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2553 Preliminary Hydrology Report
For Property Located In A Portion of the Northeast ¼ of Section 28, Township 6 South, Range 7 East, SBM La Quinta, California The Corner Tentative Tract Map 37815, Lots 134‐138 March 1, 2022 Prepared for: CM Wave Development, L.L.C. 2440 Junction Place, Suite 200 Boulder, CO 80301 JN: 2553 ` PRELIMINARY HYDROLOGY REPORT The Corner Preliminary Hydrology Report TABLE OF CONTENTS PROJECT DESCRIPTION & LOCATION ............................................................................ 1 EXISTING SITE CONDITIONS .......................................................................................... 1 Flood Rate Map .................................................................................................................... 1 Existing Topography ............................................................................................................. 1 PROPOSED FLOOD CONTROL REQUIREMENTS ............................................................. 1 HYDROLOGY ANALYSIS DESIGN CRITERIA ..................................................................... 1 Hydrologic Soil Group ........................................................................................................... 1 Antecedent Moisture Condition ............................................................................................ 2 Land Use Classifications and Runoff Index Numbers ............................................................. 2 Precipitation Frequency Estimates ........................................................................................ 2 Site Infiltration ..................................................................................................................... 2 Proposed Land Use Summaries ............................................................................................. 2 SUMMARY of SYNTHETIC UNIT (SHORTCUT METHOD) ANALYSES ................................ 2 PRELIMINARY WQMP ANALYSES .................................................................................. 3 RESULTS AND CONCLUSIONS ........................................................................................ 3 LIST OF APPENDICES A. RIVERSIDE COUNTY TLMA VICINITY MAP B. NFIP FLOOD INSURANCE RATE MAP C. PAVEDRAIN SPECIFICATIONS D. USDA NCSS HYDROLOGIC SOILS MAP E. NOAA ATLAS 14 & RCFCD REFERENCE PLATES F. RCFCD SYNTHETIC UNIT HYDROGRAPH WORKSHEETS G. EXISTING CONDITIONS EXHIBIT H. PRELIMINARY SUH EXHIBIT I. PRELIMINARY GRADING EXHIBIT The Corner Preliminary Hydrology Report 1 PROJECT DESCRIPTION & LOCATION The proposed project is a mix of commercial and agricultural uses, located on approximately 7.8 acres at the southwest corner of 58th Avenue and Madison Street in the City of La Quinta. The subject property consists of Lots 134‐138 of Tentative Tract Map No. 37815. A vicinity map obtained from the Riverside TLMA website is included as Appendix A. EXISTING SITE CONDITIONS Flood Rate Map The proposed area is part of community number 060709, but no panel has been published because FEMA has not completed a study to determine flood hazard for the selected location. The site is covered by historic Panel Number 06065C2244G, effective date of August 28, 2008, which indicates the subject property lies within Zone X (Shaded), defined as “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. Insurance purchase is not required in these areas.” Refer to the attached current unmapped designation and Historic NFIP Flood Insurance Rate Map in Appendix B. Existing Topography The property is vacant with various desert vegetation throughout the site. The site is bounded to the east by a fully improved Madison Street, to the north by a partially improved 58th Avenue, and Lot 133 to the west and south. Per the Geotechnical Investigation groundwater was encountered at a depth of 47 feet for two of the borings. Site drainage appears to be conveyed via sheet flow which occurs generally from west to east. The Existing Conditions Exhibit can be found in Appendix G PROPOSED FLOOD CONTROL REQUIREMENTS The purpose of this report is to provide preliminary basin analyses for the subject property. To establish a rural feel for the project edge bands will be used throughout the project. As such, the site will be designed as much as possible to sheet flow away from the buildings toward the retention basins. Nuisance water/low flows will be intercepted using PaveDrain or similar system (see Appendix C). The drainage requirements for this project fall under the jurisdiction of the City of La Quinta. See Appendix I for the Preliminary Grading Exhibit. HYDROLOGY ANALYSIS DESIGN CRITERIA Storm runoff volumes for the 100‐year event were obtained utilizing the Synthetic Unit Hydrograph as described in the RCFC&WCD Hydrology Manual. The hydrologic data used for the calculations are as follows: Hydrologic Soil Group The existing soil is categorized as hydrologic soil groups “A” and “B” for the subject as shown per the attached National Cooperative Soil Survey exhibits in Appendix D. Soil Group A is defined by RCFC&WCD as – “those soils having high infiltration rates. These soils consist mainly of deep, well drained to excessively drained sands or bravely sands. These soils have a high rate of water transmission.” Soil Group ‘B’ is defined by RCFC&WCD as – “soils having moderate infiltration rates when thoroughly wetted and consisting chiefly of moderately deep to deep, moderately well to well drained soils with moderately fine to moderately coarse textures. These soils have a moderate rate of water transmission”. The Corner Preliminary Hydrology Report 2 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 Plates E6.1, E6.2 and E6.3 are summarized below: Soil Group A: Commercial 32 Fallow 76 Soil Group B: Commercial 56 Fallow 85 Percent of Impervious Cover (RCFCD Plate E‐6.3): Commercial Areas 90% Fallow 5% Low Loss Rates: 85% Precipitation Frequency Estimates Precipitation depths were obtained from NOAA Atlas 14: 100 Year – 1 Hour Precipitation: 1.38 inches 100 Year – 3 Hour Precipitation: 2.09 inches 100 Year ‐ 6 Hour Precipitation 2.71 inches 100 Year – 24 Hour Precipitation 4.34 inches See Appendix E for the NOAA Atlas 14 Point Precipitation Frequency Estimates and respective RCFCD Plates. Site Infiltration No percolation tests have been performed at the current time, therefore, for the purposes of this report a design no percolation was used in the basin sizing calculations. Prior to the final design submittal, percolation tests will be performed, and should the 48‐hour drawdown rate not be achieved, Maxwell drywells will be proposed to de‐water the basins within the required time period as specified by Riverside County BMP requirements. Proposed Land Use Summaries Land uses for each of the drainage areas were analyzed based on the preliminary site plan. SUMMARY of SYNTHETIC UNIT (SHORTCUT METHOD) ANALYSES The proposed retention basins for the associated drainage areas were sized to retain the 100‐year controlling storm event flood volumes and were analyzed utilizing the RCFCD Synthetic Unit (Shortcut Method). Per the manual, for areas of less than 100 – 200 acres, and lag times less than 7 – 8 minutes, the shortcut method is applicable. This method assumes that in a small watershed, response time to effective rainfall is very short. Therefore, runoff rates for a given period of time can be assumed to be directly proportional to effective rain. This method yields only approximate results (on the conservative side) and should be used only for watersheds meeting the criteria noted above. The Corner Preliminary Hydrology Report 3 It should be noted that the peak flow for the 1‐hour storm is not necessarily representative for peak flow. Per RCFCD, peak discharges from the 3‐hour storm should normally compare well with rational peaks. The synthetic unit worksheet is included in Appendix F and are summarized on the Preliminary SUH Exhibit in Appendix H. Off‐Site Drainage The half‐street flows from 58th Avenue and Madison Street will be passed through to the existing catch basin approximately ½ mile south of 58th Avenue on Madison Street. PRELIMINARY WQMP ANALYSES A separate formal Preliminary WQMP will be prepared for this project. RESULTS AND CONCLUSIONS As the above narrative and appendices confirm, the proposed retention basins are sufficiently sized to contain the flood volume from the controlling 100‐year storm. During the final design process, a more detailed hydrologic report will be submitted to the City for review and approval. The Corner Preliminary Hydrology Report Appendix A Riverside County TLMA Vicinity Map *IMPORTANT* Maps and data are to be used for reference purposes only. Map features are approximate, and are not necessarily accurate to surveying or engineering standards. The County of Riverside makes no warranty or guarantee as to the content (the source is often third party), 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. © Riverside County GIS Legend Vicinity Map Notes REPORT PRINTED ON...2/8/2022 7:09:45 AM 0 1,505752 Feet Parcels Blueline Streams City Areas World Street Map The Corner Preliminary Hydrology Report Appendix B NFIP Flood Insurance Rate Map 58TH AVENUE MADISON STREET The Corner Preliminary Hydrology Report Appendix C PaveDrain Specifications UCF STORMWATER ACADEMY PAVEDRAIN® PERFORMANCE REPORT The final PaveDrain performance report was completed May 2016 and sub- mitted from the University of Central Florida (UCF) Stormwater Management Academy Research and Testing Laboratory (SMART Lab) by Manoj Chopra, Ph.D, P.E; Mike Hardin, Ph.D, P.E., CFM; Ikiensinma GogoAbite, Ph.D.’ and Kristen Lassen. TESTING SCOPE The UCF Stormwater Academy evaluation of the PaveDrain® system was conducted to determine: 1) Infiltration performance of different sections, 2) System’s ability to be rejuvenated (i.e. cleaned/maintained) under soil loading conditions and 3) PaveDrain® porosity (sustainable void space). INFILTRATION PERFORMANCE The PaveDrain® infiltration performance was determined by: 1)Obtaining the initial infiltration rates 2)Hyper-loading with two different types of soils to simulate a lifetime of pavement sediment loading 3)Testing as a system fully-loaded with sediment 4)Performing maintenance using the PaveDrain® VacHead attached to Vac Truck 5)Obtaining post-maintenance infiltration rates. INFILTRATION RATES Initial infiltration rates were determined using two different test methods: ERIK Method ASTM Method Initial Rate: 11,652 in/hr Initial Rate: 1,554 in/hr Clogged condition: 3.7 inches per hour Clogged condition: 2.9 in/hr Following Maintenance: 7,015 inches per hour Following Maintenance: 1,080 in/hr OPERATING POROSITY (Sustainable Void Space) Operating Porosity represents the sustainable void space of the PaveDrain system, which was calculated to be 19.5%. This means that the arch within the PaveDrain block is equal to 1.1 inches of stormwater storage ABOVE the base. Performance Testing Stormwater Management Academy at the University of Central Florida (UCF) Series™ PAVEDRAIN® ACF Environmental - Florida Warehouse - 500 Plumosa Avenue, Altamonte Springs, FL 32701 - 407.628.9375 Please email rthomas@acfenv.com to get more information or to schedule an appointment. For more information about Stormwater Management, contact Inside Sales at 800.448.3636 email at info@acfenv.com STORMWATER MANAGEMENT CONCLUSION “The testing completed on the PaveDrain® permeable pavement system shows that this system is able to infiltrate rainwater and effectively be rejuvenated by the PaveDrain® VacHead if it becomes clogged with sediment. With the amount of void space provided in the typical Pave Drain® system design, it can be inferred that these systems will be able to satisfactorily infiltrate Stormwater with longer maintenance intervals.” Mike Hardin, Ph.D., P.E., CFM PAVEDRAIN® PERFORMANCE TESTING LET’S GET IT DONE 800.448.3636acfenvironmental.com pavedrain.com 9 2016 ACF Environmental - Florida Warehouse 500 Plumosa Avenue, Altamonte Springs, FL 32701 407.628.9375 For more information about Stormwater Management, contact Inside Sales at 800.448.3636 email at info@acfenv.com ERIK Test Method ERIK Device Maintenance with Vac Head Completed job City of Melbourne Section 1 – Typical PaveDrain Cross-Section with 6” AASHTO #57 Section 3 – Integrated Infrastructure Cross-Section with PaveDrain, 6” AASHTO #57 and 2” R-TankXD R-TANKXD WITH M200 ENVELOPE The Corner Preliminary Hydrology Report Appendix D USDA NCSS Hydrologic Soils Map Hydrologic Soil Group—Riverside County, Coachella Valley Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/8/2022 Page 1 of 437207403720820372090037209803721060372114037212203720740372082037209003720980372106037211403721220569010569090569170569250569330569410569490569570569650569730 569010 569090 569170 569250 569330 569410 569490 569570 569650 569730 33° 37' 43'' N 116° 15' 22'' W33° 37' 43'' N116° 14' 52'' W33° 37' 26'' N 116° 15' 22'' W33° 37' 26'' N 116° 14' 52'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 150 300 600 900 Feet 0 50 100 200 300 Meters Map Scale: 1:3,540 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. 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 13, Sep 15, 2021 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Feb 3, 2021—May 27, 2021 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. Hydrologic Soil Group—Riverside County, Coachella Valley Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/8/2022 Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI CpA Coachella fine sand, 0 to 2 percent slopes A 12.9 27.1% CsA Coachella fine sandy loam, 0 to 2 percent slopes A 10.7 22.3% GcA Gilman fine sandy loam, wet, 0 to 2 percent slopes B 1.1 2.3% Ir Indio fine sandy loam, wet B 23.0 48.2% Totals for Area of Interest 47.7 100.0% Hydrologic Soil Group—Riverside County, Coachella Valley Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/8/2022 Page 3 of 4 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. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—Riverside County, Coachella Valley Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/8/2022 Page 4 of 4 The Corner Preliminary Hydrology Report Appendix E NOAA Atlas 14 RCFCD Reference Plates NOAA Atlas 14, Volume 6, Version 2 Location name: La Quinta, California, USA* Latitude: 33.6268°, Longitude: -116.2518° Elevation: -42.89 ft** * source: ESRI Maps ** source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES Sanja Perica, Sarah Dietz, Sarah Heim, Lillian Hiner, Kazungu Maitaria, Deborah Martin, Sandra Pavlovic, Ishani Roy, Carl Trypaluk, Dale Unruh, Fenglin Yan, Michael Yekta, Tan Zhao, Geoffrey Bonnin, Daniel Brewer, Li-Chuan Chen, Tye Parzybok, John Yarchoan NOAA, National Weather Service, Silver Spring, Maryland PF_tabular | PF_graphical | Maps_&_aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Duration Average recurrence interval (years) 1 2 5 10 25 50 100 200 500 1000 5-min 0.064 (0.054-0.078) 0.100 (0.083-0.121) 0.151 (0.126-0.184) 0.198 (0.163-0.242) 0.268 (0.214-0.340) 0.329 (0.257-0.426) 0.397 (0.302-0.527) 0.475 (0.351-0.649) 0.595 (0.422-0.849) 0.702 (0.480-1.04) 10-min 0.092 (0.077-0.112) 0.143 (0.119-0.173) 0.217 (0.181-0.264) 0.283 (0.234-0.347) 0.385 (0.307-0.487) 0.472 (0.368-0.610) 0.569 (0.433-0.756) 0.681 (0.503-0.930) 0.853 (0.604-1.22) 1.01 (0.688-1.49) 15-min 0.112 (0.093-0.135) 0.173 (0.144-0.209) 0.263 (0.218-0.319) 0.343 (0.283-0.420) 0.465 (0.371-0.589) 0.570 (0.445-0.738) 0.689 (0.524-0.914) 0.823 (0.609-1.13) 1.03 (0.731-1.47) 1.22 (0.832-1.80) 30-min 0.160 (0.133-0.193) 0.247 (0.207-0.299) 0.376 (0.313-0.456) 0.491 (0.405-0.600) 0.665 (0.531-0.843) 0.816 (0.637-1.06) 0.985 (0.750-1.31) 1.18 (0.871-1.61) 1.48 (1.05-2.11) 1.74 (1.19-2.57) 60-min 0.224 (0.187-0.271) 0.348 (0.290-0.421) 0.527 (0.439-0.640) 0.689 (0.568-0.843) 0.934 (0.745-1.18) 1.15 (0.894-1.48) 1.38 (1.05-1.84) 1.65 (1.22-2.26) 2.07 (1.47-2.96) 2.44 (1.67-3.61) 2-hr 0.311 (0.260-0.376) 0.458 (0.382-0.555) 0.678 (0.564-0.823) 0.879 (0.726-1.08) 1.19 (0.950-1.51) 1.47 (1.14-1.90) 1.78 (1.35-2.36) 2.13 (1.58-2.91) 2.68 (1.90-3.82) 3.17 (2.17-4.68) 3-hr 0.375 (0.314-0.454) 0.543 (0.453-0.657) 0.796 (0.662-0.966) 1.03 (0.850-1.26) 1.40 (1.11-1.77) 1.72 (1.34-2.23) 2.09 (1.59-2.77) 2.52 (1.86-3.44) 3.18 (2.25-4.54) 3.77 (2.58-5.58) 6-hr 0.494 (0.413-0.597) 0.708 (0.591-0.857) 1.03 (0.859-1.25) 1.33 (1.10-1.63) 1.81 (1.44-2.29) 2.23 (1.74-2.88) 2.71 (2.06-3.60) 3.27 (2.42-4.47) 4.14 (2.94-5.91) 4.93 (3.37-7.28) 12-hr 0.593 (0.495-0.716) 0.869 (0.726-1.05) 1.28 (1.07-1.56) 1.66 (1.37-2.04) 2.25 (1.80-2.86) 2.77 (2.16-3.59) 3.36 (2.55-4.46) 4.03 (2.98-5.51) 5.07 (3.59-7.24) 6.00 (4.10-8.86) 24-hr 0.740 (0.655-0.854) 1.12 (0.991-1.29) 1.68 (1.48-1.95) 2.18 (1.91-2.55) 2.95 (2.50-3.55) 3.61 (3.00-4.43) 4.34 (3.52-5.46) 5.18 (4.09-6.69) 6.44 (4.89-8.66) 7.53 (5.53-10.5) 2-day 0.850 (0.752-0.980) 1.31 (1.16-1.51) 1.97 (1.74-2.28) 2.56 (2.24-2.98) 3.44 (2.91-4.14) 4.18 (3.47-5.14) 5.00 (4.06-6.29) 5.92 (4.68-7.65) 7.29 (5.53-9.80) 8.46 (6.21-11.8) 3-day 0.914 (0.808-1.05) 1.41 (1.25-1.63) 2.13 (1.88-2.47) 2.77 (2.42-3.23) 3.71 (3.14-4.47) 4.51 (3.74-5.54) 5.38 (4.36-6.77) 6.35 (5.02-8.21) 7.80 (5.92-10.5) 9.02 (6.62-12.5) 4-day 0.970 (0.858-1.12) 1.50 (1.33-1.73) 2.26 (2.00-2.62) 2.94 (2.57-3.43) 3.93 (3.33-4.74) 4.77 (3.96-5.86) 5.69 (4.62-7.16) 6.71 (5.30-8.67) 8.22 (6.24-11.1) 9.50 (6.98-13.2) 7-day 1.03 (0.911-1.19) 1.59 (1.40-1.83) 2.39 (2.11-2.77) 3.09 (2.71-3.61) 4.14 (3.51-4.98) 5.01 (4.16-6.16) 5.96 (4.83-7.50) 7.01 (5.54-9.06) 8.56 (6.50-11.5) 9.86 (7.24-13.7) 10-day 1.06 (0.936-1.22) 1.63 (1.44-1.88) 2.46 (2.16-2.84) 3.18 (2.78-3.71) 4.25 (3.60-5.12) 5.14 (4.27-6.32) 6.11 (4.96-7.69) 7.18 (5.67-9.28) 8.75 (6.64-11.8) 10.1 (7.39-14.0) 20-day 1.13 (1.00-1.31) 1.77 (1.56-2.04) 2.68 (2.36-3.10) 3.48 (3.04-4.06) 4.65 (3.94-5.61) 5.63 (4.68-6.92) 6.69 (5.43-8.41) 7.85 (6.20-10.1) 9.53 (7.23-12.8) 10.9 (8.03-15.2) 30-day 1.20 (1.06-1.38) 1.89 (1.67-2.19) 2.90 (2.55-3.36) 3.78 (3.31-4.41) 5.08 (4.31-6.12) 6.16 (5.12-7.57) 7.32 (5.94-9.21) 8.58 (6.78-11.1) 10.4 (7.89-14.0) 11.9 (8.73-16.5) 45-day 1.29 (1.14-1.49) 2.08 (1.84-2.41) 3.22 (2.84-3.73) 4.23 (3.70-4.93) 5.71 (4.84-6.88) 6.94 (5.76-8.52) 8.25 (6.69-10.4) 9.67 (7.64-12.5) 11.7 (8.88-15.7) 13.4 (9.82-18.6) 60-day 1.37 (1.21-1.57) 2.23 (1.97-2.58) 3.49 (3.07-4.04) 4.59 (4.01-5.35) 6.21 (5.26-7.48) 7.56 (6.28-9.29) 9.00 (7.30-11.3) 10.5 (8.33-13.6) 12.8 (9.69-17.2) 14.6 (10.7-20.2) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top PF graphical Back to Top Maps & aerials Small scale terrain Large scale terrain Large scale map Large scale aerial + – 3km 2mi + – 100km 60mi + – 100km 60mi Back to Top US Department of Commerce National Oceanic and Atmospheric Administration National Weather Service National Water Center 1325 East West Highway Silver Spring, MD 20910 Questions?: HDSC.Questions@noaa.gov Disclaimer The Corner Preliminary Hydrology Report Appendix F RCFCD Synthetic Unit Hydrograph Worksheets saw 2 AMC II AREA SOIL TRIBUTARY AREAS ACRES LOW LOSS RI INFILTRATION IMPERVIOUS DESIG GROUP CONDITION NUMBER RATE PERCENT 1 A COMMERCIAL 4.900 D 32 0.74 0.90 18 A FALLOW 1.000 X 76 0.29 0.05 1 B COMMERCIAL 1.000 D 56 0.51 0.90 18 B FALLOW 0.900 X 85 0.19 0.05 350 ft 240 ft 459.0 ft ELEVATION OF CONCENTRATION POINT 456.0 ft 0.03 100 LOW LOSS RATE (Storm Events > 10 Years)85% POINT RAIN FROM NOAA ATLAS 14 1-HOUR 1.38 in 3-HOUR 2.09 in 6-HOUR 2.71 in 24-HOUR 4.34 in BASIN CHARACTERISTICS: ELEVATION AREA 455.0 ft 74,929 sf 456.0 ft 82,339 sf PERCOLATION RATE (in/hr) DRYWELL DATA NUMBER USED 0 PERCOLATION RATE LOWEST FLOWLINE ELEVATION LOWEST PAD ELEVATION LENGTH OF WATERCOURSE (L) AREA DESIGNATION ELEVATION OF HEADWATER AVERAGE MANNINGS 'N' VALUE STORM FREQUENCY (YEAR) LENGTH TO POINT OPPOSITE CENTROID (Lca) Low Loss Conditions: X=Existing; D=Developed; BS=Retention Site RCFCD SYNTHETIC UNIT HYDROGRAPH - SHORTCUT METHOD DATA INPUT SHEET WORKSHEET PREPARED BY: PROJECT NAME DATE March 1, 2022 The Corner PROJECT NUMBER CONCENTRATION POINT DESIGNATION 2553 Agriculture Areas AMC NUMBER Data Input Sheet Page 1 of 13 PROJECT: Job No.: BY: DATE: 3/1/22 [1] AMC II [2] FREQUENCY-YEARS 100 FROM NOAA ATLAS 14 [3] STORM DURATION: Point Rain 1-HOUR 1.38 in 3-HOUR 2.09 in 6-HOUR 2.71 in 24-HOUR 4.34 in STORM DURATION 1-HOUR 3-HOUR 6-HOUR 24-HOUR RAINFALL VOLUME (cu-ft) 39,073 59,176 76,731 122,883 SOIL LOSSES (cu-ft) 4,451 13,283 26,289 65,059 EFFECTIVE RAIN (in) 1.22 1.62 1.78 2.04 FLOOD VOLUME (cu-ft) 34,623 45,893 50,442 57,824 (acre-ft) 0.79 1.05 1.16 1.33 REQUIRED STORAGE (cu-ft) 34,623 45,893 50,442 57,824 (acre-ft) 0.79 1.05 1.16 1.33 FACTOR OF SAFETY 2.27 1.71 1.56 1.36 STORAGE PROVIDED (cu-ft) (acre-ft) PEAK FLOW (cfs) n/a 14.94 13.09 3.58 MAXIMUM WSEL (ft) 455.44 455.58 455.64 455.74 DEPTH (ft) 0.44 0.58 0.64 0.74 DIFFERENCE (ft) DIFFERENCE (ft) ESTIMATED TIME TO DEWATER BASIN Based on Total Flood Volume & Average Percolation Rate (days) [18] 200% OF LAG-MINUTES RAINFALL DATA 4.6 NOTE: PEAK FLOW FOR THE 1-HOUR STORM IS NOT REPRESENTATIVE. PER RCFCD PEAK DISCHARGES FROM THE 3-HOUR STORM SHOULD NORMALLY COMPARE WELL WITH RATIONAL PEAKS. LOWEST PAD ELEVATION LOWEST FLOWLINE ELEVATION STORM EVENT SUMMARY 78,605 1.80 0.03 [17] 100% OF LAG-MINUTES 2.3 2.3 [14] AVERAGE MANNINGS 'N' [15] LAG TIME-HOURS 0.04 [16] LAG TIME-MINUTES [13] L*LCA/S^0.5 6.73 [11] S-FEET/MILE [6] La-FEET [7] La-MILES [8] ELEVATION OF HEADWATER 0.000 240.00 [12] S^0.5 0.045 45.3 459 456 3 [3] AREA - ACRES [4] L-FEET [5] L-MILES 350 0.066 Agriculture Areas Site The Corner [10] H-FEET [9] ELEVATION OF CONCENTRATION POINT 7.800 PHYSICAL DATA [1] CONCENTRATION POINT HYDROLOGY MANUAL BASIC DATA CALCULATION FORM 2553 saw RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHOD [2] AREA DESIGNATION Plate E-2.1 Page 2 of 13 PROJECT:Job No.:BY: DATE: 3/1/22MAX LOW LOW MINSOIL RI PERVIOUS DECIMAL ADJUSTED AREA AREA AVERAGE LOSS LOSS RATE AVERAGEGROUP NUMBER AREA PERCENT INFILTRATION WEIGHTED ADJUSTED CONDITION PER ADJUSTEDINFILTRATION OF AREA RATE AVERAGE INFILTRATION RCFC/2322 INFILTRATIONRATE IMPERVIOUS RATE RATE(in/hr) (in/hr) (in/hr)[Plate C-1] [Plate E-6.1] [Plate E-6.2] [Plate E-6.3]A 32 0.74 90% 0.14 4.900 0.628 0.0883 DEVELOPED 0.1800 0.1131A 76 0.29 5% 0.28 1.000 0.128 0.0355 UNDEVELOPED 0.9000 0.1154B 56 0.51 90% 0.10 1.000 0.128 0.0124 DEVELOPED 0.1800 0.0231B 85 0.19 5% 0.18 0.900 0.115 0.0209 UNDEVELOPED 0.9000 0.1038SUM 7.800 SUM 0.1572 0.3554VARIABLE LOSS RATE CURVE (24-HOUR STORM ONLY)Fm= 0.078595833NOTE: Low loss rates established per RCFC/2322 (Dated: May-30-95)C= 0.00146For 10 Year Storms or LessFt=C(24-(T/60))^1.55+Fm= 0.001460.08in/hrUndeveloped Condition: Low Loss = 90%CONSTANT LOSS RATE (3 & 6 HOUR STORMS) =0.1572 Developed Condition: Low Loss = 0.9 - (0.8 * %impervious)LOW LOSS RATE =0.8500 Basin Site: Low Loss = 10%Where:For 100 Year Storm - Low Loss should be between 80% & 90%T=Time in minutes. To get an average value for each unit time period, Use T=1/2 the unit time for the first time period,of the Rainfall RateT=1 1/2 unit time for the second period, etc.(24-(T/60))^1.55 +LAND USECOMMERCIALFALLOWCOMMERCIALFALLOWAVERAGE ADJUSTED LOSS RATERCFC & WCDHYDROLOGYMANUALSYNTHETIC UNIT HYDROGRAPH METHODBASIC DATA CALCULATION FORMThe Cornersaw2553AMC IIPlate E-2.1Page 3 of 13 PROJECT:Job No.: 2553BY: saw DATE 3/1/22DRAINAGE AREA-ACRES 7.80Basin Percolation Rate 0.0 in/hrUNIT TIME-MINUTES 5LAG TIME - MINUTES 2.31Maxwell DrywellsUNIT TIME-PERCENT OF LAG 216.8Number 0TOTAL ADJUSTED STORM RAIN-INCHES 1.38Drywell Percolation Rate 0.00 cfs 0.00 cfmCONSTANT LOSS RATE-in/hr 0.16LOW LOSS RATE - PERCENT 85.00%Unit Time Pattern Storm Effective Flood Volume BasinBasinPeriod Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSELin/hr Flow Area Percolation Out(Plate E-5.9) Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft1 5 0.08 3.6 0.60 0.16 0.51 0.44 3.45 1,036 1,036 75,027 0 0 1,036 0.02 455.012 10 0.17 4.2 0.70 0.16 0.59 0.54 4.23 1,270 2,306 75,146 0 0 2,306 0.05 455.033 15 0.25 4.4 0.73 0.16 0.62 0.57 4.49 1,348 3,654 75,273 0 0 3,654 0.08 455.054 20 0.33 4.6 0.76 0.16 0.65 0.60 4.75 1,426 5,081 75,408 0 0 5,081 0.12 455.065 25 0.42 5.0 0.83 0.16 0.70 0.67 5.28 1,583 6,664 75,557 0 0 6,664 0.15 455.086 30 0.50 5.6 0.93 0.16 0.79 0.77 6.06 1,817 8,481 75,728 0 0 8,481 0.19 455.117 35 0.58 6.4 1.06 0.16 0.90 0.90 7.10 2,130 10,611 75,929 0 0 10,611 0.24 455.138 40 0.67 8.1 1.34 0.16 1.14 1.18 9.31 2,794 13,405 76,193 0 0 13,405 0.31 455.179 45 0.75 13.1 2.17 0.16 1.84 2.01 15.83 4,748 18,152 76,640 0 0 18,152 0.42 455.2310 50 0.83 34.5 5.71 0.16 4.86 5.5643.70 13,10931,262 77,876 0 0 31,262 0.72 455.4011 55 0.92 6.7 1.11 0.16 0.94 0.95 7.49 2,247 33,509 78,088 0 0 33,509 0.77 455.4312 60 1.00 3.8 0.63 0.16 0.53 0.47 3.71 1,114 34,623 78,193 0 034,623 0.79 455.44TOTAL RAINFALL 1.38 inRAINFALL VOLUME 39,073 cu-ftSOIL LOSSES 4,451 cu-ftEFFECTIVE RAIN 1.22 inFLOOD VOLUME 0.79 acftFLOOD VOLUME 34,623 cu-ftREQUIRED STORAGE 0.79REQUIRED STORAGE 34,623 cu-ftMAX WSEL 455.44 ftPEAK FLOW RATE 43.70 cfsTOTAL BASIN LOSSES 0 cu-ftAVERAGE PERCOLATION RATE 0.00 cf/minEFFECTIVE RAIN & FLOOD VOLUMES SUMMARYUNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORMTotal InBasinin/hrTime Loss RateBasin LossesThe CornerRCFC & WCDHYDROLOGYMANUALSYNTHETIC UNIT HYDROGRAPH METHODSHORTCUT METHOD1-HOUR STORMPlate E-2.21-Hour StormPage 4 of 13 PROJECT:Job No.: 2553BY: saw DATEDRAINAGE AREA-ACRES 7.80Basin Percolation Rate 0.0 in/hrUNIT TIME-MINUTES 5LAG TIME - MINUTES 2.31Maxwell DrywellsUNIT TIME-PERCENT OF LAG 216.8Number 0TOTAL ADJUSTED STORM RAIN (in) 2.09Drywell Percolation Rate 0.00 cfs 0.00 cfmCONSTANT LOSS RATE (in/hr) 0.16LOW LOSS RATE - PERCENT 85.00%Unit Time Pattern Storm Effective Flood Volume BasinBasinPeriod Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSELin/hr Flow Area Percolation Out(Plate E-5.9)Max Low in/hrcfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft1 5 0.08 1.3 0.33 0.16 0.28 0.17 1.33 398 398 74,967 0 0 398 0.01 455.012 10 0.17 1.3 0.33 0.16 0.28 0.17 1.33 398 797 75,004 0 0 797 0.02 455.013 15 0.25 1.1 0.28 0.16 0.23 0.12 0.93 280 1,077 75,031 0 0 1,077 0.02 455.014 20 0.33 1.5 0.38 0.16 0.32 0.22 1.72 517 1,594 75,079 0 0 1,594 0.04 455.025 25 0.42 1.5 0.38 0.16 0.32 0.22 1.72 517 2,110 75,128 0 0 2,110 0.05 455.036 30 0.50 1.8 0.45 0.16 0.38 0.29 2.31 694 2,805 75,193 0 0 2,805 0.06 455.047 35 0.58 1.5 0.38 0.16 0.32 0.22 1.72 517 3,321 75,242 0 0 3,321 0.08 455.048 40 0.67 1.8 0.45 0.16 0.38 0.29 2.31 694 4,016 75,308 0 0 4,016 0.09 455.059 45 0.75 1.8 0.45 0.16 0.38 0.29 2.31 694 4,710 75,373 0 0 4,710 0.11 455.0610 50 0.83 1.5 0.38 0.16 0.32 0.22 1.72 517 5,227 75,422 0 0 5,227 0.12 455.0711 55 0.92 1.6 0.40 0.16 0.34 0.24 1.92 576 5,803 75,476 0 0 5,803 0.13 455.0712 60 1.00 1.8 0.45 0.16 0.38 0.29 2.31 694 6,497 75,541 0 0 6,497 0.15 455.0813 65 1.08 2.2 0.55 0.16 0.47 0.39 3.10 931 7,428 75,629 0 0 7,428 0.17 455.0914 70 1.17 2.2 0.55 0.16 0.47 0.39 3.10 931 8,359 75,717 0 0 8,359 0.19 455.1115 75 1.25 2.2 0.55 0.16 0.47 0.39 3.10 931 9,290 75,805 0 0 9,290 0.21 455.1216 80 1.33 2.0 0.50 0.16 0.43 0.34 2.71 813 10,103 75,881 0 0 10,103 0.23 455.1317 85 1.42 2.6 0.65 0.16 0.55 0.49 3.89 1,168 11,270 75,991 0 0 11,270 0.26 455.1418 90 1.50 2.7 0.68 0.16 0.58 0.52 4.09 1,227 12,497 76,107 0 0 12,497 0.29 455.1619 95 1.58 2.4 0.60 0.16 0.51 0.44 3.50 1,049 13,546 76,206 0 0 13,546 0.31 455.1720 100 1.67 2.7 0.68 0.16 0.58 0.52 4.09 1,227 14,773 76,322 0 0 14,773 0.34 455.1921 105 1.75 3.3 0.83 0.16 0.70 0.67 5.27 1,582 16,355 76,471 0 0 16,355 0.38 455.2122 110 1.83 3.1 0.78 0.16 0.66 0.62 4.88 1,464 17,819 76,609 0 0 17,819 0.41 455.2323 115 1.92 2.9 0.73 0.16 0.62 0.57 4.48 1,345 19,164 76,736 0 0 19,164 0.44 455.2424 120 2.00 3.0 0.75 0.16 0.64 0.60 4.68 1,404 20,568 76,868 0 0 20,568 0.47 455.2625 125 2.08 3.1 0.78 0.16 0.66 0.62 4.88 1,464 22,032 77,006 0 0 22,032 0.51 455.28RCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHODThe CornerHYDROLOGYSHORTCUT METHODTotal InBasinin/hrMANUAL3-HOUR STORMUNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORMTime Loss RateBasin LossesPlate E-2.23-Hour StormPage 5 of 13 PROJECT:Job No.: 2553BY: saw DATEDRAINAGE AREA-ACRES 7.80Basin Percolation Rate 0.0 in/hrUNIT TIME-MINUTES 5LAG TIME - MINUTES 2.31Maxwell DrywellsUNIT TIME-PERCENT OF LAG 216.8Number 0TOTAL ADJUSTED STORM RAIN (in) 2.09Drywell Percolation Rate 0.00 cfs 0.00 cfmCONSTANT LOSS RATE (in/hr) 0.16LOW LOSS RATE - PERCENT 85.00%Unit Time Pattern Storm Effective Flood Volume BasinBasinPeriod Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSELin/hr Flow Area Percolation Out(Plate E-5.9)Max Low in/hrcfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ftRCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHODThe CornerHYDROLOGYSHORTCUT METHODTotal InBasinin/hrMANUAL3-HOUR STORMUNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORMTime Loss RateBasin Losses26 130 2.17 4.2 1.05 0.16 0.90 0.90 7.05 2,115 24,147 77,205 0 0 24,147 0.55 455.3127 135 2.25 5.0 1.25 0.16 1.07 1.10 8.63 2,588 26,734 77,449 0 0 26,734 0.61 455.3428 140 2.33 3.5 0.88 0.16 0.75 0.72 5.67 1,700 28,435 77,610 0 0 28,435 0.65 455.3629 145 2.42 6.8 1.71 0.16 1.45 1.55 12.18 3,653 32,088 77,954 0 0 32,088 0.74 455.4130 150 2.50 7.3 1.83 0.16 1.56 1.67 13.16 3,949 36,037 78,326 0 0 36,037 0.83 455.4631 155 2.58 8.2 2.06 0.16 1.75 1.9014.94 4,48240,518 78,749 0 0 40,518 0.93 455.5232 160 2.67 5.9 1.48 0.16 1.26 1.32 10.40 3,121 43,639 79,043 0 0 43,639 1.00 455.5633 165 2.75 2.0 0.50 0.16 0.43 0.34 2.71 813 44,452 79,119 0 0 44,452 1.02 455.5734 170 2.83 1.8 0.45 0.16 0.38 0.29 2.31 694 45,146 79,185 0 0 45,146 1.04 455.5735 175 2.92 1.8 0.45 0.16 0.38 0.29 2.31 694 45,840 79,250 0 0 45,840 1.05 455.5836 180 3.00 0.6 0.15 0.16 0.13 0.02 0.18 53 45,893 79,255 0 045,893 1.05 455.58TOTAL RAINRAINFALL VOLUMESOIL LOSSESEFFECTIVE RAINFLOOD VOLUMEFLOOD VOLUMEREQUIRED STORAGEREQUIRED STORAGEMAX WSELPEAK FLOW RATETOTAL BASIN LOSSESAVERAGE PERCOLATION RATEEFFECTIVE RAIN & FLOOD VOLUMES SUMMARY0 cu-ft0.00 cf/min1.62 in1.05 acft45,893 cu-ft1.05 acft45,893 cu-ft13,283 cu-ft2.09 in59,176 cu-ft455.58 ft14.94 cfsPlate E-2.23-Hour StormPage 6 of 13 PROJECT:Job No.: 2553BY: saw DATE 3/1/22DRAINAGE AREA-ACRES 7.80Basin Percolation Rate 0.0 in/hrUNIT TIME-MINUTES 5LAG TIME - MINUTES 2.31Maxwell DrywellsUNIT TIME-PERCENT OF LAG 216.8Number 0TOTAL ADJUSTED STORM RAIN (in) 2.71Drywell Percolation Rate 0.00 cfs 0.00 cfmCONSTANT LOSS RATE (in/hr) 0.16LOW LOSS RATE - PERCENT 85.00%Unit Time Pattern Storm Effective Flood Volume BasinBasinPeriod Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSELin/hr Flow Area Percolation Out(Plate E-5.9)Max Low in/hrcfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft1 5 0.08 0.5 0.16 0.16 0.14 0.01 0.04 13 13 74,930 0 0 13 0.00 455.002 10 0.17 0.6 0.20 0.16 0.17 0.04 0.30 89 102 74,939 0 0 102 0.00 455.003 15 0.25 0.6 0.20 0.16 0.17 0.04 0.30 89 192 74,947 0 0 192 0.00 455.004 20 0.33 0.6 0.20 0.16 0.17 0.04 0.30 89 281 74,956 0 0 281 0.01 455.005 25 0.42 0.6 0.20 0.16 0.17 0.04 0.30 89 371 74,964 0 0 371 0.01 455.006 30 0.50 0.7 0.23 0.16 0.19 0.07 0.55 166 537 74,980 0 0 537 0.01 455.017 35 0.58 0.7 0.23 0.16 0.19 0.07 0.55 166 703 74,995 0 0 703 0.02 455.018 40 0.67 0.7 0.23 0.16 0.19 0.07 0.55 166 869 75,011 0 0 869 0.02 455.019 45 0.75 0.7 0.23 0.16 0.19 0.07 0.55 166 1,036 75,027 0 0 1,036 0.02 455.0110 50 0.83 0.7 0.23 0.16 0.19 0.07 0.55 166 1,202 75,042 0 0 1,202 0.03 455.0211 55 0.92 0.7 0.23 0.16 0.19 0.07 0.55 166 1,368 75,058 0 0 1,368 0.03 455.0212 60 1.00 0.8 0.26 0.16 0.22 0.10 0.81 243 1,611 75,081 0 0 1,611 0.04 455.0213 65 1.08 0.8 0.26 0.16 0.22 0.10 0.81 243 1,854 75,104 0 0 1,854 0.04 455.0214 70 1.17 0.8 0.26 0.16 0.22 0.10 0.81 243 2,097 75,127 0 0 2,097 0.05 455.0315 75 1.25 0.8 0.26 0.16 0.22 0.10 0.81 243 2,340 75,150 0 0 2,340 0.05 455.0316 80 1.33 0.8 0.26 0.16 0.22 0.10 0.81 243 2,583 75,172 0 0 2,583 0.06 455.0317 85 1.42 0.8 0.26 0.16 0.22 0.10 0.81 243 2,826 75,195 0 0 2,826 0.06 455.0418 90 1.50 0.8 0.26 0.16 0.22 0.10 0.81 243 3,069 75,218 0 0 3,069 0.07 455.0419 95 1.58 0.8 0.26 0.16 0.22 0.10 0.81 243 3,312 75,241 0 0 3,312 0.08 455.0420 100 1.67 0.8 0.26 0.16 0.22 0.10 0.81 243 3,555 75,264 0 0 3,555 0.08 455.0521 105 1.75 0.8 0.26 0.16 0.22 0.10 0.81 243 3,798 75,287 0 0 3,798 0.09 455.0522 110 1.83 0.8 0.26 0.16 0.22 0.10 0.81 243 4,041 75,310 0 0 4,041 0.09 455.0523 115 1.92 0.8 0.26 0.16 0.22 0.10 0.81 243 4,284 75,333 0 0 4,284 0.10 455.0524 120 2.00 0.9 0.29 0.16 0.25 0.14 1.07 320 4,603 75,363 0 0 4,603 0.11 455.06Loss RateRCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHODThe CornerHYDROLOGYSHORTCUT METHODTotal InBasinin/hrMANUAL6-HOUR STORMUNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORMTimeBasin LossesPlate E-2.26-Hour StormPage 7 of 13 PROJECT:Job No.: 2553BY: saw DATE 3/1/22DRAINAGE AREA-ACRES 7.80Basin Percolation Rate 0.0 in/hrUNIT TIME-MINUTES 5LAG TIME - MINUTES 2.31Maxwell DrywellsUNIT TIME-PERCENT OF LAG 216.8Number 0TOTAL ADJUSTED STORM RAIN (in) 2.71Drywell Percolation Rate 0.00 cfs 0.00 cfmCONSTANT LOSS RATE (in/hr) 0.16LOW LOSS RATE - PERCENT 85.00%Unit Time Pattern Storm Effective Flood Volume BasinBasinPeriod Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSELin/hr Flow Area Percolation Out(Plate E-5.9)Max Low in/hrcfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ftLoss RateRCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHODThe CornerHYDROLOGYSHORTCUT METHODTotal InBasinin/hrMANUAL6-HOUR STORMUNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORMTimeBasin Losses25 125 2.08 0.8 0.26 0.16 0.22 0.10 0.81 243 4,846 75,386 0 0 4,846 0.11 455.0626 130 2.17 0.9 0.29 0.16 0.25 0.14 1.07 320 5,166 75,416 0 0 5,166 0.12 455.0727 135 2.25 0.9 0.29 0.16 0.25 0.14 1.07 320 5,486 75,446 0 0 5,486 0.13 455.0728 140 2.33 0.9 0.29 0.16 0.25 0.14 1.07 320 5,805 75,476 0 0 5,805 0.13 455.0729 145 2.42 0.9 0.29 0.16 0.25 0.14 1.07 320 6,125 75,506 0 0 6,125 0.14 455.0830 150 2.50 0.9 0.29 0.16 0.25 0.14 1.07 320 6,445 75,537 0 0 6,445 0.15 455.0831 155 2.58 0.9 0.29 0.16 0.25 0.14 1.07 320 6,764 75,567 0 0 6,764 0.16 455.0932 160 2.67 0.9 0.29 0.16 0.25 0.14 1.07 320 7,084 75,597 0 0 7,084 0.16 455.0933 165 2.75 1.0 0.33 0.16 0.28 0.17 1.32 396 7,480 75,634 0 0 7,480 0.17 455.1034 170 2.83 1.0 0.33 0.16 0.28 0.17 1.32 396 7,877 75,672 0 0 7,877 0.18 455.1035 175 2.92 1.0 0.33 0.16 0.28 0.17 1.32 396 8,273 75,709 0 0 8,273 0.19 455.1136 180 3.00 1.0 0.33 0.16 0.28 0.17 1.32 396 8,670 75,746 0 0 8,670 0.20 455.1137 185 3.08 1.0 0.33 0.16 0.28 0.17 1.32 396 9,066 75,784 0 0 9,066 0.21 455.1238 190 3.17 1.1 0.36 0.16 0.30 0.20 1.58 473 9,539 75,828 0 0 9,539 0.22 455.1239 195 3.25 1.1 0.36 0.16 0.30 0.20 1.58 473 10,012 75,873 0 0 10,012 0.23 455.1340 200 3.33 1.1 0.36 0.16 0.30 0.20 1.58 473 10,486 75,917 0 0 10,486 0.24 455.1341 205 3.42 1.2 0.39 0.16 0.33 0.23 1.83 550 11,035 75,969 0 0 11,035 0.25 455.1442 210 3.50 1.3 0.42 0.16 0.36 0.27 2.09 627 11,662 76,028 0 0 11,662 0.27 455.1543 215 3.58 1.4 0.46 0.16 0.39 0.30 2.34 703 12,365 76,095 0 0 12,365 0.28 455.1644 220 3.67 1.4 0.46 0.16 0.39 0.30 2.34 703 13,069 76,161 0 0 13,069 0.30 455.1745 225 3.75 1.5 0.49 0.16 0.41 0.33 2.60 780 13,849 76,235 0 0 13,849 0.32 455.1846 230 3.83 1.5 0.49 0.16 0.41 0.33 2.60 780 14,629 76,308 0 0 14,629 0.34 455.1947 235 3.92 1.6 0.52 0.16 0.44 0.36 2.86 857 15,486 76,389 0 0 15,486 0.36 455.2048 240 4.00 1.6 0.52 0.16 0.44 0.36 2.86 857 16,342 76,470 0 0 16,342 0.38 455.2149 245 4.08 1.7 0.55 0.16 0.47 0.40 3.11 934 17,276 76,558 0 0 17,276 0.40 455.2250 250 4.17 1.8 0.59 0.16 0.50 0.43 3.37 1,010 18,286 76,653 0 0 18,286 0.42 455.23Plate E-2.26-Hour StormPage 8 of 13 PROJECT:Job No.: 2553BY: saw DATE 3/1/22DRAINAGE AREA-ACRES 7.80Basin Percolation Rate 0.0 in/hrUNIT TIME-MINUTES 5LAG TIME - MINUTES 2.31Maxwell DrywellsUNIT TIME-PERCENT OF LAG 216.8Number 0TOTAL ADJUSTED STORM RAIN (in) 2.71Drywell Percolation Rate 0.00 cfs 0.00 cfmCONSTANT LOSS RATE (in/hr) 0.16LOW LOSS RATE - PERCENT 85.00%Unit Time Pattern Storm Effective Flood Volume BasinBasinPeriod Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSELin/hr Flow Area Percolation Out(Plate E-5.9)Max Low in/hrcfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ftLoss RateRCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHODThe CornerHYDROLOGYSHORTCUT METHODTotal InBasinin/hrMANUAL6-HOUR STORMUNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORMTimeBasin Losses51 255 4.25 1.9 0.62 0.16 0.53 0.46 3.62 1,087 19,373 76,755 0 0 19,373 0.44 455.2552 260 4.33 2.0 0.65 0.16 0.55 0.49 3.88 1,164 20,537 76,865 0 0 20,537 0.47 455.2653 265 4.42 2.1 0.68 0.16 0.58 0.53 4.13 1,240 21,777 76,982 0 0 21,777 0.50 455.2854 270 4.50 2.1 0.68 0.16 0.58 0.53 4.13 1,240 23,018 77,099 0 0 23,018 0.53 455.2955 275 4.58 2.2 0.72 0.16 0.61 0.56 4.39 1,317 24,335 77,223 0 0 24,335 0.56 455.3156 280 4.67 2.3 0.75 0.16 0.64 0.59 4.65 1,394 25,729 77,354 0 0 25,729 0.59 455.3357 285 4.75 2.4 0.78 0.16 0.66 0.62 4.90 1,471 27,200 77,493 0 0 27,200 0.62 455.3558 290 4.83 2.4 0.78 0.16 0.66 0.62 4.90 1,471 28,670 77,632 0 0 28,670 0.66 455.3659 295 4.92 2.5 0.81 0.16 0.69 0.66 5.16 1,547 30,218 77,778 0 0 30,218 0.69 455.3860 300 5.00 2.6 0.85 0.16 0.72 0.69 5.41 1,624 31,842 77,931 0 0 31,842 0.73 455.4161 305 5.08 3.1 1.01 0.16 0.86 0.85 6.69 2,008 33,850 78,120 0 0 33,850 0.78 455.4362 310 5.17 3.6 1.17 0.16 1.00 1.01 7.97 2,391 36,241 78,345 0 0 36,241 0.83 455.4663 315 5.25 3.9 1.27 0.16 1.08 1.11 8.74 2,622 38,863 78,593 0 0 38,863 0.89 455.4964 320 5.33 4.2 1.37 0.16 1.16 1.21 9.51 2,852 41,714 78,861 0 0 41,714 0.96 455.5365 325 5.42 4.7 1.53 0.16 1.30 1.37 10.78 3,235 44,950 79,166 0 0 44,950 1.03 455.5766 330 5.50 5.6 1.82 0.16 1.55 1.6613.09 3,92648,876 79,536 0 0 48,876 1.12 455.6267 335 5.58 1.9 0.62 0.16 0.53 0.46 3.62 1,087 49,963 79,639 0 0 49,963 1.15 455.6468 340 5.67 0.9 0.29 0.16 0.25 0.14 1.07 320 50,283 79,669 0 0 50,283 1.15 455.6469 345 5.75 0.6 0.20 0.16 0.17 0.04 0.30 89 50,372 79,678 0 0 50,372 1.16 455.6470 350 5.83 0.5 0.16 0.16 0.14 0.01 0.04 13 50,385 79,679 0 0 50,385 1.16 455.6471 355 5.92 0.3 0.10 0.16 0.08 0.01 0.12 35 50,419 79,682 0 0 50,419 1.16 455.6472 360 6.00 0.2 0.07 0.16 0.06 0.01 0.08 23 50,442 79,684 0 050,442 1.16 455.64TOTAL RAINFALLRAINFALL VOLUMESOIL LOSSESEFFECTIVE RAINFLOOD VOLUMEFLOOD VOLUMEREQUIRED STORAGEREQUIRED STORAGEMAX WSELPEAK FLOW RATETOTAL BASIN LOSSESAVERAGE PERCOLATION RATEEFFECTIVE RAIN & FLOOD VOLUMES SUMMARY0.00 cf/min0 cu-ft1.78 in1.16 acft50,442 cu-ft1.16 acft50,442 cu-ft76,731 cu-ft2.71 in26,289 cu-ft455.64 ft13.09 cfsPlate E-2.26-Hour StormPage 9 of 13 PROJECT:Job No.: 2553BY: saw DATE 3/1/22DRAINAGE AREA-ACRES 7.80 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 0.0 in/hrUNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr) 0.08LAG TIME - MINUTES 2.31 C 0.00146 Maxwell DrywellsUNIT TIME-PERCENT OF LAG 650% Low Loss Rate (percent) 85.00% Number0TOTAL ADJUSTED STORM RAIN (in) 4.34Drywell Percolation Rate 0.00 cfs 0.00 cfmUnit Time Time Pattern Storm Effective Flood Volume BasinBasinPeriod Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSELin/hr Flow Area Percolation Out(Plate E-5.9) Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ft1 15 0.25 0.2 0.035 0.278 0.030 0.01 0.04 37 37 74,932 0 0 37 0.00 455.002 30 0.50 0.3 0.052 0.274 0.044 0.01 0.06 55 92 74,938 0 0 92 0.00 455.003 45 0.75 0.3 0.052 0.271 0.044 0.01 0.06 55 147 74,943 0 0 147 0.00 455.004 60 1.00 0.4 0.069 0.268 0.059 0.01 0.08 74 221 74,950 0 0 221 0.01 455.005 75 1.25 0.3 0.052 0.265 0.044 0.01 0.06 55 276 74,955 0 0 276 0.01 455.006 90 1.50 0.3 0.052 0.262 0.044 0.01 0.06 55 332 74,960 0 0 332 0.01 455.007 105 1.75 0.3 0.052 0.259 0.044 0.01 0.06 55 387 74,965 0 0 387 0.01 455.008 120 2.00 0.4 0.069 0.255 0.059 0.01 0.08 74 461 74,972 0 0 461 0.01 455.019 135 2.25 0.4 0.069 0.252 0.059 0.01 0.08 74 535 74,979 0 0 535 0.01 455.0110 150 2.50 0.4 0.069 0.249 0.059 0.01 0.08 74 608 74,986 0 0 608 0.01 455.0111 165 2.75 0.5 0.087 0.246 0.074 0.01 0.10 92 700 74,995 0 0 700 0.02 455.0112 180 3.00 0.5 0.087 0.243 0.074 0.01 0.10 92 793 75,004 0 0 793 0.02 455.0113 195 3.25 0.5 0.087 0.240 0.074 0.01 0.10 92 885 75,012 0 0 885 0.02 455.0114 210 3.50 0.5 0.087 0.237 0.074 0.01 0.10 92 977 75,021 0 0 977 0.02 455.0115 225 3.75 0.5 0.087 0.234 0.074 0.01 0.10 92 1,069 75,030 0 0 1,069 0.02 455.0116 240 4.00 0.6 0.104 0.231 0.089 0.02 0.12 111 1,180 75,040 0 0 1,180 0.03 455.0217 255 4.25 0.6 0.104 0.228 0.089 0.02 0.12 111 1,290 75,051 0 0 1,290 0.03 455.0218 270 4.50 0.7 0.122 0.225 0.103 0.02 0.14 129 1,419 75,063 0 0 1,419 0.03 455.0219 285 4.75 0.7 0.122 0.223 0.103 0.02 0.14 129 1,548 75,075 0 0 1,548 0.04 455.0220 300 5.00 0.8 0.139 0.220 0.118 0.02 0.16 147 1,696 75,089 0 0 1,696 0.04 455.0221 315 5.25 0.6 0.104 0.217 0.089 0.02 0.12 111 1,806 75,099 0 0 1,806 0.04 455.0222 330 5.50 0.7 0.122 0.214 0.103 0.02 0.14 129 1,935 75,111 0 0 1,935 0.04 455.0223 345 5.75 0.8 0.139 0.211 0.118 0.02 0.16 147 2,083 75,125 0 0 2,083 0.05 455.0324 360 6.00 0.8 0.139 0.208 0.118 0.02 0.16 147 2,230 75,139 0 0 2,230 0.05 455.0325 375 6.25 0.9 0.156 0.206 0.133 0.02 0.18 166 2,396 75,155 0 0 2,396 0.06 455.0326 390 6.50 0.9 0.156 0.203 0.133 0.02 0.18 166 2,562 75,171 0 0 2,562 0.06 455.0327 405 6.75 1.0 0.174 0.200 0.148 0.03 0.20 184 2,746 75,188 0 0 2,746 0.06 455.0328 420 7.00 1.0 0.174 0.197 0.148 0.03 0.20 184 2,931 75,205 0 0 2,931 0.07 455.0429 435 7.25 1.0 0.174 0.195 0.148 0.03 0.20 184 3,115 75,223 0 0 3,115 0.07 455.0430 450 7.50 1.1 0.191 0.192 0.162 0.03 0.23 203 3,318 75,242 0 0 3,318 0.08 455.0431 465 7.75 1.2 0.208 0.190 0.177 0.02 0.15 133 3,451 75,254 0 0 3,451 0.08 455.0432 480 8.00 1.3 0.226 0.187 0.192 0.04 0.31 275 3,726 75,280 0 0 3,726 0.09 455.0533 495 8.25 1.5 0.260 0.184 0.221 0.08 0.60 539 4,264 75,331 0 0 4,264 0.10 455.0534 510 8.50 1.5 0.260 0.182 0.221 0.08 0.62 557 4,821 75,383 0 0 4,821 0.11 455.0635 525 8.75 1.6 0.278 0.179 0.236 0.10 0.78 698 5,519 75,449 0 0 5,519 0.13 455.0736 540 9.00 1.7 0.295 0.177 0.251 0.12 0.93 838 6,357 75,528 0 0 6,357 0.15 455.0837 555 9.25 1.9 0.330 0.174 0.280 0.16 1.22 1,102 7,459 75,632 0 0 7,459 0.17 455.0938 570 9.50 2.0 0.347 0.172 0.295 0.18 1.38 1,242 8,702 75,749 0 0 8,702 0.20 455.1139 585 9.75 2.1 0.365 0.169 0.310 0.20 1.54 1,383 10,084 75,880 0 0 10,084 0.23 455.1340 600 10.00 2.2 0.382 0.167 0.325 0.22 1.69 1,523 11,607 76,023 0 0 11,607 0.27 455.1541 615 10.25 1.5 0.260 0.164 0.221 0.10 0.76 680 12,287 76,087 0 0 12,287 0.28455.1642 630 10.50 1.5 0.260 0.162 0.221 0.10 0.77 696 12,983 76,153 0 0 12,983 0.30455.1743 645 10.75 2.0 0.347 0.160 0.295 0.19 1.48 1,328 14,311 76,278 0 0 14,311 0.33 455.18in/hrTotal In BasinUNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORMRCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHODLoss RateThe CornerHYDROLOGYSHORTCUT METHODMANUAL24-HOUR STORMBasin LossesPlate E-2.224-Hour StormPage 10 of 13 PROJECT:Job No.: 2553BY: saw DATE 3/1/22DRAINAGE AREA-ACRES 7.80 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 0.0 in/hrUNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr) 0.08LAG TIME - MINUTES 2.31 C 0.00146 Maxwell DrywellsUNIT TIME-PERCENT OF LAG 650% Low Loss Rate (percent) 85.00% Number0TOTAL ADJUSTED STORM RAIN (in) 4.34Drywell Percolation Rate 0.00 cfs 0.00 cfmUnit Time Time Pattern Storm Effective Flood Volume BasinBasinPeriod Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSELin/hr Flow Area Percolation Out(Plate E-5.9) Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ftin/hrTotal In BasinUNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORMRCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHODLoss RateThe CornerHYDROLOGYSHORTCUT METHODMANUAL24-HOUR STORMBasin Losses44 660 11.00 2.0 0.347 0.157 0.295 0.19 1.49 1,344 15,655 76,405 0 0 15,655 0.36 455.2045 675 11.25 1.9 0.330 0.155 0.280 0.17 1.38 1,238 16,892 76,521 0 0 16,892 0.39 455.2146 690 11.50 1.9 0.330 0.153 0.280 0.18 1.39 1,254 18,146 76,640 0 0 18,146 0.42 455.2347 705 11.75 1.7 0.295 0.150 0.251 0.14 1.14 1,024 19,170 76,736 0 0 19,170 0.44 455.2448 720 12.00 1.8 0.312 0.148 0.266 0.16 1.29 1,163 20,333 76,846 0 0 20,333 0.47 455.2649 735 12.25 2.5 0.434 0.146 0.369 0.29 2.27 2,039 22,372 77,038 0 0 22,372 0.51 455.2850 750 12.50 2.6 0.451 0.144 0.384 0.31 2.42 2,177 24,549 77,243 0 0 24,549 0.56 455.3151 765 12.75 2.8 0.486 0.142 0.413 0.34 2.71 2,438 26,987 77,473 0 0 26,987 0.62 455.3452 780 13.00 2.9 0.503 0.140 0.428 0.36 2.86 2,576 29,563 77,716 0 0 29,563 0.68 455.3853 795 13.25 3.4 0.590 0.137 0.502 0.45 3.56 3,205 32,768 78,018 0 0 32,768 0.75 455.4254 810 13.50 3.4 0.590 0.135 0.502 0.453.58 3,22035,988 78,322 0 0 35,988 0.83 455.4655 825 13.75 2.3 0.399 0.133 0.339 0.27 2.09 1,883 37,871 78,499 0 0 37,871 0.87 455.4856 840 14.00 2.3 0.399 0.131 0.339 0.27 2.11 1,897 39,768 78,678 0 0 39,768 0.91 455.5157 855 14.25 2.7 0.469 0.129 0.398 0.34 2.67 2,403 42,171 78,904 0 0 42,171 0.97 455.5458 870 14.50 2.6 0.451 0.127 0.384 0.32 2.55 2,294 44,466 79,121 0 0 44,466 1.02 455.5759 885 14.75 2.6 0.451 0.125 0.384 0.33 2.56 2,308 46,773 79,338 0 0 46,773 1.07 455.6060 900 15.00 2.5 0.434 0.123 0.369 0.31 2.44 2,199 48,972 79,546 0 0 48,972 1.12 455.6261 915 15.25 2.4 0.417 0.122 0.354 0.30 2.32 2,089 51,061 79,742 0 0 51,061 1.17 455.6562 930 15.50 2.3 0.399 0.120 0.339 0.28 2.20 1,979 53,040 79,929 0 0 53,040 1.22 455.6763 945 15.75 1.9 0.330 0.118 0.280 0.21 1.67 1,501 54,541 80,071 0 0 54,541 1.25 455.6964 960 16.00 1.9 0.330 0.116 0.280 0.21 1.68 1,513 56,055 80,213 0 0 56,055 1.29 455.7165 975 16.25 0.4 0.069 0.114 0.059 0.01 0.08 74 56,128 80,220 0 0 56,128 1.29 455.7166 990 16.50 0.4 0.069 0.113 0.059 0.01 0.08 74 56,202 80,227 0 0 56,202 1.29 455.7167 1005 16.75 0.3 0.052 0.111 0.044 0.01 0.06 55 56,257 80,232 0 0 56,257 1.29455.7268 1020 17.00 0.3 0.052 0.109 0.044 0.01 0.06 55 56,313 80,238 0 0 56,313 1.29455.7269 1035 17.25 0.5 0.087 0.107 0.074 0.01 0.10 92 56,405 80,246 0 0 56,405 1.29455.7270 1050 17.50 0.5 0.087 0.106 0.074 0.01 0.10 92 56,497 80,255 0 0 56,497 1.30455.7271 1065 17.75 0.5 0.087 0.104 0.074 0.01 0.10 92 56,589 80,264 0 0 56,589 1.30455.7272 1080 18.00 0.4 0.069 0.103 0.059 0.01 0.08 74 56,663 80,271 0 0 56,663 1.30455.7273 1095 18.25 0.4 0.069 0.101 0.059 0.01 0.08 74 56,737 80,277 0 0 56,737 1.30455.7274 1110 18.50 0.4 0.069 0.100 0.059 0.01 0.08 74 56,810 80,284 0 0 56,810 1.30455.7275 1125 18.75 0.3 0.052 0.098 0.044 0.01 0.06 55 56,866 80,290 0 0 56,866 1.31455.7276 1140 19.00 0.2 0.035 0.097 0.030 0.01 0.04 37 56,902 80,293 0 0 56,902 1.31455.7277 1155 19.25 0.3 0.052 0.096 0.044 0.01 0.06 55 56,958 80,298 0 0 56,958 1.31455.7278 1170 19.50 0.4 0.069 0.094 0.059 0.01 0.08 74 57,031 80,305 0 0 57,031 1.31455.7379 1185 19.75 0.3 0.052 0.093 0.044 0.01 0.06 55 57,087 80,311 0 0 57,087 1.31455.7380 1200 20.00 0.2 0.035 0.092 0.030 0.01 0.04 37 57,124 80,314 0 0 57,124 1.31455.7381 1215 20.25 0.3 0.052 0.090 0.044 0.01 0.06 55 57,179 80,319 0 0 57,179 1.31455.7382 1230 20.50 0.3 0.052 0.089 0.044 0.01 0.06 55 57,234 80,324 0 0 57,234 1.31455.7383 1245 20.75 0.3 0.052 0.088 0.044 0.01 0.06 55 57,289 80,330 0 0 57,289 1.32455.7384 1260 21.00 0.2 0.035 0.087 0.030 0.01 0.04 37 57,326 80,333 0 0 57,326 1.32455.7385 1275 21.25 0.3 0.052 0.086 0.044 0.01 0.06 55 57,382 80,338 0 0 57,382 1.32455.7386 1290 21.50 0.2 0.035 0.085 0.030 0.01 0.04 37 57,419 80,342 0 0 57,419 1.32455.73Plate E-2.224-Hour StormPage 11 of 13 PROJECT:Job No.: 2553BY: saw DATE 3/1/22DRAINAGE AREA-ACRES 7.80 VARIABLE LOSS RATE (AVG) IN/HR Basin Percolation Rate 0.0 in/hrUNIT TIME-MINUTES 15 Fm = Minimum value on loss curve (in/hr) 0.08LAG TIME - MINUTES 2.31 C 0.00146 Maxwell DrywellsUNIT TIME-PERCENT OF LAG 650% Low Loss Rate (percent) 85.00% Number0TOTAL ADJUSTED STORM RAIN (in) 4.34Drywell Percolation Rate 0.00 cfs 0.00 cfmUnit Time Time Pattern Storm Effective Flood Volume BasinBasinPeriod Minutes Hours Percent Rain Rain Hydrograph In Volume Percolation Maximum Percolation WSELin/hr Flow Area Percolation Out(Plate E-5.9) Max Low in/hr cfs cu-ft cu-ft sf cu-ft cu-ft cu-ft ac-ft ftin/hrTotal In BasinUNIT HYDROGRAPH and EFFECTIVE RAIN CALCULATION FORMRCFC & WCD SYNTHETIC UNIT HYDROGRAPH METHODLoss RateThe CornerHYDROLOGYSHORTCUT METHODMANUAL24-HOUR STORMBasin Losses87 1305 21.75 0.3 0.052 0.084 0.044 0.01 0.06 55 57,474 80,347 0 0 57,474 1.32455.7388 1320 22.00 0.2 0.035 0.083 0.030 0.01 0.04 37 57,511 80,350 0 0 57,511 1.32455.7389 1335 22.25 0.3 0.052 0.082 0.044 0.01 0.06 55 57,566 80,356 0 0 57,566 1.32455.7390 1350 22.50 0.2 0.035 0.082 0.030 0.01 0.04 37 57,603 80,359 0 0 57,603 1.32455.7391 1365 22.75 0.2 0.035 0.081 0.030 0.01 0.04 37 57,640 80,363 0 0 57,640 1.32455.7392 1380 23.00 0.2 0.035 0.080 0.030 0.01 0.04 37 57,677 80,366 0 0 57,677 1.32455.7393 1395 23.25 0.2 0.035 0.080 0.030 0.01 0.04 37 57,713 80,370 0 0 57,713 1.32455.7394 1410 23.50 0.2 0.035 0.079 0.030 0.01 0.04 37 57,750 80,373 0 0 57,750 1.33455.7395 1425 23.75 0.2 0.035 0.079 0.030 0.01 0.04 37 57,787 80,377 0 0 57,787 1.33455.7496 1440 24.00 0.2 0.035 0.079 0.030 0.01 0.04 37 57,824 80,380 0 057,8241.33 455.74EFFECTIVE RAIN & FLOOD VOLUMES SUMMARYTOTAL RAINFALLRAINFALL VOLUMESOIL LOSSESEFFECTIVE RAINFLOOD VOLUMEFLOOD VOLUMEREQUIRED STORAGEREQUIRED STORAGEMAX WSELPEAK FLOW RATETOTAL BASIN LOSSESAVERAGE PERCOLATION RATE0 cu-ft0.00 cf/min2.04 in1.33 acft57,824 cu-ft1.33 acft57,824 cu-ft4.34 in122,883 cu-ft65,059 cu-ft455.74 ft3.58 cfsPlate E-2.224-Hour StormPage 12 of 13 PROECT JOB No. BASIN DESIGNATION: BASIN CHARACTERISTICS CONTOUR ELEVATION INCR TOTAL INCR TOTAL INCR (ft) (ft) (sf) (sf) (cuft) (cuft) (acre-ft) 455 0 0 74,929 0 0 0.00 456 1 1 7,410 82,339 78,605 78,605 1.80 WHERE: TOTAL Agriculture Areas BASIN VOLUME WORKSHEET DEPTH AREA VOLUME The Corner 2553 2121213 1 AAAAEEV Basin Volume Worksheet Page 13 of 13 The Corner Preliminary Hydrology Report Appendix G Existing Conditions Exhibit MSA CONSULTING,INC. > PLANNING > CIVIL ENGINEERING > LAND SURVEYING 34200 Bob Hope Drive, Rancho Mirage, CA 92270 760.320.9811 msaconsultinginc.com The Corner Preliminary Hydrology Report Appendix H Preliminary Synthetic Unit Hydrograph Exhibit NOPARKINGNOPARKINGMSA CONSULTING,INC. > PLANNING > CIVIL ENGINEERING > LAND SURVEYING 34200 Bob Hope Drive, Rancho Mirage, CA 92270 760.320.9811 msaconsultinginc.com The Corner Preliminary Hydrology Report Appendix I Preliminary Grading Exhibit NOPARKINGNOPARKINGMSA CONSULTING,INC. > PLANNING > CIVIL ENGINEERING > LAND SURVEYING 34200 Bob Hope Drive, Rancho Mirage, CA 92270 760.320.9811 msaconsultinginc.com