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32279
31 Ob b CL -I..I 111 11111,11111511 -------------- 31 � 6E 11111111111111111111 V \ ae� ca. RETENTION BASIN DESIGN CALCULATIONS TRACT NO. 32279 LA QUINTA, CALIFORNIA April 12, 2004 PREPARED FOR: DUC HOUSING PARTNERS 14107 WINCHESTER BLVD., SUITE H LOS GATOS, CA. 95032 PREPARED BY: P &D CONSULTANTS, INC. 8954 RIO SAN DIEGO DRIVE, SUITE 610 SAN DIEGO, CALIFORNIA 92108 (619) 291 -1475 P &D J.N. 175754 DAN LEE RCE 38396 Prepared By: CH REGISTRATION EXPIRES 03/31/05 Reviewed By: JG i I 0 � I 20 VESTING TENTATIVE MAP SITE DATA PRELIMINARY GRADING PLAN TRACT N °- 32279 �r �r i r MA ww/ GENERAL NOTES wo M �m� wmr nrwn.w mmno mwmr.oa�.a __ — �1p mnr. ®°�u'°e�'ira ri ww•a um+e wru PERIMETER WALL DETAIL ra WW LEGEND wa- -� umwv wnar = tlI 1 6 -WEDGE CURB 'TYPICAL LOT GRADING v aae yr wq :Z=r= _ rx un. T.— N "' .�1 I � �w of wOr w 'a—v— r "L, Imo, LEGAL DESCRIPTION I I I od. d •m s.rmrery .rvv, �N _ oaawnrS �r� BENCHMARK onwm¢a PRIVATE INTERIOR 3TREE7 poPRl VATE INTERIOR STREET �� ° •°Qr1°r rO�^� �r'�v m m r•�r.ov�ua° xre WITH MEDIAN AD.mL VIn ( >G rva aup m per IG tm'au vwu wax mrm au U. I I ___ 7� AVENUE 3S PRIVATE ENTRY STREET / .r• TYPICAL STREET SECTIONS v ^ T OWNEWAPPLICANT VICINITY MAP wrr n.. �m�M CONSULTANTS, /NL, m r (fir r•r!•A0. Nf®r � �dO .... ®....... r ENGINEER OF WORK (I�y AMA Cb 09- r. roaaau Mrrrwa. Tract No.32279 ' Unit Hydrograph Report INTRODUCTION The purpose of this study is to determine the maximum sxorage volume required to contain the 100 -year peak storm. The 100 -year, 3 -hour, 6 -hour and 24 -hour unit hydrographs have been developed. Tract 32279 is located on the North side of Avenue 58, approximately 0.4 mi West of Madison Street in the City of La Quinta, Riverside County, California. The project proposes to develop approximately 9.71 acres for residential (Low Density) use. All storm flows being retained onsite are generated by this area only; there will be no additional runoff from, offsite areas. The private street and storm drain system will convey runoff to the three separate retention basins, one in the center of the site and 2 located at the southern end of the property. The two southern basins located in lots B &C will collect any overflow through the storm drain system from the center basin. The retention basin areas are as follows: Center Basin "D" (Lot D) Square Feet Acres 6321 0.140 Southerly Basin "B" (Lot B) 13280 0.294 'Southerly Basin "C" (Lot C) 13015 0.288 TOTAL 32616 0.722 P&D Consultants, Inc. 1 DUC Housing Partners. PAENGR \175754\Drainage/Basin CA Report.doc RUNO AREA RETEN BASIN (LOT D Tract No. 32279 Unit Hydrograph Report OVERVIEW OF LOT D Runoff Area Area = 114091 SF (2.62 Acres) Retention Basin in Lot D Depth 4' ( +1' Freeboard) Average Area @ 2' = 2090 SF Capacity = 8036 CF Notes: Runoff from the Northeast quarter of the site (Lots 23 -31) will be directed and contained by the retention basin in lot D. Overflow from the retention basin in lot D will be conveyed through (see detail) the storm drain system to be retained in lots B &C downstream. Calculations for flood volume in these basins will account for this overflow. The 100 -year, 3 -hour storm with a unit time of 5 minutes yielded the greatest volume of storm water. The retention basins maximum capacity would be reached at 2:25 (2h @ 25 minutes) hours, at which point flood water would be conveyed downstream through the storm drain system. P&D Consultants, Inc. 2 DUC Housing Partners. P:\ENGR \175754\Drainage/Basin Calc Report.doc u n �I PHYSICAL DATA LOT D [1] CONCENTRATION POINT CURB AT LOT D [2) AREA DESIGNATION DRAINAGE TO LOT D [3] RUNOFF AREA 2.62 ACRES [4] L (length of longest watercourse) 0.159 MILES [5] Lc, (length :o Centmid of RUNOFF AREA) 0.066 MILES [6] ELEVATION OF HEADWATER 71.5 FEET [7] ELEVATION OF CONCENTRATION POINT 64.4 FEET (8) H ([6] -[7]) 7.1 FEET [91 S ([8y[4]) 44.65 FEET /MILE [10] S 0'5 6.68 [11] L'LcA/S °'S ([4]'[5y[10j) 0.002 [12] AVERAGE MANNINGS "N" (plate E -3) 0.020 (13) LAG TIME - HOURS (24'[12]`[11]0'31) 0.041 HOURS [14] LAG TIME - MINUTES (60'[13]) 3 MINUTES [15] 25% OF LAG - MINUTES (100% for shortcut method) 3 MINUTES [16) 40% OF LAG - MINUTES (200% for shortcut method) 6 MINUTES [17) UNIT TIME -MINUTES (2540% OF LAG) or (100 -200%) 5 MINUTES [181 TOTAL RETENTION BASIN AREA 0.120 ACRES (19] TOTAL RETENTION BASIN IMPERVIOUS AREA 0.000 ACRES [20) NET RETENTION PERVIOUS BASIN AREA 0.120 ACRES [211 RETENTION BASIN PERCOLATION . 2.0 IN /HR [221 TOTAL RETENTION BASIN CAPACITY 8360.0 CF ADJUSTED LOSS RATE [1] SOIL GROUP B PLATE C -1 [2) COVER TYPE URBAN COVER - TURF (31 RI NUMBER. 65 PLATE E - 6.1 [4) PERVIOUS AREA INFILTRATION RATE 0.42 1 PLATE E -6.2 [5] LAND USE Single Family 1/2 Acre [6] DECIMAL PERCENT OF AREA IMPERVIOUS 0.65 PLATE E - 6.3 j71 ADJUSTED INFILTRATION RATE I 0.1743 IN /HR FLOODING TO LOT D 100 YEAR 3 -HOUR CHART UNIT TIME PERIOD 5 MINUTES 3-HOUR POINT RAIN FALL 2.1 INCHES RETENTION BASIN PERCOLATION 72.6 CF /5 MINS RET BAS CAPACITY 8360 CF ADJUSTED INFLITRATION RATE 0.174 IN /HR RUNOFF AREA I 2.62 ACRES LOW LOSS RATE 0.91 PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE IN /HR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF EFFECTIVE RETENTION OVERFLOW RECEIVED TOTAL BASIN VOLUME OVERFLOW UNITS H:MM PLATE - E5.9 IN /HR MAX IN /HR LOW IN /HR IN /HR CFS CF CF CF CF CF 1 0:00 1.3 0.328 0.174 0.153 0.40 121.5 48.9 0.0 48.9 0.0 2 0:05 1.3 0.328 0.174 - 0.153 0.40 121.5 48.9 0.0 97.8 0.0 3 0:10 1.1 0.277 0.174 - 0.103 0.27 81.6 9.0 0.0 106.7 0.0 4 0:15 1.5 0.378 0.174 - 0.204 0.54 161.4 88.8 0.0 195.6 0.0 5 0:20 1.5 0.378 0.174 - 0.204 0.54 161.4 88.8 0.0 284.4 0.0 6 0:25 1.8 0.454 0.174 - 0.279 0.74 221.4 148.8 0.0 433.2 0.0 7 0:30 1.5 0.378 0.174 0.204 0.54 161.4 88.8 0.0 522.0 0.0 8 0:35 1.8 0.454 0.174 0.279 0.74 221.4 148.8 0.0 670.8 0.0 9 0:40 1.8 0.454 0.174 0.279 0.74 221.4 148.8 0.0 819.6 0.0 10 0:45 1.5 0.378 0.174 0.204 0.54 161.4 88.8 0.0 908.4 0.0 11 0:50 1.6 0.403 0.174 0.229 0.60 181.4 108.8 0.0 1017.2 0.0 12 0:55 1.8 0.454 0.174 0.279 0.74 221.4 148.8 0.0 1166.0 0.0 13 1:00 2.2 0.554 0.174 0.380 1.00 301.2 228.6 0.0 1394.6 0.0 14 1:05 2.2 0.554 0.174 0.380 1.00 301.2 228.6 0.0 1623.3 0.0 15 1:10 2.2 0.554 0.174 0.380 1.00 301.2 228.6 0.0 1851.9 0.0 16 1:15 2.0 0.504 0.174 0.330 0.87 261.3 188.7 0.0 2040.6 0.0 17 1:20 2.6 0.655 0.174 0.481 1.27 381.1 308.5 0.0 2349.2 0.0 18 1:25 2.7 0.680 0.174 0.506 1.34 401.1 328.5 0.0 2677.7 0.0 19 1:30 2.4 0.605 0.174 0.431 1.14 341.2 268.6 0.0 2946.3 0.0 20 1:35 2.7 0.680 0.174 0.506 1.34 401.1 328.5 0.0 3274.8 0.0 21 1:40 3.3 0.832 0.174 0.657 1.74 520.9 448.3 0.0 3723.1 0.0 22 1:45 3.1 0.781 0.174 0.607 1.60 481.0 408.4 0.0 4131.5 0.0 23 1:50 2.9 0.731 0.174 0.557 1.47 441.1 368.5 0.0 4500.0 0.0 24 1:55 3.0 0.756 0.174 0.582 1.54 461.0 388.4 0.0 4888.4 0.0 25 2:00 3.1 0.781 0.174 - 0.607 1.60 481.0 408.4 0.0 5296.8 0.0 26 2:05 4.2 1.058 0.174 0.884 2.34 700.7 628.1 0.0 5924.9 0.0 27 2:10 5.0 1.260 0.174 1.086 2.87 860.5 787.9 0.0 6712.8 0.0 28 2:15 3.5 0.882 0.174 - 0.708 1.87 560.9 488.3 0.0 7201.0 0.0 29 2:20 6.8 1.714 0.174 1.539 4.07 1220.0 1147.4 0.0 8348.4 0.0 30 2:25 7.3 1.840 0.174 1.665 4.40 1319.8 1247.2 0.0 8360.0 1235.6 31 2:30 8.2 2.066 0.174 1.892 5.00 1499.6 1427.0 0.0 8360.0 1427.0 32 2:35 5.9 1.487 0.174 1.313 3.47 1040.2 967.6 0.0 8360.0 967.6 33 2:40 2.0 0.504 0.174 0.330 0.87 261.3 188.7 0.0 8360.0 188.7 34 2:45 1.8 0.454 0.174 0.279. 0.74 221.4 148.8 0.0 8360.0 148.8 35 2:50 1.8 0.454 0.174 0.279 0.74 221.4 148.8 0.0 1 8360.0 148.8 36 2:55 0.6 0.151 0.174 0.136 0.015 0.04 12.0 -60.6 0.0 8299.4 0.0 FLOODING TO LOT D 100 YEAR 6 -HOUR CHART UNIT TIME PERIOD 5 MINUTES 3 -HOUR POINT RAIN FALL 2.6 INCHES RETENTION BASIN PERCOLATION 72.6 CF /5 MINS RET BAS CAPACITY I 8360 CF ADJUSTED INFLITRATION RATE 0.174 IN /HR RUNOFF AREA I 2.62 ACRES LOW LOSS RATE 0.9 PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE IN /HR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF EFFECTIVE RETENTION OVERFLOW RECEIVED TOTAL BASIN VOLUME OVERFLOW UNITS H:MM PLATE - E5.9 IN /HR MAX IN /HR LOW IN /HR IN /HR CFS CF CF CF CF CF 1 0:00 0.5 0.156 0.174 0.140 0.016 0.04 12.4 -60.2 0.0 0.0 0.0 2 0:05 0.6 0.187 0.174 - 0.013 0.03 10.2 -62.4 0.0 0.0 0.0 3 0:10 0.6 0.187 0.174 0.013 0.03 10.2 -62.4 0.0 0.0 0.0 4 0:15 0.6 0.187 0.174 0.013 0.03 10.2 -62.4 0.0 0.0 0.0 5 0:20 0.6 0.187 0.174 0.013 0.03 10.2 -62.4 0.0 0.0 0.0 6 0:25 0.7 0.218 0.174 - 0.044 0.12 35.0 -37.6 0.0 0.0 0.0 7 0:30 0.7 0.218 0.174 0.044 0.12 35.0 -37.6 0.0 0.0 0.0 8 0:35 0.7 0.218 0.174 0.044 0.12 35.0 -37.6 0.0 0.0 0.0 9 0:40 0.7 0.218 0.174 0.044 0.12 35.0 -37.6 0.0 0.0 010 10 0:45 0.7 0.218 0.174 - 0.044 0.12 35.0 -37.6 0.0 0.0 0.0 11 0:50 0.7 0.218 0.174 - 0.044 0.12 35.0 -37.6 0.0 0.0 0.0 12 0:55 0.8 0.250 0.174 - 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 13 1:00 0.8 0.250 0.174 - 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 14 1:05 0.8 0.250 0.174 - 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 15 1:10 0.8 0.250 0.174 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 16 1:15 0.8 0.250 0.174 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 17 1:20 0.8 0.250 0.174 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 18 1:25 0.8 0.250 0.174 - 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 19 1:30 0.8 0.250 0.174 - 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 20 1:35 0.8 0.250 0.174 - 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 21 1:40 0.8 0.250 0.174 - 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 22 1:45 0.8 0.250 0.174 - 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 23 1:50 0.8 0.250 0.174 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 24 1:55 0.9 0.281 0.174 0.107 0.28 84.4 11.8 0.0 11.8 0.0 25 2:00 0.8 0.250 0.174 0.075 0.20 59.7 -12.9 0.0 0.0 0.0 26 2:05 0.9 0.281 0.174 0.107 0.28 84.4 11.8 0.0 11.8 0.0 27 2:10 0.9 0.281 0.174 0.107 0.28 84.4 11.8 0.0 23.6 0.0 28 2:15 0.9 0.281 0.174 0.107 0.28 84.4 11.8 0.0 35.4 0.0 29 2:20 0.9 0.281 0.174 - 0.107 0.28 84.4 11.8 0.0 47.2 0.0 30 2:25 0.9 0.281 0.174 0.107 0.28 84.4 11.8 0.0 59.0 0.0 31 2:30 0.9 0.281 0.174 - 0.107 0.28 84.4 11.8 0.0 70.8 0.0 32 .2:35 0.9 0.281 0.174 - 0.107 0.28 84.4 11.8 0.0 82.6 0.0 33 2:40 1.0 0.312 0.174 - 0.138 0.36 109.1 36.5 0.0 119.2 0.0 34 2:45 1 0.312 0.174 - 0.138 0.36 109.1 36.5 0.0 155.7 0.0 35 2:50 1 0.312 0.174 - 0.138 0.36 109.1 36.5 0.0 192.2 0.0 36 2:55 1 0.312 0.174 - 0.138 0.36 109.1 36.5 0.0 228.8 0.0 37 3:00 1.0 0.312 0.174 - 0.138 0.36 109.1 36.5 0.0 265.3 0.0 38 3:05 1.1 0.343 0.174 - 0.169 0.45 133.9 61.3 0.0 326.6 0.0 39 3:10. 1.1 0.343 0.174 - 0.169 0.45 133.9 61.3 0.0 387.8 0.0 40 3:15 1.1 0.343 0.174 - 0.169 0.45 133.9 61.3 0.0 449.1 0.0 41 3:20 1.2 0.374 0.174 - 0.200 0.53 158.6 86.0 0.0 535.1 0.0 42 3:25 1.3 0.406 0.174 - 0.231 0.61 183.3 110.7 0.0 645.8 0.0 43 3:30 1.4 0.437 0.174 - 0.263 0.69 208.0 135.4 0.0 781.3 0.0 44 3:35 1.4 0.437 0.174 - 0.263 0.69 208.0 135.4 0.0 916.7 0.0 45 3:40 1.5 0.468 0.174 - 0.294 0.78 232.8 160.2 0.0 1076.9 0.0 46 3:45 1.5 0.468 0.174 - 0.294 0.78 232.8 160.2 0.0 1237.0 0.0 47 3:50 1.6 0.499 0.174 - 0.325 0.86 257.5 184.9 0.0 1421.9 0.0 48 3:55 1.6 0.499 0.174 - 0.325 0.86 257.5 184.9 0.0 1606.8 0.0 49 4:00 1.7 0.530 0.174 - 0.356 0.94 282.2 209.6 0.0 1816.5 0.0 50 4:05 1.8 0.562 0.174 - 0.387 1.02 307.0 234.4 0.0 2050.8 0.0 51 4:10 1.9 0.593 0.174 - 0.419 1.11 331.7 259.1 0.0 2309.9 0.0 52 4:15 2.0 0.624 0.174 - 0.450 1.19 356.4 283.8 0.0 2593.7 0.0 53 4:20 2.1 0.655 0.174 - 0.481 1.27 381.1 308.5 0.0 2902.3 0.0 54 4:25 2.1 0.655 0.174 - 0.481 1.27 381.1 308.5 0.0 3210.8 0.0 55 4:30 2.2 0.686 0.174 - 0.512 1.35 405.9 333.3 0.0 3544.1 0.0 56 4:35 2.3 0.718 0.174 - 0.543 1.44 430.6 358.0 0.0 3902.0 0.0 57 4:40 2.4 0.749 0.174 - 0.575 1.52 455.3 382.7 0.0 4284.8 0.0 58 4:45 2.4 0.749 0.174 - 0.575 1.52 455.3 382.7 0.0 4667.5 0.0 59 4:50 2.5 0.780 0.174 - 0.606 1.60 480.0 407.4 0.0 5074.9 0.0 60 4:55 2.6 0.811 0.174 - 0.637 1.68 504.8 432.2 0.0 5507.1 0.0 61 5:00 3.1 0.967 0.174 - 0.793 2.09 628.4 555.8 0.0 6062.9 0.0 62 5:05 3.6 1.123 0.174 - 0.949 2.51 752.1 679.5 0.0 6742.4 0.0 63 5:10 3.9 1.217 0.174 - 1.043 2.75 826.2 753.6 0.0 7496.0 0.0 64 5:15 4.2 1.310 0.174 - 1.136 3.00 900.4 827.8 0.0 8323.8 0.0 65 5:20 4.7 1.466 0.174 - 1.292 3.41 1024.1 951.5 0.0 8360.0 915.3 66 5:25 5.6 1.747 0.174 - 1.573 4.16 1246.6 1174.0 0.0 8360.0 1174.0 67 5:30 1.9 0.593 0.174 0.419 1.11 331.7 259.1 0.0 8360.0 259.1 68 5:35 0.9 0.281 0.174 0.107 0.28 84.4 11.8 0.0 8360.0 11.8 69 5:40 0.6 0.187 0.174 - 0.013 0.03 10.2 -62.4 0.0 8297.6 0.0 70 5:45 0.5 0.156 0.174 _ 0.140 1 0.016 0.04 12.4 -60.2 0.0 8237.4 0.0 71 5:50 0.3 0.094 0.174 0.084 0.009 0.02 7.4 -65.2 0.0 8172.2 0.0 72 5:55 0.2 0.062 0.174 0.056 0.006 0.02 4.9 -67.7 0.0 8104.6 0.0 FLOODING TO LOT D 100 YEAR 24 -HOUR CHART I UNIT TIME PERIOD 15 MINUTES 3 -HOUR POINT RAIN FALL 4.8 INCHES RETENTION BASIN PERCOLATION 217.8 CF /15 MINS RET BAS CAPACITY 8360 CF ADJUSTED INFLITRATION RATE 0.174 IN /HR RUNOFF AREA 2.62 ACRES LOW LOSS RATE 0.91 PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE IN /HR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF EFFECTIVE RETENTION OVERFLOW RECEIVED TOTAL BASIN VOLUME OVERFLOW UNITS H:MM PLATE - E5.9 IN /HR MAX IN /HR LOW IN /HR IN /HR CFS CF CF CF CF CF 1 0:00 0.2 0.038 0.308 0.035 0.004 0.01 9.1 -208.7 0.0 0.0 0.0 2 0:15 0.3 0.058 0.304 0.052 0.006 0.02 13.7 -204.1 0.0 0.0 0.0 3 0:30 0.3 0.058 0.301 0.052 0.006 0.02 13.7 -204.1 0.0 0.0 -0-.o- 4 0:45 0.4 0.077 0.297 0.069 0.008 0.02 1.8.3 -199.5 0.0 0.0 0.0 5 1:00 0.3 0.058 0.294 0.052 0.006 0.02 13.7 -204.1 0.0 0.0 0.0 6 1:15 0.3 0.058 0.290 0.052 0.006 0.02 13.7 -204.1 0.0 0.0 0.0 7 1:30 0.3 0.058 0.287 0.052 0.006 0.02 13.7 -204.1 0.0 0.0 0.0 8 1:45 0.4 0.077 0.283 0.069 0.008 0.02 18.3 -199.5 0.0 0.0 0.0 9 2:00 0.4 0.077 0.280 0.069 0.008 0.02 18.3 -199.5 0.0 0.0 0.0 10 2:15 0.4 0.077 0.276 0.069 0.008 0.02 18.3 -199.5 0.0 0.0 0.0 11 2:30 0.5 0.096 0.273 0.086 0.010 0.03 22.8 -195.0 0.0 0.0 0.0 12 2:45 0.5 0.096 0.270 0.086 0.010 0.03 22.8 -195.0 0.0 0.0 0.0 13 3:00 0.5 0.096 0.266 0.086 0.010 0.03 22.8 -195.0 0.0 0.0 0.0 14 3:15 0.5 0.096 0.263 0.086 0.010 0.03 22.8 -195.0 0.0 0.0 0.0 15 3:30 0.5 0.096 0.260 0.086 0.010 0.03 22.8 -195.0 0.0 0.0 0.0 16 3:45 0.6 0.115 0.256 0.104 0.012 0.03 27.4 -190.4 0.0 0.0 0.0 17 4:00 0.6 0.115 0.253 0.104 0.012 0.03 27.4 -190.4 0.0 0.0 0.0 18 4:15 0.7 0.134 0.250 0.121 0.013 0.04 32.0 -185.8 0.0 0.0 0.0 19 4:30 0.7 0.134 0.247 0.121 0.013 0.04 32.0 -185.8 0.0 0.0 0.0 20 4:45 0.8 0.154 0.244 0.138 0.015 0.04 36.5 -181.3 0.0 0.0 0.0 21 5:00 0.6 0.115 0.240 0.104 0.012 0.03 27.4 -190.4 0.0 0.0 0.0 22 5:15 0.7 0.134 0.237 0.121 0.013 0.04 32.0 -185.8 0.0 0.0 0.0 23 5:30 0.8 0.154 0.234 0.138 0.015 0.04 36.5 -181.3 0.0 0.0 0.0 24 5:45 0.8 0.154 0.231 0.138 0.015 0.04 36.5 -181.3 0.0 0.0 0.0 25 6:00 0.9 0.173 0.228 0.156 0.017 0.05 41.1 -176.7 0.0 0.0 0.0 26 6:15 0.9 0.173 0.225 0.156 0.017 0.05 41.1 -176.7 0.0 0.0 0.0 27 6:30 1.0 0.192 0.222 0.173 0.019 0.05 45.7 -172.1 0.0 0.0 0.0 28 6:45 1.0 0.192 0.219 0.173 0.019 0.05 45.7 -172.1 0.0 0.0 0.0 29 7:00 1.0 0.192 0.216 0.173 0.019 0.05 45.7 -172.1 0.0 0.0 0.0 30 7:15 1.1 0.211 0.213 0.190 0.021 0.06 50.2 -167.6 0.0 0.0 0.0 31 7:30 1.2 0.230 0.210 - 0.020 0.05 48.2 -169.6 0.0 0.0 0.0 32 7:45 1.3 0.250 0.207 0.042 0.11 100.7 -117.1 0.0 0.0 0.0 33 8:00 1.5 0.288 0.204 0.084 0.22 198.9 -18.9 0.0 0.0 0.0 34 8:15 1.5 0.288 0:202 0.086 0.23 205.6 -12.2 0.0 0.0 0.0 35 8:30 1.6 0.307 0.199 0.109 0.29 258.0 40.2 0.0 40.2 0.0 36 8:45 1.7 0.326 0.196 - 0.131 0.34 310.3 92.5 0.0 132.7 0.0 37 9:00 1.9 0.365 0.193 - 0.172 0.45 408.2 190.4 0.0 323.1 0.0 38 9:15 2.0 0.384 0.190 - 0.194 0.51 460.4 242.6 0.0 565.7 0.0 39 9:30 2.1 0.403 0.188 - 0.216 0.57 512.5 294.7 0.0 860.4 0.0 40 9:45 2.2 0.422 0.185 - 0.237 0.63 564.6 346.8 0.0 1207.1 0.0 41 10:00 1.5 0.288 0.182 - 0.106 0.28 251.4 33.6 0.0 1240.7 0.0 42 10:15 1.5 0.288 0.180 - 0.108 0.29 257.6 39.8 0.0 1280.5 0.0 43 10:30 2.0 0.384 0.177 - 0.207 0.55 492.1 274.3 0.0 1554.9 0.0 44 .10:45 2.0 0.384 0.174 - 0.210 0.55 498.3 280.5 0.0 1835.3 0.0 45 11:00 1.9 0.365 0.172 - 0.193 0.51 458.7 1 240.9 0.0 2076.3 0.0 46 11:15 1.9 0.365 0.169 - 0.195 0.52 464.8 247.0 0.0 2323.2 0.0 47 11:30 1.7 0.326 0.167 - 0.160 0.42 379.4 161.6 0.0 2484.8 0.0 48 11:45 1.8 0.346 0.164 - 0.181 0.48 431.0 213.2 0.0 2698.0 0.0 49 12:00 2.5 0.480 0.162 - 0.318 0.84 756.4 538.6 0.0 3236.5 0.0 50 12:15 2.6 0.499 0.159 - 0.340 0.90 807.8 590.0 0.0 3826.5 0.0 51 12:30 2.8 0.538 0.157 - 0.381 1.01 904.8 687.0 0.0 4513.5 0.0 52 12:45 2.9 0.557 0.155 - 0.402 1.06 956.0 738.2 0.0 5251.7 0.0 53 13:00 3.4 0.653 0.152 - 1 0.500 1.32 1189.9 972.1 0.0 6223.8 0.0 54 13:15 3.4 0.653 0.150 - 0.503 1.33 1195.4 977.6 0.0 7201.3 0.0 55 13:30 2.3 0.442 0.148 - 0.294 0.78 698.6 480.8 0.0 7682.2 0.0 56 13:45 2.3 0.442 0.146 - 0.296 0.78 704.0 486.2 0.0 8168.3 0.0 57 14:00 2.7 0.518 0.143 - 0.375 0.99 891.8 674.0 0.0 8360.0 482.3 58 14:15 2.6 0.499 0.141 - 0.358 0.95 851.4 633.6 0.0 8360.0 633.6 59 14:30 2.6 0.499 0.139 - 0.360 0.95 856.5 638.7 0.0 8360.0 638.7 60 14:45 2.5 0.480 0.137 - 0.343 0.91 815.9 598.1 0.0 8360.0 598.1 61 15:00 2.4 0.461 0.135 0.326 0.86 775.3 557.5 0.0 8360.0 557.5 62 15:15 2.3 0.442 0.133 0.309 0.82 734.5 516.7 0.0 8360.0 516.7 63 15:30 1.9 0.365 0.131 0.234 0.62 556.7 338.9 0.0 8360.0 338.9 64 15:45 1.9 0.365 0.129 0.236 0.62 561.5 343.7 0.0 8360.0 343.7 65 16:00 0.4 0.077 0.127 0.069 0.008 0.02 18.3 -199.5 0.0 8160.5 0.0 66 16:15 0.4 0.077 0.125 0.069 0.008 0.02 18.3 -199.5 0.0 7960.9 0.0 67 16:30 0.3 0.058 0.123 0.052 0.006 0.02 13.7 -204.1 0.0 7756.8 0.0 68 16:45 0.3 0.058 0.121 0.052 0.006 0.02 13.7 -204.1 0.0 7552.7 0.0 69 17:00 0.5 0.096 0.119 0.086 0.010 0.03 22.8 -195.0 0.0 7357.7 0.0 70 17:15 0.5 0.096 0.117 0.086 0.010 0.03 22.8 -195.0 0.0 7162.8 0.0 71 17:30 0.5 0.096 0.116 0.086 0.010 0.03 22.8 -195.0 0.0 6967.8 0.0 72 17:45 0.4 0.077 0.114 0.069 0.008 0.02 18.3 -199.5 0.0 6768.2 0.0 73 18:00 0.4 0.077 0.112 0.069 0.008 0.02 18.3 -199.5 0.0 6568.7 0.0 74 18:15 0.4 0.077 0.111 0.069 0.008 0.02 18.3 -199.5 0.0 6369.2 0.0 75 18:30 0.3 0.058 0.109 0.052 1 0.006 0.02 13.7 -204.1 0.0 6165.1 0.0 76 18:45 0.2 0.038 0.107 0.035 0.004 0.01 9.1 -208.7 0.0 5956.4 0.0 77 19:00 0.3 0.058 0.106 0.052 0.006 0.02 13.7 -204.1 0.0 5752.3 0.0 78 19:15 0.4 0.077 0.104 0.069 0.008 0.02 18.3 -199.5 0.0 5552.7 0.0 79 19:30 0.3 0.058 0.103 0.052 0.006 0.02 13.7 -204.1 0.0 5348.6 0.0 80 19:45 0.2 0.038 0.102 0.035 0.004 0.01 9.1 -208.7 0.0 5140.0 0.0 81 20:00 0.3 0.058 0.100 0.052 0.006 0.02 13.7 -204.1 0.0 4935.9 0.0 82 20:15 0.3 0.058 0.099 0.052 0.006 0.02 13.7 -204.1 0.0 4731.8 0.0 83 20:30 0.3 0.058 0.098 0.052 0.006 0.02 13.7 -204.1 0.0 4527.7 0.0 84 20:45 0.2 0.038 0.097 0.035 0.004 0.01 9.1 -208.7 0.0 4319.0 0.0 85 21:00 0.3 0.058 0.095 0.052 0.006 0.02 13.7 -204.1 0.0 4114.9 6.0 86 21:15 0.2 0.038' 0.094 0.035 0.004 0.01 9.1 -208.7 0.0 3906.2 0.0 87 21:30 0.3 0.058 0.093 0.052 0.006 0.02 13.7 -204.1 0.0 3702.1 0.0 88 21:45 0.2 0.038 0.092 0.035' 0.004 0.01 9.1 -208.7 0.0 3493.4 0.0 89 22:00 0.3 0.058 0.091 0.052 0.006 0.02 13.7 -204.1 0.0 3289.3 0.0 90 22:15 0.2 0.038 0.091 0.035 0.004 0.01 9.1 -208.7 0.0 3080.7 0.0 91 22:30 0.2 0.038 0.090 0.035 0.004 0.01 9.1 -208.7 0.0 2872.0 0.0 92 22:45 0.2 0.038 0.089 0.035 0.004 0.01 9.1 -208.7 0.0 2663.3 0.0 93 23:00 0.2 0.038 0.088 0.035 0.004 0.01 9.1 -208.7 0.0 2454.7 0.0 94 23:15 0.2 0.038 0.088 0.035 0.004 0.01 9.1 -208.7 0.0 2246.0 0.0 95 23:30 0.2 0.038 0.088 0.035 0.004 0.01 9.1 -208.7 0.0 2037.3 0.0 96 1 23:45 0.2 1 0.038 1 0.087 0.035 0.004 0.01 9.1 -208.7 0.0 1828.6 0.0 RUNOFF AREA RE TEN Ti BASIN ' (L O T O) RE TEN TI, BA SIN ", (LOT B) OVERVIEW OF LOTS B &C Tract No. 32279 Unit Hydrograph Report Runoff Area Area = 273485 SF (6.28 Acres) Retention Basin in Lot B Depth 5' ( +1' Freeboard) Average Area @ 2.5' = 4227 SF Capacity = 21135 CF Retention Basin in Lot C Depth 5' ( +1' Freeboard) Average Area @ 2.5' = 4140 SF Capacity = 20700 CF Total Basin Capacity Lot B +Lot C = 41835 CF Notes: Runoff from the Northwest and Southern lots of the site (Lots 1 -22) will be conveyed to the retention basins in lots B &C as well as any overflow received from the retention basin in lot D. The 100 -year, 3 -hour storm with a unit time of 5 minutes yielded the greatest volume of storm water. At 2:50 hours (2 hours @ 50 minutes) 32743 CF of flood water would be contained between the basins in lots B &C, 78% of maximum capacity. P&D Consultants, Inc. 3 DUC Housing Partners. PAENGRU7575ADrainage/Basin Calc Report.doc PHYSICAL DATA LOTS B &C [1] CONCENTRATION POINT CURB AT LOT B&C [2] AREA DESIGNATION DRAINAGE TO LOT B&C [3] RUNOFF AREA 6.28 ACRES [4] L (length of longest watercourse) 0.249 MILES [5) LcA (length to Centroid of RUNOFF AREA) 0.127 MILES [6] ELEVATION OF HEADWATER 73.9 FEET [7] ELEVATION OF CONCENTRATION POINT 61.1 FEET [8] H ([6] -[7]) 12.8 FEET [9) S ([8y[4]) 51.41 FEET /MILE [10] S 0'5 7.17 [11) L•LcA /S °'S ([4]'[5y[10]) 0.004 [12] AVERAGE MANNINGS "N" (plate E -3) 0.020 [13] LAG TIME - HOURS (24'[12]'[11]°') 0.061 jHOURS [14] LAG TIME - MINUTES (60'[13]) 4 MINUTES [15] 25% OF LAG - MINUTES (100% for shortcut method) 4 MINUTES [16) 40% OF LAG - MINUTES (200% for shortcut method) 8 MINUTES [17] UNIT TIME - MINUTES (25 -40% OF LAG) or (100 - 200 %) 5 MINUTES (18) TOTAL RETENTION BASIN AREA 0.348 ACRES [19] TOTAL RETENTION BASIN IMPERVIOUS AREA 0.000 ACRES [20] NET RETENTION PERVIOUS BASIN AREA 0.348 ACRES [21] RETENTION BASIN PERCOLATION 2.0 IN /HR [22] TOTAL RETENTION BASIN CAPACITY 41835.0 CF ADJUSTED LOSS RATE [1] SOIL GROUP B PLATE C - 1 [2] COVER TYPE URBAN COVER - TURF [3] RI NUMBER 65 PLATE E - 6.1 [4] PERVIOUS AREA INFILTRATION RATE 0.42 PLATE E - 6.2 (5) LAND USE Single Family 1/2 Acre [6) DECIMAL PERCENT OF AREA IMPERVIOUS 0.65 IPLATE E - 6.3 [7 ADJUSTED INFILTRATION RATE 0.1743 IN /HR FLOODING TO LOT B &C 100 YEAR 3 -HOUR CHART UNIT TIME PERIOD 5 MINUTES 3-HOUR POINT RAIN FALL 2.11 INCHES RETENTION BASIN PERCOLATION 210.54 CF /5 MINS RET BAS CAPACITY 41835 CF ADJUSTED INFLITRATION RATE 0.174 IN /HR RUNOFF AREA I 6,28 ACRES LOW LOSS RATE 0.91 PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE IN /HR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF EFFECTIVE RETENTION OVERFLOW RECEIVED TOTAL BASIN VOLUME OVERFLOW UNITS H:MM PLATE - E5.9 IN /HR MAX IN /HR LOW IN /HR IN /HR CFS CF CF CF CF CF 1 0:00 1.3 0.328 0.174 0.153 0.97 291.2 80.7 0.0 80.7 0.0 2 0:05 1.3 0.328 0.174 0.153 0.97 291.2 80.7 0.0 161.4 0.0 3 0:10 1.1 0.277 0.174 0.103 0.65 195.5 -15.1 0.0 146.3 0.0 4 0:15 1.5 0.378 0.174 - 0.204 1.29 387.0 176.4 0.0 322.7 0.0 5 0:20 1.5 0.378 0.174 0.204 1.29 387.0 176.4 0.0 499.2 0.0 6 0:25 1.8 0.454 0.174 - 0.279 1.77 530.6 320.0 0.0 819.2 0.0 7 0:30 1.5 0.378 0.174 - 0.204 1.29 387.0 176.4 0.0 995.6 0.0 8 0:35 1.8 0.454 0.174 - 0.279 1.77 530.6 320.0 0.0 1315.7 0.0 9 0:40 1.8 0.454 0.174 - 0.279 1.77 530.6 320.0 0.0 1635.7 0.0 10 0:45 1.5 0.378 0.174 - 0.204 1.29 387.0 176.4 0.0 1812.2 0.0 11 0:50 1.6 0.403 0.174 - 0.229 1.45 434.8 224.3 0.0 2036.5 0.0 12 0:55 1.8 0.454 0.174 - 0.279 1.77 530.6 320.0 0.0 2356.5 0.0 13 1:00 2.2 0.554 0.174 - 0.380 2.41 722.1 511.5 0.0 2868.0 0.0 14 1:05 2.2 0.554 0.174 - 0.380 2.41 722.1 511.5 0.0 3379.6 0.0 15 1:10 2.2 0.554 0.174 - 0.380 2.41 722.1 511.5 0.0 3891.1 0.0 16 1:15 2.0 0.504 0.174 - 0.330 2.09 626.3 415.8 0.0 4306.9 0.0 17 1:20 2.6 0.655 0.174 0.481 3.05 913.6 703.0 0.0 5009.9 0.0 18 1:25 2.7 0.680 0.174 0.506 3.20 961.4 750.9 0.0 5760.8 0.0 19 1:30 2.4 0.605 0.174 0.431 2.73 817.8 607.3 0.0 6368.1 0.0 40 1:35 2.7 0.680 0.174 0.506 3.20 961.4 750.9 0.0 7119.0 0.0 21 1:40 3.3 0.832 0.174 1 0.657 4.16 1248.7 1038.1 0.0 8157.1 0.0 22 1:45 3.1 0.781 0.174 - 0.607 3.84 1152.9 942.4 0.0 9099.5 0.0 23 1:50 2.9 0.731 0.174 0.557 3.52 1057.2 846.6 0.0 9946.2 0.0 24 1:55 3.0 0.756 0.174 0.582 3.68 1105.1 894.5 0.0 10840.7 0.0 25 2:00 3.1 0.781 0.174 - 0.607 3.84 1152.9 942.4. 0.0 11783.1 0.0 26 2:05 4.2 1.058 0.174 - 0.884 5.60 1679.5 1469.0 0.0 13252.1 0.0 27 2:10 5.0 1.260 0.174 1.086 6.88 2062.5 1852.0 0.0 15104.0 0.0 28 2:15 3.5 0.882 0.174 - 0.708 4.48 1344.4 1133.9 0.0 16237.9 0.0 29 2:20 6.8 1.714 0.174 - 1.539 9.75 2924.2 2713.7 0.0 18951.6 0.0 30 2:25 7.3 1.840 0.174 1.665 10.55 3163.6 2953.0 1235.6 23140.2 0.0 31 2:30 8.2 2.066 0.174 1.892 11.98 3594.4 3383.9 1427.0 27951.1 0.0 32 2:35 5.9 1.487 0.174 - 1.313 8.31 2493.4 2282.8 967.6 31201.5 0.0 33 2:40 2.0 0.504 0.174 - 0.330 2.09 626.3 415.8 188.7 31806.0 0.0 34 2:45 1.8 0.454 0.174 0.279 1.77 530.6 320.0 148.8 32274.8 0.0 35 2:50 1.8 1 0.454 0.174 0.279 1.77 530.6 320.0 148.8 32743.7 0.0 36 1 2:55 0.6 1 0.151 0.174 0.136 0.015 0.10 28.7 -181.8 0.0 32561.9 0.0 FLOODING TO LOT B &C 100 YEAR 6 -HOUR CHART UNIT TIME PERIOD 5 MINUTES 3 -HOUR POINT RAIN FALL 2.6 INCHES RETENTION BASIN PERCOLATION 210.54 CF /5 MINS RET BAS CAPACITY 41835 CF ADJUSTED INFLITRATION RATE 0.174 IN /HR RUNOFF AREA I 6.28 ACRES LOW LOSS RATE 0.9 PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE IN /HR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF EFFECTIVE RETENTION OVERFLOW RECEIVED TOTAL BASIN VOLUME OVERFLOW UNITS H:MM PLATE - E5.9 IN /HR MAX IN /HR LOW IN /HR IN /HR CFS CF CF CF CF CF 1 0:00 0.5 0.156 0.174 0.140 0.016 0.10 29.6 -180.9 0.0 0.0 0.0 2 0:05 0.6 0.187 0.174 - 0.013 0.08 24.5 -186.0 0.0 0.0 0.0 3 0:10 0.6 0.187 0.174 0.013 0.08 24.5 -186.0 0.0 0.0 0.0 4 0:15 0.6 0.187 0.174 0.013 0.08 24.5 -186.0 0.0 0.0 0.0 5 0:20 0.6 0.187 0.174 0.013 0.08 24.5 -186.0 0.0 0.0 0.0 6 0:25 0.7 0.218 0.174 0.044 0.28 83.8 -126.8 0.0 0.0 0.0 7 0:30 0.7 0.218 0.174 0.044 0.28 83.8 -126.8 0.0 0.0 0.0 8 0:35 0.7 0.218 0.174 0.044 0.28 83.8 -126.8 0.0 0.0 0.0 9 0:40 0.7 0.218 0.174 0.044 0.28 83.8 -126.8 0.0 0.0 0.0 10 0:45 0.7 0.218 0.174 0.044 0.28 83.8 -126.8 0.0 0.0 0.0 11 0:50 0.7 0.218 0.174 0.044 0.28 83.8 -126.8 0.0 0.0 0.0 12 0:55 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 13 1:00 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 14 1:05 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 15 1:10 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 16 1:15 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 17 1:20 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 18 1:25 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 19 1:30 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 20 1:35 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 21 1:40 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 22 1:45 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 23 1:50 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 24 1:55 0.9 0.281 0.174 0.107 0.67 202.3 -8.2 0.0 0.0 0.0 25 2:00 0.8 0.250 0.174 0.075 0.48 143.0 -67.5 0.0 0.0 0.0 26 2:05 0.9 0.281 0.174 0.107 0.67 202.3 -8.2 0.0 0.0 0.0 27 2:10 0.9 0.281 0.174 0.107 0.67 202.3 -8.2 0.0 0.0 0.0 28 2:15 0.9 0.281 0.174 0.107 0.67 202.3 -8.2 0.0 0.0 0.0 29 2:20 0.9 0.281 0.174 0.107 0.67 202.3 -8.2 0.0 0.0 0.0 30 2:25 0.9 0.281 0.174 0.107 0.67 202.3 -8.2 0.0 0.0 0.0 31 2:30 0.9 0.281 0.174 0.107 0.67 202.3 -8.2 0.0 0.0 0.0 32 2:35 0.9 0.281 0.174 0.107 0.67 202.3 -8.2 0.0 0.0 0.0 33 2:40 1.0 0.312 0.174 0.138 0.87 261.6 51.0 0.0 51.0 0.0 34 2:45 1 0.312 0.174 - 0.138 0.87 261.6 51.0 0.0 102.1. 0.0 35 2:50 1 0.312 0.174 - 0.138 0.87 261.6 51.0 0.0 153.1 0.0 36 2:55 1 0.312 0.174 - 0.138 0.87 261.6 51.0 0.0 204.2 0.0 37 3:00 1.0 0.312 0.174 - 0.138 0.87 261.6 51.0 0.0 255.2 0.0 38 3:05 1.1 0.343 0.174 - 0.169 1.07 320.9 110.3 0.0 365.6 0.0 39 3:10 1.1 0.343 0.174 - 0.169 1.07 320.9 110.3 0.0 475.9 0.0 40 3:15 1.1 0.343 0.174 - 0.169 1.07 320.9 110.3 0.0 586.2 0.0 41 3:20 1.2 0.374 0.174 - 0.200 1.27 380.1 169.6 0.0 755.8 0.0 42 3:25 1.3 0.406 0.174 - 0.231 1.46 439.4 228.9 0.0 984.7 0.0 43 3:30 1.4 0.437 0.174 - 0.263 1.66 498.7 288.1 0.0 1272.8 0.0 44 3:35 1.4 0.437 0.174 - 0.263 1.66 498.7 288.1 0.0 1560.9 0.0 45 3:40 1.5 0.468 0.174 - 0.294 1.86 557.9 347.4 0.0 1908.3 0.0 46 3:45 1.5 0.468 0.174 - 0.294 1.86 557.9 347.4 0.0 2255.7 0.0 47 3:50 1.6 0.499 0.174 - 0.325 2.06 617.2 406.7 0.0 2662.4 0.0 48 3:55 1.6 0.499 0.174 - 0.325 2.06 617.2 406.7 0.0 3069.1 0.0 49 4:00 1.7 0.530 0.174 - 0.356 2.25 676.5 465.9 0.0 3535.0 0.0 50 4:05 1.8 0.562 0.174 - 0.387 2.45 735.8 525.2 0.0 4060.2 0.0 .51 4:10 1.9 0.593 0.174 - 0.419 2.65 795.0 584.5 0.0 4644.7 0.0 52 4:15 2.0 0.624 0.174 - 0.450 2.85 854.3 643.8 0.0 5288.5 0.0 53 4:20 2.1 0.655 0.174 - 0.481 3.05 913.6 703.0 0.0 5991.5 0.0 54 4:25 2.1 0.655 0.174 - 0.481 3.05 913.6 703.0 0.0 6694.5 0.0 55 4:30 2.2 0.686 0.174 - 0.512 3.24 972.8 762.3 0.0 7456.8 0.0 56 4:35 2.3 0.718 0.174 - 0.543 3.44 1032.1 821.6 0.0 8278.4 0.0 57 4:40 2.4 0.749 0.174 - 0.575 3.64 1091.4 880.8 0.0 9159.2 0.0 58 4:45 2.4 0.749 0.174 - 0.575 3.64 1091.4 880.8 0.0 10040.1 0.0 59 4:50 2.5 0.780 0.174 - 0.606 3.84 1150.6 940.1 0.0 10980.2 0.0 60 4:55 2.6 0.811 0.174 - 0.637 4.03 1209.9 999.4 0.0 11979.5 0.0 61 5:00 3.1 0.967 0.174 0.793 5.02 1506.3 1295.7 0.0 13275.3 0.0 62 5:05 3.6 1.123 0.174 0.949 6.01 1802.6 1592.1 0.0 14867.4 0.0 63 5:10 3.9 1.217 0.174 1.043 6.60 1980.4 1769.9 0.0 16637.3 0.0 64 5:15 4.2 1.310 0.174 1.136 7.19 2158.2 1947.7 0.0 18585.0 0.0 65 5:20 4.7 1.466 0.174 1.292 8.18 2454.6 2244.1 915.3 21744.3 0.0 66 5:25 5.6 1.747 0.174 1.573 9.96 2988.0 2777.5 1174.0 25695.8 0.0 67 5:30 1.9 0.593 0.174 0.419 2.65 795.0 584.5 259.1 26539.4 0.0 68 5:35 0.9 0.281 0.174 0.107 0.67 202.3 -8.2 11.8 26543.0 0.0 69 5:40 0.6 0.187 0.174 - 0.013 0.08 24.5 -186.0 0.0 26357.0 0.0 70 5:45 0.5 0.156 0.174 0.140 0.016 0.10 29.6 -180.9 0.0 26176.0 0.0 71 5:50 0.3 0.094 0.174 0.084 0.009 0.06 17.8 -192.8 0.0 25983.3 0.0 72 5:55 0.2 0.062 0.174 0.056 0.006 0.04 11.9 -198.7 0.0 25784.6 0.0 FLOODING TO LOT B &C 100 YEAR 24 -HOUR CHART UNIT TIME PERIOD 15 MINUTES 3-HOUR POINT RAIN FALL 4.8 INCHES RETENTION BASIN PERCOLATION 631.62 CF /15 MINS RET BAS CAPACITY 41835 CF ADJUSTED INFLITRATION RATE 0.174 IN /HR RUNOFF AREA I 6.28 ACRES LOW LOSS RATE 0.9. PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE IN /HR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF EFFECTIVE RETENTION OVERFLOW RECEIVED TOTAL BASIN VOLUME OVERFLOW UNITS H:MM PLATE - E5.9 IN /HR MAX IN /HR LOW IN /HR IN /HR CFS CF CF CF CF CF 1 0:00 0.2 0.038 0.308 0.035 0.004 0.02 21.9 -609.7 0.0 0.0 0.0 2 0:15 0.3 0.058 0.304 0.052 0.006 0.04 32.8 -598.8 0.0 0.0 0.0 3 0:30 0.3 0.058 0.301 0.052 0.006 0.04 32.8 -598.8 0.0 0.0 0.0 4 0:45 0.4 0.077 0.297 0.069 0.008 0.05 43.8 -587.9 0.0 0.0 0.0 5 1:00 0.3 0.058 0.294 0.052 0.006 0.04 32.8 -598.8 0.0 0.0 0.0 6 1:15 0.3 0.058 0.290 0.052 0.006 0.04 32.8 -598.8 0.0 0.0 0.0 7 1:30 0.3 0.058 0.287 0.052 0.006 0.04 32.8 -598.8 0.0 0.0 0.0 8 1:45 0.4 0.077 0.283 0.069 0.008 0.05 43.8 -587.9 0.0 0.0 0.0 9 2:00 0.4 0.077 0.280 0.069 0.008 0.05 43.8 -587.9 0.0 0.0 0.0 10 2:15 0.4 0.077 0.276 0.069 0.008 0.05 43.8 -587.9 0.0 0.0 0.0 11 2:30 0.5 0.096 0.273 0.086 0.010 0.06 54.7 -576.9 0.0 0.0 0.0 12 2:45 0.5 0.096 0.270 0.086 0.010 0.06 54.7 -576.9 0.0 0.0 0.0 13 3:00 0.5 0.096 0.266 0.086 0.010 0.06 54.7 -576.9 0.0 0.0 0.0 14 3:15 0.5 0.096 0.263 0.086 0.010 0.06 54.7 -576.9 0.0 0.0 0.0 15 3:30 0.5 0.096 0.260 0.086 0.010 0.06 54.7 -576.9 0.0 0.0 0.0 16 3:45 0.6 0.115 0.256 0.104 0.012 0.07 65.7 -566.0 0.0 0.0 0.0 17 4:00 0.6 0.115 0.253 0.104 0.012 0.07 65.7 -566.0 0.0 0.0 0.0 18 4:15 0.7 0.134 0.250 0.121 0.013 0.09 76.6 , -555.0 0.0 0.0 0.0 19 4:30 0.7 0.134 0.247 0.121 0.013 0.09 76.6 -555.0 0.0 0.0 0.0 20 4:45 0.8 0.154 0.244 0.138 0.015 0.10 87.5 -544.1 0.0 0.0 0.0 21 5:00 0.6 0.115 0.240 0.104 0.012 0.07 65.7 -566.0 0.0 0.0 0.0 22 5:15 0.7 0.134 0.237 0.121 0.013 0.09 76.6 -555.0 0.0 0.0 0.0 23 5:30 0.8 0.154 0.234 0.138 0.015 0.10 87.5 -544.1 0.0 0.0 0.0 24 5:45 0.8 0.154 0.231 0.138 0.015 0.10 87.5 -544.1 0.0 0.0 0.0 25 6:00 0.9 0.173 0.228 0.156 0.017 0.11 98.5 -533.1 0.0 0.0 0.0 26 6:15 0.9 0.173 0.225 0.156 0.017 0.11 98.5 -533.1 0.0 0.0 0.0 27 6:30 1.0 0.192 0.222 0.173 0.019 0.12 109.4 -522.2 0.0 0.0 0.0 28 6:45 1.0 0.192 0.219 0.173 0.019 0.12 109.4 -522.2 0.0 0.0 0.0 29 7:00 1.0 0.192 0.216 0.173 0.019 0.12 109.4 -522.2 0.0 0.0 0.0 30 7:15 1.1 0.211 0.213 0.190 0.021 0.13 120.4 -511.3 0.0 0.0 0.0 31 7:30 1.2 0.230 0.210 - 0.020 0.13 115.5 -516.1 0.0 0.0 0.0 32 7:45 1.3 0.250 0.207 0.042 0.27 241.4 -390.2 0.0 0.0 0.0 33 8:00 1.5 0.288 0.204 0.084 0.53 476.6 -155.0 0.0 0.0 0.0 34 8:15 1.5 0.288 0.202 0.086 0.55 492.9 -138.7 0.0 0.0 0.0 35 8:30 1.6 0.307 0.199 0.109 0.69 618.4 -13.2 0.0 0.0 0.0 36 8:45 1.7 0.326 0.196 - 0.131 0.83 743.8 112.2 0.0 112.2 0.0 37 9:00 1.9 0.365 0.193 - 0.172 1.09 978.4 346.8 0.0 459.0 0.0 38 9:15 2.0 0.384 0.190 0.194 1.23 1103.5 471.9 0.0 930.8 0.0 39 9:30 2.1 0.403 0.188 0.216 1.36 1228.4 596.8 0.0 1527.7 0.0 40 9:45 2.2 0.422 0.185 - 0.237 1.50 1353.2 721.6 0.0 2249.3 0.0 41 10:00 1.5 0.288 0.182 0.106 0.67 602.5 -29.1 0.0 2220.1 0.0 42 10:15 1.5 0.288 0.180 - 0.108 0.69 617.6 -14.1 0.0 2206.1 0.0 43 10:30 2.0 0.384 0.177 0.207 1.31 1179.6 548.0 0.0 2754.0 0.0 44 10:45 2.0 0.384 0.174 - 0.210 1.33 1194.3 562.7 0.0 3316.8 0.0 45 11:00 1.9 0.365 0.172 - 0.193 1.22 1099.5 467.9 0.0 3784.7 0.0 46 11:15 1.9 0.365 0.169 - 0.195 1.24 1114.0 482.4 0.0 4267.0 0.0 47 11:30 1.7 0.326 0.167 - 0.160 1.01 909.4 277.8 0.0 4544.9 0.0 48 11:45 1.8 0.346 0.164 - 0.181 1.15 1033.0 401.4 0.0 4946.2 0.0 49 12:00 2.5 0.480 0.162 - 0.318 2.01 1812.9 1181.3 0.0 6127.6 0.0 50 12:15 2.6 0.499 0.159 - 0.340 2.15 1936.2 1304.6 0.0 7432.1 0.0 51 12:30 2.8 0.538 0.157 - 0.381 2.41 2168.7 1537.1 0.0 8969.2 0.0 52 12:45 2.9 0.557 0.155 - 0.402 2.55 2291.6 1660.0 0.0 10629.2 0.0 53 13:00 3.4 0.653 0.152 - 0.500 3.17 2852.0 2220.4 0.0 12849.6 0.0 54 13:15 3.4 0.653 0.150 - 0.503 3.18 2865.2 2233.6 0.0 15083.1 0.0 55 13:30 2.3 0.442 0.148 - 0.294 1.86 1674.5 1042.9 0.0 16126.1 0.0 56 13:45 2.3 0.442 0.146 - 0.296 1.87 1687.4 1055.7 0.0 17181.8 0.0 57 14:00 2.7 0.518 0.143 - 0.375 2.38 2137.7 1506.1 482.3 19170.2 0.0 58 14:15 2.6 0.499 0.141 - 0.358 2.27 2040.7 1409.1 633.6 21212.9 0.0 59 14:30 2.6 0.499 0.139 - 0.360 2.28 2053.0 1421.4 638.7 23273.0 0.0 60 14:45 2.5 0.480 0.137 - 0.343 2.17 1955.7 1324.1 598.1 25195.2 0.0 61 15:00 2.4 0.461 0.135 - 0.326 2.06 1858.2 1226.6 557.5 26979.3 0.0 62 15:15 2.3 0.442 0.133 - 0.309 1.96 1760.6 1128.9 516.7 28625.0 0.0 63 15:30 1.9 0.365 0.131 - 0.234 1.48 1334.4 702.8 338.9 29666.7 0.0 64 15:45 1.9 0.365 0.129 - 0.236 1.50 1345.8 714.2 343.7 30724.6 0.0 65 16:00 0.4 0.077 0.127 0.069 0.008 0.05 43.8 -587.9 0.0 30136.7 0.0 66 16:15 0.4 0.077 0.125 0.069 0.008 0.05 43.8 -587.9 0.0 29548.9 0.0 67 16:30 0.3 0.058 0.123 0.052 0.006 0.04 32.8 -598.8 0.0 28950.1 0.0 68 16:45 0.3 0.058 0.121 0.052 0.006 0.04 32.8 -598.8 0.0 28351.3 0.0 69 17:00 0.5 0.096 0.119 0.086 0.010 0.06 54.7 -576.9 0.0 27774.4 0.0 70 17:15 0.5 0.096 0.117 0.086 0.010 0.06 54.7 -576.9 0.0 27197.5 0.0 71 17:30 0.5 0.096 0.116 0.086 0.010 0.06 54.7 -576.9 0.0 26620.6 0.0 72 17:45 0.4 0.077 0.114 0.069 0.008 0.05 43.8 -587.9 0.0 26032.7 0.0 73 18:00 0.4 0.077 0.112 0.069 0.008 0.05 43.8 -587.9 0.0 25444.9 0.0 74 18:15 0.4 0.077 0.111 0.069 0.008 0.05 43.8 -587.9 0.0 24857.0 0.0 75 18:30 0.3 0.058 0.109 0.052 0.006 0.04 32.8 -598.8 0.0 24258.2 0.0 76 18:45 0.2 0.038 0.107 0.035 0.004 0.02 21.9 -609.7 0.0 23648.5 0.0 77 19:00 0.3 0.058 0.106 0.052 0.006 0.04 32.8 -598.8 0.0 23049.7 0.0 78 19:15 0.4 0.077 0.104 0.069 0.008 0.05 43.8 -587.9 0.0 22461.8 0.0 79 19:30 0.3 0.058 0.103 0.052 0.006 0.04 32.8 -598.8 0.0 21863.0 0.0 80 19:45 0.2 0.038 0.102 0.035 0.004 0.02 21.9 -609.7 0.0 21253.3 0.0 81 20:00 0.3 0.058 0.100 0.052 0.006 0.04 32.8 -598.8 0.0 20654.5 0.0 82 20:15 0.3 0.058 0.099 0.052 0.006 0.04 32.8 -598.8 0.0 20055.7 0.0 83 20:30 0.3 0.058 0.098 0.052 0.006 0.04 32.8 -598.8 0.0 19456.9 0.0 84 20:45 0.2 0.038 0.097 0.035 0.004 0.02 21.9 -609.7 0.0 18847.2 0.0 85 21:00 0.3 0.058 0.095 0.052 0.006 0.04 32.8 -598.8 0.0 18248.4 0.0 86 21:15 0.2 0.038 0.094 0.035 0.004 0.02 21.9 -609.7 0.0 17638.7 0.0 87 21:30 0.3 0.058 0.093 0.052 .0.006 0.04 32.8 -598.8 0.0 17039.9 0.0 88 21:45 0.2 0.038 0.092 0.035 0.004 0.02 21.9 -609.7 0.0 16430.1 0.0 89 22:00 0.3 0.058 0.091 0.052 0.006 0.04 32.8 -598.8 0.0 15831.3 0.0 90 22:15 0.2 0.038 0.091 0.035 0.004 0.02 21.9 -609.7 0.0 15221.6 0.0 91 22:30 0.2 0.038 0.090 0.035 0.004 0.02 21.9 -609.7 0.0 14611.9 0.0 92 22:45 0.2 0.038 0.089 0.035 0.004 0.02 21.9 -609.7 0.0 14002.1 0.0 93 23:00 0.2 0.038 0.088 0.035 0.004 0.02 21.9 -609.7 0.0 13392.4 0.0 94 23:15 0.2 0.038 0.088 0.035 0.004 0.02 21.9 -609.7 0.0 12782.7 0.0 95 23:30 0.2 0.038 0.088 0.035 0.004 0.02 21.9 -609.7 0.0 12172.9 0.0 96 23:45 0.2 0.038 0.087 0.035 0.004 0.02 21.9 -609.7 0.0 11563.2 0.0 U 0 DETAIL OF LOTS B&C 0 TractNo.32279 Unit Hvdrot-raDh Report 10,440 A 6a4 4 7.50 67.9 24 a t Z 7.20 � 71• fi� 23 J am w.tt 59 agft. C, x V "K. to," aq.ft. 15 067.3 69, YA32' Li 40 465, 6&-q V. DETAIL OF LOT D P&D Consultants, Inc. 4 DUC Housing Partners. PAENGRU75754\Drainage/Basin Calc Report.doc RETENTION VOLUME IN LOT D 100 YEAR 3 -HOUR STORM 12000 10000 8000 L) 6000 4000 2000 Tract No. 32279 Unit Hydrograph Report 0 '`� 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 35000 30000 25000 20000 LL U 15000 10000 5000 0 TIME RETENTION VOLUME IN LOTS B &C 100 YEAR 3 -HOUR STORM 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O N M lq O 7 N M [T lq TIME m OVERFLOW o VOLUME RETAINED o RUNOFF RECEIVED cq OVERFLOW RECEIVED P&D Consultants, Inc. 5 DUC Housing Partners. PAENGR \175754\DrainageBasin Calc Report.doc Tract No. 32279 Unit Hydrograph Report CONCLUSION The unit hdrograph calculations are located on the following pages of this report. The results are summarized in the table below. MAXIMUM CF 3 -HOUR' 6 -HOUR 24 -HOUR LOT B &C 32743 26543 30742 LOT D 8360 8360 8360 TOTAL 1 41103 34903 39102 MAXIMUM CAPACITY 49871 1 49871 49871 PERCENT CAPACITY 82.4% 1 70.0% 78.4% The 100 -year, 3 -hour storm with a unit time of 5 minutes yielded the greatest volume of storm water at the retention basin. The results show that the proposed retention basins have been sized adequately to retain the entire volume of storm flow. P&D Consultants, Inc. 6 DUC Housing Partners. P:\ENGR \175754\Drainage/Basin Calc Report.doc �I i L RUNOFF INDEX NUMBERS OF HYDROLOGIC SOIL -COVER COMPLEXES FOR PERVIOUS AREAS -AMC II Quality of Soil Group Cover Type (3) Cover (2) A I B C D NATURAL COVERS - Barren 78 86 91 93 (Rockland, eroded and graded land) Chaparrel, Broadleaf Poor 53 70 80 85 (Manzonita, ceanothus and scrub oak) Fair 40 63 75 81 Good 31 57 71 78 Chaparrel, Narrowleaf Poor 71 82 88 91 (Chamise and redshank) Fair 55 72 81 86 Grass, Annual or Perennial Poor 67 78 86 89 Fair 50 69 79 84 ° Good 38 61 74 80 Meadows or Cienegas Poor 63 77 85 88 (Areas with seasonally high water table, Fair 51 70 80 84 principal vegetation is sod forming grass) Good 30 58 72 78 Open Brush Poor 62 76 84 88 (Soft wood shrubs - buckwheat, sage, etc.) Fair 46 66 77 83 Good 41 63 75 81 Woodland Poor 45 66 77 83 (Coniferous or broadleaf trees predominate. Fair 36 60 73 79 Canopy density is at least 50 percent) Good 28 55 70 77 Woodland, Grass Poor 57 73 82 86 (Coniferous or broadleaf trees with canopy Fair 44 65 77 82 density from 20 to 50 percent) Good 33 58 72 79 URBAN COVERS - Residential or Commercial Landscaping Good 32 56 69 75 (Lawn, shrubs, etc.) Turf Poor .58 74 83 87 (Irrigated and mowed grass) Fair 44 65 77 82 Good 33 58 72 79 AGRICULTURAL COVERS - Fallow 76` 85- 90 92 (Land plowed but not tilled or seeded) R C F C a W C D RUNOFF INDEX NUMBERS I FOR .. HYDROLOGY 1\/JANUAL PERVIOUS AREAS P.1 ATF F -6.1 (1 of 2) ACTUAL IMPERVIOUS COVER Recommended Value Land Use. (1) Range- Percent For Average Conditions- Percent(2 Natural or Agriculture 0 - 10 0 Single Family Residential: (3) 40,000 S. F. (1 Acre) Lots 10 - 25 20,000 S. F. (31 Acre).Lots 30 - 45 7,200 - 10,000 S. F. Lots 45 55 Multiple Family Residential: Condominiums 45 - 70 Apartments 65 - 90 Mobile Home Park 60 - 85 20 40 50 65 80 75 Commercial, Downtown 80 -100 90 Business or Industrial Notes: 1. Land use should be based on ultimate development of the watershed. Long range master plans for the County and incorporated cities should be reviewed to insure reasonable land use assumptions. 2. Recommended values are based on average conditions which may not apply to a particular study area. The percentage impervious may vary greatly even on comparable sized lots due to differences in dwelling size, improvements, etc. Landscape practices should also be considered as it is common in some areas to use ornamental grav- els underlain by impervious plastic materials in place of lawns and shrubs. A field investigation of a study area should always be made, and a review of aerial photos, where available may assist in estimat- ing the percentage of impervious cover in developed areas. 3. For typical horse ranch subdivisions increase imperv`ious� area 5 per- cent over the values recommended in the table above. RCFC 15 WCD HYDROLOGY MANUAL IMPERVIOUS COVER FOR DEVELOPED AREAS PI ATF F -6.3 r M M I tD II 1� N . u a C Sp 3 - HOUR RAINFALL STORM PATTERNS - 6 -HOUR STORM IN PERCENT 24 -HOUR STORM �.� TIME PERIOD 5 -MIN PER I00 10 -MIN PERIOD I5 -MIN 30 -MIN TIME 5 -MIN PERIOD PERIOD PERIOD PERIOD 10 -MIN 15 -MIN 30 -MIN TIME PERIOD PERIOD PER 100 PERIOD 5 -MIN PERIOD TIME PERIOD 15 -MIN PERI00 30 -MIN PERIOD 60 -MIN TIME PERIOD PERIOD 15 -MIN PERIOD D 1 1.3 2.6 3.T 8.5 I .5 1.1 I.T 3.6 ♦9 1.7 1.B 1 2 .2 •3 .5 •7 1.2 l.3 ♦9 50 2.5 2.6 2 1.3 1.1 2,6 3.3 ♦.8 10.0 2 S.l 13.9 3 ,6 .6 1.2 1.9 ♦.3 50 1.3 2.1 ♦.8 51 1.9 3 .3 .6 1.8 51 52 2.8 2.9 v 3 ♦ 1.5 3.3 ♦.9 17.♦ ♦ .6 l.♦ 2.2 4 52 1.♦ 2.♦ 5.3 53 2.0 2.1 ♦ 5 .♦ .3 .7 .B 2.1 2.8 53 3.♦ ` D 5 6 I.5 1.B 3.3 3.♦ 6.6 29.9 5 7.3 20.3 6 .6 .7 1.5 2.4 5.8 54 2.1 6 .3 I.0 1.0 2.9 3.8 5♦ 55 3.♦ 2.3 7 1.5 ♦.♦ 8.♦ 7 B .7 1.6 2.♦ 6.8 55 1.6 2.5 9.0 56 2.2 2.3 T B .3 .♦ 1.1 0.6 56 2.3 B 9 l.B 1.8 ♦.2 5.3 9.0 12.3 9 .7 .7 1.6 2.6 11.6 57 2.4 9 10 .♦ 1.3 1.5 6.3 8.2 57 58 2.7 2.6 10 1.5 5.1 17.6 10 11 .7 1.6 2.7 1♦.♦ SB 1.6 2.8 25.1 2.♦ 11 .♦ •5 1.3 7.0 59 2.5 11 12 1.6 1.8 6.♦ 5.9 16.1 ♦.2 12 .7 .8 59 1.7 3.0 ♦•♦ 60 2.5 2.6 12 13 •5 •5 1.6 1.8 7.3 10.8 60 61 2.5 2.♦ 13 1♦ 2.2 2.2 7.3 B.5 13 1♦ .8 .B 1.7 3.2 61 1.8 3.6 62 3•l 3.6 14 IS .5 2.0 2.1 11.4 10.♦ 62 2.3 ].9 15 16 2.2 2.0 1 ♦.l 14.1 15 16 .B .B 1.8 4 63 1.B ♦.7 6♦ 3.9 ♦ 2 16 •5 .6 2.5 3.0 8.5 1.♦ 63 6♦ 1.9 IT 2.6 3.8 17 .B 2.0 5.4 65 ♦•7 17 iB .6 .7 3.9 1.9 65 66 •♦ •♦ 1B 19 2.7 2•♦ 2.4 1B 19 .8 .B 2.0 6.2 66 2.1 6.9 67 5 6 1.9 19 •7 3.9 ♦.3 1.3 l.2 67: ,3 20 21 2.7 3.3 20 21 .B .8 2.2 7.5 68 2.5 10.6 69 .9 .6 20 21 22 •B •6 3.0 ♦.0 1.1 1.0 66 69 .3 .5 22 23 3.1 2.9 22 23 .8 .8 2.8 1 ♦.5 70 3.0 3.4 Ti .5 .3 23 2♦ •7 .8. .8 3.8 3.5 .9 •8 70 7] 72 ,5 .5 •• 24 3.0 24 25 .9 3.2 1.0 72 3.5 .2 25 .9 5.7 73 •♦ 25 26 3.1 4 26 .8 .9 3.9 26 27 .9 1.0 5.7 6.B 7♦ 75 •♦ •3 27 28 5.0 3.5 27 2B .9 .9 ♦,2 4.5 2B 29 1.0 1.0 ♦.6 5.3 76 77 .2 .3 29 30 6.8 7.3 29 30 .9 .9 ♦.8 5.1 30 31 1.1 1.2 5.1 ♦•7 - 78 79 .♦ •3 D 31 32 8.2 5.9 31 32 .9 .9 6.7 8•l 32 33 1.3 1.5 3.8 .B BO B1 •2 •3 Z . 33 3♦ 2.0 1.8 33 3♦ 1.0 1.0 10.3 2.8 34 35 1.5 1.6 .6 1.0 B2 83 •3 •3 35 36 1.B 35 36 1.0 1.0 1.1 .5 36 1.7 .9 B♦ .2 D .6 37 1.0 37 38 1.9 2.0 .8 .5 BS B6 .3 .2 r 39 1.1 39 2.1 •7 87 .3 T V r 40 1.l 40 4 2.2 1.5 .5 .5 B11 09 .2' .3 rn ♦1 ♦2 1.2 1.3 ♦2 1.5 .5 90 .2. �1 04 2.0 .5 92 •2 ^ IA ♦♦ 1 ♦ ♦5 46 1.9 1.9 .5 .♦ 93 94 •2 .2 1 ', Z K ♦6 1.5 ♦7 ♦8 1.7 1.B •♦ 95 q6 •2 .2 ♦8 1.6 Z NOTES: I. 3 and 6 -hour patterns based on the Indio area thunderstorm of September 24,1939. 2. 24 -hour patterns based on the general storm of March 2 a 3,1938. .1 .1 � I Department of Agriculture has investigated the hydrologic characteristics of soils as related to runoff ,potential, and has developed a system use- ful to the District to classify soils into four hydrologic soils groups as follows: Group A - Low runoff potential. Soils having high infiltration rates even when thoroughly wetted and consisting chiefly of deep, well to excessively drained sands or gravels. These soils have a high rate of water transmission. Group B - 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. ' Group C - Soils having slow infiltration rates when thoroughly wetted and consisting chiefly of soils with a layer that impedes downward movement of water, or soils with moderately fine to ' fine texture. These soils have a slow rate of water trans- mission. Group D - High runoff potential. Soils having very slow infiltration rates when thoroughly wetted and consisting chiefly of clay soils with a high swelling potential, soils with a permanent high water table, soils with a claypan or clay layer at or near the surface, and shallow soils over nearly impervious material. These soils have a very slow rate of water trans- mission. In some cases a dual soil designation such as "B -C" has been assigned ' to an area. This indicates the infiltration characteristics are too vari- able either geographically or with time, to assign the soil to a single ' classification. In such cases the more conservative value is recommended ' for design hydrology. The SCS and U. S. Forest Service (USFS) have mapped soil types and � I assigned hydrologic soils classifications in many areas of the District.,,,,,, Using this information the District has compiled generalized hydrologic soils classification maps. These maps are shown on Figures C =1.al through C -1.66. In areas which have not yet been mapped, SCS or USFS personnel may be able to supply generalized soils information. The District will C -2 I i p II "w DRAINAGE REPORT . TRACT 32279 LA QUINTA, CALIFORNIA October 2005 Final PREPARED FOR: DUC Housing Partners 14107 Winchester Blvd.,. Suite H Los Gatos, CA. 95032 PREPARED BY: P &D Consultants, INC. 8954 Rio San Diego Drive, Suite 610 San Diego, California 92108 (619) 291 -1475 QF E S e.Y � W a No. 44016 '" m Eq. 6/30/07 � ®F CA17 ��� . Paul R. KIne RCE 44016 Registration Expires 06/30/07 Prepared By: CFH .. Drainage Report For Tract 32279 Table of Contents Summary Drainage Plan Methodology Existing Drainage Exhibit Tributary Areas Exhibit Tract 32279 Hydrology Results Hydrology Exhibit Tract 32279 Retention Basin Basin Capacity Hydraulic Tailwater Flood Volumes Tract 33336 Retention Basin (Interim Calculations) Overview Basin Capacity Hydraulic Tailwater Flood Volumes Extended Tributary Analysis Appendices Hydrology Calculations (10 and 100 year) A HGL Exhibits (Interim for Tract'33336) B Unit Hydrographs and Plates (Tract 32279 and Tract 33336) C Leach Line Calculations D * * * Special Note * ** All interim calculations due to the assumed improvements of tract 33336 will be revisited in a final engineering drainage report submitted for tract 33336 to confirm acceptability. P&D Consultants, Inc. DUC Housing Partners. Drainage Report Tract No. 32279 fl Summary Drainage Plan The purpose of this study is to analyze the proposed hydrologic conditions of the developed project site. Tract 32279 is located on the North side of Avenue 58, approximately 0.4 mi West of Madison Street in the City of La Quinta, Riverside County, California. The project proposes to develop approximately 9.71 acres for residential (Low Density) use. The project site is surrounded by an existing perimeter wall that follows the boundary line to the west and north of the tract. Runoff from the site sheet flows southerly so that the drainage boundary follows the property line to the east. There is no runoff from offsite areas that naturally flows onto the property from offsite areas. All surface runoff from the project site eventually flows into Avenue 58 where it travels 100 feet easterly to an existing low point. A local depression within the street frontage of tract 33336 ponds with water during storm events then overtops Avenue 58 and continues south. The proposed onsite storm drain system consists of an onsite and offsite storm drain systems. Both tract 32279 and tract 33336 are hydraulically responsible for both their onsite runoff and the offsite runoff generated by their public street frontage. The two retention basins analyzed in this report will be sized to contain the entire flood volume generated by this tributary area. ' Methodology This report follows the guidelines and procedures outlined in the Hydrology Manual published by the Riverside County Flood Control and Water Conservation District. The peak flow rates have been calculated using the rational method. The various plates ' needed for the rational method have been included in the Appendix. This report makes reference to the Federal Highway Administration H.E.C. 22 (2nd edition, dated August 2001) titled "Urban Drainage Design Manual ". All of the equations used in this report are drawn from chapter 4 which covers pavement drainage. Interception capacities of inlets are calculated using the Weir equation for flows less than ' the top of curb and the Orifice equation for flows above the top of curb. All inlets are per the City of La Quinta Std. Dwg. No. 300, Curb Inlet Catch Basin No. 1. ' Hydraulic calculations were done using the computer program StormCAD. The standard method was used for calculation headloss through junction structures. A tailwater elevation was specified for the outfall as described herein. P&D Consultants, Inc. DUC Housing Partners. Drainage Report Tract No. 32279 i ( I I - - - -` -- �Y6a E76S - � _� S60 I • rii� .\ .r - --.` i i \ � �= `fT(l =�\`' 969 �jr ? m co7 �p --� I e t. � 1 \ \I\ O TED FJ \ \ \\ \ Q -919 2Y9 - -P\ \ 2 / / ■ 21)9 1179 ow cn /. \2 \�\ ■ INS b 7M 1 6 I ato cn uj \\)-- X59►-__-- -- \ � \ -�- (.i - - - - -- o Elpg ►yg ` /�/ - SB° �I ( ' 629 AR TED _J ; -� ` // ■ / / 1 \ -\ �- © 5'99 I E799 ' II, CL9 it *vz I 74 \/ n99 I \ \II Lr J , II 59 / ! j I I✓ . I ----- -- 79 co 9 6Y9 � L'L9 O U uj / 1 1 I I I 1 \ erg __ i li :' �, ►g9 1 11 M Lr9 ■ rL9 LLJ ' !' / > I 99 I E799 V I I I L769 � r89 E7E ■ © 1�w \ 9•!9 aL9 O r17L ILA S)S Lr9 r I 9'!L O iI N99 S CO .V9 J >CN O L ,•- PL ►2 I ►� _"o 9'll \ \ IgL , v ZUN ( t Z9 n99 YL9 0 aa9 -� \/ „a, - - -- I69 f99 C) Old O W k Ed CO 6'69 r° *mw■■ \ S _� ►YL 4�V � ■ ■ 917L / � - 1"o --�-__� ` \ = ` � N � m 26� . � ||/N ---� || | |N 27| N | | | |0 28 | ||| | |Q N l /| | | N 29| N 30 . | '/ || m \ \ � \ ` \ ` � o � � w o 12 « m x ^ / orF « « ^ 3 2 ---`--- , mm ----------------------------------------------- RETENTION BASIN ����� 0��� �� o� � �`��m�»�� ����� � ��mm������� J 1 �J [l Hydrology Calculations on the following pages are for the 10 and 100 year storm events. Their results are summarized in the tables below. 10 Year Storm Event Basin Tc Qp E Qb V y Al 16.8 4.8 4.7 0.0 1.9 0.31 B1 16.8 4.8 4.8 0.0 1.9 0.31 A2 14.8 3.4 3.4 - 1.7 0.27 B2 14.8 3.2 3.2 - 1.7 0.27 C1 8.0 1.2 0.9 0.3 1.3 0.30 C2 8.0 2.9 2.9 - 1.6 0.40 100 Year Storm Event Basin Tc Qp Qi Qb V y Al 16.8 8.6 7.5 1.1 2.2 0.38 B1 16.8 8.7 7.6 1.1 2.2 0.38 A2 14.8 7.1 7.1 - 2.1 0.36 B2 14.8 6.7 6.7 - 2.1 0.35 C1 8.0 1.9 1.2 0.8 1.4 0.35 C2 8.0 4.8 4.8 - 1.8 0.45 Tc - Time to concentration (minutes) Qp - Peak runoff rate (cfs) Qi - Flow intercepted by storm drain system (cfs) Qb - Flow bypassed downstream (cfs) V - Peak velocity of flow in street (fps) y - Peak Depth of flow at flowline (ft) ' As required: Depth of flow less than TC for 10 year storm event - Yes Depth of flow within street R/W for 100 year storm event -Yes Velocity (V) x Depth (y) < 6 - Yes ' All inlets have been sized to accept the calculated peak flow. For inlets in sag conditions, depth of approaching gutter flow has been calculated using Manning's equation. However ponding will occur until the water head depth gives an inlet capacity equal to the peak discharge. These are the depths shown in the charts above for basins A2,B2 and C2 where inlets are in sag conditions. u P&D Consultants, Inc. DUC Housing Partners. Drainage Report Tract No. 32279 i C N , I ti I I r I1�1 I - - - ------ - - - - -� i f966Z xz - - - _� _ HYDROLOGY BASINS rc-� T013% AwECf0m 10 YEAR STORM EVENT AND 100 YEAR STORM EVENT 100' 0' 100' P &D CONSULTANTS PEAK FLOW RATES 8954 RIO SAN DIEGO DRIVE, SUITE 610 GRAPHIC SCALE: 1 " =100'. SAN DIEGO, CALIFORNIA 92108 T 619.291.1475 F 619.291.1476 WWW.TCB.AECOM.COM f] i Tract 32279 Retention Basin Basin Capacity The volume of the retention basin for tract 32279 is calculated in parts by taking average sectional areas over the depth of the basin. Sectional areas at one foot depth intervals are calculated using AutoCAD and are shown in the table below. The five foot elevation of the retention basin is designed at V below the nearest street flow line of 459.0± (CB #8). rThe total capacity of the retention basin is approximately 62,850 cubic feet with a flood depth of 5 feet and is calculated as follows. V=( E A. (i =o—�d> + E A 2 Section Area at Incremental Depths water d =5, maximum capacity). Bottom 1' 2' 3' 4' 5' 7,980 9,880 11,620 13,420 15,310 17,260 ' Elevation ( +453.0) ( +454.0) ( +455.0) ( +456.0) ( +457.0) Capacity 0 8,930 19,680 32,200 46,565 ( +458.0) 62,850 (Note: the regression curve for data is y = 922x2 + 7938x, with R2 2z 1) rThe total capacity of the retention basin is approximately 62,850 cubic feet with a flood depth of 5 feet and is calculated as follows. V=( E A. (i =o—�d> + E A 2 ' To be conservative, the maximum Tc of 16.8 minutes will be used. As assumed by the Rational Method, flow increases linearly from 0 to Qp (33.0 cfs)over the duration Tc by: V @ Tc = %2(Qp•Tc) V @ Tc = %2(33.0 cfs • 16.8 min)(60 sec / 1 min) This gives 16,600 cf of flood water contained in the retention basin at the time of peak discharge. Therefore the depth of water, or tail water elevation, to be used in hydraulic ' grade line calculation can be approximated as 1.8 feet using the table above (or regression P&D Consultants, Inc. DUC Housing Partners. Drainage Report Tract No. 32279 Where Ai is the section area at depth i and d is the basin depth (in the case of five feet of water d =5, maximum capacity). ' Hydraulic Tailwater In order to accurately size the pipes based on peak flow rates, the volume of water retained at the time of concentration for the peak flow needs to be calculated. Basin Tc Q Al 16.8 8.6 A2 14.8 7.1 B1 16.8 8.7 B2 14.8 6.7 C1 8 1.9 (Note: Basin C2 is not tributary to the retention basin in tract 32279) ' To be conservative, the maximum Tc of 16.8 minutes will be used. As assumed by the Rational Method, flow increases linearly from 0 to Qp (33.0 cfs)over the duration Tc by: V @ Tc = %2(Qp•Tc) V @ Tc = %2(33.0 cfs • 16.8 min)(60 sec / 1 min) This gives 16,600 cf of flood water contained in the retention basin at the time of peak discharge. Therefore the depth of water, or tail water elevation, to be used in hydraulic ' grade line calculation can be approximated as 1.8 feet using the table above (or regression P&D Consultants, Inc. DUC Housing Partners. Drainage Report Tract No. 32279 curve). Flood Volumes Unit hydrographs for the 100 -year, 3 -hour, 6 -hour and 24 -hour storm events have been developed for tract 32279. Tributary areas for this analysis include the entire onsite area as well as the offsite street frontage to the center line of Avenue 58 as shown in the accompanying exhibit. Based on percolation test results, a conservative zero infiltration velocity will be assumed in the retention basin throughout the storm event. Results from the hydrographs are summarized in the table and chart below. 100 Year Event 3 -Hour 6 -Hour 24 -Hour Maximum Volume 48604 42630 51162 Percent Capacity 77% 68% 81% (Note: the percent capacity is percent of available volume, 62,850 cf as determined) 100 Year Storm Event 24 -Hour 60000 5.0 4.5 50000 4.0 40000 3.5 Depth 3.0 � m 3 30000 - 2.5 a > Volume 2.0 20000 1.5 10000 1.0 0.5 0 0.0 0:00 2:30 5:00 7:30 10:00 12:30 15:00 17:30 20:00 22:30 Time (Note: y = 4.2' max) The results show that the retention basin for tract 32279 has been oversized and may accommodate additional flood volumes from offsite tributaries further upstream, west along Avenue 58. P&D Consultants, Inc. DUC Housing Partners. Drainage Report Tract No. 32279. Ire Tract 33336 Retention Basin (Interim Calculations) Overview This report includes interim calculations for proposed retention basin for tract 33336. It is reasonable to assume that the development of tract 33336, .namely the increase in impervious surfaces, will result in a greater volume of flood water runoff. Therefore, the analysis herein assumes the future developed conditions and therefore suffices for the interim undeveloped conditions. Due to the large similarities between the proposed conditions of tract 32279 and 33336, the same general parameters will be used (i.e. percent impervious, point rainfall ect.). Basin Capacity The volume of the retention basin for tract 33336 is calculated in parts by taking average sectional areas over the depth of the basin. Sectional areas at one foot depth intervals are calculated using AutoCAD and are shown in the table below. The five foot elevation of the retention basin is designed at V below the nearest street flow line of 4574± (CB #5). Section Area at Incremental Depths Bottom 1' 2' 3' 4' 5' 7,380 8,590 9,900 11,350 12,890 14,460 Elevation ( +452.4) ( +453.4) ( +454.4) ( +455.4) ( +456.4) ( +457.4) Capacity 0 7,985 17,230 27,855 39,975 53,650 (Note: the regression curve for data is y = 739x2 + 6969x, with R2 = 1) The total capacity of the retention basin is approximately 53,650 cubic feet with a flood depth of 5 feet and is calculated as follows. V = ( E Ai (i =o-+d) + E A (i= 1 —>d -1) V2 Where Ai is the section area at depth i and d is the basin depth (in the case of five feet of water d =5, maximum capacity). Hydraulic Tailwater For interim calculations it is reasonable to assume the same volume of water will accumulate in the retention basin for tract 33336 as did in the retention basin for tract 32279. Hydraulic gradelines, pipe sizes and inlet capacities are calculated assuming the same peak runoff rates in the pipes computed for tract 32279 under similar conditions for a smaller drainage area and is therefore a safe conservative calculation. All interim calculations will be revisited in a final engineering drainage report submitted for tract 33336. A volume of 16,600 cf of water translates to a depth of 2.0 feet in the smaller retention basin for tract 33336. P&D Consultants, Inc. DUC Housing Partners. Drainage Report Tract No. 32279 Flood Volumes Unit hydrographs for the 100 -year, 3 -hour, 6 -hour and 24 -hour storm events have been developed for tract 33336. Tributary areas for this analysis include the entire onsite area as well as the offsite street frontage to.the center line of Avenue 58 as shown in the accompanying exhibit. Based on percolation test results, a conservative zero infiltration velocity will be assumed in the retention basin throughout the storm event. Results from the hydrographs are summarized in the table and chart below. 100 Year Event 3 -Hour 6 -Hour 24 -Hour Maximum Volume 48604 42630 51162 Percent Capacity 91% 79% 95% (Note: the percent capacity is percent of available volume, 53,650 cf as determined) 100 Year Storm Event 24 -Hour 60000 5.0 4.5 50000 . 40000 3.5 Depth::: 3.0 m E 30000 2.5 a o ° > Volume 2.0 20000 1.5 10000 — 1.0 0.5 0 0.0 0:00 2:30 5:00 7:30 10:00 12:30 15:00 17:30 20:00 22:30 Time (Note: y = 4.8' max) The results show that the retention basin for tract 33336 has been slightly oversized and may accommodate additional flood volumes from offsite tributaries further upstream, east and west along Avenue 58. P&D Consultants, Inc. DUC Housing Partners. Drainage Report Tract No. 32279 h- I �1 1 u 1 Extended Tributary Analysis The city of La Quinta requires that all new developments account for and pick up all offsite runoff along their public street frontage. However it has become apparent that some existing improvements west of tract 32279 do not meet this requirement and actually allow runoff to flow onto Avenue 58, contributing additional runoff that is not accounted for in the design herein. Exhibits for the Stone Creek development (Tract 30834) just east of tract 32279 are included in the appendix. These exhibits show a likely tributary flow during storm events coming south along Coral Mountain Court. The following calculations show the amount of additional tributary area basin could possibly hold under the 1 foot of freeboard. Amount of excess capacity from oversized basin: 62,850 — 51,162 = 11,688 cf Use V = P•C•A (P = P24 = 5.00 in, to match 24hr peak flood precipitation) �'s•Kr Scenario 1: Assume tributary from Avenue 58 C4 t Half width = 54', Use C = 0.80 V = P•C•A 11,688 cf= (5.00 in)•(lft/12 in)•(0.80)(54 ft • x) x�650ft Scenario 2: Assume tributary from Coral Mountain Court Half width = 27.5', Use C = 0.80 V = P•C•A 11,688 cf= (5.00 in)•(lft/12 in)•(0.80)(27.5 ft • x) x z 1,275 ft These calculations show that although it is not part of the design requirements of tract 32279 to accommodate for any additional flood volumes, there is some extra storage available. The retention basin in tract 32279 could potentially contain runoff volumes from an additional 650 feet of Avenue 58 west, 1,275 feet of Coral Mountain Court or an equivalent combination thereof. Interim calculations for the retention basin for tract 33336 show that it may also have been oversized and could potentially hold more flood volumes than required. However it is more appropriate at this point to hold that extra capacity for onsite contingency at this interim stage in design calculations. ' P&D Consultants, Inc. DUC Housing Partners. Drainage Report Tract No. 32279 1 1 it L V xipuaddV 1 f 1 J Basin area Length of watercourse Difference in elevation Longitudinal slope Time to concentration Rainfall intensity Infiltration rate for pervious areas Percent impervious Percent pervious Runoff coefficient Peak runoff rate A ac = La ft = AE ft = S ft/ft = Tc min = I in /hr = Fp in /hr = Ai % _ Ap % _ C % _ Qp cfs = Approach velocity V fps = Approach depth at flowline y ft = Width of gutter depression W ft = Cross slope street Sx ft = Cross slope of gutter depression Sw ft = Spread of flow T ft = Ratio of frontal flow to total flow Eo = Effective cross slope Se _ English units constant Ku = Manning's n n = Total length required Lt ft = Length of curb opening L ft = Inlet interception efficiency E _ Intercepted flow Qi cfs = Bypassed flow Qb cfs = Bypass velocity V fps = Bypass depth at flowline y ft = Basin Al 10 Year 100 Yeai 2.84 2.84 850 850 4.25 4.25 0.005 0.005 16.8 16.8 2.15 3.65 0.51 0.51 45 45 55 55 0.78 0.83 4.8 8.6 CB #1 (flow -by) 10 Year 100 Yeai 1.9 2.2 0.31 0.38 4.0 4.0 0.020 0.020 0.083 0.083 15.5 19.0 0.55 0.47 0.07 0.06 0.6 0.6 0.015 0.015 15.0 20.6 14.0 14.0 0.99 0.87 4.7 7.5 0.0 1.1 - 1.3 - 0.17 Plate D -3 Plate D -4.7 Plate E -6.2 Plate E -6.3 Page D -3 Q =C+A Chart Chart T =y /Sx (appx.) Eo= 1- (1 -W!T) ^2.67 Se= Sx +Sw. Eo Lt= Ku-Q^.42 _SA .3.(1- /(n.Se)) ^.6 E= 1- (1- L /Lt) ^1.8 Qi =Qp.E Qb =Qp -Qi Chart Chart Basin area Length of watercourse Difference in elevation Longitudinal slope Time to concentration Rainfall intensity Infiltration rate for pervious areas Percent impervious Percent pervious Runoff coefficient Peak runoff rate Approach velocity Approach depth at flowline Width of gutter depression Cross slope street Cross slope of gutter depression Spread of flow Ratio of frontal flow to total flow Effective cross slope English units constant Manning's n Total length required Length of curb opening Inlet interception efficiency Intercepted flow Bypassed flow Bypass velocity Bypass depth at flowline A ac = La ft = DE ft = S ft/ft - Tc min = I in /hr = Fp in /hr = AI % _ Ap % _ C % _ Qp cfs = V fps y ft W ft Sx ft Sw ft T ft . Eo Se Ku n Lt ft L ft E Qi cfs Qb cfs V fps y ft Basin B1 10 Year 100 Yeai 2.88 2.88 850 850 4.25 4.25 0.005 0.005 16.8 16.8 2.15 3.65 0.51 0.51 45 45 55 55 0.78 0.83 4.8 8.7 CB #2 (flow -by) 10 Year 100 Yeai 1.9 2.2 0.31 0.38 4.0 4.0 0.020 0.020 0.083 0.083 15.5 19.0 0.55 0.47 0.07 0.06 0.6 0.6 0.015 0.015 15.1 20.7 14.0 14.0 0.99 0.87 4.8 7.6 0.0 1.1 - 1.3 - 0.17 Plate D -3 Plate D -4.7 Plate E -6.2 Plate E -6.3 Page D -3 Q =C +A Chart Chart T =y /Sx (appx.) Eo= 1- (1 -W/T) ^2.67 Se= Sx +Sw- Eo Lt= Ku.Q^.42 _SA .3.(1- /(n.Se)) ^.6 E= 1- (1- L /Lt) ^1.8 Qi =Qp-E Qb =Qp -Qi Chart Chart Basin area Length of watercourse Difference in elevation Longitudinal slope Time to concentration Rainfall intensity Infiltration rate for pervious areas Percent impervious Percent pervious Runoff coefficient Peak runoff rate A ac = La ft = AE ft = S ft/ft - Tc min - I in /hr = Fp in /hr = AI % _ Ap % _ C % _ Qp cfs = Approach velocity V fps = Approach depth at flowline y ft = Assumed ponding depth y ft = Weir coefficient Cw = Length of curb opening L ft = Lateral width of depression W ft = Intercepted flow capacity Qi cfs = Basin A2 10 Year 100 Yeai 1.82 1.82 600 600 3.00 3.00 0.005 0.005 14.8 14.8 2.35 3.95 0.51 0.51 45 45 55 55 0.79 0.84 3.4 7.1 CB #4 (sag) 10 Year 100 Yeai 1.7 2.1 0.27 0.36 0.27 0.45 2.30. 2.30 4.0 4.0 4.0 4.0 3.6 7.8 Plate D -3 Plate D -4.7 Plate E -6.2 Plate E -6.3 Page D -3 Include bypass flow from Al Qi= Cw•(L-1.8 *W).y ^1.5 Basin area Length of watercourse Difference in elevation Longitudinal slope Time to concentration Rainfall intensity Infiltration rate for pervious areas Percent impervious Percent pervious Runoff coefficient Peak runoff rate A ac = La ft = DE ft = S ft/ft = Tc min = I in /hr = Fp in /hr = Ai % _ Ap % _ C % _ Qp cfs = Approach velocity V fps = Approach depth at flowline y ft = Assumed ponding depth y ft = Weir coefficient Cw = Length of curb opening L ft = Lateral width of depression W ft = Intercepted flow capacity Qi cfs = Basin B2 10 Year 100 Yeai 1.68 1.68 600 600 3.00 3.00 0.005 0.005 14.8 14.8 2.35 3.95 0.51 0.51 45 45 55 55 0.79 0.84 3.2 6.7 CB #4 (sag) 10 Year 100 Yeai 1.7 2.1 0.27 0.35 0.27 0.45 2.30 2.30 4.0 4.0 4.0 4.0 3.6 7.8 Plate D -3 Plate D -4.7 Plate E -6.2 Plate E -6.3 Page D -3 Include bypass flow from Bi Qi= Cw.(L- 1.8'W ).y ^1.5 Basin area Length of watercourse Difference in elevation Longitudinal slope Time to concentration Rainfall intensity Infiltration rate for pervious areas Percent impervious Percent pervious Runoff coefficient Peak runoff rate A ac = La ft = AE ft = S ft/ft - Tc min = I in /hr = Fp in /hr = Ai % _ Ap % _ C % _ Qp cfs = Approach velocity V fps = Approach depth at flowline y ft = Width of gutter depression W ft = Cross slope street Sx ft = Cross slope of gutter depression Sw ft = Spread of flow T ft = Ratio of frontal flow to total flow Eo = Effective cross slope Se = English units constant Ku = Manning's n n = Total length required Lt ft = Length of curb opening L ft = Inlet interception efficiency E _ Intercepted flow Qi cfs = Bypassed flow Qb cfs = Bypass velocity V fps = Bypass depth at flowline y ft = Basin C1 10 Year 100 Yeai 0.38 0.38 250 250 1.00 1.00 0.004 0.004 8.0 8.0 3.50 5.75 0.51 0.61 90 90 10 10 0.89 0.89 1.2 1.9 Plate D -3 Plate D -4.7 Plate E -6.2 Plate E -6.3 Page D -3 Q =C+A CB #8 (flow -by) 4.0 10 Year 100 Year 0.60 1.3 1.4 Chart 0.30 0.35 Chart 4.0 4.0 1.2 0.020 0.020 0.28 0.083 0.083 15.0 17.5 T =y /Sx (appx.) 0.56 0.50 Eo= 1- (1 -W/T) ^2.67 0.07 0.06 Se= Sx +Sw.Eo 0.6 0.6 0.015 0.015 7.7 10.0 Lt= Ku.Q ^.42 S ^.3•(1- /(n-Se)) ^.6 4.0 4.0 0.73 0.60 E= 1- (1- L /Lt) ^1.8 0.9 1.2 Qi =Qp. E 0.3 0.8 Qb =Qp -Qi 1.0 1.2 Chart 0.20 0.28 Chart Basin area Length of watercourse Difference in elevation Longitudinal slope Time to concentration Rainfall intensity Infiltration rate for pervious areas Percent impervious Percent pervious Runoff coefficient Peak runoff rate A ac = La ft = AE ft = S ft/ft = Tc min = I in /hr = Fp in /hr = AI % _ Ap % _ C % _ Qp cfs = Approach velocity V fps = Approach depth at flowline y ft = Assumed ponding depth y ft = Weir coefficient Cw = Length of curb opening L ft = Lateral width of depression W ft = Intercepted flow capacity Qi cfs = Basin C2 Iv rear IVV rear 0.94 0.94 250 250 1.00 1.00 0.004 0.004 8.0 8.0 . 3.50 5.75 0.51 0.51 90 90 10 10 0.89 0.89 2.9 4.8 CB #5 (sag) 10 Year 100 Yeai 1.6 1.8 0.40 0.45 0.40 0.45 2.30 2.30 4.0 4.0 4.0 4.0 6.5 7.8 Plate D -3 Plate D -4.7 Plate E -6.2 Plate E -6.3 Page D -3 Q =C-I-A Qi= Cw.(L-1.8'W)•y ^1.5 ~ ° P&D Consultants 8S54 Rio San Diego Dr. Suite 610 San Diego, CA 92108 (619) 291-1475 (519)2S1'147SFax By Date Client Sheet No. Of ��� Checked Date Job Job No. 0"I I 7.00 y Q fq c m 5.00 43M 1.00 Compound- Gutter (on Street Slopes Shown) 10.0% _ r___ r.__ r___ r___ r___ r___ r___ r___ r ___r___-___-___-___i.._�.__ .__. . _ ..___r ___r ___r___r___r___r___ r___r___r. __r___r___{ }___ }___T __i___i___i___ -___ i___ i___ i___ .0% ' =----------- ----------- --------------- -- -- -- -- •• 20% . ___ _.__. ..__A___ ___ ___ ___ . __ ___-___ _ 1 1 ; i 1 ' .- -•-- •--- • - - - - -- -- -- -- -- -- -- -- ----- -- - -- -- ----- -------------------------------- -- -- -- 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 Depth of Flow (ft) Compound- Gutter (on Street Slopes Shown) 10.0% 5.0% • - - - -- - - - - - - - - - - - - - - - ; - - - ; - - - - - ; 22.00 ----------- r = r , , , _ _ , , , , , , } --- r___ r___ r --- r --- r --- r___r___r --- r___r___r___r___ }_ r --- r___r. __r___ __i___�___�___i___i___i___ i i i N , .0% 17.00 ° i ----------------------- V- .�. L --- `---`------- `--------------- `---`---`--- `--- '---`---`---`-- -`---t---`-- --- - -- --- -- --- --- --- - --- - --- - -- --- - 12.00 . ............................... -- - - -; - -. ••.--- .- - -..- -- •. - -- - -- -- -- - -- ------ --------- ' y -- -- -- - -- -- -- -- - ...... 1.0% -- -- - -- -------- -------------- 7.00 . - -- .--- ....... -- = _ _ :___' 5% ......... -- -- -- 2.00 , 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 Depth of Flow (ft) P&D Consultants 8954 Rio San Diego Dr. Suite 610 WIN San Diego, CA 92108 (619) 291-1475 (619) 291-1476 Fax By Date Client Sheet No. Of Checked Date Job Job No. 4 71 T_ J� 4 _A- I A _T T" —4 -4- — L LQ T11, 7 1 L OR J T-rt- -4 T_ 5.00 4.00 1/1 CL -' 3.00 u O W N 11 V- Gutter (0.5 %,0.7 %,1.0 %,1.4 %,2.0 %) -- - -- 2 - -- --- h ' ` r i-- ; ; -------- --- +- --+--- 0. i--- r.............. -___ , r __r___r --- r --- r___r ___ +___ _____ ___ ____ _ _ ......... ___ ___ ___ __ ___ ___ __ ___ ___ ___ -, ; ; ; _ _ _ _ ; ; ; " " ; . - - - - - - - - - - - - - - 1.00 0.20 16.00 14.00 12.00 N V 10.00 !0 8.00 N • 11 4.00 0.25 0.30 0.35 0.40 0.45 0.50 Depth of Flow (ft) V- Gutter (0.5 %,0.7 %,1.0 %,1.4 %,2.0 %) 0.55 _ 2 0% o - 5% r--- r --- r --- r --- r --- � r__ ---T---' ___r___� r__ --- + ___ }___r --- r___r___r___r___r___ ________ ____ ____ ____ ________ ____ ___ ___ -------- _ --------- ----------------------------------------- _r___ +_ r --- r___ __ i___ r___ r___ r --- r --- r___r___r___r --- r___r___r___r ___r___r___r___ -- - - - - - - - - - - - - - - - - - - - - - - 0 • - - - - - - - - -- - - - - - - - --•---•-------•--- o -- - • - - - • - - - - - - - - - - • - - 11 — 1 1 0.25 0.30 0.35 0.40 0.45 0.50 0.55 Depth of Flow (ft) U, 3 3.5 3. rn W 2.5 U Z Z Z 2 f- 2.5 2 W J lQ 1.5 Q 1.5 Lj 1.' .5 ol- •7 .5 D A 0 2 5 .10 25 50 100 RETURN PERIOD IN YEARS NOTE; I. For intermediate return periods plot. 2 -year and 100 -year one hour values from maps,thel connect points and read value for desired return period. For example given 2 -year one hour =.50 and 100 - year one hour, 1.60 °,25 -year one hour = 1.18' Reference: NOAA Atlas 2,Volume Xr- California, 1973. RAINFALL DEPTH VERSUS R C FC & W C D RETURN PERIOD FOR HYDROLOGY 1\/JANUAL PARTIAL DURATION. SERIES PLATE D- 4.5 I 4 LIMITATIONS: TC1 L 100 1000 90 900 80 800 70 700 60 - c 600 0. 50 I 4 LIMITATIONS: 500 1. Maximum v =1000' .- m 35 a, w a 4A a - 400 ` 0 30 .- .0 0-350 0 25 v C c c } _c E 300 c c 20 ° N 19 01- ^ 250 17 v v 16 = 0 15 o, 0-200 �= 14 13 0 U 12 tg 11 0 K 150 w 9 ~ 8 7 Good Cover 6 100 I 4 LIMITATIONS: 1. Maximum length =1000' 2. Maximum area = 10 Acres a - 0 H •-• U 500 300 C71 c S ` 200 ° N 0 ` o 0 E 0 CL f l 4CEL 0 K Undevel oped Good Cover Undeveloped 0 1e0 Fair Cover ,^ •6 RCFC a WCD HYDROLOGY MANUAL Undeveloped Poor Cover- 0 .2 `21 Single Family ° 50 (1/4 Acre) Commercial 0 (Pov c m d w 0 KEY L-H -Tc -K -Tc' Tc 5-n 6 v Q 7 =- c a� 8 n. 0 m 9 0 10 I I U. a� 12 c 0 14 15 y 16—.S 17 E 18 19 20-9 C O i- C 25 v c 0 U w 30 EXAMPLE: E (1) L =550, .H =5.0, K= Single Family(1 /4Ac.) 35 Development , Tc = 12.6 min: (2) L =550 , H =5.0% K = Commercial .40 Development , Tc = 9.7 min. . Reference: Bibliography item No. 35. PLATE D -3 g xipuodd-V 1 O 21 1 -1 1 -2 20 J -1 II II II 12 II 19 II II it II II II 18 13 2 II ' II II � II 14 J -2 II 17 III � II II ' 1 15 6 II II J -3 II �-- I� 1 -4 0 -1 L ►O is �i �w.�S-j-w I� o 'L-J � STORM DRAIN ' ANNOTATION FOR HGL EXHIBITS 1 -5 I -1 1 -2 / -3 1 -4 -0.509 p -1 - - - -- 100 1R HGL WS= 454.8± Y O 48.48' OF 18° RCP 36.00' OF 24° RCP 54.00' OF 24° RCP STORM DRAIN D -LOAD STORM DRAIN STORM DRAIN 0 8.7 C CPS FS D -LOAD 1350 D -LOAD 1350 ,,= V,T 4.9 FPS 0 =31.1 CFS 0 „F6.7 CFS V =25.4 FPS Vey .1 FPS HGL EXHI BI T 100 YEAR 1 HOUR STORM EVENT i m m J -1 1 -4 O " —0.509 —0.509 —0.509 Y 8747' OF 24" RCP 324.49' OF 24" RCP 41.51' OF 24" RCP STORM DRAIN STORM DRAIN STORM DRAIN O —LOAD 1350 D —LOAD 1350 D —LOAD 1350 0 „� 17.3 CFS Q„d= 173 CFS QW =17.3 CFS V„ f 5.5 FPS V,�p 5.5 FPS V „r 5.5 FPS H GL EXHI BI T 100 YEAR 1 HOUR STORM EVENT 1 -8 1 -5 0 -7 100 YR HGL 0— 4 WS= 45 4.St 100 1R HGL --- - --p -- -- - - - -- WS =454.5 _2.0% 78.50' OF 18" RCP STORM DRAIN O -LOAD 1350 50.00' OF 18" RCP 0 =1.2 CFS STORM DRAIN V =0.7 FPS D -LOAD 1350 Q,� 4.8 CFS V,d=27 FPS HGL EXHIBI T 100 YEAR 1 HOUR STORM EVENT J- 4 1 -7 1 -6 1 -6 0 -3 -0.509 -0.50% 48.00' OF 24" RCP STORM DRAIN 90.00' OF 24" RCP 76.13" OF 24" RCP D -LOAD 1350 0„24.0 CFS STORM DRAIN STORM DRAIN V „d= 7 6 FPS D -LOAD 1350 D -LOAD 1350 Q,d=31.1 CFS Q,,,p31.I CFS V, .p9.9 FPS V,e9.9 FPS H GL EXHI BI T 100 YEAR 1 HOUR STORM EVENT r--, I' Lam' 5 L 1 Appendix C Retention Basin for TR# 32279 RETENTION BASIN AREA 17260 SF RETENTION BASIN POINT PERCOLATION 0.00 IN /HR RETENTION BASIN PERCOLATION 0.00 CF /M PHYSICAL DATA RUNOFF AREA 10.0 ACRES 100 YEAR P3 2.25 IN 100 YEAR P6 2.75 IN 100 YEAR P24 5.00 IN ADJUSTED LOSS RATE SOIL GROUP B PAGE C -2 SOIL COVER TYPE GOOD PAGE C -3 ANTECEDENT MOISTURE CONDITIONS AMC II PAGE C-4 RUNOFF INDEX NUMBER FOR PREVIOUS AREAS 56 RESIDENTIAL PLATE E 6.1 INFILTRATION RATE FOR PREVIOUS AREAS (Fp) 0.52 IN /HR PLATE E -6.2 INPREVIOUS COVER FOR DEVELOPED AREAS (Ai) 0.45 PERCENT PLATE E -6.3 ADJUSTED LOSS RATE (Fp * (1.00 -.09 * Ai)) 0.309 IN /HR PLATE E -1.1 LAG TIME RUNOFF AREA 0.016 SQUARE MILES LENGTH OF LONGEST WATERCOURSE (L) 0.21 MILES LENGTH TO CENTROID OF RUNOFF AREA (Lca)AREA) 0.11 MILES ELEVATION OF HEADWATER 69.5 FEET ELEVATION OF CONCENTRATION POINT 60 FEET ELEVATION CHANGE 9.5 FEET SLOPE (S) 45.24 FEET /MILE MANNINGS NUMBER (n) 0.02 PLATE E -3 LAG TIME (24 * n) * (L * Lca / S ^.5) ^.38 0.0556 HOURS LAG TIME 3.33 MINUTES UNIT TIME FOR 3 HOUR STORM 5 MINUTES UNIT TIME FOR 6 HOUR STORM 5 MINUTES UNIT TIME FOR 24 HOUR STORM 15 MINUTES i 17 Retention Basin for TR# 32279 100 YEAR 3-HOUR CHART 3 -HOUR POINT RAIN FALL I 2.25 INCHES IRETENTION BASIN PERCOLATION 0.00 CF /5 MINS UNIT TIME PERIOD 5 MINUTES JADJUSTED INFLITRATION RATE 0.309 IN/HR RUNOFFAREA 10 ACRES LOW LOSS RATE 0.9 PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE IN /HR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF EFFECTIVE RETENTION TOTAL BASIN VOLUME UNITS H:MM IN /HR MAX IN/HR LOW IN/HR IN /HR CFS CF CF CF' 1 0:00 -PLATE-E5.9 1.3 0.351 0.309 0.042 0.42 125.8 125.8 126 2 0:05 1.3 0.351 0.309 0.042 0.42 125.8 125.8 252 3 0:10 1.1 0.297 0.309 0.267 0.030 0.30 89.8 89.8 342 4 0:15 1.5 0.405 0.309 - 0.096 0.96 289.2 289.2 1 631 5 0:20 1.5 0.405 0.309 0.096 0.96 289.2 289.2 920 6 0:25 1.8 0.486 0.309 0.177 1.78 534.2 534.2 1454 7 0:30 1.5 0.405 0.309 0.096 0.96 289.2 289.2 1743 8 0:35 1.8 0.486 0.309 0.177 1.78 534.2 534.2 2278 9 0:40 1.8 0.486 0.309 0.177 1.78 534.2 534.2 2812 10 0:45 1.5 0.405 0.309 0.096 0.96 289.2 289.2 3101 11 0:50 1.6 0.432 0.309 0.123 1.24 370.9 370.9 3472 12 0:55 1.8 0.486 0.309 0.177 1.78 534.2 534.2 4006 13 1:00 2.2 0.594 0.309 0.285 2.87 860.9 860.9 4867 14 1:05 2.2 0.594 0.309 0.285 2.87 860.9 860.9 5728 15 1:10 2.2 0.594 0.309 0.285 2.87 860.9 860.9 6589 16 1:15 2.0 0.540 0.309 0.231 2.33 697.6 697.6 7286 17 1:20 2.6 0.702 0.309 0.393 3.96 1187.6 1187.6 8474 18 1:25 2.7 0.729 0.309 0.420 4.23 1269.3 1269.3 9743 19 1:30 2.4 0.648 0.309 0.339 3.41 1024.3 1024.3 10767 20 1:35 2.7 0.729 0.309 0.420 4.23 1269.3 1269.3 12037 21 1:40 3.3 0.891 0.309 0.582 5.86 1759.3 1759.3 13796 22 1:45 3.1 0.837 0.309 0.528 5.32 1596.0 1596.0 15392 23 1:50 2.9 0.783 0.309 0.474 4.78 1432.6 1432.6 16825 24 1:55 3.0 0.810 0.309 0.501 5.05 1514.3 1514.3 18339 25 2:00 3.1 0.837 0.309 0.528 5.32 1596.0 1596.0 19935 26 2:05 4.2 1.134 0.309 0.825 8.31 2494.4 2494.4 22429 27 2:10 5.0 1.350 0.309 1.041 10.49 3147.8 3147.8 25577 28 2:15 3.5 0.945 0.309 0.636 6.41 1922.7 1922.7 27500 29 2:20 6.8 1.836 0.309 1.527 15.39 4618.0 4618.0 32118 30 2:25 7.3 1.971 0.309 1.662 16.75 5026.3 5026.3 37144 31 2:30 8.2 2.214 0.309 1.905 19.20 5761.4 5761.4 42906 32 2:35 5.9 1.593 0.309 1.284 12.94 3882.9 3882.9 46789 33 2:40 2.0 0.540 0.309 0.231 2.33 697.6 697.6 47486 34 2:45 1.8 0.486 0.309 0.177 1.78 534.2 534.2 48020 35 2750 1.8 0.486 0.309 0.177 1.78 534.2 534.2 48555 36 2:55 0.6 0.162 0.309 0.146 0.016 0.16 49.0 49.0 48604 1 1 1 Retention Basin for TR# 32279 100 YEAR 6 -HOUR CHART 6-HOUR POINT RAIN FALL 2.75 INCHES I RETENTION BASIN PERCOLATION 0.00 CF /5 MINS UNIT TIME PERIOD 5 MINUTES JADJUSTED INFLITRATION RATE 0.309 IN /HR RUNOFF AREA 10 ACRES LOW LOSS RATE 0.9 PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE IN /HR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF EFFECTIVE RETENTION TOTAL BASIN VOLUME UNITS H:MM PLATE - E5.9 IN /HR MAX IN /HR LOW IN /HR INIHR CFS CF' CF CF 1 0:00 0.5 0.165 0.309 0.149 0.017 0.17 49.9 49.9 50 2 0:05 0.6 0.198 0.309 0.178 0.020 0.20 59.9 59.9 110 3 0:10 0.6 0.198 0.309 0.178 0.020 0.20 59.9 59.9 170 4 0:15 0.6 0.198 0.309 0.178 0.020 0.20 59.9 59.9 230 5 0:20 0.6 0.198 0.309 0.178 0.020 0.20 59.9 59.9 289 6 0:25 0.7 0.231 0.309 0.208 0.023 0.23 69.9 69.9 359 7 0:30 0.7 0.231 0.309 0.208 0.023 0.23 69.9 69.9 429 8 0:35 0.7 0.231 0.309 0.208 0.023 0.23 69.9 69.9 499 9 0:40 0.7 0.231 0.309 0.208 0.023 0.23 69.9 69.9 569 10 0:45 0.7 0.231 0.309 0.208 0.023 0.23 69.9 69.9 639 11 0:50 0.7 0.231 0.309 0.208 0.023 0.23 69.9 69.9 709 12 0:55 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 789 13 1:00 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 868 14 1:05 0.8 0.294 0.309 0.238 0.026 0.27 79.9 79.9 948 15 1:10 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1028 16 1:15 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1108 17 1:20 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1188 18 1:25 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1268 19 1:30 0.8 0.264 0.309 0.238 0.026 0.27 1 79.9 79.9 1348 20 1:35 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1427 21 1:40 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1507 22 1:45 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1587 23 1:50 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1667 24 1:55 0.9 0,297 0.309 0.267 0.030 0.30 89.8 89.8 1 1757 25 2:00 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1837 26 2:05 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 1927 27 2:10 0.9 0.297 0.309 0.267 0.030 0.30 89.6 89.8 2016 28 2:15 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 2106 29 2:20 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 2196 30 2:25 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 2286 31 2:30 0.9 0.297 0.309 0.267 0.030 0.30 89.8 1 89.8 2376 32 2:35 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 2466 33 2:40 1.0 0.330 0.309 - 0.021 0.21 62.3 62.3 2528 34 2:45 1 0.330 0.309 0.021 0.21 62.3 62.3 2590 35 2:50 1 0.330 1 0.309 0.021 0.21 62.3 62.3 2653 36 2:55 1 0.330 0.309 0.021 0.21 62.3 62.3 2715 37 3:00 1.0 0.330 0.309 0.021 0.21 62.3 62.3 2777 38 3:05 1.1 0.363 0.309 0.054 0.54 162.1 162.1 2939 39 3:10 1.1 0.363 0.309 0.054 0.54 162.1 162.1 3102 40 3:15 1.1 0.363 0.309 0.054 0.54 162.1 162.1 3264 41 3:20 1.2 0.396 0.309 0.087 0.87 262.0 262.0 3526 42 3:25 1.3 0.429 0.309 0.120 1.21 361.8 361.8 3887 43 3:30 1.4 0.462 1 0.309 0.153 1.54 461.6 461.6 4349 44 3:35 1.4 0.462 0.309 0.153 1.54 461.6 461.6 4811 45 3:40 1.5 0.495 0.309 0.186 1.87 561.4 561.4 5372 46 3:45 1.5 0.495 0.309 0.186 1.87 561.4. 561.4 5934 47 3:50 1.6 0.528 0.309 0.219 2.20 661.3 661.3 6595 48 3:55 1.6 0.528 0.309 0.219 2.20 661.3 661.3 7256 49 4:00 1.7 0.561 0.309 0.252 2.54 761.1 761.1 8017 50 4:05 1.8 0.594 0.309 0.285 2.87 860.9 860.9 8878 51 4:10 1.9 0.627 0.309 0.318 3.20 960.7 960.7 9839 52 4:15 2.0 0.660 0.309 0.351 3.54 1060.6 1060.6 10899 53 4:20 2.1 0.693 0.309 0.384 3.87 1160.4 1160.4 12060 54 4:25 2.1 0.693 0.309 0.384 3.87 1160.4 1160.4 13220 55 4:30 2.2 0.726 0.309 0.417 4.20 1260.2 1260.2 14480 56 4:35 2.3 0.759 0.309 0.450 4.53 1360.0 1360.0 15840 57 4:40 2.4 0.792 0.309 0.483 4.87 1459.9 1459.9 17300 58 4:45 2.4 0.792 0.309 0.483 4.87 1459.9 1459.9 18760 59 4:50 2.5 0.825 0.309 0.516 5.20 1559.7 1559.7 20320 60 4:55 2.6 0.858 0.309 0.549 5.53 1659.5 1659.5 21979 61 5:00 3.1 1.023 0.309 0.714 7.20 2158.6 2158.6 24138 62 5:05 3.6 1.188 0.309 0.879 8.86 2657.8 2657.8 26796 63 5:10 3.9 1.287 0.309 0.978 9.86 2957.2 2957.2 29753 64 5:15 4.2 1.386 0.309 1.077 10.86 3256.7 3256.7 33010 65 5:20 4.7 1.551 0.309 1.242 12.52 3755.8 3755.8 36766 66 5:25 5.6 1.848 0.309 1.539 15.51 4654.3 4654.3 41420 67 5:30 1.9 0.627 0.309 0.318 3.20 960.7 960.7 42381 68 5:35 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 42470 69 5:40 0.6 0.198 0.309 0.178 0.020 0.20 59.9 59.9 42530 70 5:45 0.5 0.165 0.309 0.149 0.017 0.17 49.9 49.9 42580 71 5:50 0.3 0.099 0.309 0.089 0.010 0.10 29.9 29.9 42610 72 5:55 0.2 0.066 0.309 0.059 0.007 0.07 20.0 20.0 42630 7 L _i 11 11 1 Li Retention Basin for TR# 32279 100 YEAR 24 -HOUR CHART 24 -HOUR POINT RAIN FALL 5.00 INCHES RETENTION BASIN PERCOLATION 0.00 CF /15 MINS UNIT TIME PERIOD 15 MINUTES ADJUSTED INFLITRATION RATE 0.308 INMR RUNOFF AREA 10 ACRES ILOW LOSS RATE 0.9 PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE INMR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF EFFECTIVE RETENTION TOTAL BASIN VOLUME UNITS H:MM PLATE -E5.9 IN/HR MAX IN/HR LOWIN/HR IN/HR CFS CF CF CF 1 0:00 0.2 0.040 0.546 0.030 0.004 0.04 36.3 36.3 36 2 0:15 0.3 0.060 0.540 0.054 0.000 0406 54.5 54.5 91 3 0:30 0.3 0.060 0.534 0.054 0.006 0.06 54.5 54.5 145 4 0:45 0.4 0.080 0.527 0.072 0.008 0.08 7246 72.6 218 5 1:00 0.3 0.060 0.521 04054 0.006 0.08 54.5 54.5 272 8 1:15 0.3 0.060 0.515 0.054 0.006 0.06 64.5 54.5 327 7 1:30 0.3 0.000 0.509 0.054 0.008 0.06 64.5 54.6 381 8 1:45 0.4 0.080 0.503 0.072 0.008 0.08 72.6 72.6 454 9 2:00 0.4 0.080 0.497 0.072 0.008 0.08 72.6 72.8 526 10 2:15 0.4 0.080 0.491 04072 0.008 0.08 72.6 72.8 599 11 2:30 065 04100 0.485 0.090 0.010 0.10 90.7 90.7 690 12 2:45 0.5 0.100 0.479 0.000 0.010 0.10 90.7 90.7 780 13 3:00 0.5 0.100 0.473 0.090 0.010 0.10 90.7 90.7 871 14 3:15 0.5 0.100 0.407 0.090 0.010 0.10 90.7 80.7 962 15 3:30 0.5 0.100 0.481 0.090 0.010 0.10 90.7 90.7 1053 16 3:45 0.8 1 0.120 0.456 0.108 0.012 0.12 108.9 108.9 1162 17 4:00 0.8 1 0.120 0.449 0.108 0.012 0.12 108.9 108.9 1271 18 4:15 0.7 0.140 0.444 1 0.126 0.014 0414 127.1 12741 1398 • 19 4:30 0.7 0.140 0.438 0.126 0.014 0.14 127.1 127.1 1525 20 4:45 0.8 0.160 0.432 0.144 0.016 0.16 10.5.2 145.2 1870 21 5:00 0.6 0.120 0.427 0.108 0.012 0.12 108.9 108.9 1779 22 6:15 01 0.140 0.421 0.120 0.014 0.14 127.1 127.1 1906 23 5:30 0.8 0.180 0.416 0.144 0.018 0.16 145.2 145.2 2051 24 5:45 048 0.180 0.410 0.144 0.016 0.16 145.2 1451 2196 25 6:00 0.9 0.180 0.405 0.162 0.018 0.18 183.4 163.4 2360 26 8:15 0.0 0.180 0.399 04162 0.018 0.18 183.4 1 163.4 2523 27 6:30 1.0 0.200 0.394 0.180 0.020 020 181.5 181.5 2704 28 6:45 1.0 0.200 0.389 0.100 0.020 0.20 1815 181.5 2886 29 7:00 1.0 0.200 0.383 0.180 0.020 0.20 181.5 181.5 3067 30 7:15 1.1 0.220 6.378 0.188 0.022 0.22 199.7 199.7 3267 31 7:30 1.2 0240 0.373 0.216 0.024 0.24 217.8 217.8 3485 32 7:45 1.3 0.260 0.368 0.234 0.020 0426 238.0 236.0 3721 33 8:00 1.5 0.300 0.383 0.270 0.030 0.30 272.3 272.3 3993 34 8:15 1.6 0.300 0.358 0270 0.030 0.30 272.3 272.3 4265 35 8:30 1.6 0.320 0.353 0.286 0.032 0.32 290.4 290.4 4566 36 8:45 1.7 0.340 0.348 1 0.306 0.034 0.34 308.6 308.6 4664 37 9:00 1.0 0.380 0.343 0.037 0.38 337.5 337.5 5202 38 8:15 2.0 0.400 0.338 0.062 0.63 563.3 563.3 5765 39 9:30 2.1 0.420 0.333 0.087 0.88 788.8 788.6 8554 40 9:45 2.2 0.440 0.328 - 0.112 1.13 1013.6 1013.6 7587 41 10:00 1.5 0.300 0.324 0.270 0 0.30 272.3 272.3 7839 42 10:15 1.5 0.300 0.319 0.270 0 0.30 272.3 272.3 8112 43 10:30 2.0 0.400 0.314 0 0.86 778.3 776.3 8890 44 10:45 2.0 0.400 0.310 0 0.91 820.1 820.1 9710 45 11:00 1.9 0.380 0.305 5 10.044 0.76 679.9 079.9 10390 48 11:15 1.9 0.380 0.301 - 9 0.80 720.7 720.7 11111 47 11:30 Ti 0.340 0.298 0.44 398.1 398.1 11500 48 11:45 1.8 0.360 0.282 8 0.69 818.8 818.8 12128 49 12:00 2.5 0.500 0.287 0.213 2.14 1929.0 1929.6 14058 50 12:15 2.6 0.520 0.283 0.237 2.39 2150.2 2150.2 16208 51 12:30 2.8 0.560 0.279 0.281 2.84 2551.8 255178 18760 52 12:45 2.9 0.580 0.275 0.305 108 2771.4 2771.4 21531 53 13:00 1 3.4 0.880 0.270 0.410 4.13 3716.6 3716.6 25248 54 13:15 3.4 0.680 0266 0.414 4.17 3753.8 3753.8 20002 55 13:30 2.3 0.460 0.262 0.198 1.99 1794.0 1794.0 30788 58 13:45 2.3 0.460 0.258 0.202 2403 1830.2 1830.2 32026 57 14:00 2.7 0.540 0.254 0.286 2.88 2592.0 2592.0 35218 58 14:15 2.8 0.520 0.251 0.289 2.72 2445.7 2445.7 37683 59 14:30 2.6 0.520 0.247 0.273 2.76 2480.5 2480.5 40144 60 14:45 2.5 0.500 0.243 0257 2.59 2333.2 2333.2 42477 61 15:00 2.4 0.480 0.239 0.241 2.43 2185.4 2185.4 44883 62 15:15 2.3 0.460 0.236 0.224 2.26 2037.1 2037.1 46700 63 15:30 1.9 0.380 0.232 0.148 1.49 1343.8 1343.8 48044 64 15:45 1.9 0.380 0.228 0.152 1.53 1376.0 1376.0 49420 65 10:00 0.4 0.080 0.225 1 0.072 0.008 0.08 72.6 72.6 49492 86 16:15 0.4 0.080 0.221 0.072 0.008 0.08 72.6 72.6 48585 67 16:30 0.3 0.080 0.218 0.054 0.006 0.06 54.5 54.5 49619 68 16:45 0.3 0.000 0.215 0.054 0.006 0.06 54.5 54.5 49674 69 17:00 0.5 0.100 0.212 04090 0.010 0.10 90.7 90.7 49764 70 17:15 045 0.100 0.208 0.090 0.010 0.10 90.7 90.7 49855 71 17:30 0.5 0.100 0.205 0.080 0.010 0.10 90.7 90.7 49946 72 17:45 0.4 0.080 0.202 0.072 0.008 0.08 72.0 72.6 50019 73 18:00 0.4 0.080 0.198 0.072 0.008 0.08 72.6 72.6 50091 74 18:15 0.4 0.080 0.196 0.072 0.008 0.08 72.6 72.6 50184 75 18:30 03 0.060 0.194 0.054 0.006 0.06 54.5 54.5 50218 70 18:45 0.2 0.040 0.191 0.036 0.004 0.04 36.3 36.3 50254 77 19:00 03 0.060 0.188 0.054 0.006 0.06 54.5 54.5 50308 78 19:15 0.4 0.080 0185 0.072 0.008 0.08 72.6 72.6 50382 79 19:30 0.3 0.060 0.183 0.054 0.000 0.06 54.5 54.5 60436 80 19:45 0.2 0.040 0.180 0.036 0.004 0.04 36.3 363 50472 81 20:00 0.3 0.060 0.178 0.054 0.006 0.00 54.5 54.5 60527 82 20:15 0.3 0.060 0.176 0.054 0.006 0.06 54.5 54.5 50581 63 20:30 03 0.050 0.174 0.054 0.006 0.06 64.5 54.5 50838 84 20:45 0.2 0.040 0.171 1 0.036 0.004 0.04 36.3 36.3 50672 85 21:00 0.3 0.060 0.189 0.054 0.000 0.08 54.5 54.6 50726 Be 21:16 0.2 0.040 0.167 0.036 0.004 0.04 36.3 38.3 50763 87 21:30 0.3 0.060 0.166 0.054 0.000 0.06 54.5 54.5 50817 88 21:45 0.2 01040 04104 0.036 0.004 0.04 38.3 36.3 60863 69 22:00 0.3 0.060 0.162 04054 0.006 0.06 54.5 54.5 50908 80 22:15 0.2 1 0.040 0.161 0.036 0.004 0.04 36.3 38.3 50944 91 22:30 0.2 1 0.040 0.159 0.030 04004 0.04 36.3 36.3 SOB 80 92 22:45 0.2 0.040 0.158 0.036 0.004 0.04 38.3 36.3 51017 B3 23:00 0.2 0.040 0.157 0.030 0.004 0.04 36.3 36.3 51053 B4 23:15 0.2 0.040 0.158 0.038 0.004 0.04 38.3 38.3 51088 95 23:30 0.2 0.040 0.155 0.038 0.004 0.04 38.3 36.3 51128 BB 23:45 0.2 0.040 0.155 0.038 0.004 0.04 36.3 36.3 51182 m m= m m m i m m m r w w m m m m w m Retention Basin for TR# 33336 RETENTION BASIN AREA 14460 SF RETENTION BASIN POINT PERCOLATION 0.00 IN /HR RETENTION BASIN PERCOLATION 0.00 CF /M PHYSICAL DATA RUNOFF AREA 10.0 ACRES 100 YEAR P3 2.25 IN 100 YEAR P6 2.75 IN 100 YEAR P24 5.00 IN ADJUSTED LOSS RATE SOIL GROUP B PAGE C -2 SOIL COVER TYPE GOOD PAGE C -3 ANTECEDENT MOISTURE CONDITIONS AMC II PAGE C -4 RUNOFF INDEX NUMBER FOR PREVIOUS AREAS 56 RESIDENTIAL PLATE E 6.1 INFILTRATION RATE FOR PREVIOUS AREAS (Fp) 0.52 IN /HR PLATE E -6.2 INPREVIOUS COVER FOR DEVELOPED AREAS (Ai) 0.45 PERCENT PLATE E -6.3 ADJUSTED LOSS RATE (Fp * (1.00 -.09 * Ai)) 0.309 IN /HR PLATE E -1.1 LAG TIME RUNOFF AREA 0.016 SQUARE MILES LENGTH OF LONGEST WATERCOURSE (L) 0.21 MILES LENGTH TO CENTROID OF RUNOFF AREA (Lca)AREA) 0.11 MILES ELEVATION OF HEADWATER 69.5 FEET ELEVATION OF CONCENTRATION POINT 60 FEET ELEVATION CHANGE 9.5 FEET SLOPE (S) 45.24 FEET /MILE MANNINGS NUMBER (n) 0.02 PLATE E -3 LAG TIME (24 * n) * (L * Lca / S ^.5) ^.38 0.0556 HOURS LAG TIME 3.33 MINUTES UNIT TIME FOR 3 HOUR STORM 5 MINUTES UNIT TIME FOR 6 HOUR STORM 5 MINUTES UNIT TIME FOR 24 HOUR STORM 15 MINUTES h L.J 1 1 J I� L.J Retention Basin for TR# 33336 100 YEAR 3 -HOUR CHART 3 -HOUR POINT RAIN FALL 2.25 INCHES IRETENTION BASIN PERCOLATION 0.00 CF /5 MINS UNIT TIME PERIOD 5 MINUTES JADJUSTED INFLITRATION RATE 0.309 IN /HR RUNOFF AREA 10 ACRES ILOW LOSS RATE 0.9 PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE IN /HR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF EFFECTIVE RETENTION TOTAL BASIN VOLUME UNITS H:MM PLATE - E5.9 IN/HR MAX IN/HR LOW IN/HR IN /HR CFS CF CF CF 1 0:00 1.3 0.351 0.309 0.042 0.42 125.8 125.8 126 2 0:05 1.3 0.351 0.309 - 0.042 0.42 125.8 125.8 252 3 0:10 1.1 0.297 0.309 0.267 0.030 0.30 89.8 89.8 342 4 0:15 1.5 0.405 0.309 - 0.096 0.96 289.2 289.2 631 5 0:20 1.5 0.405 0.309 0.096 0.96 289.2 289.2 920 6 0:25 1.8 0.486 0.309 0.177 1.78 534.2 534.2 1454 7 0:30 1.5 0.405 0.309 0.096 0.96 289.2 289.2 1743 8 0:35 1.8 0.486 0.309 0.177 1.78 534.2 534.2 2278 9 0:40 1.8 0.486 0.309 0.177 1.78 534.2 534.2 2812 10 0:45 1.5 0.405 0.309 0.096 0.96 289.2 289.2 3101 11 0:50 1.6 0.432 0.309 0.123 1.24 370.9 370.9 3472 12 0:55 1.8 0.486 0.309 0.177 1.78 534.2 534.2 4006 13 1:00 2.2 0.594 0.309 0.285 2.87 860.9 860.9 4867 14 1:05 2.2 0.594 0.309 0.285 2.87 860.9 860.9 5728 15 1:10 2.2 0.594 0.309 0.285 2.87 860.9 860.9 6589 16 1:15 2.0 0.540 0.309 0.231 2.33 697.6 697.6 7286 17 1:20 2.6 0.702 0.309 0.393 3.96 1187.6 1187.6 8474 18 1:25 2.7 0.729 0.309 0.420 4.23 1269.3 1269.3 9743 19 1:30 2.4 0.648 0.309 0.339 3.41 1024.3 1024.3 10767 20 1:35 2.7 0.729 0.309 0.420 4.23 1 1269.3 1269.3 12037 21 1:40 3.3 0.891 0.309 0.582 5.86 1759.3 1759.3 13796 22 1:45 3.1 0.837 0.309 0.528 5.32 1596.0 1596.0 15392 23 1:50 2.9 0.783 0.309 0.474 4.78 1432.6 1432.6 16825 24 1:55 3.0 0.810 0.309 0.501 5.05 1514.3 1514.3 18339 25 2:00 3.1 0.837 0.309 0.528 5.32 1596.0 1596.0 19935 26 2:05 4.2 1.134 0309 0.825 8.31 2494.4 2494.4 22429 27 2:10 5.0 1.350 0.309 1.041 10.49 3147.8 3147.8 25577 28 2:15 3.5 0.945 0.309 0.636 6.41 1922.7 1922.7 27500 29 2:20 6.8 1.836 0.309 1.527 15.39 4618.0 4618.0 32118• . 30 2:25 7.3 1.971 0.309 1.662 16.75 5026.3 1 5026.3 37144 31 2:30 8.2 2.214 0.309 1.905 19.20 5761.4 5761.4 42906 32 2:35 5.9 1.593 0.309 1.284 12.94 3882.9 3882.9 46789 33 2:40 2.0 0.540 0.309 0.231 2.33 697.6 697.6 47486 34 2:45 1.8 0.486 0.309 - 0.177 1.78 534.2 534.2 48020 35 2:50 1.8 0.486 0.309 0.177 1.78 534.2 534.2 48555 36 2:55 0.6 0.162 0.309 1 0.146 0.016 0.16 1 49.0 49.0 48604 L� J 1 u 1 Retention Basin for TR# 33336 100 YEAR 6 -HOUR CHART 6-HOUR POINT RAIN FALL I 2.75 INCHES IRETENTION BASIN PERCOLATION 0.00.CF /5 MINS UNIT TIME PERIOD 5 MINUTES JADJUSTED INFLITRATION RATE 0.309 IN /HR RUNOFF AREA 10 ACRES LOW LOSS RATE 0.9 PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE IN /HR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF EFFECTIVE RETENTION TOTAL BASIN VOLUME UNITS H:MM PLATE - E5.9 IN /HR MAX IN /HR LOW IN /HR IN /HR CFS CF CF CF 1 0:00 0.5 0.165 0.309 0.149 0.017 0.17 49.9 49.9 50 2 0:05 0.6 0.198 0.309 0.178 0.020 0.20 59.9 59.9 110 3 0:10 0.6 0.198 0.309 0.178 0.020 0.20 59.9 59.9 170 4 0:15 0.6 0.198 0.309 0.178 0.020 0.20 59.9 1 59.9 230 5 0:20 0.6 0.198 0.309 0.178 0.020 0.20 59.9 59.9 289 6 0:25 0.7 0.231 0.309 0.208 0.023 0.23 69.9 69.9 359 7 0:30 0.7 0.231 0.309 0.208 0.023 0.23 69.9 69.9 429 8 0:35 0.7 0.231 0.309 0.208 .0.023 0.23 69.9 69.9 499 9 0:40 0.7 0.231 0.309 0.208 0.023 0.23 69.9 69.9 569 10 0:45 0.7 0.231 0309 0.208 0.023 0.23 69.9 69.9 639 11 0:50 0.7 0.231 0.309 0.208 0.023 0.23 69.9 69.9 709 12 0:55 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 789 13 1:00 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 868 14 1:05 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 948 15 1:10 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1028 16 1:15 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1108 17 1:20 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1188 18 1:25 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1268 19 1:30 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1348 20 1:35 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1427 21 1:40 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1507 22 1:45 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1587 23 1:50 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1667 24 1:55 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 1757 25 2:00 0.8 0.264 0.309 0.238 0.026 0.27 79.9 79.9 1837 26 2:05 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 1927 27 2:10 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 2016 28 2:15 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 2106 29 2:20 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 2196 30 2:25 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 2286 31 2:30 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 2376 32 2:35 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 2466 33 2:40 1.0 0.330 0.309 0.021 0.21 1 62.3 62.3 2528 34 2:45 1 0.330 0.309 0.021 0.21 62.3 62.3 2590 35 2:50 1 0.330 0.309 0.021 0.21 62.3 62.3 2653 36 2:55 1 0.330 0.309 0.021 0.21 62.3 62.3 2715 37 3:00 1.0 0.330 0.309 0.021 0.21 62.3 62.3 2777 38 3:05 1.1 0.363 0.309 0.054 0.54 162.1 162.1 2939 39 3:10 1.1 0.363 0.309 0.054 0.54 162.1 162.1 3102 40 3:15 1.1 0.363 0.309 0.054 0.54 162.1 162.1 3264 41 3:20 1.2 0.396 0.309 0.087 0.87 262.0 262.0 3526 42 3:25 1.3 0.429 0.309 0.120 1.21 361.8 361.8 3887 43 3:30 1.4 0.462 0.309 0.153 1.54 461.6 461.6 4349 44 3:35 1.4 0.462 0.309 0.153 1.54 461.6 461.6 4811 45 3:40 1.5 0.495 0.309 0.186 1.87 561.4 561.4 5372 46 3:45 1.5 0.495 0.309 0.186 1.87 561.4 561.4 5934 47 3:50 1.6 0.528 0.309 0.219 2.20 661.3 1 661.3 6595 48 3:55 1.6 0.528 0.309 0.219 2.20 661.3 1 661.3 7256 49 4:00 1.7 0.561 0.309 0.252 2.54 761.1 761.1 8017 50 4:05 1.8 0.594 0.309 0.285 2.87 860.9 860.9 8878 51 4:10 1.9 0.627 0.309 0.318 3.20 960.7 960.7 9839 52 4:15 2.0 0.660 0.309 0.351 3.54 1060.6 1060.6 10899 53 4:20 2.1 0.693 0.309 0.384 3.87 1160.4 1160.4 12060 54 4:25 2.1 0.693 0.309 0.384 3.87 1160.4 1160.4 13220 55 4:30 2.2 0.726 0.309 0.417 4.20 1260.2 1260.2 14480 56 4:35 2.3 0.759 0.309 0.450 4.53 1360.0 1360.0 15840 57 4:40 2.4 0.792 0.309 0.483 4.87 1459.9 1459.9 17300 58 4:45 2.4 0.792 0.309 0.483 4.87 1459.9 1459.9 18760 59 4:50 2.5 0.825 0.309 0.516 5.20 1559.7 1559.7 20320 60 4:55 2.6 0.858 0.309 0.549 5.53 1659.5 1659.5 21979 61 5:00 3.1 1.023 0.309 0.714 7.20 2158.6 2158.6 24138 62 5:05 3.6 1.188 0.309 0.879 8.86 2657.8 2657.8 26796 63 5:10 3.9 1.287 0.309 0.978 9.86 2957.2 2957.2 29753 64 5:15 4.2 1.386 0.309 1.077 10.86 3256.7 3256.7 33010 65 5:20 4.7 1.551 0.309 1.242 12.52 3755.8 3755.8 36766 66 5:25 5.6 1.848 0.309 1.539 15.51 4654.3 4654.3 41420 67 5:30 1.9 0.627 0.309 - 0.318 3.20 960.7 960.7 42381 68 5:35 0.9 0.297 0.309 0.267 0.030 0.30 89.8 89.8 42470 69 5:40 0.6 0.198 0.309 0.178 0.020 0.20 59.9 59.9 42530 70 5:45 0.5 0.165 0.309 0.149 0.017 0.17 49.9 49.9 42580 71 5:50 1 0.3 0.099 0.309 0.089 0.010 0.10 29.9 29.9 42610 72 5:55 1 0.2 0.066 0.309 0.059 0.007 0.07 20.0 20.0 42630 L✓ 1 7� 11 -7 i `J Retention Basin for TR# 33336 100 YEAR 24 -HOUR CHART 24 -HOUR POINT RAIN FALL 6.L01 INCHES RETENTION BASIN PERCOLATION 0.00 CF /15 MINS UNIT TIME PERIOD 15 MINUTES ADJUSTED INFLITRATION RATE 0.309 INMR RUNOFF AREA 10 ACRES LOW LOSS RATE 0.9 PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE INMR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF L BASIN LUME UNITS H:MM PLATE -E5.9 IN/HR MAXIN/HR LOW INMR INMR CFS CF CF 1 0:00 0.2 0.040 0.548 0.036 0.004 0.04 38.3 !F327 36 2 0:15 0.3 0.060 0.540 01054 0.006 0.06 54.5 91 3 0:30 0.3 0.080 0.534 0.054 0.006 0.06 54.5 145 4 0:45 0.4 0.080 0.527 0.072 0.008 0.08 72.6 218 5 1:00 0.3 0.060 0.521 0.054 06000 0.06 54.5 272 6 1:15 0.3 0.060 0.515 0.054 0.006 0.00 54.5 54.5 7 1:30 0.3 0.060 0.509 0.054 0.006 0.06 54.5 54.5 381 8 1:45 0.4 0.080 0.503 0.072 0.008 0.08 72.6 72.8 454 9 2:00 0.4 0.080 0.497 0.072 0.008 0.08 72.6 72.6 526 10 2:15 0.4 0.080 0.491 0.072 0.008 0.08 72.6 72.6 688 11 2:30 0.5 0.100 0.485 0.090 0.010 0.10 90.7 90.7 690 12 2:45 0.6 0.100 0.478 0.090 0.010 1 0.10 80.7 9047 780 13 3:00 0.5 0.100 0.473 0.090 0.010 0.10 90.7 90.7 871 14 3:15 0.5 0.100 0.487 0.090 0.010 0.10 90.7 90.7 962 15 3:30 0.5 0.100 0.461 0.090 0.010 0.10 90.7 00.7 1053 18 3:45 0.0 0.120 0.455 0.108 0.012 0.12 106.9 108.9 1162 17 4:00 0.6 0.120 0.449 0.108 0.012 0.12 108.9 108.8 1271 18 4:15 0.7 0.140 0.444 1 0.128 0.014 0.14 127.1 127.1 1398 19 4:30 0.7 0.140 0.438 0.128 0.014 0.14 127.1 127.1 1525 20 4:45 0.8 0.100 0.432 0.144 0.016 0.16 145.2 145.2 1670 21 5:00 0.6 0.120 0.427 0.108 0.012 0.12 108.9 108.9 1779 22 5:15 0.7 0.140 0.421 0.126 0.014 0.14 127.1 127.1 1906 23 5:30 0.8 0.160 0.416 0.144 0.016 0.16 145.2 145.2 20511 24 5:45 0.8 0.180 0.410 0.144 0.016 0.16 145.2 145.2 2196 25 6:00 0.9 1 0.180 0.405 0.162 0.018 0.18 183.4 183.4 2380 26 0:15 0.9 0.180 0.399 0.162 0.018 0.18 163.4 163.4 2523 27 0:30 1.0 0.200 0.394 0.180 0.020 0.20 181.5 181.5 2704 28 6:45 1.0 0.200 0.389 0.180 0.020 0.20 181.5 181.6 2888 29 7:00 1.0 0.200 0.383 0.180 0.020 0.20 181.5 181.6 3067 30 7:15 1.1 0.220 0.378 0.198 0.022 0.22 199.7 199.7 3267 31 7:30 1.2 0.240 0.373 0.216 0.024 0.24 217.6 217.8 3485 32 7:45 1.3 0.260 0.368 0.234 0.026 0.28 236.0 236.0 3721 33 8:00 1.5 0.300 0.363 0.270 0.030 0.30 272.3 272.3 3983 34 8:15 1.5 0.300 04358 0.270 0.030 0.30 272.3 272.3 4265 35 8:30 1.0 0.320 0.353 0.288 0.032 0.32 290.4 290.4 4556 36 8:45 1.7 0.340 0.348 0.306 0.034 0.34 308.8 30848 4864 37 9:00 1.9 0.380 0.343 04037 0.38 337.5 337.5 5202 38 9:15 2.0 0.400 0.338 0.082 0.63 563.3 563.3 5785 39 9:30 2.1 0.420 0.333 0.087 0088 788.6 788.6 6554 40 9:45 2.2 0.440 0.328 - 0.112 1.13 1013.8 1013.6 7587 41 10:00 1.5 0.300 0.324 0.270 0.030 0.30 272.3 272.3 7839 42 10:15 1.5 0.300 0.319 0.270 0.030 0.30 272.3 272.3 8112 43 10:30 2.0 0.400 0.314 0.086 0.80 778.3 778.3 8890 44 10:45 2.0 0.400 0.310 0.090 0.91 820.1 820.1 9710 45 11:00 1.9 0.380 0.305 0.075 0.76 879.9 679.9 10390 48 11:15 1.9 0.380 0.301 0.079 0.80 720.7 720.7 11111 47 11:30 0.340 0.288 0.044 0.44 388.1 398.1 11509 48 11:45 0.360 0.292 0.068 0.69 619.8 619.6 12128 49 12:00 0.500 0.287 0.213 2.14 1028.8 1929.6 14058 50 12:15 0.520 0.283 0.237 2.39 2150.2 2160.2 16208 51 12:30 j2.8 0.560 0.279 0.261 2.84 2551.6 2551.8 18760 52 12:45 0.580 0.275 - 0.305 3.08 2771.4 2771.4 21531 53 13:00 0.680 0.270 0.410 4.13 3718.6 3718.0 25248 54 13:15 0.680 0168 0.414 4.17 37518 37618 28002 66 13:30 2.3 0.460 0.262 0.198 1.99 1794.0 1794.0 30796 50 13:45 2.3 0.460 0.258 0.202 2.03 1830.2 1830.2 32628 67 14:00 2.7 0.540 0.254 0.286 2.68 2592.0 2592.0 35218 68 14:15 2.6 0.520 0.251 0.209 2.72 1 2445.7 2445.7 37663 69 14:30 2.8 0.520 0.247 0.273 2.76 2480.5 248015 40744 60 14:45 2.5 0.500 0.243 0.257 2.59 2333.2 2333.2 42477 61 16:00 2.4 0.480 0.239 0.241 2.43 2185.4 2185.4 44883 62 15:15 243 0.480 0.230 0.224 2.26 2037.1 2037.1 46700 63 15:30 1.9 0.380 0.232 0.148 1.49 1343.8 1343.8 48044 84 15:45 1.9 0.380 0.228 0.162 1.53 1376.0 1376.0 48420 65 78:00 0.4 0.080 0.225 0.072 0.008 0.08 72.6 72.6 49492 08 18:15 0.4 00080 0.221 0.072 0.008 0.08 72.6 72.6 49565 67 16:30 0.3 0.060 0.218 0.054 0.000 0.06 54.5 54.5 49619 68 16:45 0.3 0.060 0.215 0.054 0.008 0.08 54.5 54.5 48874 69 17:00 0.5 0.100 0.212 0.080 0.010 0.10 80.7 90.7 49764 70 1715 0.6 0.100 0.208 0.090 0.010 0.10 90.7 90.7 49855 71 17:30 0.5 0.100 0.205 0.090 0.010 0.10 90.7 90.7 49846 72 17:45 0.4 0.080 0.202 0.072 0.008 0.08 72.0 72.8 50019 73 18:00 0.4 0.080 1 0.199 0.072 0.008 0.08 72.6 72.6 50091 74 18:15 0.4 0.080 0.196 0.072 0.008 0.08 72.6 72.6 50184 75 16:30 043 0.080 0.194 0.054 0.006 0.06 54.5 54.5 50218 76 18:45 0.2 0.040 0.181 0.036 0.004 0.04 36.3 36.3 60254 77 19:00 0.3 0.080 0.188 0.054 0.006 0.00 54.5 54.5 50309 78 19:15 0.4 0.080 0.186 0.072 0.008 0.08 72.0 72.6 50382 79 19:30 0.3 meo 0.183 0.054 0.006 0.06 54.5 54.5 50436 80 19:45 0.2 0.040 0.180 0.038 0.004 0.04 36.3 38.3 50472 81 20:00 03 0.060 0.178 0.054 0.006 0.06 54.5 54.5 50527 82 20:15 0.3 0.060 0.176 0.054 0.006 0.00 54.5 54.5 50581 83 20:30 0.3 0.060 0.174 0.054 0.006 0.06 54.6 54.5 50836 84 20:45 0.2 0.040 0.171 0.038 0.004 0.04 36.3 36.3 50872 85 21:00 0.3 0.060 0.169 0.054 0.000 0.08 54.5 54.5 50726 80 21:15 0.2 0.040 0.167 0.036 0.004 1 0.04 38.3 36.3 50763 87 21:30 0.3 0.000 0.180 04054 0.006 0.06 54.5 54.5 50817 88 21:45 0.2 0.040 0.184 0.036 0.004 0.04 36.3 38.3 50853 89 22:00 0.3 0.080 0.182 0.054 0.008 0.08 54.5 54.5 50808 90 22:15 0.2 0.040 0.161 0.036 0.004 0.04 38.3 36.3 50944 91 22:30 0.2 0.040 0.159 0.036 0.004 0.04 36.3 36.3 50980 02 22:45 0.2 0.040 0.158 0.036 0.004 0.04 36.3 36.3 51017 93 23:00 0.2 0.040 0.157 0.038 0.004 0.04 38.3 36.3 51053 94 23:15 0.2 0.040 0.158 0.036 0.004 0.04 36.3 36.3 51089 95 23:30 0.2 0.040 0.155 0.036 0.004 0.04 36.3 38.3 51126 9B 23:45 0.2 0.040 0.155 0.036 0.004 0.04 36.3 36.3 51162 TtUNCFF INDEX NUMBERS OF HYDROLOGIC 'SOIL-COVER COMPLEXES FOR PERVIOUS AREAS -AMC II Cover Type (3) Quality of Soil G'r A B I C I D Cover (2) NATURAL COVERS - Barren 78 86 91 93 (Rockland, eroded and graded land) Chaparrel, Broadleaf Poor 53 70 80 85 (Manzonita, ceanothus and scrub oak) Fair 40 63 75 81 Good 31 57 71 78 Chaparrel, Narrowleaf Poor 71 82 88 91 (Chamise and redshank) Fair 55 72 81 86 Grass, Annual or Perennial Poor 67 78 86 89 Fair 50 69 79 84 Good 38 61 74 80 Meadows or Cienegas Poor 63 77 85 88 (Areas with seasonally high water table, Fair 51 70 80 84 principal vegetation is sod forming grass) Good 30 58 72 78 Open Brush Poor 62 76 84 88 (Soft wood shrubs - buckwheat, sage, etc..) Fair 46 66 77 83 Good 41 63 75. 81 Woodland Poor 45 66 77 83 (Coniferous or broadleaf trees predominate. Fair 36 60 73 79 Canopy density is at least 50 percent) Good 28 55 70 77 Woodland, Grass Poor 57 73 82 86 (Coniferous or broadleaf trees with canopy Fair 44 65 77 82 density frcm 20 to 50 percent) Good 33 58 72 79 URBAN COVERS - Residential or Commercial Landscaping Good 32 56 69 75 (Lawn, shrubs, etc.) Turf Poor 58 74 83 87 (Irrigated and mowed grass) Fair 44 65 77 82 Good 33 58 72 79 AGRICULTURAL COVERS - Fallow 76 85 90 92 (Land plowed but not tilled or seeded) R C F C& W C D RUNOFF INDEX NUMBERS FOR HYDROLOGY MANUAL PERVIOUS AREAS PI OTF F -A.1 ( I of 21 ACTUAL IMPERVIOUS COVER Recommended Value Land Use. (1) Range- Percent For Average Conditions- Percent(2 Natural or Agriculture 0 - 10 0 Single Family Residential: (3) 40,000 S. F. (1 Acre) 20,000 S. F. (]� Acre) 7,200 - 10,000 S. F. Multiple Family Residen Condominiums Apartments Mobile Home Park Lots 10 - 25 20 Lots 30 - 45 40 Lots 45 -'55 50 tial: UsE .45 - 70 65 65 - 90 80 60 - 85' 75 Commercial, Downtown I 80 -100 I 90 Business or Industrial Notes: 1. Land use should be based on ultimate development of the watershed. Long range master plans for the County and incorporated cities should be reviewed to insure reasonable land use assumptions. 2. Recommended values are based on average conditions which may not apply,to a particular study area. The percentage impervious may vary greatly even on comparable sized lots due to differences in dwelling size, improvements, etc. Landscape practices should also be considered as it is common in some areas to use ornamental grav- els underlain by impervious plastic materials in place of lawns and shrubs. A field investigation of a study area should always be made, and a review of aerial photos, where available may assist in estimat- ing the percentage of impervious cover in developed areas. 3. For typical horse ranch subdivisions increase impervious area 5 per- cent over the values recommended in the table above. RCFC a WCD HYDROLOGY, MANUAL IMPERVIOUS COVER FOR DEVELOPED AREAS PLATE D -5.6 Appendix D 1 Ll TIW7- 3533.6 f vblic . 5f reef + lgnds cop A ✓eq s 04l) SANDFILTER SIZING CALCULATIONS Calculation #1 Determines how many standard size sandfilters are needed. No.* of Sandfilters = -.homes--. 40 homes /sandfilter * Round all fractions up to the nearest whole number Each sandfilter has 48 sf of filter surface (iie 6'x 8'); assume the incoming nuisance water will percolate through the sand at the rate of 4.6 inches per hour. The sandfilter must be sized to handle the "surge inflow rate" of 0.458 cf/house /hour, which is based on the assumption that, on average, each house releases 12 gallons in a 3.5 hour `surge" period. Therefore, each sandfilter is capable of handling 18.4 cf /hour. As a result, each,sandflter can handle the nuisance water released by 40 homes (18.4/0.458 =40). Calculation #2 - Determines how long the leach line.must be. Leach Line Length* = V homes x 1.9 If /home (sandy soil) * In feet to be divided evenly between the number of sandfilters Leach Line Length* = homes x 3.8 If /home (silty soil) * In feet to be divided evenly between the number of sandfilters The critical aspect in sizing the leach line length is related to its ability to maintain'a sustained percolation fate (ie 24 -7 -365) in saturated soil, therefore, for the. purposes of this calculation, it is assumed that the sustained percolation rate in saturated soil is 0.25 in /hr (Note: if the soil is silty, more than 5% by weight passing the 200 sieve, the percolation rate shall be reduced to 0.125 in/hr). The leach line arch provides 2.8 sf of'percolation surface per lineal foot of leach line length. If the average nuisance water discharge per house in the neighborhood is 20 gallons per day that means each house must have 5.35 sf of percolation area in the leach field to percolate its 24 -hr nuisance water discharge. Therefore, the leach line length must. be 1.9 If /home. REVISIONS: APPROVED 08 21 01 STANDARD CHRIS A: VOGT 4 CITY ENGINEER 370 RCE. 44250 SAND FIL TER SHEET 6 OF 7 T�.4cr 3333 6 SANDFILTER SIZING CALCULATIONS Calculation #1 Determines how many standard size sandfilters are needed. No.* of Sandfilters = e homes = 40 homes /sandfilter " Round all fractions up to the nearest whole number Each sandfilter has 48 sf of filter surface (ie 6'x 8'); assume the incoming nuisance water will percolate through the sand at the rate of 4.6 inches per hour. The sandfilter must be sized to handle the "surge inflow rate" of 0.458 cf /house /hour, which is based on the assumption that, on average, each house releases 12 gallons in a 3.5 hour "surge" period. Therefore, each sandfilter is capable of handling 18.4 cf /hour. As a result, each,sandflter can handle the nuisance water released by 40 homes (18.4/0.458 =40). Calculation #2 - Determines how long the leach line must be. Leach Line Length* _ �LI homes x 1.9 If /home (sandy soil) " In feet to be divided evenly between the number of sandfilters Leach Line Length* = homes x 3.8 If /home (silty soil) In feet to be divided evenly between the number of sandfilters The critical aspect in sizing the leach line length is related to its ability to maintain a sustained percolation rate (ie 24 -7 -365) in saturated soil, therefore, for the purposes of this calculation, it is assumed that the sustained percolation rate in saturated soil is 0.25 in /hr.(Note: if the soil is silty, more than 5% by weight passing the 200 sieve, the percolation rate shall be reduced to 0.125 in /hr). The leach line arch provides 2.8 sf of percolation surface per lineal foot of leach line length. If the average nuisance water discharge per house in the neighborhood is 20 gallons per day that means each house must have 5.35 sf of percolation area in the leach field to percolate its 24 -hr nuisance water discharge. Therefore, the leach line length must be 1.9 If /home. REVISIONS: APPROVED 08/21/01 CHRIS A: VOGT CITY ENGINEER RCE 44250 r � SAND FILTER STANDARD 370 SHEET 6 OF 7 7-2,t6 T 8Z2 7q SANDFILTER SIZING CALCULATIONS Calculation #1 Determines how many standard size sandfilters are needed. NO.* of Sand filters = 33 homes 40 homes /sandfilter * Round all fractions up to the nearest whole number Each sandfilter has 48 sf of filter surface (ie 6'x 8'); assume the incoming nuisance water will percolate through the sand at the rate of 4.6 inches per hour. The sandfilter must be sized to handle the "surge inflow rate" of 0.458 cf/house /hour, which is based on the assumption that, on average, each house releases 12 gallons in a 3.5 hour "surge" period. Therefore, each sandfilter is capable of handling 18.4 cf /hour. As a result, each ,sandfilter can handle the nuisance water released by 40 homes (18.4/0.458 =40). Calculation #2 - Determines how long the leach line must be. Leach Line Length* = 3S homes x 1.9 If /home (sandy soil) * In feet to be divided evenly between the number of sandfilters Leach Line Length* = homes x 3.8 If /home (silty soil) * In feet to be divided evenly between the number of sandfilters The critical aspect in sizing the leach line length is related to its ability to maintain'a sustained percolation rate (ie 24 -7 -365) in saturated soil, therefore, forthe purposes of this calculation, itis assumed that the sustained percolation rate in saturated soil is 0.25 in /hr.(Note: if the soil is silty, more than 5% by weight passing the 200 sieve, the percolation rate shall be reduced to 0.125 in /hr). The leach line arch provides 2.8 sf of. percolation surface per lineal foot of leach line length. If the average nuisance water discharge per house in the neighborhood is 20 gallons per day that means each house must have 5.35 sf of percolation' area in the leach field to percolate its 24 -hr nuisance water discharge. Therefore, the leach line length must be 1.9 If /home. ZO home's + <000 sF �Sy_ REVISIONS% APPROVED --08/21101 STANDARD CHRIS A: VOGT Wt 4 CITY ENGINEER 370 RCE 44250 SAND FILTER SHEET 6 OF 7