easier on the environment, but don't confuse them for being toxic free. Soapy water entering the storm drain system can impact the delicate aquatic environment. When cleaning surfaces with a high - pressure washer or steam cleaner, additional precautions should be taken to prevent the discharge of pollutants into the storm drain system. These two methods of surface cleaning can loosen additional material that can contaminate local waterways. - Think Water Conservation Minimize water use by using high pressure, low volume nozzles. Be sure to check all hoses for leaks.. Screening Wash. Water A thorough dry cleanup before washing exterior surfaces, such as buildings and decks without loose paint, sidewalks, or plaza areas should be sufficient to protect receiving waters. Keep debris from entering the storm drain after cleaning by first passing the wash water first through a "20 mesh" or finer screen to catch the solid materials, then disposing the mesh in a refuse container. Drain Inlet Protection & Collection of Wash Water • Prior to any washing, block all. storm drains with an impervious barrier such as sandbags or berms, or seal the storm drain with plugs or rubber mats. • Create a containment area with berms and traps or take advantage of a low spot to keep wash water contained. • Wash vehicles and equipment on grassy or gravel areas so that the wash water can seep into the ground. • Pump or vacuum up all wash water in the contained area. Equipment and Supplies For special materials, equipment and supplies: • New Pig — (800) 468 74647 • Lab Safety Supply — (800) 356 -0783 • C&H — (800) 558 -90966 • W.W. Grainger — (800) 994 -9174 • Cleaning Equipment Trade Association — (800) 441 -0111 imptid telephone numbers and links: WATER AGENCY LIST in Riverside County City of Banning (951) 922 -3130 City of Beaumont (951) 769 -8520 City of Blythe (760) 922 -6161 City of Coachella (760) 398 -3502 Coachella Valley Water District (760) 398 -2651 City of Corona (951) 736 -2259 Desert Center, CSA #51 (760) 227 -3203 Eastern Municipal Water District (951) 928 -3777 Flsinore Valley MWD (951) 674 -3146 Farm Mutual Water Company (951) 244 -4198 City of Hemet (951) 765 -3712 Idyllwild Water District (951) 659 -2143 lurupa Community Services District (951) 360 -8795 Lake Hemet MWD (951) 658 -3241 Lee Lake Water District (951) 277 -1414 March Air Force Base (951) 656 -7000 Mission Springs Water District (760) 329 -6448 City of Palm Springs (760),323 -8253 Rancho Caballero (951) 780 -9272 Rancho California Water District (951) 296 -6900 Ripley, CSA #62 (760) 922 -4951 City of Riverside (951) 351 -6170 Rubidoux Services District (951) 684 -7580 Silent Valley Club, Inc (951) 849 -4501 Valley Sanitary District (760) 347 -2356 Western Municipal Water District (951) 789 -5000 Yucaipa Valley Water District (909) 797 -5117 REPORT ILLEGAL STORM DRAIN DISPOSAL 1- 800 -506 -2555 or online at www.rcflood.ora Online resources include: Riverside County Flood Control and Water Conservation District www.rcflood.ora California Storm Water Quality Association www.casaa.ora State Water Resources Control Board www.swrcb.ca.aov/ • Power Washers of North America www.theowna.org Sluml,1181 PAIM What you should know for.,,. OUTDOOR CLEANING_ ACTIVITIES AND PROFESSIONAL MOBILE SERVICE PROVIDERS Storm drain pollution proventim information for: Car Washing / Mobile Detailers j Window and Carpet Cleaners ,-) Power Washers j Waterproofers I Street Sweepers J Equipment cleaners or degreasers and all mobile service providers Storm Drains are NOT connected to sanitary sewer systems and treatment plants! ONLY RAIN IN THE The primary purpose of storm drains is to carry rain water away from developed areas to. prevent flooding. _ Pollutants discharged to storm drains are transported directly into rivers, lakes and streams. Soaps, degreasers, automotive fluids, litter and a host of materials are washed off buildings, sidewalks, plazas and parking areas. Vehicles and equipment must be properly managed to prevent the pollution of local waterways. j Unintentional spills by mobile service operators can flow into storm drains and pollute our waterways. Avoid mishaps. Always have a Spill Response Kit on hand to clean up unintentional spills. Only emergency Mechanical repairs should be done in City streets and use drip pans for spills. Plumbing should be done on private property. Always store chemicals in a leak -proof container and keep covered when not in use. Window /Power Washing waste water shouldn't be released into the streets, but should be disposed of in a sanitary sewer, landscaped area or in the soil. Soiled Carpet Cleaning wash water should be filtered before being discharged into the sanitary sewer. Dispose of all filter debris properly. Car Washing/ Detailing operators should wash cars on private property and use a regulated hose nozzle for water flow control and runoff prevention. Capture and dispose of waste water and chemicals properly. Always prevent runoff water from entering storm 1 1 L REPORT ILLEGAL STORM DRAIN - DISPOSAL 1- 800 - 506 -2555 • • • Adopt a pet from your local animal shelter or adoption. centers. at pet stores. A variety of animals, from purebred tomixe- d breed are waiting for loving arms and good homes. Consider N1 � volunteering at your local_ animal 49 shelters. Volunteers, donations, food, newspapers, old towels and linens are needed to help the animals. RIVERSIDE COUNTY ANIMAL SHELTER LOCATIONS: BLYTHE 16450 West Hobson' Way Blythe, CA 92225 760 - 921 -7857 HEMET 800 South Sanderson Hemet, CA 92545 909 925 -8025 INDIO 45 -355 Van Buren Indio, CA 92201 -760- 347 -2319 RIVERSIDE 5950 Wilderness Avenue Riverside, CA 92504 909 - 358 -7387 FOR ALL OTHER AREAS CALL 1- 888 = 636 -7387 Riverside County gratefully acknowledges the City of Los Angeles Stormwater Program for the design concept of this brochure. TIPS FOR A HEALTHY PET AND A HEALTHIER ENVIRONMENT 1 CREATE A HEALTHY ENVIRONMENT in and around your home by-following these simple pet practices. Your pet, family and neighbors will appreciate their. clean comfortable surroundings. HOUSEHOLD PETS We all love our pets, but pet waste is a subject everyone likes to avoid.. Pet waste left on trails, sidewalks, streets, and grassy areas is immediately flushed into the nearest waterway, when it rains. Even if you can't see water near you, the rain or waste water WASHES all that PET WASTE and BACTERIA INTO THE STORMDRAIN, where it travels to your neighborhood creek or lake untreated. These animal droppings also contain nutrients that can promote the growth of algae, if they enter our streams and lakes. The risk of STORMWATER CONTAMINATION INCREASES, if pet wastes is allowed to accumulate in animal pen areas or left on sidewalks, streets, or driveways where runoff can carry them to storm sewers. Some of the DISEASES THAT CAN SPREAD from pet -waste are: Campy lobacteriosis — a' bacterial infection that causes diarrhea in humans. Salmonellosis — the most common bacterial infection transmitted to humans from animals. Toxocarisis — roundworms transmitted from animals to humans. Flies and other pest insects can also increase when pet waste is disposed of improperly, becoming a nuisance and adding yet another vector for disease transmission. WHAT CAN YOU DO? . SCOOP up pet waste and flush it down the toilet. NEVER DUMP pet waste into a storm drain or catch basin. USE the complimentary BAGS or mutt mitts offered in dispensers at local parks. CARRY EXTRA BAGS when walking your dog and make them available to other pet owners who are without. TEACH CHILDREN how to. properly clean up of ter a pet. TELL FRIENDS AND NEIGHBORS about the ill effects of animal waste on the environment. Encourage them to cleanup after pets. Did You Know ... that Californians illegally dump about 80 million gallons of motor oil:each year? o.. 6: �. 6: �. d: 6• o: o. o: o. 6: �_ �, ra: �; o: �; �_ �= a: m; I►;: �; o: �; e;= o; .es 6= o= �; �: o: o: D',: - 0, 'tix t: 4 iSs -c C;: 4 (;s •� fj Us t L G,: `;• Us K �: ,x Many communities have "Scoop the Poop" laws that govern pet waste cleanup. Some of these laws specifically require anyone who walks an animal off of their property to carry a bag, shovel, or scooper. Any waste left by the animal must be cleaned up immediately. CALL YOUR LOCAL CODE ENFORCEMENT OFFICER to find out more about pet waste regulations. Pets are only one of the many fixtures of suburban America that add to water pollution. Lawn fertilizers, rinse water from driveways and motor oil commonly end up in streams and lakes. CALL 1- 800 -506 -2555 FOR HOUSEHOLD HAZARDOUS WASTE COLLECTION LOCATION AND DATES. Maintain your automobile to avoid leaks. Dispose of used vehicle fluids properly. Your pets can be poisoned if they ingest gas, oil or antifreeze that drips onto the pavement or is stored in open containers. NEVER HOSE VEHICLE FLUIDS into the street or gutter. USE ABSORBENT MATERIALS such as cat litter to clean- up spills. SWEEP UP used absorbent materials and place in the trash. HORSES AND LIVESTOCK Fortunate enough to own a horse or livestock? You, too, can play a part in protecting and cleaning up our water resources. The following are l a few simple Best Management Practices (BMPs) specifically designed for horse � owners and landowners with horses. STORE your manure properly. Do not store unprotected piles of manure in places where runoff may enter streams, or flood waters may wash the manure away. Place a cover or tarp over the pile to keep rainwater out. CHECK with your local conservation district to design manure storage facilities to protect water quality. These structures usually consist of a concrete pad to protect ground water and a short wall on one or two sides to make manure handling easier. TRY composting - A vegetative cover placed around buildings or on steeper slopes can help minimize erosion and absorb nutrients while improving the Ir appearance of your property. In addition, avoid costlier erosion controls, vegetative covers will provide animals with better traction during wet or icy conditions. KEEP animals out of steams - Designed stream crossings provide a safe, easy way for horses and livestock to ford streams. Fencing encourages the use of the crossing instead of the streambed to navigate streams. This will allow vegetation to stabilize stream banks and reduce sediment pollution. • MOW pastures to proper height, six inches is typically recommended. Material STORAGE SAFETY TIPS - Many of the chemicals found in barns require careful handling and proper disposal. When using these chemicals, be certain to follow these common sense guidelines: • Buy only what you need. Treat spills of hoof oils like fuel spill. Use kitty litter to soak up the oil and dispose in a tightly sealed plastic bag. • Store pesticides in a locked, dry, well - ventilated area. • Protect stored fertilizer and pesticides from rain and surface water. Call 1 -800 -506 -2555 to locate your local conservation district to find out what to do with your current backyard manure pile, how to re- establish a healthy pasture, what to do about weeds, and what grasses grow best in your soils. Thank you for doing your part to protect your watershed, the environment, and the equestrian way of life in your community! Whitewater River Region WQMP Coral Mountain Apartments Appendix E Soils Report 0 I ) � 0 I• } Earth Systems %`r Southwest 79 -811B Country Club Drive 0 Bermuda Dunes, CA 92203 • (760) 345 -1588 (800) 924 -7015 FAX (760) 345 -7315 September 9, 2010 Shovlin Companies 76 -753 Adams Street La Quinta, California 92253 Attention: Mr. John Durso Project: Proposed 9.5 -Acre Residential Development South of Highway 111 and East of Dune Palms Road La Quinta, California Subject: Geotechnical Engineering Report Addendum File No.: 09354 -02 Doc. No.: 10 -05 -787 Reference: Earth Systems Southwest, Geotechnical Engineering Report, Proposed 9.5 -Acre Residential Development, South of Highway 111 and East of Dune'Palms Road, La Quinta, California, File No.: 09354 -02, Doc. No.: 10 -07 -753, dated July 20, 2010. At the request of Shovlin Companies, .Earth Systems Southwest [ESSW] has prepared this addendum for the purpose of providing geotechnical engineering recommendations to include isthe approximately 10 -acre parcel to the north of the referenced proposed development, as requested by the City of La Quinta. This addendum included a field reconnaissance of the site. The subject lot is located approximately 600 feet east of Dune Palms Road, and immediately south of Highway 111 in the City of La Quinta, Riverside County, California. The property boundaries are defined by Highway 111 to the north, commercial developments to the east, and the wall.bounding the Desert Sands Unified School District facilities to the south. The western boundary was not sharply demarcated, but was assumed to be the eastern edge of the developed area for the commercial properties west of the site. The western half of the site is undeveloped land while the eastern half is currently abandoned agricultural land with the remnants of a trailer park, located in the northeastern quarter of the site. The site currently consists of native desert soil and vegetation, with sand dunes covering the western half of the property. The eastern half of the site was smoothed for agricultural use. Please see the referenced geotechnical engineering report, for a detailed site description and regional geology. We understand that proposed developments to the site consist of an automobile dealership. We recommend a design level geotechnical engineering report, when site plans for the proposed development become available. Site Grading At the start of site grading, existing vegetation, trees, large roots; pavements, foundations, non - engineered fill, construction debris, trash, and abandoned underground utilities should be • removed from the proposed building, structural, and pavement areas. The surface should be September 9, 2010 2 File No.: 09354 -02 Doc. No.: 10 -08 -787 stripped of organic growth and removed from the construction area. Areas disturbed during clearing should be properly backfilled and compacted as described below. Dust control should also be implemented during construction. Site grading should be in strict compliance with the requirements of the South Coast Air Quality Management District [SCAQMD]. Building Pad Preparation: Because of the relatively non - uniform and under- compacted nature of the site soils, we recommend recompaction of soils in building areas. The existing surface soils within the building pad and foundation areas should be over - excavated to a minimum of 5 feet below existing grade or a minimum of 4 feet below the footing level (whichever is lower). The over - excavation should extend for 5 feet beyond the outer edge of exterior footings, where possible. The bottom of the sub - excavation should be scarified, moisture conditioned, and recompacted to at least 90% relative compaction (ASTM D 1557) for an additional depth of one foot. Subgrade Preparation: In areas to receive fill, pavements, or hardscape, the subgrade should be scarified, moisture conditioned, and compacted to at least 90- percent relative compaction (ASTM D 1557) for a depth of one -foot below finished'siibgrades or one -foot below the bottom of the foundation, whichever is deeper. Compaction should be verified by testing. Engineered Fill Soils: The native soil is suitable for use as engineered fill and utility trench backfill, provided it is free of significant organic or deleterious matter. The native soil should be placed in maximum 8 -inch lifts (loose) and compacted to at least 90- percent relative compaction (ASTM D 1557) near its optimum moisture content. Compaction should be verified by testing. Rocks larger than 6 inches in greatest dimension should- be removed from fill or backfill material. Imported fill soils (if .needed) should be non - expansive, granular soils meeting the USCS classifications. of SM, SP -SM, or SW -SM with a maximum rock size of 3 inches and 5 to 35percent passing the No. 200 sieve. The geotechnical engineer should evaluate the import fill soils before hauling to' the site. - However, because of the potential variations within the borrow source, import soil will not be prequalifed by ESSW. The imported fill should be placed in lifts no greater than 8 inches in loose thickness and compacted to at least 90- percent relative compaction (ASTM D 1557) near optimum moisture content. Shrinkage: The shrinkage factor for earthwork is expected to range from 15 to 20 percent for the upper excavated or scarified site soils. This estimate is based on compactive effort to achieve an average relative compaction of about 92- percent and may vary with contractor methods. Subsidence is estimated to be less than 0.2 feet. Losses from site clearing and removal of existing site improvements may affect. earthwork quantity calculations and should be considered. Seismic Design Criteria This site is subject to strong ground shaking due to potential fault movements along the San Andreas and San Jacinto faults. Engineered design and earthquake- resistant construction increase safety and allow development of seismic areas. The minimum seismic design should EARTH SYSTEMS SOUTHWEST September 9, 2010 3 File No.: 09354 -02 Doc. No.: 10 -08 -787 is comply with the 2007 edition of the California Building Code and ASCE 7 -05 using the seismic coefficients given in the table below. 2007 CBC (ASCE 7 -05) Seismic Parameters The intent of the CBC lateral force requirements is to provide a structural design that will resist collapse to provide reasonable life safety from a major earthquake, but may experience some structural and nonstructural damage. A fundamental tenet of seismic design is that inelastic yielding is allowed to adapt to the seismic demand on the structure. In other words, damage is allowed. The CBC lateral force requirements should be considered a minimum design. The • owner and the designer may evaluate the level of risk and performance that is acceptable. Performance based criteria could be set in the design. The design engineer should exercise special care so that all components of the design are fully met with attention to providing a continuous load path. An adequate quality assurance and control program is urged during project construction to verify that the design plans and good construction practices are followed. This is especially important for sites lying close to the major seismic sources. • Estimated peak horizontal site accelerations based upon a probabilistic analysis (10- percent probability of occurrence in 50 years) is approximately 0.57 g for a stiff soil site. Actual accelerations may be more or less than estimated. Vertical accelerations are typically '/3 to % of the horizontal accelerations, but can equal or exceed the horizontal accelerations, depending upon the local, site effects and amplification. Closing Except as modified in this report, it is our opinion that the referenced documents are applicable to the proposed development. We make no representation as to the accuracy of the dimensions, measurements, calculations, or any portion of the design. This report is issued with the understanding that the owner or the owner's representative has the responsibility to bring the information and recommendations contained herein to the attention of the architect and engineers for the project so that they are incorporated into the plans and specifications for the project. The owner or the owner's representative also has the responsibility to take the necessary steps to see that the general contractor and all subcontractors follow such EARTH SYSTEMS SOUTHWEST Reference Seismic Category: D Table 1613.5.6 Site Class: D Table 1613.5.2 Maximum Considered Earthquake [MCE] Ground Motion Short Period Spectral Response SS: 1.50 g Figure 1613.5 1 second Spectral Response, S I : 0.60 g Figure 1613.5 Site Coefficient, Fa: 1.0 Table 1613.5.3(1) Site Coefficient, F,,: 1.5 Table 1613.5.3(2) Design Earthquake Ground Motion Short Period Spectral Response, SDS 1.00 g 1 second Spectral Response, SDI 0.60 g The intent of the CBC lateral force requirements is to provide a structural design that will resist collapse to provide reasonable life safety from a major earthquake, but may experience some structural and nonstructural damage. A fundamental tenet of seismic design is that inelastic yielding is allowed to adapt to the seismic demand on the structure. In other words, damage is allowed. The CBC lateral force requirements should be considered a minimum design. The • owner and the designer may evaluate the level of risk and performance that is acceptable. Performance based criteria could be set in the design. The design engineer should exercise special care so that all components of the design are fully met with attention to providing a continuous load path. An adequate quality assurance and control program is urged during project construction to verify that the design plans and good construction practices are followed. This is especially important for sites lying close to the major seismic sources. • Estimated peak horizontal site accelerations based upon a probabilistic analysis (10- percent probability of occurrence in 50 years) is approximately 0.57 g for a stiff soil site. Actual accelerations may be more or less than estimated. Vertical accelerations are typically '/3 to % of the horizontal accelerations, but can equal or exceed the horizontal accelerations, depending upon the local, site effects and amplification. Closing Except as modified in this report, it is our opinion that the referenced documents are applicable to the proposed development. We make no representation as to the accuracy of the dimensions, measurements, calculations, or any portion of the design. This report is issued with the understanding that the owner or the owner's representative has the responsibility to bring the information and recommendations contained herein to the attention of the architect and engineers for the project so that they are incorporated into the plans and specifications for the project. The owner or the owner's representative also has the responsibility to take the necessary steps to see that the general contractor and all subcontractors follow such EARTH SYSTEMS SOUTHWEST September 9, 2010 4 File No.: 09354 -02 Doc. No.: 10 -08 -787 recommendations. It is further understood that the owner or the owner's representative is responsible for submittal of this report to the appropriate governing agencies. As the Geotechnical Engineer of Record for this project, Earth Systems Southwest [ESSW] has striven to provide our services in accordance with generally accepted geotechnical engineering practices in this locality at this time. No warranty or guarantee is express or implied. This report was prepared for the exclusive use of the Client and the Client's authorized agents. ESSW should be provided the opportunity for a general review of final. design and specifications in order that earthwork and foundation recommendations may be properly interpreted and implemented in the design and specifications. If ESSW is not accorded the privilege of making this recommended review, we can assume no responsibility for misinterpretation of our recommendations. This report is based on the assumption that an adequate program of client consultation, construction monitoring, and testing will be performed during the final design and construction phases to check compliance with these recommendations. Maintaining ESSW as the geotechnical consultant from beginning to end of the project will provide continuity of services. The geotechnical engineering firm providing tests and observations shall assume the responsibility of Geotechnical Engineer of Record. Should you have any questions concerning our report, please give us a call and we will be pleased to assist you. f Respectfully submitted, EAR4SY MS SO ST n. 5y 0 EYftR ath8249 Joseph E. McKinney '�oPCA"Fpa ?� GP 1052, PG 8249 SER/jem/mwl /cen Distribution: 4 /Shovlin Companies' 2BD File y PR�OFES%,�\ eviewed L* CH # GE 2�539 It 10 m N�GP OF CAttFC� Michael W. Laney, RCE 56686, GE 2539 EARTH SYSTEMS SOUTHWEST SHOVLIN COMPANIES 46 -753 ADAMS STREET LA QUINTA, CALIFORNIA 92253 • GEOTECHNICAL ENGINEERING REPORT PROPOSED 9.5 -ACRE RESIDENTIAL DEVELOPMENT SOUTH OF HIGHWAY III AND EAST OF DUNE PALMS ROAD LA QUINTA, CALIFORNIA • July 20, 2010 © 2010 Earth Systems Southwest ' Unauthorized use or copying of this document is strictly prohibited without the express written consent of Earth Systems Southwest. • File No.: 09354 -02 Doc. No.: 10 -07 -753 Earth Systems �i Southwest July 20, 2010 Shovlin Companies 76 -753 Adams Street La Quinta, California 92253 Attention: Mr. John Durso Project: Proposed 9.5 -Acre Residential Development South of Highway 111 and East of Dune Palms Road La Quinta, California Subject: Geotechnical Engineering Report 79 -811 B Country Club Drive Bermuda Dunes, CA 92203 (760) 345 -1588 (800) 924 -7015 FAX (760) 345 -7315 File No.: 09354 -02 Doc. No.: 10 -07 -753 We take pleasure in presenting this geotechnical engineering report prepared for the proposed 9.5 -acre residential development to be located south of Highway 111 and east of Dune Palms Road in the City of La Quinta, California. This report presents our findings and recommendations for site grading and foundation design, incorporating the information provided to our office. The site is suitable for the proposed development, provided the recommendations in this report are followed in design and construction. This report should stand as a whole and no part of the report should be excerpted or used to the exclusion of any other part. This report completes our scope of services in accordance with our agreement, dated June 7, 2010 and authorized on June 13, 2010. Other services that may be required, such as plan review and grading observation, are additional services and will be billed according to our Fee Schedule in effect at the time services are provided. Unless requested in writing, the client is responsible for distributing this report to the appropriate governing agency or other members of the design team. We appreciate the opportunity to provide our professional services. Please contact our office if there are any questions or comments concerning this report or its recommendations. Respectfully submitted, EARTH SYSTEM SO E. McK' y GP 105 , 49 SER/jem/csh/ajm 5�' \CNHL GF� EST !p 6) Joseph lw f�cK6uley tPj, N10.8249 OPCAL%f. � Distribution: 6 /Shovlin Companies 2/BD File Reviewed by, rip— *'1 CE SUM E70' 1131/i - Craig S. Hill CE 38234 � JOSEPH E. McMNEY No. 1052 OF Cp,� - \F� I TABLE OF CONTENTS Page • EXECUTIVE SUMMARY ........................................................... ............................... ii Section 1 INTRODUCTION .............................................................. ..............................1 1.1 Project Description .............................................................. ..............................1 1.2 Site Description .................................................................... ..............................1 1.3 Purpose and Scope of Services ............................................ ..............................2 Section 2 METHODS OF INVESTIGATION ................................. ..............................3 2.1 Field Exploration ................................................................. ..............................3 2.2 Laboratory Testing ............................................................... ..............................3 Section3 DISCUSSION ..................................................................... ..............................4 3.1 Soil Conditions .................................................................... ..............................4 3.2 Groundwater ........................................................................ ..............................4 3.3 Geologic Setting ................................................................... ..............................4 3.4 Geologic Hazards ................................................................. ..............................5 Additional Services ............................................................. .............................18 3.4.1 Seismic Hazards ....................................................... ..............................5 3.4.2 Secondary Hazards .................................................. ..............................6 3.4.3 Site Acceleration and Seismic Coefficients ............. ..............................7 Section4 CONCLUSIONS .............................:.................................. ..............................8 Section 5 RECOMMENDATIONS ................................................... ..............................9 SITE DEVELOPMENT AND ......................................................... ..............................9 5.1 Site Development — Grading ................................................ ..............................9 • 5.2 5.3 Excavations and Utility Trenches ::::::::::::::::::::::::::::::::::::::: .............................10 Slope Stability of Graded Slopes . .11 STRUCTURES............................................................................... .............................11 5.4 Foundations ......................................................................... .............................11 5.5 Slabs -on -Grade ................................................................... .............................12 5.6 Retaining Walls ................................................................... .............................13 5.7 Mitigation of Soil Corrosivity on Concrete ........................ .............................14 5.8 Seismic Design Criteria ...................................................... .............................15 5.9 Pavements ........................................................................... .............................16 Section 6 LIMITATIONS AND ADDITIONAL SERVICES ....... .............................17 6.1 Uniformity of Conditions and Limitations ......................... .............................17 6.2 Additional Services ............................................................. .............................18 REFERENCES.............................................................................. .............................21 APPENDIX A Figure 1 — Site Location Map Figure 2 — Boring Location Map Table 1 — Fault Parameters Terms and Symbols used on Boring Logs Soil Classification System Logs of Borings APPENDIX B Laboratory Test Results • EARTH SYSTEMS SOUTHWEST 11 EXECUTIVE SUMMARY Earth Systems Southwest has prepared this executive summary solely to provide a general overview of the report. The report itself should be relied upon for information about the findings, conclusions, recommendations, and other concerns. The site is located south of Highway 111 and east of Dune Palms Road in the City of La Quinta, California. The proposed development will consist of a 180 -unit affordable housing project comprised of 11 two -story apartment structures and one single -story apartment stpacture. We understand that the proposed structure will be wood -frame and stucco construction supported with perimeter wall foundations and concrete slabs -on- grade. The proposed project may be constructed as planned, provided that the recommendations in this report are incorporated in the final design and construction. Site development will include clearing and grubbing of vegetation, site grading, building pad preparation, underground utility installation, street and parking lot construction, and concrete driveway and sidewalks placement. Based on the non - uniform nature and hydrocollapse potential of the near surface sods, remedial site grading is recommended to provide uniform support for the foundations. Laboratory testing of the site soils indicate low levels of sulfate and chloride ion content, therefore normal concrete mixes may be used. However, indications are that the on -site soils exhibit moderate resistivity resulting in a severe corrosion potential for buried metal pipes. Underground utilities and buried metal pipes will require corrosion protection from the surrounding soil. We consider the most significant geologic hazard to the project to be the potential for severe seismic shaking that is likely to occur during the design life of the proposed structures. The project site is located in the highly seismic Southern California region within the influence of several fault systems that are considered to be active or potentially active. Structur--s should be designed in accordance with the values and parameters given within the 2007 California Building Code [CBC] and ASCE 7 -05. The seismic design parameters are presented in the following table and within the report. EARTH SYSTEMS SOUTHWEST • .• iii SUMMARY OF RECOMMENDATIONS Design Item Recommended Parameter Reference Section No. Foundations Allowable Bearing Pressure Continuous wall footings Pad Column footings 1,500 psf 2,000 psf 5.4 Foundation Type Spread Footing 5.4 Bearing Materials Engineered fill Allowable Passive Pressure 350 psf per foot 5.4 and 5.6 Active Pressure 35 pcf 5.6 At -rest Pressure 55 pcf 5.6 Allowable Coefficient of Friction 0.35 5.4 Soil Expansion Potential Very low EI <20 3.1 Geologic and Seismic Hazards Liquefaction Potential Low 3.4.2 Significant Fault and Magnitude San Andreas, M7.7 3.4.1 Fault Type and Distance A, 8.5 km 3.4.1 Seismic Design Category D 5.8 Site Class D 5.8 Maximum Considered Earthquake MCE Short Period Spectral Response, S, 1.50 g 5.8 Second Spectral Response, S, 0.60 g 5.8 Site Coefficient, Fa 1.00 5.8 Site. Coefficient, F,, 1.50 5.8 Pavement TI equal to 4.5 (Light Traffic) 3.0" AC / 4.0" AB 5.9 TI equal to 7.0 (Heavy Traffic) 4.0" AC / 4.5" AB 5.9 Slabs Building Floor Slabs On engineered fill 5.5 Modulus of Sub grade Reaction 200 pci 5.5 Existing Site Conditions Existing Fill Possibly along West Boundary Soil Corrosivity low sulfates low chlorides Severe Resistivity 5.7 Groundwater Depth Presently 110 feet, Historic 70 feet 3.2 Estimated Fill and Cut excludes over - excavation 10 feet - fill and cut 1.1 The recommendations contained within this report are subject to the limitations presented in • Section 6 of this report. We recommend that all individuals using this report read the limitations. EARTH SYSTEMS SOUTHWEST July 20, 2010 GEOTECHNICAL ENGINEERING REPORT PROPOSED 9.5 -ACRE RESIDENTIAL DEVELOPMENT SOUTH OF HIGHWAY 111 AND EAST OF DUNE PALMS ROAD LA QUINTA, CALIFORNIA Section 1 INTRODUCTION 1.1 Project Description File No.: 09354 -02 Doc. No.: 10-07-753 This geotechnical engineering report has been prepared for the proposed 9.5 -acre residential development to be located south of Highway 111 and east of Dune Palms Road in the City of La Quinta, California. The proposed 180 -unit affordable housing project will include 11 two -story structures and one single -story apartment structure. We understand that the proposed structures will be of wood frame construction supported by conventional shallow continuous or pad footings and will have a stucco exterior. Other site improvements will include a playground, sport court, pool, exterior concrete flatwork, asphalt drive lanes and parking stalls (348 parking spaces), 201 covered parking spaces, and landscaping. Site development will include clearing and grubbing of vegetation, site grading, building pad preparation, underground utility installation, street and parking lot construction, and concrete driveway and sidewalk placement. Site development may also include abandonment of an existing well. Based on existing site topography and ground conditions, site grading is expected to consist of cuts and fills not exceeding 10 feet. We used maximum column loads of 30 kips and a maximum wall loading of 2.0 kips per linear foot as a basis for the foundation recommendations. All loading is assumed to be dead plus actual live load. The preliminary design loading was assumed. If actual structural loading exceeds these assumed values, we would need to reevaluate the given recommendations. 1.2 Site Description The proposed 180 -unit multi - family complex is to be constructed on the approximate 9.5 -acre site. The site is a "flag" parcel accessed from Dune Palms Drive between the north side the Desert Sands Unified School District Office and the south side of an existing storage facility, in the City of La Quinta, California. The site location is shown on Figure 1 in Appendix A. The project site presently consists of open desert with no apparent signs of previous development, except for an area of possible fill along the west boundary. There is an abandoned residential trailer park to the north, an existing storage facility to the west, Desert Sands Unified School District offices to the south, and a Costco retail store to the east. The history of past use and development of the property was not investigated as part of our scope of services. No evidence of past development was observed on the site during our reconnaissance. Nonetheless, some previous development of the site is possible. Buried remnants, such as old foundations, slabs, or septic systems, may exist on the site. There are underground utilities near and within the building area. These utility lines include, but are not limited to, domestic water, electric, sewer, telephone, cable, and irrigation lines. EARTH SYSTEMS SOUTHWEST July 20, 2010 2 File No.: 09354 -02 Doc. No.: 10 -07 -753 • 1.3 Purpose and Scope of Services The purpose for our services was to evaluate the site soil conditions and to provide professional opinions and recommendations regarding the proposed development of the site. The scope of work included the following: ➢ A general reconnaissance of the site. ➢ Shallow subsurface exploration by drilling 9 exploratory borings to depths ranging from 16.5 to 31.5 feet below existing grade. ➢ Laboratory testing of selected soil samples obtained from the exploratory borings. ➢ A review of selected published technical literature pertaining to the site and previous geotechnical reports prepared for other projects in the immediate area. ➢ An engineering analysis and evaluation of the acquired data from the exploration and Not Contained in This Report: Although available through Earth Systems Southwest, the current scope of our services does not include: ➢ A corrosive study to determine cathodic protection of concrete or buried pipes. ➢ An environmental assessment. ➢ An investigation for the presence or absence of wetlands, hazardous or toxic materials in the soil, surface water, groundwater, or air on, below, or adjacent to the subject property. The client did not direct ESSW to provide any service to investigate or detect the presence of moisture, mold, or other biological contaminates in or around any structure, or any service that was designed or intended to prevent or lower the risk or the occurrence of the amplification of the same. Client acknowledges that mold is ubiquitous to the environment, with mold amplification occurring when building materials are impacted by moisture. Client further acknowledges that site conditions are outside of ESSW's control and that mold amplification will likely occur or continue to occur in the presence of moisture. As such, ESSW cannot and • shall not be held responsible for the occurrence or recurrence of mold amplification. EARTH SYSTEMS SOUTHWEST testing programs. ➢ A' summary of our findings and recommendations in this written report. This report contains the following: ➢ Discussions on subsurface soil and groundwater conditions- ➢ Discussions on regional and local geologic conditions. ➢ Discussions on.geologic and seismic hazards. ➢ Graphic and tabulated results of laboratory tests and field studies. ➢ Recommendations regarding: • Site development and grading criteria. • Excavation conditions and buried utility installations. • Structure foundation type and design. • • Allowable foundation bearing capacity and expected total and differential settlements. • Concrete slabs -on- grade. • Lateral earth pressures and coefficients. • Mitigation of the potential corrosivity of site soils to concrete and steel reinforcement. • Seismic design parameters. • Preliminary pavement structural sections. Not Contained in This Report: Although available through Earth Systems Southwest, the current scope of our services does not include: ➢ A corrosive study to determine cathodic protection of concrete or buried pipes. ➢ An environmental assessment. ➢ An investigation for the presence or absence of wetlands, hazardous or toxic materials in the soil, surface water, groundwater, or air on, below, or adjacent to the subject property. The client did not direct ESSW to provide any service to investigate or detect the presence of moisture, mold, or other biological contaminates in or around any structure, or any service that was designed or intended to prevent or lower the risk or the occurrence of the amplification of the same. Client acknowledges that mold is ubiquitous to the environment, with mold amplification occurring when building materials are impacted by moisture. Client further acknowledges that site conditions are outside of ESSW's control and that mold amplification will likely occur or continue to occur in the presence of moisture. As such, ESSW cannot and • shall not be held responsible for the occurrence or recurrence of mold amplification. EARTH SYSTEMS SOUTHWEST July 20, 2010 Section 2 METHODS OF INVESTIGATION 2.1 Field Exploration 3 File No.: 09354 -02 Doc. No.: 10 -07 -753 Nine exploratory borings were drilled to depths ranging from 16.5 to 31.5 feet below the existing ground surface to observe the soil profile and to obtain samples for laboratory testing. The borings were drilled on August 28, 2003 using 8 -inch outside diameter hollow -stem augers, powered by a CME 45 truck - mounted drilling rig. The boring locations are shown on the boring location map, Figure 2, in Appendix A. The locations shown are approximate, established by pacing and sighting from existing topographic features. Samples were obtained within the test borings using a Standard Penetration [SPT] sampler (ASTM D 1586) and a Modified California [MC] ring sampler (ASTM D 3550 with shoe similar to ASTM D 1586). The SPT sampler has a 2 -inch outside diameter and a 1.38 -inch inside diameter. The MC sampler has a 3 -inch outside diameter and a 2.37 -inch inside diameter. The samples were obtained by driving the sampler with a 140 -pound hammer, manually activated by rope and cathead, dropping 30 inches in general accordance with ASTM D 1586. Recovered soil samples were sealed in containers and returned to the laboratory. Bulk samples were also obtained from auger cuttings, representing a mixture of soils encountered at the depths noted. The final logs of the borings represent our interpretation of the contents of the field logs and the results of laboratory testing performed on the samples obtained during the subsurface exploration. The final logs are included in Appendix A of this report. The stratification lines represent the approximate boundaries between soil types, although the transitions may be gradational. 2.2 Laboratory Testing Samples were reviewed along with field logs to select those that would be analyzed further. Those selected for laboratory testing include soils that would be exposed and used during grading and those deemed to be within the influence of the proposed structure. Test results are presented in graphic and tabular form in Appendix B of this report. The tests were conducted in general accordance with the procedures of the American Society for Testing and Materials [ASTM] or other standardized methods as referenced below. Our testing program consisted of the following: ➢ In -situ Moisture Content and Unit Dry Weight for the ring samples (ASTM D 2937). ➢ Maximum density tests to evaluate the moisture - density relationship of typical soils encountered (ASTM D 1557). ➢ Particle Size Analysis (ASTM D 422) to classify and evaluate soil composition. The gradation characteristics of selected samples were made by hydrometer and sieve analysis procedures. ➢ Consolidation (Collapse Potential, ASTM D 2435 and D 5333) to evaluate the compressibility and hydroconsolidation (collapse) potential of the soil. ➢ Chemical Analyses (Soluble Sulfates and Chlorides, pH, and Electrical Resistivity) to evaluate the potential adverse effects of the soil on concrete and steel. EARTH SYSTEMS SOUTHWEST July 20, 2010 • Section 3 DISCUSSION 3.1 Soil Conditions 4 File No.: 09354 -02 Doc. No.: 10 -07 -753 The field exploration indicates that site soils consist generally of sand, silty sand, and silt (Unified Soils Classification System symbols of SP -SM, SM, SM/ML, and ML). The boring logs provided in Appendix A include more detailed descriptions of the soils encountered. The soils are visually classified to be in the very low expansion (EI < 20) category. Site soils are classified as Type C in accordance with CalOSHA. In and climatic regions, granular soils may have a potential to collapse upon wetting. Collapse (hydroconsolidation) may occur when the soluble cements (carbonates) in the soil matrix dissolve, causing the soil to densify from its loose configuration from deposition. Consolidation tests indicate 0.7 to 2.6% collapse upon inundation and collapse is therefore considered a low to moderate site risk. The hydroconsolidation potential is commonly mitigated by recompaction of a zone beneath building pads. The site lies within a recognized blow sand hazard area. Fine particulate matter (PMjo) can create an air quality hazard if dust is blowing. Watering the surface, planting grass or landscaping, or placing hardscape normally mitigates this hazard. 3.2 Groundwater Free groundwater was not encountered in the borings during exploration. The depth to • groundwater in the area is believed to be about 110-feet below existing grade based on 1986 water well data obtained from the Coachella Valley Water District. Historical high groundwater is estimated to be about 70 feet below existing grade. However, there is uncertainty in the accuracy of short-term water level measurements. Groundwater levels may fluctuate with precipitation, irrigation, drainage, regional pumping from wells, and site grading. The absence of groundwater levels detected may not represent an accurate or permanent condition. Groundwater should not be a factor in design or construction at this site. • 3.3 Geologic Setting Regional Geology: The site lies within the Coachella Valley, a part of the Colorado Desert geomorphic province. A significant feature within the Colorado Desert geomorphic province is the Salton Trough. The Salton Trough is a large northwest- trending structural depression that extends approximately 180 miles from the San Gorgonio Pass to the Gulf of California. Much of this depression in the area of the Salton Sea is below sea level. The Coachella Valley forms the northerly part of the Salton Trough. The Coachella Valley contains a thick sequence of Miocene to Holocene sedimentary deposits. Mountains surrounding the Coachella Valley include the Little San Bernardino Mountains on the northeast, foothills of the San Bernardino Mountains on the northwest, and the San Jacinto and Santa Rosa Mountains on the southwest. These mountains expose primarily Precambrian metamorphic and Mesozoic granitic rocks. The San Andreas fault zone within the Coachella Valley consists of the Garnet Hill fault, the Banning fault, and the Mission Creek fault that traverse along the northeast margin of the valley. EARTH SYSTEMS SOUTHWEST July 20, 2010 5 File No.: 09354 -02 Doc. No.: 10 -07 -753 Local Geolo : The project site is located approximately ' /z mile south of the Whitewater River channel, about '/4 mile northwest of the La Quinta evacuation channel, and 18 feet below mean sea level in the eastern part of the Coachella Valley. The sediments within the valley consist of fine- to coarse - grained sands with interbedded clays, silts, gravels, and cobbles of aeolian (wind- blown), lacustrine (lake -bed), and alluvial (water -laid) origin. The depth to crystalline basement rock beneath the site is estimated to be in excess of 2000 feet (Envicom, 1976). 3.4 Geologic Hazards Geologic hazards that may affect the region include seismic hazards (ground shaking, surface fault rupture, soil liquefaction, and other secondary earthquake- related hazards). A discussion follows on the specific hazards to this site. 3.4.1 Seismic Hazards Seismic Sources: Several active faults or seismic zones lie within 62 miles (100 kilometers) of the project site as shown on Table 1 in Appendix A. The primary seismic hazard to the site is strong ground shaking from earthquakes along the San Andreas and San Jacinto faults. The Maximum Magnitude Earthquake (Mme) listed is from published geologic information available for each fault (Cao et al., CGS, 2003). The Mora,, corresponds to the maximum earthquake believed to be tectonically possible. Surface Fault Rupture: The project site does not lie within a currently delineated State of California, Alquist - Priolo Earthquake Fault Zone (Hart, 1997). Well- delineated fault lines cross through this region as shown on California Geological Survey [CGS] maps (Jennings, 1994); however, no active faults are mapped in the immediate vicinity of the site. Therefore, active fault rupture is unlikely to occur at the project site. While fault rupture would most likely occur along previously established fault traces, future fault rupture could occur at other locations. Historic Seismicity: Six historic seismic events (5.9 M or greater) have significantly affected the Coachella Valley in the last 100 years. They are as follows: • Desert Hot Springs Earthquake — On December 4, 1948, a magnitude 6.5 ML (6.OMW) earthquake occurred east of Desert Hot Springs. This event was strongly felt in the Palm Springs area. • Palm Springs Earthquake — A magnitude 5.9 ML (6.2Mw) earthquake occurred on July 8, 1986 in the Painted Hills, causing minor surface creep of the Banning segment of the San Andreas fault. This event was strongly felt in the Palm Springs area and caused structural damage, as well as injuries. • Joshua Tree Earthquake — On April 22, 1992, a magnitude 6.1 ML (6.1Mw) earthquake occurred in the mountains 9 miles east bf Desert Hot Springs. Structural damage and minor injuries occurred in the La Quinta area as a result of this earthquake. • Landers and Big Bear Earthquakes — Early on June 28, 1992, a magnitude 7.5 Ms (7.3Mw) earthquake occurred near Landers, the largest seismic event in Southern California for 40 years. Surface rupture occurred just south of the town of Yucca Valley and extended some 43 miles toward Barstow. About three hours later, a magnitude 6.6 Ms (6.4Mw) earthquake occurred near Big Bear Lake. No significant structural damage from these earthquakes was reported in the La Quinta area. EARTH SYSTEMS SOUTHWEST July 20, 2010 6 File No.: 09354 -02 Doc. No.: 10 -07 -753 • Hector Mine Earthquake — On October 16, 1999, a magnitude 7.1MW earthquake occurred on the Lavic Lake and Bullion Mountain faults north of Twentynine Palms. While this event was widely felt, no significant structural damage has been reported in the Coachella Valley. Seismic Risk: While accurate earthquake predictions are not possible, various agencies have conducted statistical risk analyses. In 2002 and 2008, the California Geological Survey [CGS] and the United States Geological Survey [USGS] published a set of probabilistic seismic hazard maps. We have used these maps in our evaluation of the seismic risk at the site. The recent Working Group of California Earthquake Probabilities (WGCEP, 2008) estimated a 58% conditional probability that a magnitude 6.7 or greater earthquake may occur between 2008 and 2038 along the southern segment of the San Andreas fault. The primary seismic risk at the site is a potential earthquake along the San Andreas fault, located about 8.5 km (5.3 miles) from the site and considered as fault Type A (CGS). Geologists believe that the San Andreas fault has characteristic earthquakes that result from rupture of each fault segment. The estimated characteristic earthquake is magnitude 7.7 for the Southern Segment of the fault (USGS, 2002). This segment has the longest elapsed time since rupture of any part of the San Andreas fault. The last rupture occurred about 1680 AD, based on dating by the USGS near Indio (WGCEP, 2008). This segment has also ruptured on about 1020, 1300, and 1450 AD, with an average recurrence interval of about 220 years. The San Andreas fault may rupture in multiple segments, producing a higher magnitude earthquake. Recent paleoseismic studies suggest that the San Bernardino Mountain Segment to the north and the Coachella Segment may have ruptured together in 1450 and 1690 AD (WGCEP, 1995). • 3.4.2 Secondary. Hazards Secondary seismic hazards related to ground shaking include soil liquefaction, ground subsidence, tsunamis, and seiches. The site is far inland, so the hazard from tsunamis is non- existent. At the present time, no water storage reservoirs are located in the immediate vicinity of the site. Therefore, hazards from seiches are considered negligible at this time. • Soil Liquefaction: Liquefaction is the loss of soil strength from sudden shock (usually earthquake shaking), causing the soil to become a fluid mass. In general, for the effects of liquefaction to be manifested at the surface, groundwater levels must be within 50 feet of the ground surface and the soils within the saturated zone must also be susceptible to liquefaction. The potential for liquefaction to occur at this site is considered negligible because the depth of groundwater beneath the site exceeds 50 feet. No free groundwater was encountered in our exploratory borings. In addition, the project does not lie within the liquefaction hazard zone identified by the City of La Quinta General Plan. Ground Subsidence: The potential for seismically induced ground subsidence is considered to be low at the site. Dry sands tend to settle and densify when subjected to strong earthquake shaking. The amount of subsidence is dependent on relative density of the soil, ground motion, and earthquake duration. Uncompacted fill areas may be susceptible to seismically induced settlement. Slope Instability: The site is relatively flat. Therefore, potential hazards from slope instability, landslides, or debris flows are considered negligible. EARTH SYSTEMS SOUTHWEST July 20, 2010 7 File No.: 09354 -02 Doc. No.: 10 -07 -753 Flooding: The approximate northeast third of the project site lies. within a designated FEMA 100 -year flood plain. The project site may be in an area where sheet flooding and erosion could occur. If significant changes are proposed for the site, appropriate project design, construction, and maintenance can minimize the site sheet flooding potential. 3.4.3 Site Acceleration and Seismic Coefficients Site Acceleration: The potential intensity of ground motion may be estimated by the horizontal peak ground acceleration [PGA], measured in "g" forces. Included in Table 1 are deterministic estimates of site acceleration from possible earthquakes at nearby faults. Ground motions are dependent primarily on the earthquake magnitude and distance to the seismogenic (rupture) zone. Accelerations are also dependent upon attenuation by rock and soil deposits, direction of rupture, and type of fault. For these reasons, ground motions may vary considerably in the same general area. This variability can be expressed statistically by a standard deviation about a mean relationship. The PGA alone is an inconsistent scaling factor and is generally a poor indicator of potential structural damage during an earthquake. Important factors influencing the structural performance are the duration and frequency of strong ground motion, local subsurface conditions, soil - structure interaction, and structural details. The following table provides the probabilistic estimate of the PGA taken from the 2002 CGS/USGS seismic hazard maps /data. Estimate of PGA from 2002 CGS /USGS Probabilistic Seismic Hazard Maps/Data Risk Equivalent Return Period ears PGA 10% exceedance in 50 ears 475 0.57 Notes: I Based on Site Class B/C and soil amplification factor of 1.0 for Site Class D. 2007 CBC Seismic Coefficients: The California Building Code [CBC] seismic design parameters criteria are based on a Design Earthquake that has an earthquake ground motion z/3 of the lesser of 2% probability of occurrence in 50 years or 150% of mean deterministic limit. The PGA estimate given above is provided for information on the seismic risk inherent in the CBC design. The seismic and site coefficients given in Chapter 16 of the 2007 California Building Code are provided in Section 5.8 of this report. Seismic Hazard Zones: The site lies in a low liquefaction potential zone designated by the 2003 Riverside County Integrated Project because of intermediate groundwater (50 -100 feet), and very susceptible sediments. This portion of Riverside County has not been mapped by the California Seismic Hazard Mapping Act (Ca. PRC 2690 to 2699). EARTH SYSTEMS SOUTHWEST July 20, 2010 8 File No.: 09354 -02 Doc. No.: 10 -07 -753 • Section 4 CONCLUSIONS The following is a summary of our conclusions and professional opinions based on the data obtained from a review of selected technical literature and the site evaluation. General: ➢ From a geotechnical perspective, the site is suitable for the proposed development, provided the recommendations in this report are followed in the design and construction of this project. Geotechnical Constraints and Mitigation: ➢ The primary geologic hazard is severe ground shaking from earthquakes originating on nearby faults. A major earthquake above magnitude 7 originating on the local segment of the San Andreas fault zone would be the critical seismic event that may affect the site within the design life of the proposed development. Engineered design and earthquake - resistant construction increase safety and allow development of seismic areas. ➢ The underlying geologic condition for seismic design is Site Class D. The site is about 8.5 km from a Type A seismic source as defined by the California Geological Survey. A qualified professional should design any permanent structure constructed on the site. The • minimum seismic design should comply with the 2007 edition of the California Building Code. ➢ Ground subsidence from seismic events or hydroconsolidation is a potential hazard in the Coachella Valley area. Adherence to the grading and structural recommendations in this report should reduce potential settlement problems from seismic forces, heavy rainfall or irrigation, flooding, and the weight of the intended structures. L� ➢ The soils are susceptible to wind and water erosion. Preventative measures to reduce seasonal flooding and erosion should be incorporated into site grading plans. Dust control should also be implemented during construction. Site grading should be in strict compliance with the requirements of the South Coast Air Quality Management District [SCAQMD]. ➢ Other geologic hazards, including fault rupture, liquefaction, seismically induced flooding, and landslides, are considered low or negligible on this site. ➢ The upper soils were found to be variable from relatively loose to dense sand, silty sand, and silt, and are unsuitable in their present condition to support structures, fill, and hardscape. The soils within the building and structural areas will require moisture conditioning, over - excavation, and recompaction to improve bearing capacity and reduce the potential for differential settlement from static loading. Soils can be readily cut by normal grading equipment. EARTH SYSTEMS SOUTHWEST July 20, 2010 9 File No.: 09354 -02 Doc. No.: 10 -07 -753 Section 5 RECOMMENDATIONS SITE DEVELOPMENT AND GRADING 5.1 Site Development — Grading A representative of Earth Systems Southwest [ESSW] should observe site clearing, grading, and the bottoms of excavations before placing fill. Local variations in soil conditions may warrant increasing the depth of recompaction and over - excavation. Clearing and Grubbing: At the start of site grading, existing vegetation, trees, large roots, pavements, foundations, non - engineered fill, construction debris, trash, and abandoned underground utilities should be removed from the proposed building, structural, and pavement areas. The surface should be stripped of organic growth and removed from the construction area. Areas disturbed during clearing should be properly backfilled and compacted as described below. Dust control should also be implemented during construction. Site grading should be in strict compliance with the requirements of the South Coast Air Quality Management District [SCAQMD]. Building Pad Preparation: Because of the relatively non - uniform and under- compacted nature of the site soils, we recommend recompaction of soils in the building area. The existing surface soils within the building pad and foundation areas should be over - excavated to a minimum of 5 feet below existing grade or a minimum of 4 feet below the footing level (whichever is lower). The over - excavation should extend for 5 feet beyond the outer edge of exterior footings, where possible. The bottom of the sub - excavation should be scarified, moisture conditioned, and recompacted to at least 90% relative compaction (ASTM D 1557) for an additional depth of one foot. As an alternative, over - excavation in the building pad areas may be achieved on a pad -by -pad schedule as follows (elevations based on the referenced mass grading plans authored by MSA and supplied by the client): • Building A: 49.8 feet • Building B: 48.0 feet • Building C: 47.0 feet • Building D: 46.7 feet • Building E: 47.2 feet • Building F: 46.8 feet • Building G: 49.2 feet • Building H: 47.9 feet • Building I: 49.8 feet • Building J: 55.0 feet • Building K: 49.5 feet • Building L: 48.7 feet EARTH SYSTEMS SOUTHWEST July 20, 2010 10 File No.: 09354 -02 Doc. No.: 10 -07 -753 • As previously stated, the over - excavation should extend for 5 feet beyond the outer edge of exterior footings, where possible. The bottom of the sub - excavation should be scarified, moisture conditioned, and recompacted to at least 90% relative compaction (ASTM D 1557) for an additional depth of one foot. Auxiliary Structures Subgrade Preparation: Auxiliary structures such as garden or retaining walls should have the foundation subgrade prepared similar to the building pad recommendations given above. The lateral extent of the over - excavation needs to extend only 2 feet beyond the face of the footing. Subgrade Preparation: In areas to receive fill, pavements, or hardscape, the subgrade should be scarified, moisture conditioned, and compacted to at least 90% relative compaction (ASTM D 1557) for a depth of one foot below finished subgrades or one foot below the bottom of the foundation, whichever is deeper. Compaction should be verified by testing. Engineered Fill Soils: The native soil is suitable for use as engineered fill and utility trench backfill, provided it is free of significant organic or deleterious matter. The native soil should be placed in maximum 8 -inch lifts (loose) and compacted to at least 90% relative compaction (ASTM D 1557) near its optimum moisture content. Compaction should be verified by testing. Rocks larger than 6 inches in greatest dimension should be removed from fill or backfill material. Imported fill soils (if needed) should be non - expansive, granular soils meeting the USCS classifications of SM, SP -SM, or SW -SM with a maximum rock size of 3 inches and 5 to 35% passing the No. 200 sieve. The geotechnical engineer should evaluate the import fill • soils before hauling to the site. However, because of the potential variations within the borrow source, import soil will not be prequalified by ESSW. The imported fill should be placed in lifts no greater than 8 inches in loose thickness and compacted to at least 90% relative compaction (ASTM D 1557) near optimum moisture content. Shrinkage: The shrinkage factor for earthwork is expected to range from 15 to 20 percent for the upper excavated or scarified site soils. This estimate is based on compactive effort to achieve an average relative compaction of about 92% and may vary with contractor methods. Subsidence is estimated to be less than 0.2 feet. Losses from site clearing and removal of existing site improvements may affect earthwork quantity calculations and should be considered. Site Drainage: Positive drainage should be maintained away from the structures (5% for 5 feet minimum) to prevent ponding and subsequent saturation of the foundation soils. Gutters and downspouts should be considered as a means to convey water away from foundations if adequate drainage is not provided. Drainage should be maintained for paved areas. Water should not pond on or near paved areas. 5.2 Excavations and Utility Trenches Excavations should be made in accordance with CalOSHA requirements.. Using the Cal/OSHA standards and general soil information obtained from the field exploration, classification of the near surface on -site soils will likely be characterized as Type C. Actual classification of site specific soil type per Cal /OSHA specifications as they pertain to trench safety should be based on real -time observations and determinations of exposed soils by the Competent Person during grading and trenching operations. • EARTH SYSTEMS SOUTHWEST July 20, 2010 11 File No.: 09354 -02 Doc. No.: 10 -07 -753 Our site exploration and knowledge of the general area indicates there is a potential for caving of site excavations (utilities, footings, etc.). Excavations within sandy soil should be kept moist, but not saturated, to reduce the potential of caving or sloughing. Where excavations over 4 feet deep are planned, lateral bracing or appropriate cut slopes of 1.5:1 (horizontal: vertical) should be provided. No surcharge loads from stockpiled soils or construction materials should be allowed within a horizontal distance measured from the top of the excavation slope and equal to the depth of the excavation. Utility Trenches: Backfill of utilities within roads or public right -of -ways should be placed in conformance with the requirements of the governing agency (water district, public works department, etc.). Utility trench backfill within private property should be placed in conformance with the provisions of this report. In general, service lines extending inside of property may be backfilled with native soils compacted to a minimum of 90% relative compaction. Backfll operations should be observed and tested to monitor compliance with these recommendations. 5.3 Slope Stability of Graded Slopes Unprotected, permanent graded slopes should not be steeper than 3:1 (horizontal: vertical) to reduce wind and rain erosion. Protected slopes with ground cover may be as steep as 2:1. However, maintenance with motorized equipment may not be possible at this inclination. Fill slopes should be overfilled and trimmed back to competent material. Slope stability calculations are not presented because of the expected minimal slope heights (less than 5 feet). STRUCTURES In our professional opinion, structure foundations can be supported on shallow foundations bearing on a zone of properly prepared and compacted soils placed as recommended in Section 5.1. The recommendations that follow are based on very low expansion category soils. 5.4 Foundations Footing design of widths, depths, and reinforcing are the responsibility of the Structural Engineer, considering the structural loading and the geotechnical parameters given in this report. A minimum footing depth of 12 inches below lowest adjacent grade should be maintained. A representative of ESSW should observe foundation excavations before placement of reinforcing steel or concrete. Loose soil or construction debris should be removed from footing excavations before placement of concrete. Conventional Spread Foundations: Allowable soil bearing pressures are given below for foundations bearing on recompacted soils as described in Section 5.1. Allowable bearing pressures are net (weight of footing and soil surcharge may be neglected). ➢ Continuous wall foundations, 12 -inch minimum width and 12 inches below grade: 1500 psf for dead plus design live loads Allowable increases of 300 psf per each foot of additional footing width and 300 psf for each additional 0.5 -foot of footing depth may be used up to a maximum value of 2500 psf. EARTH SYSTEMS SOUTHWEST July 20, 2010 12 File No.: 09354 -02 Doc. No.: 10 -07 -753 • ➢ Isolated pad foundations, 2 x 2 foot minimum in plan and 18 inches below grade: 2000 psf for dead plus design live loads Allowable increases of 200 psf per each foot of additional footing width and 400 psf for each additional 0.5 -foot of footing depth may be used up to a maximum value of 2500 psf. A one -third ('/3) increase in the bearing pressure may be used when calculating resistance to wind or seismic loads. The allowable bearing values indicated are based on the anticipated maximum loads stated in Section 1.1 of this report. If the anticipated loads exceed these values, the geotechnical engineer must reevaluate the allowable bearing values and the grading requirements. Minimum reinforcement for continuous wall footings should be two No. 4 steel reinforcing bars, one placed near the top and one placed near the bottom of the footing. This reinforcing is not intended to supersede any structural requirements provided by the structural engineer. Expected Settlement: Estimated total static settlement should be less than one -inch, based on footings founded on firm soils as recommended. Differential settlement between exterior and interior bearing members should be less than '/2 -inch, expressed in a post - construction angular distortion ratio of 1:480 or less. Frictional and Lateral Coefficients: Lateral loads may be resisted by soil friction on the base of foundations and by passive resistance of the soils acting on foundation walls. An allowable coefficient of friction of 0.35 of dead load may be used. An allowable passive equivalent fluid pressure of 350 pcf may also be used. These values include a factor of safety of 1.5. Passive resistance and frictional resistance may be used in combination if the friction coefficient is • reduced by one - third. A one -third ('/3) increase in the passive pressure may be used. when calculating resistance to wind or seismic loads. Lateral passive resistance is based on the assumption that backfill next to foundations is properly compacted. 5.5 Slabs -on -Grade Sub rade: Concrete slabs -on -grade and flatwork should be supported by compacted soil placed in accordance with Section 5.1 of this report. • Vapor Retarder: In areas of moisture sensitive floor coverings, an appropriate vapor retarder should be installed to reduce moisture transmission from the subgrade soil to the slab. For these areas, an impermeable membrane (10 -mil thickness) should underlie the floor slabs. The membrane should be covered with 2 inches of sand to help protect it during construction and to aid in concrete curing. The sand should be lightly moistened just prior to placing the concrete. Low -slump concrete should be used to help reduce the potential for concrete shrinkage. The effectiveness of the membrane is dependent upon its quality, the method of overlapping, its protection during construction, and the successful sealing of the membrane around utility lines. The following minimum slab recommendations are intended to address geotechnical concerns such as potential variations of the subgrade and are not to be construed as superseding any structural design. The design engineer and/or project architect should ensure compliance with SB800 with regards to moisture and moisture vapor. EARTH SYSTEMS SOUTHWEST July 20, 2010 13 File No.: 09354 -02 Doc. No.: 10 -07 -753 Slab Thickness . and Reinforcement: Slab thickness and reinforcement of slabs -on -grade are contingent on the recommendations of the structural engineer or architect and the expansion index of the supporting soil. Based upon our findings, a modulus of subgrade reaction of approximately 200 pounds per cubic inch can be used in concrete slab design for the expected very low expansion subgrade. Concrete slabs and flatwork should be a minimum of 4 inches thick (actual, not nominal). We suggest that the concrete slabs be reinforced with a minimum of No. 3 rebars at 18 -inch centers, both horizontal directions, placed at slab mid - height to resist potential cracking. Concrete floor slabs may either be monolithically placed with the foundations or doweled after footing placement. The thickness and reinforcing given are not intended to supersede any structural requirements provided by the structural engineer. The project architect or geotechnical engineer should continually observe all reinforcing steel in slabs during placement of concrete to check for proper location within the slab. Control Joints: Control joints should be provided in all concrete slabs -on -grade at a maximum spacing of 36 times the slab thickness (12 feet maximum on- center, each way) as recommended by American Concrete Institute [ACI] guidelines. All joints should form approximately square patterns to reduce the potential for randomly oriented shrinkage cracks. Construction joints in the slabs should be tooled at the time of the concrete placement or saw cut ('/4 of slab depth) as soon as practical but not more than 8 hours from concrete placement. Construction (cold) joints should consist of thickened butt joints with '/2 -inch dowels at 18- inches on center or a thickened keyed joint to resist vertical deflection at the joint. All construction joints in exterior flatwork should be sealed to reduce the potential of moisture or foreign material intrusion. These procedures will reduce the potential for randomly oriented cracks, but may not prevent them from occurring. Curing and Quality Control: The contractor should take precautions to reduce the potential of curling of slabs in this and desert region using proper batching, placement, and curing methods. Curing is highly affected by temperature, wind, and humidity. Quality control procedures may be used, including trial batch mix designs, batch plant inspection, and on -site special inspection and testing. Typically, for this type of construction and using 2500 -psi concrete, many of these quality control procedures are not required. 5.6 Retaining Walls The following table presents lateral earth pressures for use in retaining wall design. The values are given as equivalent fluid pressures without surcharge loads or hydrostatic pressure. Lateral Pressures and Sliding Resistance t Granular Backfill Passive Pressure 350 pcf - level ground Active Pressure (cantilever walls) Use when wall is permitted to rotate 0.1 to 0.2% of wall 35 pcf - level ground height for granular backfill At -Rest Pressure restrained walls 55 pcf - level ground Dynamic Lateral Earth Pressure 2 Acting at 0.6H, 15 pcf Where H is height of backfill in feet Base Lateral Sliding Resistance 0.50 Dead load x Coefficient of Friction: EARTH SYSTEMS SOUTHWEST July 20, 2010 14 File No.: 09354 -02 Doc. No.: 10 -07 -753 40 Notes: These values are ultimate values. A factor of safety of 1.5 should be used in stability analysis except for dynamic earth pressure where a factor of safety of 1.2 is acceptable. 2 Dynamic pressures are based on the Mononobe -Okabe 1929 method, additive to active earth pressure. Walls retaining less than 6 feet of soil and not supporting inhabitable structures need not consider this increased pressure (reference: CBC Section 1630A.1.1.5). Upward sloping backfill or surcharge loads from nearby footings can create larger lateral pressures. Should any walls be considered for retaining sloped backfill or placed next to foundations, our office should be contacted for recommended design parameters. Surcharge loads should be considered if they exist within a zone between the face of the wall and a plane projected 45 degrees upward from the base of the wall. The increase in lateral earth pressure should be taken as 35% of the surcharge load within this zone. Retaining walls subjected to traffic loads should include a uniform surcharge load equivalent to at least 2 feet of native soil. Drainage: A backdrain or an equivalent system of backfill drainage should be incorporated into the retaining wall design, whereby, the collected water is conveyed to an approved point of discharge. Our firm can provide construction details when the specific application is determined. Backfill immediately behind the retaining structure should be a free - draining granular material. Waterproofing should be according to the designer's specifications. Water should not be allowed to pond near the top of the wall. To accomplish this, the final backfill grade should be such that all water is diverted away from the retaining wall. Backfill and Subgrade Compaction: Compaction on the retained side of the wall within a • horizontal distance equal to one wall height should be performed by hand - operated or other lightweight compaction equipment. This is intended to reduce potential locked -in lateral pressures caused by compaction with heavy grading equipment. Foundation subgrade preparation should be as specified in Section 5.1. 5.7 Mitigation of Soil Corrosivity on Concrete Selected chemical analyses for corrosivity were conducted on soil samples from the project site as shown in Appendix B. • Sulfate and other salts can attack the cement within concrete causing weakening of the cement matrix and eventual deterioration by raveling. This attack can be in the form of a physical attack or chemical attack whereby there may be a chemical reaction between the sulfate and the cement used in the concrete. According to ACI 318 as referenced by the 2007 California Building Code, if sulfate concentrations exceed 1000 ppm there will be special requirements. For this project, the results of those samples tested suggest a low sulfate ion concentration (65 ppm). Normal concrete mixes may be used. Electrical resistivity is a process whereby metal (ferrous) objects in direct contact with soil may be subject to attack by electrochemical corrosion. This typically pertains to buried metal pipes, valves, culverts, etc. made of ferrous metal. To avoid this type of corrosion or to slow the process, buried metal objects are generally protected with waterproof resistant barriers, i.e. epoxy corrosion inhibitors, asphalt coatings, cathodic protection, or encapsulating with densely consolidated concrete. Electrical resistivity testing of the soil suggests that the site soils may present a severe potential for metal loss from electrochemical corrosion processes. EARTH SYSTEMS SOUTHWEST July 20, 2010 15 File No.: 09354 -02 Doc. No.: 10 -07 -753 Chloride ions can cause corrosion of reinforcing steel. For this project, the results of those samples tested suggest a low chloride ion concentration (99 ppm). ACI 318 is referenced by the California Building Code, and provides commentary relative to the effects of chlorides present in the soil; from both internal and external sources. It is possible that long term saturation of foundations with chloride rich water could allow the chloride access to the reinforcing steel. A minimum concrete cover of cast -in -place concrete should be in accordance with Section 7.7 of the 2007 edition of ACI 318. Additionally, the concrete should be thoroughly vibrated during placement. The information provided above should be considered preliminary. These values can potentially change based on several factors, such as importing soil from another job site and the quality of construction water used during grading and subsequent landscape irrigation. Earth Systems does not practice corrosion engineering. We recommend that a qualified corrosion engineer evaluate the corrosion potential on metal construction materials and concrete at the site to provide mitigation of corrosive effects, if further guidance is desired. 5.8 Seismic Design Criteria This site is subject to strong ground shaking due to potential fault movements along the San Andreas and San Jacinto faults. Engineered design and earthquake - resistant construction increase safety and allow development of seismic areas. The minimum seismic design should comply with the 2007 edition of the California Building Code and ASCE 7 -05 using the seismic coefficients given in the table below. 2007 CBC (ASCE 7 -05) Seismic Parameters The intent of the CBC lateral force requirements is to provide a structural design that will resist collapse to provide reasonable life safety from a major earthquake, but may experience some structural and nonstructural damage. A fundamental tenet of seismic design is that inelastic yielding is allowed to adapt to the seismic demand on the structure. In other words, damage is allowed. The CBC lateral force requirements should be considered a minimum design. The owner and the designer may evaluate the level of risk and performance that is acceptable. Performance based criteria could be set in the design. The design engineer should exercise EARTH SYSTEMS SOUTHWEST Reference Seismic Category: D Table 1613.5.6 Site Class: D Table 1613.5.2 Maximum Considered Earthquake [MCE] Ground Motion Short Period Spectral Response SS: 1.500 g Figure 1613.5 1 second Spectral Response, SI: 0.600 g Figure 1613.5 Site Coefficient, Fa: 1.00 Table 1613.5.3(1) Site Coefficient, F,,: 1.50 Table 1613.5.3(2) Design Earthquake Ground Motion Short Period Spectral Response, SDS 1.00 g 1 second Spectral Response, SDI 0.60 g The intent of the CBC lateral force requirements is to provide a structural design that will resist collapse to provide reasonable life safety from a major earthquake, but may experience some structural and nonstructural damage. A fundamental tenet of seismic design is that inelastic yielding is allowed to adapt to the seismic demand on the structure. In other words, damage is allowed. The CBC lateral force requirements should be considered a minimum design. The owner and the designer may evaluate the level of risk and performance that is acceptable. Performance based criteria could be set in the design. The design engineer should exercise EARTH SYSTEMS SOUTHWEST July 20, 2010 16 File No.: 09354 -02 Doc. No.: 10 -07 -753 • special care so that all components of the design are fully met with attention to providing a continuous load path. An adequate quality assurance and control program is urged during project construction to verify that the design plans and good construction practices are followed. This is especially important for sites lying close to the major seismic sources. • Estimated peak horizontal site accelerations based upon a probabilistic analysis (10% probability. of occurrence in 50 years) is approximately 0.57 g for a stiff soil site. Actual accelerations may be more or less than estimated. Vertical accelerations are typically '/3 to % of the horizontal accelerations, but can equal or exceed the horizontal accelerations, depending upon the local site effects and amplification. 5.9 Pavements Since no traffic loading was provided by the design engineer or owner, we have assumed traffic loading for comparative evaluation. The design engineer or owner should decide the appropriate traffic conditions for the pavements. Maintenance of proper drainage is advised to prolong the service life of the pavements. Water should not pond on or near paved areas. The following table provides our preliminary recommendations for pavement sections. Final pavement sections recommendations should be based on design traffic indices and R -value tests conducted during grading after actual subgrade soils are exposed. PRELIMINARY RECOMMENDED PAVEMENTS SECTIONS R -Value Subgrade Soils - 50 (assumed) Design Method — CALTRANS Notes: 1. Asphaltic concrete should be Caltrans, Type B, %2 -in. or 3 /4 -in. maximum- medium grading and compacted to a minimum of 95% of the 75 -blow Marshall density (ASTM D 1559) or equivalent. 2. Aggregate base should be Caltrans Class 2 (3/4 in. maximum) and compacted to a minimum of 95% of ASTM D1557 maximum dry density near its optimum moisture. 3. All pavements should be placed on 12 inches of moisture- conditioned subgrade, compacted to a minimum'of 90% of ASTM D 1557 maximum dry density near its optimum moisture. 4. Portland cement concrete should have a minimum of 3250 psi compressive strength at 28 days. 5. Equivalent Standard Specifications for Public Works Construction (Greenbook) may be used instead of Caltrans specifications for asphaltic concrete and aggregate base. EARTH SYSTEMS SOUTHWEST Flexible Pavements Rigid Pavements Asphaltic Aggregate Portland Aggregate Traffic Concrete Base Cement Base Index Pavement Use Thickness Thickness Concrete Thickness Assumed Inches Inches Inches Inches 4.5 Auto Parking Areas 3.0 4.0 4.0 4.0 5.0 Drive Lanes 1 3.0 4.0 5.0 4.0 7.0 Garbage Truck Areas F 4.0 4.5 6.0 4.0 Notes: 1. Asphaltic concrete should be Caltrans, Type B, %2 -in. or 3 /4 -in. maximum- medium grading and compacted to a minimum of 95% of the 75 -blow Marshall density (ASTM D 1559) or equivalent. 2. Aggregate base should be Caltrans Class 2 (3/4 in. maximum) and compacted to a minimum of 95% of ASTM D1557 maximum dry density near its optimum moisture. 3. All pavements should be placed on 12 inches of moisture- conditioned subgrade, compacted to a minimum'of 90% of ASTM D 1557 maximum dry density near its optimum moisture. 4. Portland cement concrete should have a minimum of 3250 psi compressive strength at 28 days. 5. Equivalent Standard Specifications for Public Works Construction (Greenbook) may be used instead of Caltrans specifications for asphaltic concrete and aggregate base. EARTH SYSTEMS SOUTHWEST July 20, 2010 17 File No.: 09354 -02 Doc. No.: 10 -07 -753 Section 6 LIMITATIONS AND ADDITIONAL SERVICES 6.1 Uniformity of Conditions and Limitations Our findings and recommendations in this report are based on selected points of field exploration, laboratory testing, and our understanding of the proposed project. Furthermore, our findings and recommendations are based on the assumption that soil conditions do not vary significantly from those found at specific exploratory locations. Variations in soil or groundwater conditions could exist between and beyond the exploration points. The nature and extent of these variations may not become evident until construction. Variations in soil or groundwater may require additional studies, consultation, and possible revisions to our recommendations. Findings of this report are valid as of the issued date of the report. However, changes in conditions of a property can occur with passage of time, whether they are from natural processes or works of man, on this or adjoining properties. In addition, changes in applicable standards occur, whether they result from legislation or broadening of knowledge. Accordingly, findings of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and should not be relied upon after a period of one year. In the event that any changes in the nature, design, or location of structures are planned, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and the conclusions of this report are modified or verified in writing. This report is issued with the understanding that the owner or the owner's representative has the responsibility to bring the information and recommendations contained herein to the attention of the architect and engineers for the project so that they are incorporated into the plans and specifications for the project. The owner or the owner's representative also has the responsibility to verify that the general contractor and all subcontractors follow such recommendations. It is further understood that the owner or the owner's representative is responsible for submittal of this report to the appropriate governing agencies. As the Geotechnical Engineer of Record for this project, Earth Systems Southwest [ESSW] has striven to provide our services in accordance with generally accepted geotechnical engineering practices in this locality at this time. No warranty or guarantee is express or implied. This report was prepared for the exclusive use of the Client and the Client's authorized agents. ESSW should be provided the opportunity for a general review of final design and specifications in order that earthwork and foundation recommendations may be properly interpreted and implemented in the design and specifications. If ESSW is not accorded the privilege of making this recommended review, we can assume no responsibility for misinterpretation of our recommendations. EARTH SYSTEMS SOUTHWEST July 20, 2010 18 File No.: 09354 -02 Doc. No.: 10 -07 -753 • Although available through ESSW, the current scope of our services does not include an environmental assessment or an investigation for the presence or absence of wetlands, hazardous or toxic materials in the soil, surface water, groundwater, or air on, below, or adjacent to the subject property. 6.2 Additional Services This report is based on the assumption that an adequate program of client consultation, construction monitoring, and testing will be performed during the final design and construction phases to check compliance with these recommendations. Maintaining ESSW as the geotechnical consultant from beginning to end of the project will provide continuity of services. The geotechnical engineering firm providing tests and observations shall 'assume the responsibility of Geotechnical Engineer of Record. Construction monitoring and testing would be additional services provided by our firm. The costs of these services are not included in our present fee arrangements, but can be obtained from our office. The recommended review, tests, and observations include, but are not necessarily limited to, the following: • Consultation during the final design stages of the project. • A review of the building and grading plans to observe that recommendations of our report have been properly implemented into the design. • • Observation and testing during site preparation, grading, and placement of engineered fill as required by CBC Sections 1704.7 and Appendix J or local grading ordinances. • • Consultation as needed during-construction. •m Appendices as cited are attached and complete this report. EARTH SYSTEMS SOUTHWEST July 20, 2010 19 File No.: 09354 -02 Doc. No.: 10 -07 -753 REFERENCES Abrahamson, N., and Shedlock, K., editors, 1997, Ground motion attenuation relationships: Seismological Research Letters, v. 68, no. 1, January 1997 special issue, 256 p. American Concrete Institute [ACI], 2004, ACI Manual of Concrete Practice, Parts 1 through 5. American Concrete Institute (2004) `Building Code Requirements for Structural Concrete (ACI 318 -05) and Commentary (ACI 318R -05)." American Society of Civil Engineers [ASCE], 2006, Minimum Design Loads for Buildings and Other Structures, ASCE 7 -05. California Geologic Survey [CGS], 1997, Guidelines for Evaluating and Mitigating Seismic Hazards in California, Special Publication 117. Cao, T, Bryant, W.A., Rowhandel, B., Branum. D., and Wills, C., 2003, The Revised 2002 California Probabilistic Seismic Hazard Maps, California Geologic Survey [CGS], June 2003. Envicom Corporation and the County of Riverside Planning Department, 1976, Seismic Safety and Safety General Plan Elements Technical Report, County of Riverside. Frankel, A.D., et al., 2002, Documentation for the 2002 Update of the National Seismic Hazard Maps, USGS Open -File Report 02420. Hart, E.W., 1997, Fault- Rupture Hazard Zones in California: California Division of Mines and Geology Special Publication 42. International Code Council [ICC], 2007, California Building Code, 2007 Edition. Jennings, C.W, 1994, Fault Activity Map of California and Adjacent Areas: California Division of Mines and Geology, Geological Data Map No. 6, scale 1:750,000. MSA Consulting, Inc., Copyright 2010, Mass Grading Plan, sheets 1 to 4 (of 4). Petersen, M.D., Bryant, W.A., Cramer, C.H., Cao, T., Reichle, M.S., Frankel, A.D., Leinkaemper, J.J., McCrory, P.A., and Schwarz, D.P., 1996, Probabilistic Seismic Hazard Assessment for the State of California: California Division of Mines and Geology Open -File Report 96 -08. Riverside County Planning Department, 2003, Geotechnical Element of the Riverside County General Plan. Rogers, T.H., 1966, Geologic Map of California - Santa Ana Sheet, California Division of Mines and Geology Regional Map Series, scale 1:250,000. Tokimatsu, K, and Seed, H.B., 1987, Evaluation of Settlements in Sands Due To Earthquake Shaking, ASCE, Journal of Geotechnical Engineering, Vol. 113, No. 8, August 1987. United States Department of Homeland Securities, FEMA Map Center, flood map number 06065C2234G, Riverside CO, dated August 8, 2008. United States Geological Survey, 2008, Documentation for the 2008 Update of the United States National Seismic Hazard Maps: U.S. Geological Survey Open -File Report 2008 -1128, 61 p. Wallace, R. E., 1990, The San Andreas Fault System, California: U.S. Geological Survey Professional Paper 1515, 283 p. Working Group on California Earthquake Probabilities, 2008, The Uniform California Earthquake Rupture Forecast, Version 2 [UCERF 2]: U.S. Geological Survey Open -File Report 2007 -1437 and California Geological Survey Special Report 203, 104 p. EARTH SYSTEMS SOUTHWEST C� APPENDIX A EARTH SYSTEMS SOUTHWEST dy i Trailer Weil VENUE 2� Pal '•Oi t » _ r� •1 11 r,! V /y A � ' AVENUE j 1 _ • •• } "'EPA %fit � Q ? • 4' {' `• I `ti • R• ! le - 1 —�� fr t 1t .ii S ) .'uY "t. L t • R., t C b" P I (_ �/� � {. -1i t� '��... - ._ ».._�.. .ii? .•+ ' • • R ... Arm.. �� I.. 1 II 2 • to 0 o o Wi I� .. Q .'t •L..� 7 raJ F •� a k.. „ li . • li f ' 4i /...� Ii It _1 it it a> ' Trailer <0e'Fk At V• ••••.�• SITE,.` •! l+tUE �. Well =Weil•. _ 0 .,^ � it.. r �'., .. ..t .y a �}.. 1.._. yWyy�� Q ! _ t Ir J �! •ii ' si • t rr ✓ t ; L� ENUE cot ap 4 t 1 a Water • e, 3j • .. :, +!% � �' �.y N � it ') a j t ! ,,� ,• a O � ry 4 x It II ... `S r .. � 91t y •�i st -i! •� i ':a i ,.. p � II f5 � w,,, 1 II i }• • , . ' •« g 0 14 U q AVENUJ al u > Soli (� Well m { I! to C, Base Map: U.S.G.S. 7.5 Minute Quadrangle, la Quinta, CA (1959, photo- revised 1980) Figure 1 Site Location 9.5 Acre Residential Development South of Highway 111 and East of Dune Palms Road V La Quinta, Riverside Coun California Approximate Scale: I"= 2,000' ��j Earth Systems �! Southwest I 0 2,000' 4,000' 07/20/10 1 File No.: 09354 -02 9.5 -Acre Residential Development 09354 -02 Table 1 Fault Parameters Avg Avg Avg Trace Mean Dip Dip Rake Length Fault Mean Return Slip Fault Section Name Distance Angle Direction Type Mag Interval Rate (miles) (km) (deg.) (deg.) (deg.) (km) (years) (mm/yr) San Andreas (Coachella) rev 5.3 8.5 90 224 180 69 A 7.2 69 20 San Andreas (San Gorgonio Pass -Garnet Hlll) 5.9 9.5 58 20 180 56 A 7-6 219 10 San Andreas, (North Branch, Mill Creek) 5.9 9.5 76 204 180 106 A 7.5 110 17 Blue Cut 13.8 22.3 90 177 na 79 B' 7.1 Joshua Tree (Seismicity) 15.7 25.3 90 271 na 17 B' 6.5 Burnt Mtn 17.2 27.6 67 265 180 21 B 6.7 0.6 Eureka Peak 18.0 29.0 90 75 180 19 B 6.6 0.6 San Jacinto (Anza) rev 20.3 32.7 90 216 180 46 A 7.6 151 18 San Jacinto (Clark) rev 20.4 32.9 90 214 180 47 A 7.6 211 14 San Jacinto (Coyote Creek) 22.7 36.5 90 223 180 43 A 7.3 259 4 Mission Creek 26.8 43.1 65 5 180 31 B' 6.9 Pinto Mtn 30.2 48.5 90 175 0 74 B 7.2 2.5 So Emerson - Copper Mtn 31.7 51.0 90 51 180 54 B 7.0 0.6 Calico - Hidalgo 33.0 53.1 90 52 180 117 B 7.4 1.8 Landers 33.0 53.2 90 60 180 95 B 7.4 0.6 San Gorgonio Pass 33.2 53.5 60 11 na 29 B' 6.9 Pisgah - Bullion Mtn- Mesquite Lk 33.6 54.0 90 60 180 88 B 7.3 0.8 San Jacinto (Borrego) 34.7 55.8 90 223 180 34 A 7.0 146 4 Brawley (Seismic Zone), alt 1 35.4 57.0 90 250 na 60 B' 7.0 San Andreas (San Bernardino S) 35.9 57.7 90 210 180 43 A 7.6 150 16 San Jacinto (San Jacinto Valley, stepover) 36.3 58.4 90 224 180 24 A 7.4 199 9 San Jacinto (Anza, stepover) 36.8 59.3 90 224 180 25 A 7.6 151 9 San Jacinto (Stepovers Combined) 36.8 59.3 90 229 180 25 B' 6.7 Earthquake Valley (No Extension) 39.0 62.7 90 221 180 33 B' 6.9 Earthquake Valley 40.5 65.1 90 217 180 20 B 6.7 2 Brawley (Seismic Zone), alt 2 41.1 66.1 90 250 na 61 B' 7.0 Elsinore (Julian) 43.2 69.5 84 36 180 75 A 7.6 725 3 Johnson Valley (No) 43.3 69.6 90 51 180 35 B 6.8 0.6 North Frontal (East) 44.2 71.1 41 187 90 27 B 6.9 0.5 Earthquake Valley (So Extension) 44.5 71.6 90 204 180 9 B' 6.3 Elsinore (Temecula) rev 48.5 78.1 90 230 180 40 A 7.4 431 5 San Jacinto (San Jacinto Valley) rev 48.8 78.5 90 223 180 18 A 7.4 199 18 Elmore Ranch 49.1 79.1 90 310 0 29 B 6.6 1 Lenwood - Lockhart-Old Woman Springs 49.2 79.2 90 43 180 145 B 7.5 0.9 Elsinore (Coyote Mountain) 50.6 81.4 82 35 180 39 A 7.1 322 3 Superstition Hills 51.2 82.5 90 220 180 36 A 7.4 199 4 San Jacinto (Superstition Mtn) 52.3 84.1 90 210 180 26 B' 6.6 Helendale -So Lockhart 52.8 85.0 90 51 180 114 B 7.4 0.6 Superstition Mountain 53.2 85.7 37 37 37 37 B 73 0.1 Hector Mine 54.2 87.3 90 246 na -28 B' 6.7 Reference: USGS OFR 2007 -1437 (CGS SP 203) Based on Site Coordinates of 33.7056 Latitude, - 116.2739 Longitude Mean Magnitude for Type A Faults based on 0.1 weight for unsegmented section, 0.9 weight for segmented model (weighted by probability of each scenario with section listed as given on Table 3 of Appendix G :n OFR 2007 - 1437). Mean magntude is average of Ellworths -B and Hanks & Bakun moment area relationship. DESCRIPTIVE SOIL CLASSIFICATION Soil classification is based on ASTM Designations D 2487 and D 2488 (Unified Soil Classification System). Information on each boring log is a compilation of subsurface conditions obtained from the field as well as from laboratory testing of selected samples. The indicated boundaries between strata on the boring logs are approximate only and may be transitional. SOIL GRAIN SIZE U.S. STANDARD SIEVE 12° 3" .4141, 4 in 40 200 BOULDERS COBBLES GRAVEL SAND j:::FINE SILT CLAY COARSE I FINE COARSE I MEDIUM 305 76.2 19.1 4.76 2.00 0.42 0.074 SOIL GRAIN SIZE IN MILLIMETERS 0.002 RELATIVE DENSITY OF GRANULAR SOILS (GRAVELS, SANDS, AND NON - PLASTIC SILTS) Very Loose *N =0-4 RD =0 -30 Easily push a 1/2 -inch reinforcing rod by hand Loose N =5 -10 RD =30 -50 Push a 1/2 -inch reinforcing rod by hand Medium Dense N =11 -30 RD =50 -70 Easily drive a 1/2 -inch reinforcing rod with hammer Dense N =31 -50 RD =70 -90 Drive a 1/2 -inch reinforcing rod 1 foot with difficulty by a hammer Very Dense N >50 RD =90 -100 Drive a 1/2 -inch reinforcing rod a few inches with hammer *N =Blows per foot in the Standard Penetration Test at 60% theoretical energy. For the 3 -inch diameter Modified California sampler, 140 -pound weight, multiply the blow count by 0.63 (about 2/3) to estimate N. If automatic hammer is used, multiply a factor of 1.3 to 1.5 to estimate N. RD= Relative Density ( %). C= Undrained shear strength (cohesion). CONSISTENCY OF COHESIVE SOILS (CLAY OR CLAYEY SOILS) Very Soft *N =0 -1 *C =0 -250 psf Squeezes between fingers Soft N =24 C= 250 -500 psf Easily molded by finger pressure Medium Stiff N =5 -8 C= 500 -1000 psf Molded by strong finger pressure Stiff N =9 -15 C= 1000 -2000 psf Dented by strong finger pressure Very Stiff N =16 -30 C= 2000 -4000 psf Dented slightly by finger pressure Hard N >30 C >4000 Dented slightly by a pencil point or thumbnail MOISTURE DENSITY Moisture Condition: An observational term; dry, damp, moist, wet, saturated. Moisture Content: The weight of water in a sample divided by the weight of dry soil in the soil sample expressed as a percentage. Dry Density: The pounds of dry soil in a cubic foot. MOISTURE CONDITION RELATIVE PROPORTIONS Dry .....................Absence of moisture, dusty, dry to the touch Trace ............. minor amount ( <5 %) Damp ................Slight indication of moisture with /some...... significant amount Moist .................Color change with short period of air exposure (granular soil) modifier /and... sufficient amount to Below optimum moisture content (cohesive soil) influence material behavior Wet ....................High degree of saturation by visual and touch (granular soil) (Typically >30 %) Above optimum moisture content (cohesive soil) Saturated .......... Free surface water LOG KEY SYMBOLS PLASTICITY ' Bulk, Bag or Grab Sample DESCRIPTION FIELD TEST Nonplastic A 1/8 in. (3 -mm) thread cannot be rolled at any moisture content. Standard Penetration Split Spoon Sampler Low The thread can barely be rolled. (2" outside diameter) Medium The thread is easy to roll and not much time is required to reach the plastic limit. ' Modified California Sampler (3" outside diameter) High The thread can be rerolled several times after reaching the plastic limit. No Recovery GROUNDWATER LEVEL V Water Level (measured or after drilling) Terms and Symbols used on Logs Water Level (during drilling) — Earth Systems Southwest GRAPHIC LETTER MAJOR DIVISIONS SYMBOL SYMBOL TYPICAL DESCRIPTIONS Well- graded gravels, gravel -sand CLEAN GW mixtures, little or no fines GRAVELS <5 %FINES GRAVEL AND • • • ■ ''f'''' �••r••r••r••r••r••r••r•• GP Poorl raded ravels, ravel -sand Y-9 9 9 GRAVELLY •• •• •• .• .• .• .• .• mixtures. Little or no fines SOILS GM Silty gravels, gravel- sand -silt COARSE More than 50% of GRAVELS mixtures GRAINED SOILS coarse fraction WITH FINES > 12% FINES retained on No. 4 GC Clayey gravels, gravel- sand -clay sieve mixtures SW Well sands, gravelly sands, SAND AND CLEAN SAND little or no fines SANDY SOILS (Little or no fines) < 5% SF Poorly- graded sands, gravelly More than 50% of sands, little or no fines material is lar er than No. 200 sieve size SAND WITH FINES :::: • :.::.::.::.:::•.::.::•.::.:•:. SM Silty sands, sand -silt mixtures More than 50% of (appreciable coarse fraction amount of fines) ap ssing No. 4 sieve 12% SC Clayey sands, sand -clay mixtures Inorganic silts and very fine sands, ML rock flour, silty low clayey fine sands or clayey silts with slight plasticity LIQUID LIMIT medium FINE - GRAINED LESS THAN 50 CL plasticity, cry gravelly clays, sandy y SOILS clays, silty clays, lean clays ' ' NUM, iiii ' ' ' OL Organic silts and organic silty 9 9 ' ' NUM: ' ' clays of low plasticity SILTS AND Inorganic silty, micaceous, or CLAYS MH diatomaceous fine sand or silty soils 50% or more of material is smaller LIQUID LIMIT CH Inorganic clays of high plasticity, than No. 200 GREATER fat clays sieve size THAN 50 ............. Organic clays of medium to high ............. ............. plasticity, organic silts J'y.Yy.YYJ'.Y .Yyy yy.Yy.Yyy.Yy.Yyy yyyyyyyyyyyy Peat, humus, swamp soils with HIGHLY ORGANIC SOILS yyyyyyyyyyyy PT high organic contents yJ'yy.YYyJV'y.Yy VARIOUS SOILS AND MAN MADE MATERIALS Fill Materials MAN MADE MATERIALS Asphalt and concrete Soil Classification System Earth Systems Southwest is • C7 Earth Systems 79 -811B Country Club Drive ^� Southwest Phone (760) 345 -1588, Fax (760) 345 -7315 Boring-No: B-1 Drilling Date: August 28, 2003 Project Name: La Quinta Family Apartments, La Quinta, CA Drilling Method 8" HSA File Number: 09354 -01 Drill Type CME 45 with cathead Boring Location: See Figure 2 Logged By: Karl Hewes Sample Type Penetration N o Pa e 1 of 1 Description of Units g U Resistance c Q _ Note: The stratification lines shown represent the CL o o (Blows /6 ") �, v) rn 0. ° 4 approximate boundary between soil and/or rock types Graphic Trend A N En q U and the transition may be gradational. Blow Count Dry Density En 0 SP -SM SAND WITH SILT: grayish olive, medium dense, dry, fine grained 8,12,15 7,12,16 102 0 5, SM/ML SILTY SAND TO SANDY SILT:. grayish olive, medium dense, 8,13,16 91 1 dry, very fine grained 10 VIA I 14,27,36 ML SILT: light olive, dense, dry, very fine grained, with sand and clay, non plastic 15 SM/ML SILTY SAND TO SANDY SILT: grayish olive, dense, dry, very 15,24,28 fine grained 20 10,14,20 25 7,10,12 ML SILT: light olive, dense, dry, very fine grained, non plastic 30 trace clay laminations 9,11,16 SM/ML SILTY SAND TO SANDY SILT: grayish olive, dry, very fine grained Boring completed at 31.5 feet 35 No bedrock or groundwater encountered nn Earth Systems WI Southwest 79.811 B Country Club Drive Phone (760) 345 -1588, Fax (760) 345 -7315 Boring No: B -2 Drilling Date: August 28, 2003 Project Name: La Quinta Family Apartments, La Quinta, CA Drilling Method: 8" HSA File Number: 09354 -01 Drill Type: CME 45 with cathead Boring Location: See Figure 2 Logged By: Karl Hewes atnple T yp e Penetration it „� Description of Units Page I of 1 v = U1 Resistance a U A a Z = aCi Note: The stratification lines shown represent the Y o ") T q o approximate boundary between soil and/or rock types Graphic Trend q a. 0 US (Blows/6 � q U and the transition may be gradational. Blow Count Dry Density 3,5,7 SM SILTY SAND: grayish olive, loose, dry, fine grained 5,10,13 5 11,10,14 micaceous band, trace clay lenses, non plastic 10,14,17 SM/ML SILTY SAND TO SANDY SILT: grayish olive, medium dense, dry, very fine grained 10 17,18,23 15 ML SILT: grayish olive, dense, dry, very fine grained 17 18 28 SM SILTY SAND: grayish olive, dense, dry, fine 20 grained Boring completed at 18.5 feet No bedrock or groundwater encountered 25 30 35 en • Earth Systems Snuihwaast 79 -811 B Country Club Drive 5 10 • � 15 20 25 30 35 • 40 Phone (16U) 343 - 053. tax (40U) 391 = /313 Boring No: B -3 sm Drilling Date: August 28, 2003 Project Name: La Quinta Family Apartments, La Quinta, CA Drilling Method: 8" HSA File Number: 09354 -01 Drill Type: CME 45 with cathead Boring Location: See Figure 2 Logged By: Karl Hewes Sample Type'. Penetration — 2 o Description of Units Page 1 of 1. z Resistance �° U °' A o 4 �+ .c Note: The stratification lines shown represent the p /6 ") to � approximate boundary between soil and/or rock types Graphic Trend q m (Blows q U and the transition may be gradational. Blow Count Dry Density 5 10 • � 15 20 25 30 35 • 40 sm SILTY SAND: grayish olive, loose, dry, fine grained 5,5,8 4,4,6 4,5,6 SMIML SILTY SAND TO SANDY SILT: grayish olive, loose, dry, very fine grained medium dense, 2" light olive brown laminated clay, non 6,9,12 plastic sM SILTY SAND: grayish olive, medium dense, dry, fine grained: 4s,to ML SILT: grayish olive, medium dense, dry, very fine grained 4,8,13 Boring completed at 21.5 feet No bedrock or groundwater encountered Earth Systems �- Snuthwp-at 79.811 B Country Club Drive 5 10 15 20 25 • 30 35 • 40 Phone (7W) 345 -1 588, tax (7en) 343 -7315 Boring No: B -4 SM Drilling Date: August 28, 2003 Project Name: La Quinta Family Apartments, La Quinta, CA Drilling Method: 8" HSA File Number: 09354 -01 Drill Type: CME 45 with cathead Boring Location: See Figure 2 grained Logged By: Karl Hewes v Sample Type Penetration '� ° Description of Units Page 1 of 1 a � v Resistance N q a � .14 d ° c Note: The stratification lines shown represent the boundary between /or types Graphic Trend o Z) approximate soil and rock q a m rn � (Blows/6") ML SILT: moderate olive brown, dense, dry, very fine q � j and the transition may be gradational. Blow Count Dry Density 5 10 15 20 25 • 30 35 • 40 1,2 2 SM SILTY SAND: grayish olive, very loose, dry, fine grained 2,4,8 2,6,8 ML SILT: moderate olive brown, dense, dry, very fine grained, non plastic 14,15,24 91 6 SM SILTY SAND: grayish olive, fine grained 10,20,26 102 1 sm/Ml. SILTY SAND TO SANDY SILT: dense, dry, very fine to fine grained micaceous bands 5,7,7 Boring completed at 18.5 feet No bedrock or groundwater encountered • Earth Systems ^�— Snuthwest 79 -811 B Country Club Drive — rnone t ioul sn3 -t 3aa, tax t iou) svD- i s u Boring No: B -5 SM Drilling Date: August 28, 2003 Project Name: La Quinta Family Apartments, La Quinta, CA Drilling Method: 8" HSA Pile Number: 09354 -01 Drill Type: CMG 45 with cathead fine grained Boring Location: See Figure 2 Logged By: Karl Hewes 4,7.8 Sample rype Penetration ° Description of Units page 1 of 1 4,6,7 Resistance n ti A a " a°i Note: The stratification lines shown represent the q m o (Blows /6 ") T cn �� 5 o approximate boundary between soil and/or rock types Graphic Trend m o Mi. SILT: grayish olive, medium dense, dry, very fine CJ U and the transition may be gradational. Blow Count Dry Density 5 10 • IS 20 25 30 35 • -40 SM SILTY SAND: grayish olive, medium dense, dry, 4 8 9 fine grained 4,7.8 4,6,7 Mi. SILT: grayish olive, medium dense, dry, very fine 6,8,10 grained, trace clay laminations, non plastic SM/ML SILTY SAND TO SANDY SILT: grayish olive, medium dense, dry 6,7,11 Boring completed at 16.5 feet No bedrock or groundwater encountered Earth Systems Southwest 79.81 IB Counuy Club Drivc 5 10 15 20 25 30 35 40 rnonc tiov/ 39i-i iao, rax tiov) Boring No: B -6 SM /ML Drilling Date: August 28, 2003 Project Name: La Quinta Family Apartments, La Quinta, CA Drilling Method: 8" HSA File Number: 09354 -01 2,3,5 Drill Type: CMG 45 with cathead Boring Location: See Figure 2 Logged By: Karl Hcwcs Sample Type Penetration :' ° Pa e 1 of 1 Description of Units g fs w Resistance a° U V) ) 0 q a C d Note: The stratification lines shown represent the 0 Q V3 ") T N q o approximate boundary between soil and/or rock types Graphic Trend q V3 I (Blows/6 J. TE q V and the transition may be gradational. Blow Count Dry Density 5 10 15 20 25 30 35 40 2 2 3 SM /ML SILTY SAND TO SANDY SILT: grayish olive, loose, dry, very fine to fine grained 2,3,5 trace silt and clay laminations, non plastic 4,8,10 5 7 t l J. TE SM SILTY SAND: light olive brown, medium dense, dry, clay laminations, no to low plasticity SM/ML SILTY SAND TO SANDY SILT: grayish olive, 5,7,9 medium dense, dry very fine grained SM SILTY SAND: medium dense, dry, fine grained 7,9,10 Boring completed at 18.5 feet No bedrock or gorundwater encounter • Earth Systems t�l S a u t h w e s t 79 -8118 Country Club Drive 5 10. • IS 2C 2� 30 35 • 40 rnone trou) J43-1355, rax t /UV) 343 -N U Boring No: B -7 S Drilling Date: August 28, 2003 Protect Name: La Quinta Family Apartments, La Quinta, CA Drilling Method: 8" HSA Pile Number: 09354 -01 Drill Type: CME 45 with cathead Boring Location: See Figure 2 fine to very fine grained, trace silt and clay Logged By: Karl Hewes v Sample Type Penetration Description of Units Page I of I a u Resistance g E N q a •" Note: The stratification lines shown represent the •rrend A o (Blows/6 ") A �� o approximate boundary between soil and /or rock types Graphic 5,7,8 IM 89 5 A U and the transition may be gradational. Blow Count Dry Density 5 10. • IS 2C 2� 30 35 • 40 S SILTY SAND: grayish olive, medium dense, dry, fine to very fine grained, trace silt and clay 10,15,15 laminations, non plastic 6,6,7 88 4 5,7,8 89 5 6,9,13 T. 107 5 9,14,20 Boring completed at 16.5 feet No bedrock or groundwater encountered Earth Systems lk Southwest 79 -811B Country Club Crive 5 10 15 • 20 25 30 35 40 rnone tiou) rya -iaaa, rax tiou) Boring No: B -8 SM Drilling Date: August 28, 2003 Project Name: La Quinta Family Apartments, La Quinta, CA Drilling Method: 8" HSA File Number: 09354 -01 Drill Type: CMG 45 with cathead Boring Location: See Figure 2 Logged By: Karl Hewes fine grained Sample Type Penetration Description of Units Pagel of 1 a 3 Resistance a N U q a " a°i Note: The stratification lines shown represent the x p ") T W a o approximate boundary between soil and /or rock types Graphic Trend q y 0 (Blows/6 2,3,3 A U and the transition may be gradational. Blow Count Dry Density 5 10 15 • 20 25 30 35 40 5,7 8 SM SILTY SAND: grayish olive, medium dense, dry, fine grained loose 3,3,4 2,3,3 SM/ML SILTY SAND TO SANDY SILT: loose, dry, very fine to fine grained damp 3,4,5 ML SILT: grayish olive, medium dense, dry, very fine grained, trace clay and silt laminated layer, non 4'6'7 plastic becomes more micaceous 7,9,9 Boring completed at 18.5 feet No bedrock or groundwater encountered • �1 Earth Systems J Southwest Boring No: B -9 Preject Name: La Quinta Family Apartments, La Quinta, CA File Number: 09354 -01 SM /ML Boring Location: See Figure 2 SILTY SAND TO SANDY SILT: grayish olive, Sample Type Penetration 0 dense, dry a u Resistance E A g y o (Blows /6 ") N q U° m <n. 5 10 • 15 20 25 30 3.5 .40 79.81 113 Country Club Drive Phone (760) 345 -1M, Fax (760) 345 -7315 Drilling Date: August 28, 2003 Drilling Method: 8" HSA Drill Type: CME 45 with cathead Logged By: Karl Hewes Description of Units Page I of 1 Note: The stratification lines shown represent the approximate boundary between soil and /or rack types Graphic Trend and the transition may be gradational Blow Count Dry Density SM /ML SILTY SAND TO SANDY SILT: grayish olive, dense, dry sM SILTY SAND: grayish olive, medium dense, dry SMIML SILTY SAND TO SANDY SILT: grayish olive, loose, damp SM SILTY SAND: grayish olive, medium dense, dry, fine grained ML SILT: grayish olive, medium dense, dry, very fine grained, trace silt and clay laminations, non plastic SM/ML SILTY SAND TO SANDY SILT- grayish olive, medium dense, dry, very fine grained Boring completed at 16.5 feet No bedrock or groundwater encountered APPENDIX B Laboratory Test Results EARTH SYSTEMS SOUTHWEST File No.: 09354 -01 July 20, 2010 • UNIT DENSITIES AND MOISTURE CONTENT ASTM D2937 & D2216 Job Name: 9.5 -Acre Residential Development, La Quinta, CA • • Sample Location Depth (feet) Unit Dry Density ( cf) Moisture Content N USCS Group Symbol B4 BI B1 3 5 102 91 0 1 SP -SM SM B4 7 91 6 ML B4 12 102 1 SM/ML B7 3 88 4 SM B7 5 89 5 SM B7 10 107 5 SM EARTH SYSTEMS SOUTHWEST File No.: 09354 -01 July 20, 2010 SIEVE ANALYSIS ASTM C -136 Job Name: 9.5 -Acre Residential Development, La Quinta, CA Sample ID: B 1 @ 0 -5' Feet Description: Sand: F (SP -SM) 100 90 80 70 60 an c 50 a 40 30 20 10 0 Sieve Size 311 2" 1 -1/2" 1" 3/4" 1/2" 3/8" #4 #8 #16 #30 #50 #100 #200 % Passing 100 100 100 100 100 100 100 100 100 100 99 80 32 9 100 10 1 0.1 0.01 Particle Size, mm EARTH SYSTEMS SOUTHWEST File No.: 09354 -01 July 20, 2010 • SIEVE ANALYSIS ASTM C -136 Job Name: 9.5 -Acre Residential Development, La Quinta, CA Sample ID: B3 @ 0 -5' Feet Description: Sl Silty Sand: F (SM) • • 100 90 80 70 on 60 a 50 a 40 30 20 10 0 Sieve Size % Passing 3" 100 2" 100 1-1/2" 100 1" 100 3/4" q 100 1/2" 100 3/8" 100 #4 100 #8 100 #16 100 #30 99 #50 84 #100 46 #200 19 100 10 1 0.1 0.01 Particle Size, mm EARTH SYSTEMS SOUTHWEST File No.: 09354 -01 July 20, 2010 CONSOLIDATION TEST ASTM D 2435 & D 5333 9.5 -Acre Residential Development, La Quinta, CA Initial Dry Density: 84.9 pcf B4 @ 7' Feet Initial Moisture, %: 5.8% Sandy Silt (ML) Specific Gravity (assumed): 2.67 Ring Sample Initial Void Ratio: 0.964 2 1 0 -1 P" r L -3 2 c -4 d tM c -5 M t V +- -6 c a� v d -7 CL -8 -9 -10 -11 -12 0.1 Hydrocollapse: 2.6% @ 2.0 ksf % Change in Height vs Normal Presssure Diagram —e— Before Saturation ®Hydrocollapse ■ After Saturation —*—Rebound 1.0 10.0 Vertical Effective Stress, ksf EARTH SYSTEMS SOUTHWEST • • • File No.: 09354 -01 July 20, 2010 CONSOLIDATION TEST ASTM D 2435 & D 5333 9.5 -Acre Residential Development, La Quinta, CA Initial Dry Density: 84.8 pcf 137 @ 5' Feet Initial Moisture, %: 5.1% Silty Sand: F (SM) Specific Gravity (assumed): 2.67 Ring Sample Initial Void Ratio: 0.966 Hydrocollapse: 0.7% @ 2.0 ksf 2 1 0 -1 -2 t M -3 x -4 d m ca -5 t U .� -6 c m m -7 a -8 -9 -10 -11 -12 % Change in Height vs Normal Presssure Diagram —@ - Before Saturation Hydrocollapse ■ After Saturation -it— Rebound 0.1 1.0 Vertical Effective Stress, ksf EARTH SYSTEMS SOUTHWEST 10.0 File No.: 09354 -01 July 20, 2010 CONSOLIDATION TEST ASTM D 2435 & D 5333 9.5 -Acre Residential Development, La Quinta, CA Initial Dry Density: 87.6 pcf B7 @ 10' Feet Initial Moisture, %: 4.9% Silty Sand: F /Sandy Silt (SM/ML) Specific Gravity (assumed): 2.67 Ring Sample Initial Void Ratio: 0.904 2 1 0 -1 P" w t P -3 2 -4 d _ -5 M r V _ -6 a� 2 y -7 IL -8 -9 -10 -11 -12 0.1 Hydrocollapse: 1.3% @ 2.0 ksf - % Change in Height vs Normal Presssure Diagram —&— Before Saturation Hydrocollapse ■ After Saturation -- Rebound 1.0 10.0 Vertical Effective Stress, ksf EARTH SYSTEMS SOUTHWEST File No.: 09354 -01 July 20, 2010 • MAXIMUM DENSITY / OPTIMUM MOISTURE ASTM D 1557 -91 (Modified) Job Name: 9.5 -Acre Residential Development, La Quinta, CA Procedure Used: A Sample ID: B 1 @ 0 -5' feet Preparation Method: Moist Location: Native Rammer Type: Mechanical Description: Gray Brown: Sand, F (SP -smSM) Sieve Size % Retained Maximum Density: 109.5 pcf 3/4" 0.0 Optimum Moisture: 7.5% 3/8" . 0.0 #4 0.0 • • 140 135 130 125 w v CL vi 120 C m D r 115 110 105 100 4 0 < - - - -- Zero Air Voids Lines, sg =2.65, 2,70, 2,75 5' 10 15 20 Moisture Content, percent EARTH SYSTEMS SOUTHWEST . 25 30 File No.: 09354 -01 SOIL CHEMICAL ANALYSES July 20, 2010 Job Name: 9.5. -Acre Residential Development, La Quinta, CA Job No.: 09354 -01 Sample ID: B -1 Sample Depth, feet: 0 -5 pH: 8.4 Resistivity (ohm -cm): 1,140 Chloride (Cl), mg/Kg: 99 Sulfate (SO4), mg/Kg: 65 Note: Tests performed by Subcontract Laboratory: Surabian Ag Laboratory and Consultants, Inc. 79 -607 Country Club Drive. Bermuda Dunes, CA 92201 Tel: (760) 772 -7995 General Guidelines for Soil Corrosivitv Chemical Agent Amount in Soil Degree of Corrosivity Soluble 0 -1000 ppm Low Sulfates 1000-2000 ppm Moderate 2000-5000 ppm Severe > 5000 ppm Very Severe Resistivity 1 -1000 ohm -cm Very Severe 1000 -2000 ohm -cm Severe 2000 - 10,000 ohm -cm Moderate 10,000+ ohm -cm Low EARTH SYSTEMS SOUTHWEST Whitewater River Region WQMP Coral Mountain Apartments Appendix F Site Design and Treatment Control BMP Sizing Calculations and Design Details � 0 I I • Riverside County - Whitewater River Region Water Quality Management Plan Exbibit C Worksheet 1 • • Design Procedure for BMP Design Volume Designer: DLS Company: MSA Consulting Inc. . Date: June 15, 2011 . Prcject: Coral Mountain Affordable Housing Drainage Area: DA A - Offsite Commercial Site 1. Determine the Tributary Area to the BMP Alib) Atrib= 9.07 acres 2. Determine the impervious area ratio (i) a. Determine the impervious area within Atr;b A;mp 8.16 acres (2) b. Calculate I = Aimp/Atdb = (0(1) i= 0.90 3 3. Determine Runoff Coefficient C C= 0.858 *i3 - 0.78 *i2 +0.774 *i +0.04 C= 0.73 (4) C= 0.858 *(3)3 - 0.78 *(3)2 +0.774 *(3) +0.04 4. Determine Unit Storage Volume (V„) V„= 0.40 *C = 0.40 *(4) Vu= 0.29 acre -in /acre 5 5. Determine Design Storage Volume VBMP = * Atrib = (5) *(1) VBMP= 2.65 acre -in (6) /Vu VBMP _ 16)/12 VBMP= 0.22 acre -ft (7) VBMP = (7) *43560 VBMP= 9,611 cubic ft 8 Notes: IMPERVIOUS AREA ASSUMED TO BE 90% (NO SITE PLAN TO DETERMINE ACTUAL AREAS) Riverside County - Whitewater River Region Water Quality Management Plan Exbibit C Worksheet 1 Design Procedure for BMP Design Volume Designer: DLS Company: MSA Consulting Inc. Date: June 15, 2011 Project: Coral Mountain Affordable Housing Drainage Area: DA B - Offsite Street 'A' 1. Determine the Tributary Area to the BMP (Asb) At,;b= 1.22 acres 2. Determine the impervious area ratio (i) a. Determine the impervious area within kib A;mP 1.02 acres (2) b. Calculate I = A;m^6b =(2)1(1) i= 0.84 3 3. Determine Runoff Coefficient C C= 0.858 *i3 - 0.78 *i2 +0.774 *i +0.04 C= 0.65 (4) C =0. 858 *(3)3 - 0.78 *(3)2 +0.774 *(3) +0.04 4. Determine Unit Storage Volume (V„) V„= 0.40 *C = 0.40 *(4) Vu= 0.26 acre -in /acre 5 5. Determine Design Storage Volume VBMP = Vu * Atib = (5) *(1) VBMP= 0.31 acre -in (6) VBMp = (6)/12 VBMP= 0.03 acre -ft (7) VBMp = (7) *43560 VBMp= 1,143 cubic ft 8 Notes: PERVIOUS AREAS (CALCULATED FROM THE SITE PLAN) WERE REDUCED BY A FACTOR OF 10 %. THIS ADJUSTED PERVIOUS AREA WAS SUBTRACTED FROM THE TOTAL AREA TO DETERMINE THE IMPERVIOUS AREA USED IN THESE CALCULATIONS. • Riverside County - Whitewater River Region Water Quality Management Plan Exbibit C Worksheet 1 • . • Design Procedure for BMP Design Volume Designer: DLS Company: MSA Consulting Inc. Date: June 15, 2011 Project: Coral Mountain Affordable Housing Drainage Area: DA C 1. Determine the Tributary Area to the BMP 010b) Atftb 9.44 acres 2. Determine the impervious area ratio (i) a. Determine the impervious area within Atr;b A;mP 7.15 acres (2) b. Calculate I = AmdAWb = (2)/(1) i= 0.76 3 3. Determine Runoff Coefficient C C= 0.858 *i3 - 0.78 *i2+0.774 *i +0.04 C= 0.55 (4) C= 0.858 *(3)3 - 0.78'(3)2+0 .774*(3)+0.04 4. Determine Unit Storage Volume (V„) V„= 0.40 *C = 0.40 *(4) Vu= 0.22 acre -in /acre 5 5. Determine Design Storage Volume VBMP = Vu * Aft = (5) *(1) VBMP= 2.08 acre -in (6) VBMP = (6)/12 VBMP= 0.17 acre -ft (7) VBMP = (7) *43560 VBMP= 7,553 cubic ft 8 Notes: PERVIOUS AREAS (CALCULATED FROM THE SITE PLAN) WERE REDUCED BY A FACTOR OF 10 %. THIS ADJUSTED PERVIOUS AREA WAS SUBTRACTED FROM THE TOTAL AREA TO DETERMINE THE IMPERVIOUS AREA USED IN THESE CALCULATIONS. • Riverside County - Whitewater River Region Water Quality Management Plan Exbibit C Worksheet 2 • • Design Procedure for BMP Design Flow Uniform Intensity. Design Flow Designer: DLS Company: MSA Consulting Inc. Date: June 15, 2011 Project: Coral Mountain Affordable Housing Drainage Area: Drainage Area A - Offsite Commercial Site 1. Determine the Tributary Area to the BMP (Anb) Atrib= 9.07 acres (1) 2. Determine the impervious area ratio (i) a. Determine the impervious area within Aft ^imp 8.16 acres b. Calculate I = A; Atrib (Note: Rounded to nearest 5 %) i= 90% (2) 3. Determine Runoff Coefficient C Use Table 4. and impervious % (2) A Soil Runoff Coefficient Ca= 0.82 (3) B Soil Runoff Coefficient Cb= 0.82 (4) C Soil Runoff Coefficient C�= 0.83 (5) D Soil Runoff Coefficient Cd= 0.84 (6) 4. Determine the Area Decimal Fraction of Each Soil Type A. Area of Soil Type'A'/ (1) 0.00 acres Aa= 0.00 (7) A. Area of Soil Type '13 (1) 9.07 acres Ab= 1.00 (8) A. Area of Soil Type 'C' / (1) 0.00 acres Ac= 0.00 (9) A. Area of Soil Type 'D' / (1) 0.00 acres Ad= 0.00 (10) 5. Determine Runoff Coefficient C = (3)x(7) + (4)x(8) + (5)x(9) + (6)x(10) = C= 0.82 (11) 6. Determine BMP Design Flow QBMp = C'I "A = (11) x 0.2 x (1) QBMp= 1.49 cfs (12) Notes: IMPERVIOUS AREA ASSUMED TO BE 90% (NO SITE PLAN TO DETERMINE ACTUAL AREAS) FLOW BASED BMP NOT USED Riverside County - Whitewater River Region Water Quality Management Plan Exbibit C Worksheet 2 Design Procedure for BMP Design Flow Uniform Intensity Design Flow Designer: DLS Company: MSA Consulting Inc. Date: June 15, 2011 Project: Coral Mountain Affordable Housing Drainage Area: Drainage Area B - Offsite Street'A' 1. Determine the Tributary Area to the BMP (Anb) Atftb 1.22 acres (1) 2. Determine the impervious area ratio (i) a. Determine the impervious area within Arib Aimp 1.02 acres b. Calculate I = Amp Atrib (Note: Rounded to nearest 5 %), i= 85% (2) 3. Determine Runoff Coefficient C Use Table 4 and impervious % (2) A Soil Runoff Coefficient Ca= 0.77 (3) B Soil Runoff Coefficient Cb= 0.79 (4) C Soil Runoff Coefficient Cc= 0.80 (5) D Soil Runoff Coefficient Cd= 0.81 (6) 4. Determine the Area Decimal Fraction of Each Soil Type A. Area of Soil Type 'A' / (1) 0.00 acres Aa= 0.00 (7) A. Area of Soil Type 'B ' / (1) 1.22 acres Ab= 1.00 (8) A. Area of Soil Type 'C' / (1) 0.00 acres Ac= 0.00 (9) A. Area of Soil Type 'D' / (1) 0.00 acres Ad= 0.00 (10) 5. Determine Runoff Coefficient C = (3)x(7) + (4)x(8) + (5)x(9) + (6)x(10) = C= 0.79 (11) 6. Determine BMP Design Flow QBMP = C'I'A = (11) x 0.2 x (1) QBMP= 0.19 cfs (12) Notes: PERVIOUS AREAS (CALCULATED FROM THE SITE PLAN) WERE REDUCED BY A FACTOR OF 10 %. THIS ADJUSTED PERVIOUS AREA WAS SUBTRACTED FROM THE TOTAL AREA TO DETERMINE THE IMPERVIOUS AREA USED IN THESE CALCULATIONS. FLOW BASED BMP NOT USED • C� Riverside County - Whitewater River Region Water Quality Management Plan Exbibit C Worksheet 2 Design Procedure for BMP Design Flow Uniform Intensity Design Flow Designer: DLS Company: MSA Consulting Inc. Date: June 15, 2011 Project: Coral Mountain Affordable Housing Drainage Area: Drainage Area C 1. Determine the Tributary Area to the BMP (q, b) Atdb= 9.44 acres (1) 2. Determine the impervious area ratio (i) a. Determine the impervious area within AHb AMP 7.15 acres b. Calculate I = AsmdAmb (Note: Rounded to nearest 5 %) i= 75% (2) 3. Determine Runoff Coefficient C Use Table 4 and impervious % (2) A Soil Runoff Coefficient Ca= 0.69. (3) B Soil Runoff Coefficient Cb= 0.71 (4) C Soil Runoff Coefficient C�= 0.73 (5) D Soil Runoff Coefficient Cd= 0.74 (6) 4. Determine the Area Decimal Fraction of Each Soil Type A. Area of Soil Type'A'/ (1) 0.00 acres Aa= 0.00 (7) A. Area of Soil Type 'B'/ (1) 9.44 acres Ab= 1.00 (8) A. Area of Soil Type'C'/ (1) 0.00 acres Ac= 0.00 (9) A. Area of Soil Type'D'/ (1) 0.00 acres Ad= 0.00 (10) 5. Determine Runoff Coefficient C = (3)x(7) + (4)x(8) + (5)x(9) + (6)x(10) = C= 0.71 (11) 6. Determine BMP Design Flow `+6Mp = C "I "A = (11) x 0.2 x (1)- QBMP= 1.34 cfs,. _ (12) Notes: PERVIOUS AREAS (CALCULATED FROM THE SITE PLAN) WERE REDUCED BY A FACTOR OF 10 %. THIS ADJUSTED PERVIOUS AREA WAS SUBTRACTED FROM THE TOTAL AREA TO DETERMINE THE IMPERVIOUS AREA USED IN THESE CALCULATIONS. FLOW BASED BMP NOT USED Riverside County - Whitewater River Region Water Quality Management Plan Exhibit C Table 4 Runoff Coefficients for an Intensity = 0.2 in /hr for Urban Soil Types Impervious % 0 (Natural) 5 10 15 20 (1 -Acre) 25 30 35 40 (1/2 -Acre) 45 50 (1/4 -Acre) 55 60 65 (Condominiums) 70 75 (Mobilehomes) 80 (Apartments) 85 90 (Commercial) 95 100 A Soil B Soil C Soil D Soil RI =32 RI =56 RI =69 RI =75 0.06 0.14 0.23 0.28 0.10 0.18 0.23 0.31 0.14 0.22 0.29 0.34 0.19 0.26 0.33 0.37 0.23 0.30 0.36 0.40 0.27 0.33 0.39 0.43 0.31 0.37 0.43 0.47 0.35 0.41 0.46 0.50 0.40 0.45 0.50 0.53 0.44 0.48 0.53 0.56 0.48 0.52 0.56 0.59 0.52 0.56 0.60 0.62 0.56 0.60. 0.63 0.65 0.61 0.64 0.66 0.68 0.65 0.67 0.70 0.71 0.69 0.71 0.73 0.74 0.73 0.75 0.77 0.78 0.77 0.79 0.80 0.81 0.82 0.82 0.83 0.84 0.86 0.86 0.87 0.87 0.90 0.90 0.90 0.90 Whitewater River Region WQMP Coral Mountain Apartments Appendix G . AGREEMENTS — CC&RS, COVENANT AND AGREEMENTS AND /OR OTHER MECHANISMS FOR ENSURING ONGOING OPERATION, MAINTENANCE, FUNDING AND TRANSFER OF REQUIREMENTS FOR THIS PROJECT- SPECIFIC WQMP • Whitewater River Region WQMP Coral Mountain Apartments 'Appendix H PHASE I ENVIRONMENTAL SITE ASSESSMENT \L SITE ASSESSMENT LA QUINTA REDEVELOPMENT AGENCY • 78 -495 CALLE TAMPICO LA QUINTA, CALIFORNIA 92253 REPORT OF PHASE I ENVIRONMENTAL SITE ASSESSMENT SOUTH SIDE OF HIGHWAY 111 AND EAST OF DUNE PALMS ROAD LA QUINTA, RIVERSIDE COUNTY, CALIFORNIA June 20, 2006 © 2006 Earth Systems Southwest Unauthorized use or copying of this document is strictly prohibited without the express written consent of Earth Systems Southwest. • File No.: 10661 -01 06 -06 -821 Earth Systems 1i/ Southwest 79 -811B Country Club Drive Bennuda Dunes, CA 92203 (760) 345 -1588 (800) 924 -7015 FAX (760) 345 -7315 June 20, 2006 La Quinta Redevelopment Agency 78 -495 Calle Tampico La Quinta, California 92253 Attention: -Mr. Thomas Genovese Subject: Report of Phase I Environmental Site Assessment Project: South Side of Highway 111 and East of Dune Palms Road La Quinta, Riverside County, California Dear Mr. Genovese: File No.: 10661 -01 06 -06 -821 As you requested, Earth Systems Southwest [ESSW] has completed this Phase I Environmental Site Assessment [ESA] of the site referenced above. This report was prepared for your exclusive use. It was prepared to stand as a whole and no part should be excerpted or used in exclusion of any other part. This project was conducted in accordance with our proposal dated May 11, 2006 and authorized on May 23, 2006. This report completes the scope of services outlined in our proposal. Thank you for this opportunity to be of service. If you have any questions regarding this report, or the information contained herein, please contact this office at your convenience. Respectfully Submitted, D G� EARTH SYSTEMS SOUTHWEST ter' SCOT A. � /�j-- 0Z STORMO /f J� //bfb "YY �IC HYDRoGEOLO OGEOLOGI5T RG Scot A. Stormo, RG 4826, CHG 204 cSj, HG 2� os Vice President ESA/ko /sas /ajf Distribution: 6/La Quinta Redevelopment Agency 1 /Field File . 2 /BD File I /RC File • REPORT OF PHASE I ENVIRONMENTAL SITE ASSESSMENT SOUTH SIDE OF HIGHWAY 111 AND EAST OF DUNE PALMS ROAD LA QUINTA, RIVERSIDE COUNTY, CALIFORNIA June 20, 2006 TABLE OF CONTENTS 1.0 INTRODUCTION .....................................................................:.......... ..............................1 1.1 Project Information ........................ . ....... ............. ... ..................... .................. .............1 1.2 Purpose and Scope of Work ....................................................... ..............................1 1.3 Exclusions and Data Gaps ......................................................... ..............................2 1.4_ Limitations and Reliance ........................................................:.. ..............................3 2.0 GENERAL SITE INFORMATION ................................................... ..............................3 2.1 Size, Location, and Name ................................................. ............................... 3 2.2 Assessor's Parcel Number(s) .......................:............................. ..............................3 2.3 Township, Range, Section ......................................................... .....:........................4 2.4 Site Boundaries .......................................................................... ..............................4 2.5 Current Development ................................................................. ..............................4 2.6 Site Topography .................................................................. ...................... 4 2.7 Surface Water Bodies ...................... ............................... 4 2.8 Geology and Hydrogeology ....................................................... ..............................4 F�] L 4.0 HISTORICAL INFORMATION ....................................................... ..............................6 4.1 Aerial Photographs .................................................................... ..............................7 4.2 Topographic Maps ..................................................................... ....:.........................8 4.3 Munger Oil Maps ....................................................................... ..............................8 4.4 Eire Insurance Maps ................................................................... ..............................8 4.5 Local Street Directories ............................................................. ..............................8 4.6 Zoning/Land Use Records ......................................................... ..............................8 4.7 Recorded Land Title Information ............................. ........................:... 9 4.8 Building Department Records ................................................... ..............................9 4.9 Tribal Records ......................................................... ............................... 9 4.10 Engineering and Institutional Controls...., 9 4.11 Environmental Cleanup Liens .......................... ............................... ......9 .................. 5,0 AGENCY DATABASE SEARCH REPORT .................................... ..............................9 6.0 INTERVIEWS, GENERAL RESEARCH, AND PRIOR REPORTS ........................10 6.1 Current owners /occupants/ operators ......................................... .............................10 6.2 Past owners /occupants/ operators .............................................. .............................10 6.3 Owners /occupants of neighboring properties ........................... ........................:....10 6.4 Riverside County Department of Environmental Health .......... .............................11 6.5 Riverside County Agricultural Commissioner's Office ........... .............................11 6.6 Interviews Regarding Common Farm Practices ....................... .............................11 EARTH SYSTEMS SOUTHWEST 3.0 SITE RECONNAISSANCE .... .... .... .................................:.........,.................... • 3.1 On -Site Observations . ..............................5 5 3.2 Site Vicinity Observations ......................................................... ..............................6 F�] L 4.0 HISTORICAL INFORMATION ....................................................... ..............................6 4.1 Aerial Photographs .................................................................... ..............................7 4.2 Topographic Maps ..................................................................... ....:.........................8 4.3 Munger Oil Maps ....................................................................... ..............................8 4.4 Eire Insurance Maps ................................................................... ..............................8 4.5 Local Street Directories ............................................................. ..............................8 4.6 Zoning/Land Use Records ......................................................... ..............................8 4.7 Recorded Land Title Information ............................. ........................:... 9 4.8 Building Department Records ................................................... ..............................9 4.9 Tribal Records ......................................................... ............................... 9 4.10 Engineering and Institutional Controls...., 9 4.11 Environmental Cleanup Liens .......................... ............................... ......9 .................. 5,0 AGENCY DATABASE SEARCH REPORT .................................... ..............................9 6.0 INTERVIEWS, GENERAL RESEARCH, AND PRIOR REPORTS ........................10 6.1 Current owners /occupants/ operators ......................................... .............................10 6.2 Past owners /occupants/ operators .............................................. .............................10 6.3 Owners /occupants of neighboring properties ........................... ........................:....10 6.4 Riverside County Department of Environmental Health .......... .............................11 6.5 Riverside County Agricultural Commissioner's Office ........... .............................11 6.6 Interviews Regarding Common Farm Practices ....................... .............................11 EARTH SYSTEMS SOUTHWEST TABLE OF CONTENTS, continued ii 6.7 Other Sources of Information ................................................... .............................12 6.8 Prior Investigations and Experience ......................................... .:...........................12 7.0 SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS ... .............................13 APPENDIX A Figures APPENDIX B Photographs - APPENDIX C Additional Documentation APPENDIX D Agency Database Search Report APPENDIX E Qualifications Statement EARTH SYSTEMS SOUTHWEST • U June 20, 2006 - 1 - File No.: 10661 -01 06 -06 -821 1.0 INTRODUCTION 1.1 Project Information This report presents the findings of the Phase I Environmental Site Assessment [ESA] conducted by Earth Systems Southwest [ESSW] for a property located on the south side of Highway 111 east of Dune Palms Road in the City of La Quinta, Riverside County, California. This project was conducted for the La Quinta Redevelopment Agency in accordance with our proposal dated May 11, 2006 and authorized on May 23, 2006. We understand the client is purchasing the site. This project has been performed at the request of the client for due diligence purposes. 1.2 Purpose and Scope of Work The purpose of an ESA is to evaluate the potential for the presence of soil or groundwater contamination that may be present because of the past use, handling, storage, or disposal of hazardous materials or petroleum products on or near the property. The scope of work for this evaluation is based on the United States Environmental Protection Agency Final All Appropriate Inquiry Rule (2006) [US EPA AAI]; and, the ASTM Standard E- 1527 -05, Standard Practice for Environmental Site Assessments, and consisted of the tasks listed below. Site Reconnaissance: This involved: {A) a -visual reconnaissance of the site, noting physical evidence of potential contamination or possible sources of contamination; (B) interviews with persons familiar with the site (if possible) regarding present and past site usage; and' (C) observation of adjacent properties to identify readily observable visual evidence of possible impacts to the subject site. Significant on -site conditions were photographed to document current conditions'. Selected site photographs are presented in Appendix B. Site History Investigation: The history of the site was investigated regarding past land use at and near the site, specifically as it relates to the storage, production, use, or disposal of hazardous materials. The sources of information for this evaluation are listed in the references section of this report, and may include the following categories of information (note that each category is utilized at the discretion of Environmental Professional (EP) to determine how much historical data is sufficient): ■ Aerial photographs ■ Topographic maps ■ Munger Oil maps ■ Fire Insurance Maps ■ Zoning/Land Use Records • Personnel Interviews ■ Tribal Records ■ Local Government (County and City) Records records Relevant documents are provided in Appendix C. • EARTH SYSTEMS SOUTHWEST i.e., building department June 20, 2006 - 2 - File No.: 10661 -01 06 -06 -821 Regulatory Agency Record Review: Many regulatory agencies compile information concerning sites that generate, store, use, and/or release hazardous materials. This information can be accessed by reviewing lists published by the regulatory agencies. A report listing known sites that generate, store, use, and/or have released hazardous materials was obtained from a firm that specializes in maintaining a database of this type of information. A copy of the agency database search report is presented in Appendix D, and is discussed in Section 4. The search radius for this review was in general accordance with the US EPA AAI and ASTM standard E- 1527 -05 as measured from the property boundary. In addition, selected government agencies were contacted for information they may have regarding environmental conditions at or near the site. Report Preparation: This report was prepared to present our findings, conclusions, and recommendations. A qualifications statement regarding the personnel who performed this evaluation is presented in Appendix E. 1.3 Exclusions.and Data Gaps Testing the air, groundwater, soil, or building materials for the presence of hazardous constituents was beyond the scope of this evaluation. The US EPA AAI and ASTM standard E1527 -05 require the identification of gaps in the data used in evaluating the site. Data gaps encountered in this project, and their significance to the project, are summarized below. • As stated in the proposal, land title information would only be reviewed if furnished by the Client. Land title information was not provided to ESSW, and .therefore was not reviewed. Because of the availability of other data sources, the. lack of title information is not considered to be significant. • ESSW personnel were not able to enter an area north of the center of the site due to dense, overgrown vegetation. This area was visually observed from the east and west. Small amounts of debris consisting of wind -blown trash and rusted 5 -. .gallon paint cans were noted along the east and west sides of the dense overgrowth. The debris did not appear to extend deeper into the brush. • At the time of the site visit, it appeared that transients were living in a camper in the northeastern portion of the abandoned trailer park. ESSW personnel did not approach this camper out of concern for their personal safety, but visually observed the area from a distance of approximately 50 feet. The area around the camper did not appear to contain any drums or suspicious looking materials. ESSW is not able to offer opinions regarding portions of the site to which we did not have access or to which vision was obscured. However, given the conditions observed on the rest of the site, and the primarily residential history of the site, lack of entry into the two areas mentioned above is probably not significant. Further investigations of data gaps do not appear warranted. EARTH SYSTEMS SOUTHWEST June 20, 2006 - 3 - File No.: 10661 -01 • 06 -06 -821 1.4 Limitations and Reliance This report has been prepared for the exclusive use of the La Quinta Redevelopment Agency. The conclusions and recommendations rendered in this report are opinions based on readily available information obtained to date within the scope of the work authorized by the client. The scope of work for this project was developed to address the needs of the client as part of a property transaction (buy, sell, refinance, etc.) and may not meet the needs of other users. Other parties participating in the transaction for which this project was conducted may also use the information presented in this report, provid ed said parties agree that ESSW shall have no additional liability arising from such use than described in the contract under which this project was conducted (a copy of that contract will be provided upon request). Any other use of or reliance on the information and opinions contained in this report without the written authorization of ESSW is at the sole risk of the user. It should be noted that any level of assessment cannot ascertain that a property is completely free of chemical or toxic substances. We believe the scope of work has been appropriate to allow the client to make an informed business decision. The results contained in this report are based upon the information acquired during the assessment, including information obtained from third parties. ESSW makes no claim as to the accuracy of the information obtained from others. In addition, it is possible that variations exist beyond or between points explored during the course of the investigation, and that changes in conditions can occur in the. future due to the works of man, contaminant migration, variations in rainfall, temperature, and /or other factors not apparent at the time of the field investigation. It should also be noted that in active blow -sand areas, sand can accuinulate quickly behind windbreaks. Consequently, materials can be buried out of view by natural wind -blown sand in a relatively short period of time under favorable conditions. The'services performed by ESSW have been conducted in a manner consistent with the level of care and skill ordinarily exercised by members of. our profession currently practicing under similar conditions.in the site vicinity. No warranty, express or implied, is offered. 2.0 GENERAL SITE INFORMATION 2.1 Size, Location, and Name The site consists of approximately 19.61 acres of land located on the south side of Highway 111 a short distance east of Dune Palms Road in the City of La Quinta, Riverside County, California. The site is not known by a particular name, though it has been referred to as the Lou Mazella property in some correspondence we have received. The site location is depicted in Figure 1. The site layout is depicted in Figure 2. 2.2 Assessor's Parcel Number(s) The site is identified as Assessor's Parcel Numbers [APNs] 600 - 020 -004 and -005. • - EARTH SYSTEMS SOUTHwEST June 20, 2006 - 4 - File No.: 10661 -01 06 -06 -821 2.3 Township, Range, Section The site is located in the northwest quarter of the southeast quarter of Section 29, Township 5 South, Range 7 East, San Bernardino Baseline and Meridian. 2.4 Site Boundaries The property boundaries are defined by Highway 111 to the north, a temporary chain -link construction fence to the east, and the wall bounding the Desert Sands Unified School District facilities to the south. The western boundary was not sharply demarcated, but was assumed to be the eastern edge of the developed area for the commercial properties west of the site. 2.5 Current Development The western half of the site is undeveloped land while the eastern half is currently abandoned agricultural land with the remnants of a trailer park located in the northeastern quarter of the site. 2.6 Site Topography Sand dunes cover the western half of the site except along the southwest boundary, which appears to have been a borrow'source for construction of the commercial facilities west of the site. The eastern half of the site was smoothed for agricultural use. According to the Riverside County Land Information Service on the Riverside County Transportation and Land Management website (www.tlma.co. riverside .ca.us /gis /gisdevelop.html), the elevation of the site ranges from about 36 to 49 feet above mean sea level. 2.7 Surface Water Bodies Surface water bodies are not present on the site, either as lakes or streams. The Whitewater River is located within man -made embankments approximately 650 feet north of the site, and the All American Canal is located less than 500 feet southeast of the site. The Whitewater River contains water only as a result of significant rainfall events. Water bodies are not located in a position to transport contaminants onto the site, or be affected by contaminants released at the site. A narrow infiltration basin is located along the northwestern site boundary and appears to handle run -off from the adjacent commercial development to the west. It does not appear to drain onto the subject property. 2.8 Geology and Hydrogeology The site is located in the Coachella Valley of Southern California. The Coachella Valley is part of the tectonically active Salton Trough, which is a closed, internally draining basin bound by the San Jacinto and Santa Rosa Mountains to the southwest, the San Bernardino Mountains to the northwest, and the Little San Bernardino and Orocopia Mountains to the northeast and east. These mountain ranges, and the basement rock underlying the Coachella Valley, are primarily composed of granitic and .metamorphic rock. Within the Coachella Valley, the basement complex is overlain by a series of unconsolidated and semi - consolidated continental clastic sediments eroded from the surrounding mountain ranges, lacustrine deposits of ancient Lake EARTH SYSTEMS SOUTHWEST June 20, 2006 - 5 - File No.: 10661 -01 • 06 -06 -821 Cahuilla, and wind -blown sand deposited in the- active blow -sand area of Riverside County (DWR, 1964). The site is located on aeolian (wind- blown) sand deposits. The northwest trending San Andreas Fault zone is the major geologic feature of the Coachella Valley. The Banning, Mission Creek, and Garnet Hill faults, which are part of the San Andreas Fault system, divide the Coachella Valley into four distinct hydrogeologic subbasins. Each subbasin is further divided into subareas, based on either the type of water - bearing formation, water quality, areas of confined groundwater, forebay areas, groundwater divides, or surface water divides. The site is located within the Thermal subarea of the Indio subbasin. This subarea consists of the confined portion of the Indio subbasin, where water from the up- gradient Palm Springs subarea moves into the interbedded sands, silts and clays underlying the central portion of the valley. Groundwater in this subarea generally flows in a southeasterly direction toward the Salton Sea. The water bearing materials in this area have been divided into four units: a semi - perched zone at the ground surface and extending to a depth of up to 100 feet; an upper aquifer which is 150 to 300 feet thick; a lower aquifer in excess of 500 feet thick; and an aquitard between these two aquifers which is 100 to 200 feet thick. The semi - perched zone may be the uppermost water - bearing zone under the site. Water quality within this zone is generally poor. The deeper and upper aquifers are typically used for water supply. Throughout the Thermal subarea, the horizontal permeability is several times the vertical permeability resulting in a predominantly lateral flow of groundwater (DWR, 1964). The depth to groundwater at the site was evaluated. by contacting the Coachella Valley Water District (CVWD). Mr. Brad Gummer of the CVWD indicated the depth to groundwater in a well • located less than one half mile southwest of the site averaged 176.6 feet for the year 2005: Note that the CVWD obtains depth to water information from production wells that tend to tap deeper aquifers, and may not represent upper -most groundwater. 3.0 SITE RECONNAISSANCE 3.1 On -Site Observations ESSW personnel visited the site on June 14, 2006, to observe current site conditions and adjacent land use. A summary of our findings is presented below. The site was observed to consist of native desert sand dunes on the west half and abandoned agricultural land with an abandoned trailer park on the east half (Photo 1). The agricultural area appeared to have been abandoned for many years. Outlets for a gravity feed flood irrigation system and irrigation valve housings were observed south of the center of the site. Mature native shrubs covered the entire site, with the exception of the abandoned trailer park located in the northeastern quarter of the site. Extremely dense vegetation covered an area north of the center of the site and prevented access to that immediate area. The vegetation did not show unusual signs of stress. ■ All terrain vehicle tracks crossed the entire site. A shallow depressed area was located in the southwest corner of the site, along the southwestern site boundary. This area was probably a borrow source for sand associated with construction of the commercial property to the west. The area appeared to have contained standing water at some point, most likely run -off from . • EARTH SYSTEMS SOUTHWEST June 20, 2006 - 6 - File No.: 10661 -01 06 -06 -82.1 the site and possibly the area west of the site. Evidence of staining or debris as a result of the drainage was not noted. Windblown trash was noted throughout the site, but accumulated primarily in the northwest corner of the site. Significant amounts of debris were located in the southeastern comer of the site (Photo 2). The debris consisted of waste plant material apparently from clearing trees or mature shrubs; household trash; 5- and 10- gallon paint cans; rusted metal food cans; wooden debris; carpet; and random trash that may have originated from the -trailer park. With the exception of the paint cans, hazardous materials were not observed. Evidence of significant spillage or intentional disposal of waste liquids was not observed. An abandoned trailer park was located in the northeast quarter of the site. The trailer park consisted of several (more than twenty) concrete trailer pads, each with a hook -up for water, electric, and septic; a multi- roomed laundry facility with shower and restroom facilities; and a pool (Photos 3 and 4). Debris consisting of household trash, windblown trash, and mattresses were scattered throughout the laundry facility. A pipeline for natural gas was noted on the north side of the laundry facility. A pool with pumping equipment located below grade was located west of the laundry facility along the southern border of the trailer park. Remnants of the electrical system for the park were located between the laundry facility and the pool. ■ Transients appeared to be occupying a camper in the northeastern portion of the trailer park for residential use. ESSW personnel did not approach this area due to safety concerns, but visually observed the area from a distance of approximately 50 feet. The area outside the camper contained two vehicles, chairs, and one or two bags of trash, but did not appear to contain drums or suspicious looking materials. A water well with two tanks and a pump was located north of the trailer park, south of Highway 111 (Photo 5). The well most likely supplied water to the trailer park during its operation but may also-have provided water for the agricultural use of the site pre - dating the trailer .park. 3.2 Site Vicinity Observations The site vicinity consisted of commercial properties and an active construction site. A commercial development consisting of a Chevron gas station, office buildings, self - storage buildings, and a narrow infiltration .basin was located west of the site. The Desert Sands Unified School District headquarters facilities were located to the south, Highway 111 was located to the north with a retail development beyond, and an active construction site was located to the east. Evidence was not observed that the site was adversely affected by activities on properties in the site vicinity. 4.0 HISTORICAL INFORMATION Information regarding the history of the site was obtained from various sources of information, as listed in the References section of this report. The results of this research are summarized below. EARTH SYSTEMS SOUTHWEST June 20, 2006 - 7 - File No.: 10661 -01 • 06 -06 -821 4.1 Aerial Photographs ESSW and Coachella Valley Water evaluate the history of the site an d potential- use, storage, or disposal photographs are presented below: District (CVWD) aerial photo archives were reviewed to vicinity, with particular attention to indications of the of hazardous materials. Our interpretations of these • In 1939, the site and vicinity appeared to be native desert with low vegetation density. Highway 111 was visible along the northern site boundary. • In 1949, the eastern half of the site appeared to be agricultural. At least two structures, or possibly the water tanks observed during the. site visit, were located in the northeastern portion of the agricultural area (in the area depicted on Figure 2). The western half of the site was unchanged. The immediate vicinity consisted of a mix of undeveloped and agricultural properties, while the greater vicinity contained primarily agricultural properties. • In 1955, the eastern half of the site remained agricultural. Mature trees bordered the western boundary of the agricultural area, and divided the acreage into three equal sized parcels. The western half of the site appeared unchanged. The site vicinity appeared to be predominantly agricultural with small residences scattered throughout the area., Dune Palms Road extended north of Highway 111. Jefferson Street was visible east of the site as a dirt road. • In 1974, the agricultural portion of the site had been abandoned and the trailer park was visible in the northeastern quarter of the site and appeared to be densely populated. A pool, • the laundry building, and another permanent structure were visible along the southern boundary of the trailer park. The western half of the site and site vicinity appeared relatively unchanged. • In 1980, the site appeared to be unchanged except for a small area south of the trailer park that had been cleared. The western half of the site remained undeveloped. Four to five trailers were visible north of the trailer park, south of Highway 111. The site vicinity appeared to be slightly less agricultural. • In 1984, the site appeared relatively unchanged. The western half of the site remained undeveloped.. Two small structures, possibly storage sheds, were visible southeast of the trailer park, and a dirt trail was visible leading from the southern end of the trailer park into the southern portion of the site. In the vicinity, the All American Canal had been developed southeast of the site. ■ In 1990, several (at least five) trailers and - vehicles were visible just north of the trailer park. In the southern portion of the park, at least three trailers had been parked between the pool and laundry room. The larger of the two `storage shed' structures southeast of the trailer park was no longer visible. The western half of the site remained undeveloped. The site vicinity was increasingly developed. ■ By 1995, the area north of the trailer park and the area between the pool and the .laundry building east of the pool appeared less cluttered with trailers and/or vehicles. Neither of the `storage shed' structures southeast of the park were visible. The western half of the site • EARTH SYSTEMS SOUTHWEST June 20, 2006 - 8 - File No.: 10661 -01 06 -06 -821 remained undeveloped. The site vicinity appeared relatively unchanged. Development of the area was still progressing. In 2000, the trailer park was much less populated. Most of the trailers had been removed except for approximately seven trailers in the southern portion of the park. The structure west of the pool appeared to have been demolished. Debris was visible along the southwestern site boundary, and the smaller `storage shed' structure was once again visible southeast of the trailer park. A portion of the site in the soutbwest corner of the site appeared to have been cleared, most likely in conjunction with the development of the adjacent parcel to the west. In the vicinity, construction of the commercial development west of the site had begun,'and properties north of Highway 111 had been cleared for development. The Desert Sands Unified School District facility was visible south of the site. 4.2 Topographic Maps Topographic maps produced by the U.S.G.S. were reviewed for information concerning the development history of the site. The 7.5- minute La Quinta, California Quadrangle, dated 1959 and photo- revised in 1980, was reviewed. This map depicts the site as primarily undeveloped land with a "Trailer Park" added in the 1980 revision. The site vicinity. is depicted as a mixture of undeveloped and agliculhiral land, sparsely populated with small structures. The Coachella Valley Stormwater Channel, located less than 1,000 feet north of the site, is depicted as having been built by 1980. 4.3 Munger Oil Maps The Munger Oil map book was reviewed for information regarding historic oil -well drilling activities near the site. The map book did not depict oil wells having been drilled within 1 mile of the site. 4.4 Fire Insurance Maps From 1887 until present, the Sanborn Company compiled detailed maps used for fire insurance purposes that depicted buildings and other structures in selected urban areas in the United States and Canada. Sanborn maps can provide valuable information as to the historical usage of a particular building. Sanborn maps for the site and vicinity were requested from Track Info Services LLC (aka Environmental FirstSearch or FirstSearch), a firm that specializes in maintaining this type of information; They indicated that Sanborn Fire Insurance maps ate not available for the site. 4.5 Local Street Directories Due to the sparsely developed nature of the site, street directories were not reviewed. 4.6 Zoning/Land Use Records Zoning/Land Use records were not available from the Riverside County Land Information Service on the Riverside County Transportation and Land Management website (www.tlma.co.riverside.ca.us/gis/gisdevelop.litrril). EARTH SYSTEMS SOUTHWEST June 20, 2006 - 9 - File No.: 10661 -01 06 -06 -821 4.7 Recorded Land Title Information A copy of the title was not provided for our review. 4.8 Building Department Records The City of La Quinta building department was contacted regarding records on file for the site. No files were available for the subject site. The County of Riverside Department of Building and Safety [RCDBS] was contacted regarding records on file for the site. A file search was conducted and multiple files for the installation of mobile homes and septic tanks were found. The files did not contain information regarding the manufacturing, storage, or disposal or hazardous materials on the site. 4.9 Tribal Records This site is not within %, mile of tribal land. Therefore, Tribal records for the subject property or adjoining properties were not reviewed. 4.10 ,Engineering and Institutional Controls A search to identify Engineering and Institutional Controls (i.e. deed restrictions and restrictive zoning) to a radius of 1/2 mile was conducted by FirstSearch. Engineering and Institutional were not identified for the subject site. • 4.11 Environmental Cleanup Liens Recorded Environmental Cleanup Liens [ECL] on a property are indicators that contamination exists or existed at the site. ECLs are "encumbrances on a property for the recovery of incurred cleanup costs on the part of'a state, tribal, or federal government agency or other third party" (EPA 2006). 'The Riverside County Department of Environmental Health [RCDEH]) did not indicate that ECLs are assigned to the site. 5.0 AGENCY DATABASE SEARCH REPORT A report summarizing the information available from regulatory agencies regarding sites that generate, store, .use, and /or have released hazardous materials was obtained from a firm that specializes in maintaining a database of this type of information. The publications reviewed in the database search are referenced in the database report, presented in Appendix D. The search radii used for each list were in accordance with the EPA AAI and ASTM E- 1527 -05 guidelines as measured from the property boundary. Significant information obtained in the database search is summarized below. ■ The site is not listed in the database report. ■ Nine sites within the search radii are listed a total of fourteen times in the database report. These consist of three gasoline stations, three auto dealerships, two retail stores, and the Desert Sands Unified School District facilities. The sites are listed as being either generators • EARTH SYSTEMS SOUTHWEST June 20, 2006 _10- File No.: 10661 -01 06 -06 -821 of small quantities of hazardous waste, or as having USTs. No problems are reported at these sites. These sites do not appear to pose a threat to the site due to the distance, direction, or nature of the issues at those sites. ■ The database search report lists one additional site as unmapped, due to vague address listings or the inability of the automated search system to identify the location of the release site. This listing is for a USA Gasoline Station, which was one of the nine sites discussed above. The information in the unmapped data file pertains to that site being a generator of hazardous waste. No problems are reported. 6.0 INTERVIEWS, GENERAL RESEARCH, AND PRIOR REPORTS 6.1 Current owners /occupants /operators The current owners of the site, Mr. and Mrs. Lou Mazella, and their son Mr. Lou Mazella Jr., were interviewed by telephone on June 5, 2006. Mr. and Mrs. Mazella indicated that they have owned the property for approximately 50 years. They purchased the property as an investment, at which time the property contained only the trailer park located in the northeast quarter of the site. Mr. Mazella indicated that he thought the trailers were on septic systems, and that the park was in operation until approximately 10 years ago. When queried about the possible agricultural history of the site, the presence of above - ground or underground storage tanks, or the storage of chemicals on -site, Mr. and Mrs. Mazella indicated that they were not aware of the property ever being used for agricultural purposes, and that the only tanks located on -site were the water tanks located in the northeastern portion of the site. With regards to the storage of chemicals or hazardous materials, the Mazellas indicated that they were not aware of any activities related to the storage or use of chemicals or hazardous materials on -site. Mr. Lou Mazella Jr. indicated that the structure in the southeastern corner of the trailer park was utilized as a laundry/restroom facility for the trailer park and that he thought the pool had been backfilled and abandoned. Mr. Mazella Jr. also indicated that another structure on -site, west of the pool, had been demolished. Mr. Mazella Jr. was not aware of any activities related to the storage or use of chemicals or hazardous materials on -site. 6.2 Past owners /occupants /operators Mr. and Mrs. Mazella indicated that they had purchased the site from Mr. Elmer Plum approximately fifty years ago, but that they did not have contact information for Mr. Plum. Given the length of time that the property has been possessed by the Mazellas, efforts to contact Mr. Plum were not attempted. 6.3 Owners /occupants of neighboring properties The US EPA recommends that interviews with persons on adjoining properties be conducted for properties that are "abandoned." Ms. Idelma Nunez of Coldwell Banker Real Estate, located in the commercial center west of the site was interviewed at the time of the site visit regarding historical usage of the site. Ms. Nunez indicated that'she bad not witnessed nor was aware of any dumping or illegal activities on the site. EARTH SYSTEMS SOUTHWEST June 20, 2006 - 11 - File No.:' 10661 -01 • 06 -06 -821 6.4 Riverside County Department of Environmental Health Ms. Linda Shurlow with the Riverside County Department of Environmental Health [ RCDEH] was contacted regarding known problems at the site or in the site vicinity. Ms. Shurlow indicated that she was not aware of any problems at the site or in the site vicinity. Mr. Doug Thompson with the RCDEH was contacted during a prior project regarding the RCDEH's approach to pesticide residues at agricultural sites. Mr. Thompson indicated that pesticide residues that result from use in conformance with legal requirements at the time of use are not subject to hazardous waste regulations, unless those soils are exported from the site (at which time they become subject to hazardous waste regulations). However, the RCDEH is concerned that on -site workers and future residents may suffer adverse health effects from the presence of these residues when the agricultural properties are converted to other uses. The RCDEH has started requiring that Phase II investigations be performed to evaluate whether pesticide residues are present at elevated concentrations. 6.5 Riverside County Agricultural Commissioner's Office Ms. Carolyn Brown with the Riverside County Agricultural Commissioner's office [RCAC] was contacted previously for general information regarding pesticide use. Ms. Brown indicated that the pesticide DDT was widely used throughout the Coachella Valley prior to its ban in the early 1970.'s. Consequently, it should be assumed that DDT could have been used on all properties used for agriculture prior to that time. • 6.6 Interviews Regarding Common Farm Practices Mr. Tom Brickley with Brickley Environmental, an asbestos removal contractor, was contacted during a previous project regarding the use of asbestos. piping -in irrigation systems. Mr. Brickley indicated that they-have been involved in the removal of asbestos- containing irrigation piping at numerous sites, and that finding this type of piping common. He also stated that these pipes are not considered a hazardous material and can be left in place, but are often removed due to engineering and site development considerations. If the pipes are removed, the removal needs to be performed by a licensed asbestos contractor and disposed to a permitted landfill following appropriate protocols. The costs to remove and dispose of the asbestos pipe is dependent upon the condition it is in, but he stated that pipe in good condition can be removed for an average cost of about $500 to $2,000 per 100 linear feet of pipe. Mr. Bob Sheppard with CV Grading, a contractor that installs irrigation systems, was contacted during a previous project for information regarding typical uses of asbestos - cement (AC) pipe. He indicated that AC pipe is used in irrigation systems when the pressure is anticipated to exceed the design strength of common concrete pipe. Commonly used concrete pipe has a design strength sufficient for a hydrostatic head of about 20 feet, while AC pipe can have design strengths of 50 to 100 feet of hydrostatic head. AC pipe is more expensive than common concrete pipe, and therefore AC pipe is usually used only when the head is anticipated to exceed 20 feet of head. Non - pressurized gravity feed irrigation systems are usually constructed of non - asbestos concrete pipe. • EARTH SYSTEMS SOUTHWEST June 20, 2006 -12- File No.: 10661 -01 06 -06 -821 6.7 Other Sources of Information Information regarding DDT was obtained from the reference books "Agricultural Chemicals: Book I - Insecticides" (Thompson, 1998). That reference indicates that DDT is one of the most widely used insecticides in the world. It is stable under most conditions, and accumulates in the body fat of animals and in the soil. In other references: The half -life of DDT in soil has been estimated to be about 30 years under normal conditions (Saltzman and Yaron, 1986). A shorter half -life can be obtained under optimum conditions. ■ A 1985 study by the California Department of Food and Agriculture (CDT &A) found DDT. and its breakdown by- products in 95 of 97 soil samples collected from agricultural soils throughout California, typically at concentrations of about 1 mg/kg or less. The highest concentration detected was 31 mg/kg (total DDT and its breakdown by- products) in a sample from Los Angeles County. DDT is listed as a hazardous material in the California Code of Regulations governing the classification of hazardous waste (CCR Title 22). The Total Threshold Limit Concentration for DDT and its breakdown by- products is 1 mg/kg, which is the concentration of DDT which would classify a waste as hazardous. The US EPA Preliminary Remediation Goal (PRG) for DDT is 1.7 mg/kg in a residential setting. The PRG is a value based on health risks from exposure to the substance in a residential setting for 70 years (US EPA 2000). Organochlorine pesticides [OCPs] comprise a category of pesticide that includes DDT, DDE, DDD, Gamma -BHC (Lindane), Technical Chlordane, Dieldrin, Endosulfan II, Endrin, Endrin Aldehyde, Lindane, and Toxaphene. These compounds are notable for both their toxicity and their longevity in the soil. As such, residues of these compounds can be found at concentrates of concern well after usage of the material has ceased. Some of these chemicals were widely used well into the 1980's. 6.8 Prior Investigations and Experience ESSW has conducted numerous Phase II investigations of agricultural sites throughout the Coachella Valley. Elevated concentrations of DDT and other organochlorine pesticides [OCPs] have been found at about' /4 of these sites. The most common pesticides found at concentrations of concern are DDT, DDE, Toxaphene, and Dieldrin, which were de- registered for use by 1990. We have not identified a pattern indicative of where elevated levels of OCPs will be found, though spills at storage areas are more frequent than elevated concentrations in field areas. The level of concern expressed by the regulatory agencies regarding the potential presence of pesticide residues has begun to increase in the last few years, including the publication of a guidance document by the California Department of Toxic Substance Control [DTSC] concerning sampling of agricultural properties that are proposed to be developed as schools. That guidance document may become a basis for defining the "standard of care" for the EARTH SYSTEMS SOUTHWEST June 20, 2006 -13- File No.: 10661 -01 06 -06 -821 evaluation of pesticide residues at agricultural land. Given our prior experience with pesticide residues and the increasing focus this issue has received by the regulatory agencies, we believe testing for the presence of OCP residues is appropriate for land that was in use for agriculture prior to 1990. 7.0 SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS This report presents the findings of the Phase I Environmental Site Assessment (ESA) conducted by Earth Systems Southwest (ESSW) for the Lou Mazella property, consisting of approximately -19.61 acres of land located on the south side of Highway 111, east of Dune. Palms Road, in the City of La Quinta, Riverside County, California. The purpose of this assessment was to evaluate the potential for "the presence of soil or groundwater contamination related 'to the past use, handling, storage, or disposal of hazardous materials or petroleum products on or near the subject property. The scope of work for this evaluation included a reconnaissance ,of the site and vicinity, a review of the history of the site, and a review of information obtained from regulatory agencies regarding the use, storage, generation, or release of hazardous materials on the site or in the site vicinity. Based on this review, ESSW presents the following summary and conclusions: 1. The site was observed to consist of fallow agricultural land, undeveloped desert, and an abandoned trailer park. Wind -blown trash and household waste was scattered throughout the site, with the wind -blown trash located primarily in the northwestern portion of the site. The debris does not appear to contain hazardous materials. Further investigations • regarding these materials do not appear warranted. 2. Significant amounts of debris were located in the southeastern corner of the site. The debris consisted of plant material apparently from clearing trees or mature shrubs; household trash; 5- and 10- gallon paint cans; rusted metal food cans; wooden debris; carpet; and random trash that may have originated from the trailer park formerly located in the northeastern quarter of the site. Except for the paint cans, hazardous materials were not observed. The paint cans did not appear to have leaked and were too few to be a concern. Evidence of significant spillage or intentional disposal of waste liquids was not observed. Further investigations regarding these materials do not appear warranted. 3. Septic systems were used for waste disposal in the former trailer park. Septic systems provide a pathway for contaminants to be released into the ground, if contaminants are disposed into the waste water system. We did not obtain information that indicates hazardous materials were disposed into the septic system. and it is unlikely that the current systems have been used in this manner. Given the use of the site, further investigations of this issue do not appear warranted. 4. Rural residences and farms often have on -site fuel storage tanks, either above - ground or underground (ASTs and USTs respectively). Evidence of these features was not observed during the site visit. The concern with USTs is that a release can occur and not be noticed until 'the UST is removed. A farm house may have been located in the northern portion of the site, in the vicinity of the well and water tanks; and storage buildings may have been located southeast of the trailer park. We recommend a • EARTH SYSTEMS SOUTHWEST June 20, 2006 -14- File No.: 10661 -01 06 -06 -821 geophysical survey be conducted to look for buried metallic objects in those areas to look for the presence of abandoned USTs. 5. The site had been used for agriculture from at least 1949 to 1955, according to available aerial photographs. Therefore, the potential exists for residues of DDT and other organochlorine pesticides [OCPs] to be present at the site. The RCDEH has previously indicated that residues of pesticides that result from their application as part of farming operations are not classified as a hazardous material, unless soil is going to be exported from the site (at which time it falls under the waste classification criteria). Recently, the RCDEH has indicated that they feel it would be prudent to analyze soils for pesticide residues at sites proposed for residential development. We have observed a shift in the regulatory approach to former agricultural sites, and suspect that testing requirements will become more widespread in the future. Prior testing at other agricultural sites has occasionally found residues of OCPs- at concentrations of concern. Therefore, we recommend collection of soil samples from those portions of the site used for agriculture prior to 1990, and analysis of these samples for OCPs. Due to the disturbance inherent in building and operating a trailer park, the collection of samples within the trailer park area is not recommended. 6. The potential exists for asbestos - cement (AC) pipe to be present in the on -site irrigation system. However, AC pipe is not normally used in gravity -flow irrigation systems. Evidence of a gravity flood irrigation system was observed as part of the distribution system, therefore we believe the potential is fairly low for AC pipe to be present in the on -site irrigation system. The site vicinity consists of commercial and active construction properties. A flat area in the southwestern portion of the site appears to have been a borrow area during construction of the adjacent self- storage facility to the southwest. A basin for containing stormwater is located along the property boundary to the northwest, which collects surface water from the parking lot for the retail /commercial property to the west. Evidence was not observed that the site was adversely affected.by these or activities in the site vicinity. Further investigations regarding these issues do not appear warranted. 8. The site was not identified in the agency database review. The sites in the site vicinity do not appear to pose a risk to the subject site based on the status of those sites, the distance, or direction from the subject site, or the nature of the issue(s) at those sites. -000- EARTH SYSTEMS SOUTHWEST • June 20, 2006 - 15 - File No.: 10661 -01 06- 06 -82i REFERENCES Agency forToxic Substances and Disease Registry, www .atsdr.cdc.gov /tfacts3l.htm], website accessed February 15, 2006. Brickley, Tom, with Brickley Environmental, personal interview, February 24, 1998. Brown, Carolyn, RCAC, personal communication, July 17, 1997. California Code of Regulations, Title 22 (for TTLC values). California Department of Food and Agriculture, 1985. Agricultural Sources of DDT Residues in California's Environment, dated September, 1985. Department of Toxic Substances Control, EnviroStor website, ttp://www.envirostor.dtse.ek.gov/public/default.asp, accessed June 19, 2006. California Department of Water Resources (DWR), 1964, Bulletin Number 108 — Coachella Valley Investigation, July 1964. Coachella Valley Water District (CVWD), aerial photograph archives, as listed below: Date Source/Ffi ht Frame Approximate Scale 1939 Fairchild N/A N/A 02 -15 -49 USDA AXM -1F -28 1" = 660' 12 -55 MacPherson Sheet 27 1" = 1000' ESSW, aerial photograph archives, as listed below: Date Source/Flight Frame Approximate Scale 06 -20 -74 RCFCD 633 & 634 1" = .2,200' 04 -15 -80 RCFCD 666 & 667 1" — 2,200' 01 -20 -84 RCFCD 868 & 869 1" = 1,700' 01 -15 -90 RCFCD 12 -90 & 12 -91 1" = 1,700' 03 -18 -95 RCFCD 12 -76 & 12 -77 1" = 1,700' 03 -14 -00 RCFCD 12 -78 & 12 -79 1" = 1,700' Gummer, Brad, Coachella Valley Water District, telephone interview, June 16, 2006. Integrated Atmospheric Deposition Network, Atmospheric Deposition of Toxic Substances to the Great Lakes: IADN Results through 2000. Mazzela, Anne, Current Property Owner, telephone interview, June 5, 2006. Lou, Current Property Owner, telephone interview, June 5, 2006. EARTH SYSTEMS SOUTHWEST June 20, 2006 -16- File No.: 10661 -01 06 -06 -821 Lou Jr., Son of Current Property Owners, telephone interview, June 5, 2006. Munger Map Book, 1997, California - Alaska Oil and Gas Fields. Nunez, Idelma, Coldwell Banker Real Estate, personal interview, June 14, 2006. Pesticide Action Network North America, www.pesticideinfo.or , website accessed February 15, 2006. Riverside County Transportation and Land Management Agency, Riverside County Land Information Service, www.ttma.co. riverside .ca.us /jzis /gisdevelop.litml, website accessed June 19, 2006. Department of Building and Safety, faxed information request, June 6, 2006. Saltzman, Sarina, and Bruno Yaron, editors, 1986. Pesticides in Soil, published by Van Nostrand Reinhold Soil Sciences Series, New York. Sheppard, Bob, with Coachella Valley Grading, personal interview, August 1999. Shurlow, Linda, Riverside County Department of Environmental Health, phone interview, June 19; 2006. Thompson, Doug, RCDEH, personal communication, October 12, 2004. Thomson, W. T., 1985. Agriciultural Chemicals: Book I - Insecticides. Thomson Publications, Fresno, California. Track Info Services LLC, Environmental FirstSearch Report, dated June 1, 2006. United States Geologic Survey, 7.5 minute La Quinta, California Quadrangle, 1959, photo - revised 1980. US EPA, 2000, Region 9, Preliminary Remediation Goals Table 2000. EARTH SYSTEMS SOUTHWEST • • • SI-IOVLIN COMPANIES 46 -753 ADAMS STREET LA QUINTA, CALIFORNIA 92253 REPORT OF PHASE II INVESTICATION ASSESSOR'S PARCEL NUMBERS 600 - 020 -004 AND -005 HICHWAY 111 EAST OF DUNE PALMS ROAD LA QUINTA, CALIFORNIA February 7, 2007 © 2007 Earth Systems Southwest Unauthorized use or copying of this document is strictly prohibited without the express written consent of Earth Systems Southwest. File No.: 10661 -02 07 -02 -730 Earth Systems r,QZft7i Southwest February 7, 2007 Shovlin Companies 46 -753 Adams Street La Quinta, California 92253 Attention: Mr. John Durso Subject: Report of Phase II Investigation Project: Assessor's Parcel Numbers 600 - 020 -004 and -005 Highway 111, Cast of Dunc Palms Road La Quinta, California Dear Mr. Durso: 79 -811 B Country Club Drive Bermuda Dunes, CA 92203 (760) 345 -1588 (800) 924 -7015 FAX (760) 345 -7315 File No.: 10661 -02 07 -02 -730 As you requested, Earth Systems Southwest [CSSW] has completed this Phase 11 investigation of the site referenced above. Note that this report was prepared for your exclusive use. It was prepared to stand as a whole and no part should be excerpted or used in exclusion of any other part. This project was conducted in accordance with our Proposal No.: SWP- 07 -505R, dated December 7, 2006 and authorized December 11, 2006. This report completes the scope of services outlined in our proposal. Thank you for this opportunity to be of service. If you have any questions regarding this report or the information contained herein, please contact this office at your convenience. Sincerely, EARTH SYSTEMS SOUTH W ST I�SV'R scyqz,O�� No. 1198 Alex nder Schriener, Jr., RG 7198 *n� Senior Geologist EaF cnu4o"�� Phase II /as /rch Distribution: 6 /Shovlin Companies l /AS 1 /SAS 1 /RC File 2BD File 3 • r• n • REPORT OF PHASE II INVESTIGATION ASSESSOR'S PARCEL NUMBERS 600- 020 -004 AND -005 HIGHWAY 1 I I EAST OF DUNE PALMS ROAD LA QUINTA, CALIFORNIA January 30, 2007 TABLE OF CONTENTS Page 1.0 INTRODUCTION ............................................................................... ..............................1 2.0 SCOPE OF WORK ............................................................................. ..............................1 3.0 METHODS ........................................................................................... ..............................2 4.0 COMPARISON CRITERIA .............................................................. ..............................3 5.0 FINDINGS, CONCLUSIONS, AND RECOMMENDATIONS ...... ..............................3 5.1 Agricultural Fields ........................................... ..............................: 5.2 Former Building Areas .............................................................. ..............................3 5.3 Subsurface Metals Survey and Trenching Activities ................ ..............................4 6.0 LIMITATIONS .................................................................................... ..............................4 APPENDIX A — Figures, Photos, and Tables APPENDIX B — Laboratory Report EARTH ws'rnms sou- n-IlvBs'I, February 7, 2007 - 1 - File No.: 10661 -02 07 -02 -730 1.0 INTRODUCTION The site consists of approximately 20.24 acres of land located on the south side of Highway 11 1, a short distance east of Dune Palms Road, in the City of La Quinta, Riverside County, California (Figure 1). As shown on Figure 2, the site is rectangular, with the long axis oriented in a north -south direction. The site is identified as Assessor's Parcel Numbers [APNs] 600 -020 -004 and -005, which are nearly equal in size at about 10 acres. Figures depicting the site location and layout are presented in Appendix A. This project was conducted for Shovlin Companies in accordance With our Proposal No.: SWP -07 -5058, dated December 7, 2006. The site is located in the northwest quarter of the southeast quarter of Section 29, Township 5 South, Range 7 East, San Bernardino Baseline and Meridian. The property boundaries are defined by Highway 111 to the north, the Costco shopping center to the east, and the wall bounding the Desert Sands Unified School District facilities to the south. The Western boundary was not sharply demarcated, but was assumed to be the eastern edge of the developed area for the commercial properties West of the site. Surface water bodies are not present on the site, either as lakes or streams. Sand dunes cover the Western half of the site (APN 600 -020 -005) except along the southwest boundary, which appears to have been a borrow source for construction of the commercial facilities west of the site. The eastern half of the site (APN 600- 020-004) was smoothed for agricultural use and contained a former trailer park in the northern half. The elevation of the site ranges from about 36 to 49 feet above mean sea level. ESSW completed a Phase I Environmental Site Assessment [ESA] of the site in June 2006 (ESSW, 2006a). Most of the noted development activity occurred on the eastern part of the site (APN 600- 020 -004). From approximately the early 1940s to the early 1970s, the eastern part of the site was used for agricultural purposes. From the early 1970s to about 2000, a trailer park existed in the middle of the eastern parcel. More recently, two aboveground storage tanks [ASTs] for water and a well with pump are located at the northeast corner of the site. Currently, the trailer park is abandoned and the site is unused. Two primary issues of concern were identified at the site: • Rural residential properties and farms commonly used underground storage tanks [USTs] to store gasoline and /or diesel fuel. USTs are a concern because leaks can go unnoticed for long periods of time, and cleaning up those leaks can be required to protect groundwater resources. • Portions of the property were agricultural at a time when DDT Was commonly used on agricultural land. DDT is a concern because it is persistent in the soil and has low clean -up thresholds. Therefore, the potential exists for residues of DDT and similar pesticides to be present in the soil at concentrations of concern. 2.0 SCOPE OF WORK The scope of Work for this project involved evaluating the two concerns identified above, and included the following tasks: EARTH SYSTEMS soU'rtnwr:S'r i. February 7, 2007 - 2 - File No.: 10661 -02 07 -02 -730 1. A site - specific health and safety plan was prepared, in accordance with state and federal • regulations and ESSW corporate policy. s, 2. A geophysical survey was conducted by Terra GeoSciences on January 4, 2007 to look for usTs, buried drums and other buried metal debris. The survey consisted of using a Terrain Conductivity Meter [TCM], a type of metal detector, and Ground Penetrating Radar [GPR]. Pour geophysical anomalies were located. 013-1 through 013 -3 were located at the former buildings at the north- central portion of the site around the existing water ASTs, and 0134 was located directly south of the former trailer park laundry /sho\ver building. 3. Eight soil samples (SS -1 through SS -8) were collected on January 4, 2007 from the former agricultural portion of the site and analyzed for the presence of Organochlorine ' Pesticides [OCPs] (which includes DDT, Dieldrin, and Toxaphene, as well as other similar currently banned pesticides). ' 4. Four soil samples were collected on January 4, 2007 from the vicinity of the former building locations in the east - central portion of the site (southeast of the former trailer park laundry /shower building) (SS -101) and at the north- central portion of the site (SS -102 through SS -104) and analyzed for OCPs. 5. USA Service Alert was notified on January 23, 2007 to mark utility locations near the excavation locations at 013 -3 and 013 -4. 6. A diesel - powered backlioe was used on January 26, 2007 to excavate and evaluate two • buried geophysical objects (0I3 -3 and 0134) identified by the TCM and GPR Surveys. 7. This report has been prepared to summarize our activities, findings, conclusions, and recommendations. 3.0 METHODS Tema Geosciences performed a GPR and TCM survey on January 4, 2007. The GPR survey was conducted by dragging the. radar antenna across the ground in a grid pattern to investigate subsurface conditions. The TCM survey was performed by walking a Gemini III TCM instrument in a grid pattern over the area of interest while holding the instrument at a height of approximately 3 feet above ground surface. The function /sensitivity of the TCM was checked using visible metal objects. The limits of geophysical anomalies \were noted and flagged for further investigation. The diesel- powered backhoe and a hand shovel were used to exhume the metallic objects identified during the geophysical surveys. Field observations were made as to the source of the geophysical anomalies. Surface soil samples were collected by using a disposable tool and clearing away the upper 2 to 4 inches of organic soil and plant debris. Once an area \vas cleared, a laboratory - supplied glass jar was driven into the Soil until the jar was filled. The jars were sealed \vith Teflon -lined lids. Sample locations were marked \with a small labeled flag. Samples \were labeled, logged onto a • EARTH SYSTEIMS SOUI'tl \vGSi' February 7, 2007 -3 - File No.: 10661 -02 07 -02 -730 chain -of- custody form, placed in an ice - cooled chest, and delivered to Centrum Analytical Laboratory for analysis. Centrum is a California - certified hazardous waste testing laboratory. 4.0 COMPARISON CRITERIA The significance of the analytical results was evaluated by comparing on -site concentrations to several benchmark values. OCP concentrations were compared to: 1) the US EPA Preliminary Remediation Goal for a residential setting [PRG -r], to see if the concentration posed a risk of adverse health effects to future residents; and 2) the California Title 22 Total Threshold Limit Concentration [TTLC], a criterion used to classify wastes as hazardous. PRGs should be used to evaluate whether site -wide concentrations pose a risk to future residents, while the TTLC should be used to see whether wastes (such as spills or soils to be disposed of off -site) exceed regulatory thresholds for classification as "hazardous." The regulatory status of pesticide residues is dependent upon how the residue was formed. Pesticide residues that result from legal use of the product are not subject to hazardous waste regulations, even as the property is developed for other uses, because the material is present as a result of its intended use. Residues from spills are subject to hazardous waste regulations, because spills are not an intended use and a spilled material is a "waste" if it can no longer be used for its intended purpose. In addition, if soil containing pesticide residues is disposed of, then the hazardous waste regulations apply because the soil has become a waste. Regardless of whether the hazardous waste regulations apply, adverse health effects can result from exposure to pesticide residues. Mitigation of the adverse health effects may be warranted even if the material is not classified as a hazardous waste. 5.0 FINDINGS, CONCLUSIONS, AND RECOMMENDATIONS The findings of this investigation are summarized below. Figures depicting the sample locations and tables of laboratory results are presented in Appendix A. The laboratory reports are presented in Appendix B. 5.1 Agricultural Fields Trace amounts of the OCPs DDT and DDE (a breakdown product of DDT) were detected in four of the eight samples collected in the agricultural fields at the site ('fable 1). Other OCPs were not detected above laboratory reporting limits. Sample SS -4 contained the maximum concentrations of DDT and DDE at 0.002 mg/kg and 0.046 mg /kg, respectively. These concentrations are significantly under the PRG -r and TTLC benchmark values of 1.7 mg/kg and 1.0 mg /kg, respectively. Thus, OCP concentrations in the fields do not appear to pose a concern. 5.2 Former Building Areas Trace amounts of the OCPs DDT, DDE, and Technical Chlordane were detected in three of the four samples collected around the former building site. Other OCPs were not detected. One sample, SS -101 (Photo 1), contained all three OCPs. ']'his sample also contained the maximum concentrations of the detected OCPs in the former building areas (DDT at 0.007 mg /kg, DDE at 0.018 mg /kg, and Technical Chlordane at 0.76 mg /kg). These concentrations are well below the EARTH sys'n':ms sou'ri- nvrs'r February 7, 2007 - 4 - File No.: 10661 -02 07 -02 -730 PRG -r and TTLC levels for the detected OCPs. Further investigations related to this location do • not appear warranted. 5.3 Subsurface Metals Survey and Trenching Activities Three suspected buried objects were detected by the GPR survey in the northern building location. The TCM survey was less effective due to the presence of the two large metallic ASTs and metal underground .water distribution lines. • Objects OB -Land OB -2 were less than 2 feet in diameter and located directly adjacent to and in between the two ASTs. These were determined to be too small to be significant and are likely buried junk metal or parts of the water distribution system. • Geophysical Object OB -3 had several signatures covering an area approximately 30 feet by 30 feet in size and was located south of and adjacent to the existing water ASTs (Photo 2). It was characterized by two strong reflectors on the GPR survey — one at about 2 to 3 feet below ground surface [bgs] and one at about 7 to 10 feet bgs. Two trenches, T- I and T -2, were excavated using a backhoe at right angles to each other in the middle of the anomaly (Photo 3). Care was taken to stay at least 15 feet away from the ASTs. The excavation revealed several dark- colored ash and charcoal layers at about 1.5 feet bgs and a metal water pipe at about 3 feet bgs (Photo 4). The ash and charcoal layers are likely from the former building site that existed on -site from about 1940 to 1970. There did not appear to be any staining or odor and these layers are considered non - hazardous. The metal piping was considered the source of one of the geophysical signatures. The soil below 3 feet bgs was • typical fine- grained silty sand and appeared native, showing the typical layering found in this part of the Coachella Valley. At approximately 9 to 10 feet bgs (the limit of the excavation), the soil became siltier. This soil change is likely the source of the second geophysical signature. Water was not encountered. Evidence of disrupted soil, a UST, or buried drums was not observed. The excavation area was backfilled and compacted by driving the backhoe over the soils (Photo 5). The area of geophysical object OB -4 was excavated to a depth of approximately 4 feet bgs south of the former laundry /shower complex (Photo 6). The excavation uncovered several pieces of concrete debris (approximately 2 feet in diameter) and a 4 -inch diameter PVC pipe used as part of a leach -line for gray water from the laundry room complex. These are the likely source of the geophysical anomalies. It was noted that the soil had slight moisture content at about 3 to 4 feet bgs, likely as a result of the former septic system and leach line. Further investigation related to potential USTs does not appear warranted. Based on the findings of this investigation, OCPs and USTs do not appear to pose an issue for this site. Further investigation or remediation concerning these issues does not appear warranted. 6.0 LIMITATIONS This report has been prepared for the exclusive use of Shovlin Companies. 'The conclusions and recommendations rendered in this report are opinions based on readily available 1n format 1011 obtained to date within the scope of the .work authorized by the client. The scope of work for • EAwri-i sys'rums soui,iiwvrs,r February 7, 2007 - 6 - rile No.: 10661 -02 07 -02 -730 REFERENCES Agency for Toxic Substances and Disease Registry, Chla,•dane, http ://sN ,\snv.atsdr.cdc.gov /tfacts3 I - litml, updated September 1995. 1' DDT, DDE, an DDD, ss,Ns ,\v.atsdr.cdc.gov /tfacts35.hlml, updated September 2002. California Department of rood and Agriculture, 1985. Agricultural Sow-ces of DDT Residues in California's Environment, dated September, 1985. California Department of Water Resources (DWR), 1964, Bulletin Number 108 — Coachella Valley Investigation, July 1964. Earth Systems Southwest, 2006a, Report of Phase I Envt,•onmentol Site Assessment, South Side of High►va}i 111 and East of Dune Pahns Road, La Quinra, Colfbmio, Pile No.: 10661- 01, Document No.: 06 -06 -821, dated June 20, 2006. 2006b, Revised Proposal for Phase 11 Investigation, Assessor's Parcel Numbers 600- E ' 020 -004 and -005, South Side o Hi htiva) 111 and East o Dune Palms Rood, L a f g � l Q :, ;,,ra, California, Proposal No.: SWP -07 -5058, dated December 7, 2006. ' Rodgers, Thomas, 1965, Geologic Reap of California Santa Ana Sheet, California Division of Mines and Geology. Saltzman, Sarina, and Bruno Yaron, editors, 1986. Pesticides in Soil, published by Van Nostrand Reinhold Soil Sciences Series, New York. Telford, Wm, Gcodart, LP, Sheriff, RE and Keys, DA, 1976, Applied Geophysics, Cambridge University Press, 860 pp. Thomson, W. T., 1985. Agricultural Chemicals: Book I - Insecticides. 'Thomson Publications, Fresno, California. United States Geological Survey, 7.5 minute La Quinta, Calif Quadrangle, 1959, photo- revised 1980. US EPA, 2000, Region 9, Preliminary Remediation Goals "Table 2000. EARTH SYSTEMS soUTIMLST Whitewater River Region WQMP' Coral Mountain Apartments Appendix-.1' pp endix I PROJECT - SPECIFIC WQMP SUMMARY DATA FORM • 1 . " � 0 • • is Project- Specific WQMP Summary Data Form Applicant Information Name and Title John E. Durso Company Shovlin Companies Phone (760) Email durso@kdhousing.com Project Information Project Name (as shown on project application /project - specific WQMP) Coral Mountain Apartments Street Address 9500 Block of Highway 111 Nearest Cross Streets Dune Palms Road and Highway 111 Municipality (City or Unincorporated County) City of La Quinta Zip Code 92253 Tract Number(s) and /or Assessor Parcel Number(s) 600- 020 -012; -047; - 048 Other (other information to help identify location of project) The Thomas Guide: Page 849, grid J3.(2007 Riverside County Edition) Watershed I Whitewater River Indicate type of project. Priority Development Projects (Use an "X" in cell preceding project type): SF hillside residence; impervious area z 10,000 sq. ft.; Slope z 25% SF hillside residence; impervious area z 10,000 sq. ft.; Slope z 10% & erosive soils Commercial or Industrial z 100,000 sq. ft.. Automotive repair shop Retail Gasoline Outlet disturbing > 5,000 sq. ft. Restaurant disturbing > 5,000 sq. ft. X Home subdivision z 10 housing units Parking lot z 5,000 sq. ft. or z 25 parking spaces Date Project - Specific WQMP Submitted March 16, 2011 Size of Project Area (nearest 0.1 acre) 10.6 (19.6 -acre site) Project Area managed with Site Design or Low Impact Development (LID) BMPs (nearest 0.1 acre) 10.6 Is the project subject to onsite retention by ordinance or policy? Yes .Are Treatment Control BMPs required ?. Yes Name of the entity will implement, operate, and maintain the post- construction BMPs To be determined in the Final WQMP Contact Name To be determined in the Final WQMP Street or Mailing Address To be determined in the Final WQMP City To be determined in the Final WQMP Zip Code To be determined in the Final WQMP Phone To be determined in the Final WQMP Space Below for Use by City /County Staff Only Preceding Information Verified by (consistent with information in project- specific WQMP) Name: Date: Date Project - Specific WQMP Approved: Data Entered by Name: Date: Other Comments