The URL can be used to link to this page

33801.33 80 F', CPreliminag1 `HYDROLOGY-STUDY 3 For Tentative Tract No. 33801 In the City of La Quinta, California January, 2006 PREPARED FOR: Blake Jumper 47750 Caleo Bay Drive La Quinta, CA 92253 PREPARED BY.- P &D Consultants, Inc. 8954 Rio San Diego Drive, Suite 610 San Diego, CA 92108 (619) 291 -1475 P &D J.N. 175846 --- � i o awrence R. Rega RCE 25908 Registration Expires 12/31/07 ,RpFESS GE 3 ►�Q, G259o8 D n=+ d EXP.12/31 /07 CIVIV 9lFOF CAI�F�� Prepared By: CFH rI' ! r s 13 � %� J • r1 � {ate; r r � •. OVERVIEW The purpose of this study is to determine the maximum storage volume required to contain the entire runoff from the 100 -year peak storm event. In order to determine the maximum flood volume the 3, 6 and 24 hour 100 year storm events have been analyzed. The project site is located west of Madison Street just north of Avenue 60. The existing topography shows that in general the terrain slopes at about-2 -3% to the northeast. There are no areas of concentrated flow within the project area. The proposed conditions will develop eight numbered lots each approximately 8,500 square feet. Lot B which fronts the property to Madison Street will serve as a retention basin. A proposed street boarders the property to the south and will slope east towards Madison Street. There are three proposed catch basins with the project. The two onsite. curb inlets are in sag and the one offsite is on grade. The project site is hydraulically responsible for all flood. volumes generated by the property boundary as well the public street frontage to the centerline of Madison Street. This area totals 2.8 acres, 2.6 onsite and 0.2 offsite. Any overflow from the proposed onsite retention basin will back flow out through the curb inlet located in Madison Street and flow north along the street. 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. A percolation test was not conducted on this site and calculations herein assume the conservative case with no infiltration. BASIN VOLUME The volume of the retention basin for tract 32225 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 451.7+ (CB #6). Section Area at Incremental Depths Bottom if 2' 3' 4' • 5' 1,650 2,275 3,000 3,775 4,615 5,460 Elevation ( +445.7) ( +446.7) ( +447.7) '( +448.7) ( +449.7) ( +450.7) Capacity 0 1,963 4,600 7,988 12,183 17,220 (Note: the regression curve for data is y = 400x2 + 1407x + 165, with R2 =1) Tract 3380.1 :TM January 2005 The total capacity of the retention basin is approximately 17,220 cubic feet with a flood depth of 5 feet and was calculated as follows. V = ( E Ai li =o-► d) + E A (i =t— d -1) %2 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). ANALYSIS The following chart shows the results from the flood analysis. Results show that the 100 year 24 -hour storm resulted in the greatest volume of water produced. 100 Year Event 3 -Hour 6 -Hour 24 -Hour Maximum Volume 14430 12693 15839- Percent Capacity 84% 74% 92% (Note: the percent capacity is percent of available volume, 17,220 cf as determined) 18000 16000 14000 12000 IF d 10000 E c 8000 6000 4000 2000 0 100 Year Storm Event 24 -Hour Rainfall Depth 0:00 5:00 10:00 15:00 20:00 Time (Note: y = 5.0' max) 5.0 4.5 4.0 3.5 3.0 2.5 a CD 2.00 1.5 1.0 0.5 0.0 The results show that the retention basin for tract 33801 has been adequately sized to contain-the entire flood volume produced by the designated tributary area. Tract 33801 TM January 2005 TRIBUTARY AREA BOUNDARY B l 12, 333 sq. H. 7&& CT 1p NO Jw LOT 8 ws a - eonom a + 5.0 WS - 454.4 (17,000 CF CAPAOM Rw 1 1 2 3 4 5 6 7 8 DRY ` di 9,516 Sq. /f. 4627 461.5 460.8 460.1 489.4 4585 457.5 ,;� 8,408 sq. ft. 8,580 sq. R. 8,580 sq. ft 8,580 sq. /f. 8,580 sq. /t. $580 sq. /t. 6,580 sq. /t. (PRIVATE STREET) 1.5% LOT A '. °� �I -� - T 1 LOT C" 7 MCTJ NO , . 1 PROPOSED CONDITIONS NI SCALE 1`80' Retention Basin For TR# 33801 RETENTION BASIN AREA 5,500 SF RETENTION BASIN VOLUME 17,220 CF RETENTION BASIN POINT PERCOLATION 0.00 IN /HR RETENTION BASIN PERCOLATION 0.00 CF /M PHYSICAL DATA RUNOFF AREA 2.80 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) 0.51 IN /HR PLATE E -6.2 INPREVIOUS COVER FOR DEVELOPED AREAS (Ai) 0.50 PERCENT PLATE E -6.3 ADJUSTED LOSS RATE (Fp' (1.00 - .09' Ai)) 0.281 IN /HR PLATE E -1.1 LAG TIME RUNOFF AREA 0.004 SQUARE MILES LENGTH OF LONGEST.WATERCOURSE (L) 0.12 MILES LENGTH TO CENTROID OF RUNOFF AREA (Lca) 0.06 MILES ELEVATION OF HEADWATER 465 FEET ELEVATION OF CONCENTRATION POINT 455 FEET ELEVATION CHANGE 10 FEET 'SLOPE (S) 83.33 FEET /MILE MANNINGS NUMBER (n) 0.02 PLATE E -3 LAG TIME (24' n)' (L' Lea / S ^.5) ^.38 0.0318 HOURS. LAG TIME 1.91 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 Retention Basin For TR# 33801 100 YEAR 3 -HOUR CHART 3 -HOUR POINT RAIN FALL 2.25 1 INCHES I RETENTION BASIN PERCOLATION 0.00 CF /5 MINS UNIT TIME PERIOD S MINUTES JADJUSTED INFLITRATION RATE 0.281 IN /HR RUNOFF AREA 2.8 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 1.3 0.351 0.281 0.071 0.20 59.7 59.7 60 2 0:05 1.3 0.351 0.281 0.071 0.20 59.7 59.7 119 3 0:10 1.1 0.297 0.281 0.017 0.05 14.0 14.0 133. 4 0:15 1.5 0.405 0.281 0.125 0.35 105.5 105.5 239 5 0:20 1.5 0.405 0.281 0.125 0.35 105.5 105.5 344 6 0:25 1.8 0.486 0.281 0.206 0.58 174.1. 174.1 518 7 0:30 1.5 0.405 0.281 0.125 0.35 105.5 105.5. 624 B 0:35 1.8 0.486 0.281 0.206 0.58 174.1 174.1 798 9 0:40 1.8 0.486 0.281 0.206 0.58 174.1 174.1 972 10 0:45 1.5 0.405 0.281 0.125 0.35 105.5 105.5 1077 11 0:50 1.6 0.432 0.281 0.152 0.43 128.3 128.3 1206 12 0:55 1.8 0.486 0.281 0.206 0.58 174.1 174.1 1380 13 1:00 22 0.594 0.281 0.314 0.89 265.5 265.5 1645 14 1:05 2.2 0.594 0.281 0.314 0.89 265.5 265.5 1911 15 110 2.2 0.594 0.281 0.314 0.89 265.5 265.5 2176 16 1:15 2.0 0.540 0.281 0.260 0.73 219.8 219.8 2396 17 1:20 2.6 0.702 0.281 0.422 1.19 357.0 357.0 2753 18 1:25 2.7 0.729 0.281 0.449 1.27 379.9 379.9 3133 19 1:30 2.4 0.648 0.281 0.368 1.04 311.3 311.3 3444 20 1:35 2.7 0.729, 0.281 0.449 127 379.9 379.9 3824 21 1:40 3.3 0.891 0281 0.611 1.72 517.1. 517.1 4341 22 1:45 3.1 0.837 0.281 0.557 1.57 471.4 471.4 4813 23 1:50 2.9 0.783 0.281 0.503 1.42 425.6 425.6 5236 24 1:55 3.0 0.810 0.281 0.530 1.49 446.5 448.5 5687 25 2:00 3.1 0.837 0.281 0.557 1.57 471.4 471.4 6158 26 2:05 42 1.134 0.281 0.854 2.41 722.9 722.9 6881 27 2:10 5.0. 1.350 0.281 1.070 3.02 905.9 905.9 7787 28 2:15 3.5 0.945 0.281 0.665 1.88 562.8 562.8 8350 29 2:20 6.8 1.836 0.281 1.556 4.39 1 1317.5 1317.5 9667 30 2:25 7.3 1.971 0.281 1.691 4.77 1431.9 1431.9 11099 31 2:30 8.2 2.214 ' 0.281 1.934 5.46 1637.7 1637.7 12737 32 2:35 5.9 1.593 0.281 1.313 3.71 1111.7 1111.7 13848 33 2:40 2.0 0.540 0.281 0.260 0.73 219.8 219.8 14068 34 2:45 1.8 0.486 0.281 0.206 0.58 174.1 174.1 14242 35 2:50 1.8 6486 0.281 0.206 0.58 174.1 174.1 14416 36 2:55 0.6 0.162 0.281 0.146 0.016 0.05 13.7 13.7 14430 Retention Basin For TR# 33801 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 0.281 IN/HR RUNOFF AREA 2.8 ACRES LOW LOSS RATE 0.9 PERCENT EFFECTIVE RAIN FLOODING RETENTION BASIN UNIT TIME HOUR PATTERN PERCENT STORM RAIN LOSS RATE IWHR EFFECTIVE RAIN FLOW EFFECTIVE RUNOFF EFFECTIVE RETENTION TOTAL BASIN VOLUME UNITS H:MM PLATE -E5.9 IN/HR MAXIN /HR LOWIN/HR IN /HR CFS CF CF CF' .1 0:00 0.5 0.165 0.281 .0.149 0.017 0.05 14.0 14.0 14 2 005 0.6 0.198 0.281 0.178 0.020 0.06 16.8 16.8 31 3 010 0.6 0.198 0.281 0.178 0.020 1 0.06 16.8 16.8 48 4 0:15 0.6 0.198 0.281 0.178 0.020 0.06 16.8 1 16.8 64 5 0:20 0.6 0.198 0.281 0.178 0.020 0.06 16.8 16.8 81 6 0:25 0.7 0.231 0.281 0.206 0.023 0.07 19.6 19.6 101 7 0:30 0.7 0.231 0.281 1 0.208 0.023 0.07 19.6 19.6 120 8 0:35 0.7 0.231 0.281 0.208 0.023 0.07 19.6 19.6 140 9 0:40 0.7 0.231 0.281 0.208 0.023 0.07 19.6 19.6 159 10 0:45 0.7 0.231 0.281 0.208 0.023 0.07 19.6 19.6 170 11 0:50 0.7 0.231 0.281 0.208 0.023 0.07 ' 19.6 19.6 198 12 0:55 0.8 0.264 0.281 0.238 0.026 0.07 22.4 22.4 1 221 13 100 0.8 0.264 0.281 0.238 0.026 0.07 22.4 22.4 243 14 1:05 0.8 0.264 0.281 0.238 0.026 0.07 22.4 22.4 266 15 1:10 0.8 0.264 0.281 0.238 0.026 0.07 22.4 22.4 288 16 1:15 0.8 0.264 0.281 0.238 0.026 0.07 22.4 22.4 310 17 1:20 0.8 0.264 0.281 0.238 0.026 0.07 22.4 22.4 333 18 1:25 0.8 0.264 0.281 0.236 0.026 0.07 22.4 22.4 355 19 1:30 0.8 0.264 0.281 0.238 0.026 0.07 22.4 22.4 377 20 1:35 0.8 0.264 0.281 0.238 0.028 0.07 22.4 22.4 400 21 1:40 0.8 0.264 0.281 0.238 0.026 0.07 2264 22.4 422 22 1:45 0.8 0.264 0.281 0.238 0.026 0.07 22.4 22.4 444 23 1:50 0.8 0.264 0.281 0.238 0.026 0.07 22.4 22.4 467 24 1:55 0.9 0.297 0.281 0.017 0.05 14.0 14.0 481 25 2:00 0.8 0.264 0.281 0.238 0.026 0.07 22.4 22.4 503 26 2:05 0.9 0.297 0.281 0.017 0.05 14.0 14.0 517 27 2:10 0.9 0.297 0.281 - 0.017 0.05 14.0 14.0 531 28 1 215 0.9 0.297 0.281 0.017 0.05 14.0 14.0 545 29 2:20 0.9 0.297 0.281 06017 0.05 14.0 14.0 559 30 2:25 0.9 0.297 0.281 - 0.017 0.05 1460 14.0 573 31 2:30 0.9 0.297 0.281 - 0.017 0.05 14.0 14.0 587 32 2:35 0.9 0.297 0.281 0.017 0.05 14.0 14.0 601 33 2:40 1.0 0.330 0.281 0.050 0.14 41.9 41.9 643 34 2:45 1 0.330 0.201 - 0.050 0.14 41.9 41.9 685 35 2:50 1 0.330 0.281 0.050 0.14 41.9 41.9 727 36 2:55 1 0.330 0.281 - 0.050 0.14 41.9 41.9 759 37 3:00 1.0 0.330 0.281 - 06050 0.14 41.9 41.9 811 38 3:05 1.1 0.363 0.281 0.083 0.23 69.9 69.9 880 39 3:10 1.1 0.363 0.281 0.083 0.23 69.9 69.9 950 40 3:15 1.1 0.363 0.281 0.083 0.23 69.9 69.9 1020 41 3:20 1.2 0.396 1 0.281 0.116 0.33 97.6 97.8 1118 42 3:25 1.3 0.429 0.281 - 0.149 0.42 125.8 125.8 1244 43 3:30 1.4 0.462 0.281 0.182 0.51 153.7 153.7 1398 44 3:35 1.4 0.462 0.281 - 0.182 0.51 153.7 153.7 1551 45 3:40 1.5 0.495 0.281 06215 0.61 181.7 18167 1733 46 3:45 1.5 0.495 0.281 - 0.215 0.61 181.7 181.7 1915 47 150 1.6 0.528 0.281 - 0.248 0.70. 209.6 209.6 2124 48 3:55 1.6 0.528 0.281 - 0.246 0670 209.6 209.6 2334 49 4:00 1.7 0.561 0.281 0.281 0.79 237.6 237.6 2571 50 4:05 1.8 0.594 0.281 0.314 0.89. 265.5 26565 2837 51 4:10 1.9 0.627 0.281 0.347 0.98 293.5 293.5 3131 52 4:15 2.0 0.660 0.281 0.380 1.07 321.4 321.4 3452 53 4:20 2.1 06693 0.281 - 0.413 1.16 349.4 349.4 3801 54 4:25 2.1 0.693 0.281 - 0.413 l 16 349.4 349.4 4151 55 4:30 2.2 0.728 0.281 06446 1.26 377.3 377.3 4528 56 4:35 2.3 0.759 0.281 0.479 1.35 405.3 405.3 4933 57 4:40 2.4 0.792 0.281 0.512 1.44 433.2 433.2 5367 58 4:45 2.4 0.792 0.281 0.512 1.44 433.2 433.2 5800 59 4:50 2.5 0.825 0.281 0.545 1.54 461.2 461.2 6261 60 4:55 2.6 0.858 0.281 0.576 1.63 489.1 489.1 6750 61 5:00 3.1 1.023 0.281 0.743 2.10 628.9 828.9 7379 62 5:05 3.6 1.188 0.281 0.908 2.56 768.7 768.7 8148 63 5:10 3.9 1.287 0.281 1.007 2.84 652.5 852.5 9000 64 5:15 4.2 1.386 0.281 1.106 3.12 936.4 936.4 9937 65 5:20 4.7 1.551 0.281 1.271 3.59 1076.1 1076.1 11013 66 5:25 5.6 1.848 0.281 16568 4.43 1327.7 1327.7 12340 67 5:30 1.9 0.627 0.281 0.347 0.98 293.5 293.5 12634 68 5:35 0.9 0.297 06281 0.017 0.05 14.0 14.0 12648 69 5:40 0.6 0.198 0.281 0.178 0.020 0.06 16.6 1668 12885 70 5:45 0.5 0.165 0.281 0.149 0.017 0.05 14.0 14.0 12679 71 5:50 0.3 0.099 0.281 0.089 0.010 0.03 8.4 8.4 12687 72 5:55 0.2 0.066 0.281 0.059 0.007 0.02 5.6 1 5.8 12693 Retention Basin For TR# 33801 100 YEAR 24 -HOUR CHART 24-HOUR POINT RAIN FALL I 5.00 INCHES RETENTION BASIN PERCOLATION 0.00 CFHS MINS UNIT TIME PERIOD 15 MINUTES 1ADJUSTED INFUTRAMON RATE 0.281 INMR RUNOFF AREA 2.8 ACRES 1LOWLOSSRATE 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 TOTALBASIN VOLUME UNITS H:MM PLATE -E5.9 I INMR MAXIN/HR LOW IN/HR INMR C CF CF CF 1 0:00 0.2 0.040 0.495 0.038 0.004 0.01 10.2 10.2 10 2 01.15 0.3 0.060 0.490 0.054 0.006 0.02 15.2 15.2 25 3 0:30 0.3 0.060 0.484 0.054 0.006 0.02 15.2 15.2 41 4 0:45 0.4 0.080 OA78 0.072 0.008 0,02 20.3 20.3 61 5 1:00 0.3 0060 0.473 0.054 0.006 0.02 151 15.2 76 8 1:15 03 0.080 0.487 0.054 0.006 0.02 15.2 15.2 91 7 1:30 0.3 0.060 0.461 0.054 0.006 0.02 15.2 15.2 107 B 1:45 0.4 0.080 0.458 0.072 0.008 0.02 20.3 20.3 127 9 2:00 0.4 0.080 0.450 0.072 0.008 0.02 20,3 20.3 147 10 2:15 0.4 0.080 0.445 0.072 0.008 0.02 20.3 20.3 188 11 2:30 0.5 0.100 OA38 6.090 0.010 0.03 25.4 25.4 193 12 2:45 045 0.100 0.434 0.090 0.010 0.03 2544 25.4 219 13 3:00 0.5 0.100 0.429 0.090 0.010 0.03 25.4 25.4 211 W 3:15 0.5 0.100 0.423 0.090 0.010 0.03 25.4 254 269 15 3:30 0.5 0.100 0.418 0.090 0.010 0.03 25.0 7 25.4 295 18 3:45 0.6 0.120 0.413 0.108 0.012 0.03 1 30.5 30.5 1 325 17 4:00 0.6 0.120 0.407 0.108 0.012 0.03 30.5 30.5 358. 18 4:15 0.7 0.140 0.402 0.126 0.014 0.04 35.6 35.6 391 19 4;30 0.7 0.140 0.397 0.128 0.014 0.04 35.8 35,8 427 20 4:45 0.6 0.160 0.392 0.144 0.016 0.05 40.7 40.7 468 21 5:00 0.6 0.120 0.387 0.108 0.012 0.03 30.5 30.5 498 22 5:15 0.7 0.140 0.382 0.126 0.014 0.04 35.6 35.6 534 23 5:30 0.8 0.160 0.377 0.144 0.016 0.05 40.7 40.7 574 24 5:45 0.8 0.160 0.372 0.144 0.016 0.05 40.7 40.7 615 25 8:00 0.9 0.180 0.387 0.182 0.018 0.05 45.7 45,7 661 26 SAS 0.9 0.180. 0.382 0.182 0.018 0.05 45,7 45.7 706 27 6:30 1.0 0.200 0.357 0.180 0.020 0.08 50.8 50,8 757 215 6:45 1.0 0.200 0.352 0.180 0.020 0.06 50.8 .50.8 9015 29 7:00 1.0 0.200 0.348 0.180 0.020 0.08 50.8 50,8 659 30 7:15 1.1 0.220 0.343 0.198 0.022 0.06 55.9 55.9 915 31 7:30 1.2 0.240 0.338 0216 0.024 0.07 61.0 61.0 976 32 7:45 1.3 0.260 0.334 0.234 0.026 0.07 66.1 661 1042 33 8:00 1.5 0.300 0329 0.270 0.030 0.08 76.2 76.2 1118 34 8:15 1.5 0.300 0.324 0.270 0.030 0.08 76.2 76.2 1184 35 6:30 1.6 0.320 0.320 0.000 0.00 0.8 0.8 1195 36 8:45 1.7 0.340 0.315 0.025 0.07 62.9 62.9 1256 37 8:00 1.9 0.360 0.311 0.069 0.20 175.9 175.9 1434 38 8:15 2.0 0.400 0.306 0.094 0.26 237.8 237.8 1672 38 9:30 2.1 0.420 0.302 0.118 0.33 299.9 299,8 1971 40 9:45 2.2 0.440 0.298 0.142 0.40 361.7 361.7 2333 41 10:00 145 0.300 0.293 0.007 0.02 16.9 16.8 2350 42 10:15 1.5 0.300 0.289 0.011 0.03 27.7 27.7 2378 43 10.30 2.0 0.400 0.285 0.115 0.33 292.5 292.5 2670 44 10:45 2.0 0.400 0.281 0.119 0.34 303.1 303.1 2973 45 11:00 1.9 0.380 0.277 0.103 0.29 262.8 262.8 3236 46 11:15 1.9 0.380 0.273 0.107 0.30 273.1 273.1 3509 47 11:30 1.7 0.340 0.268 0.072 0.20 181.8 181.8 3691 48 11:45 1.8 0.360 0.264 0.0'6 0.27- 242.7 242.7 3934 49 12:00 25 0.500 0.261 0239 0.68 608.5 608.5 4542 50 12:15 2.6 0.520 0.257 0.263 034 669.2 669.2 5212 51 12:30 2.8 0.550 0.253 0.307 0.87 780,7 780.7 5992 52 12:45 2.9 0.580 0.249 0.331 0.03 8412 841.2 6833 53 13:00 3.4 0.680 0.245 0.435 1.23 1104.8 1104.8 7938 54 13:15 3.4 0.680 0.241 0.439 1.24 1114.3 1114.7 9052 55 13:30 2.3 0.480 0.238 0.222 0.83 564.6 564.6 9617 58 13:45 2.3 0.460 0.234 0.226 0.64 573.8 573.8 10191 57 14:00 2.7 0.540 0.231 0.309 1 0.87 786.1 786.1 ' 10977 58 14:15 2.6 0.520 0.227 0.293 0,83 744.3 744.3 11721 59 14:30 2.6 0.520 0.224 0.296 0.84 753,1 753.1 12474 60 14:45 2.5 0.500 0.220 0.280 0.79 710.9 710.9 M85 61 15:00 2.4 0.480 0.217 0.263 0.74 668.7 1 668.7 13854 62 15:15 2.3 0.460 0.214 0.246 0.70 626.3 626.3 14480 63 15:30 1.8 0.380 0.210 0.170 0.46 431.3 431.3 14912 64 15:45 1.9 0.380 0.207 0.173 0.49 439.5 439.5 15351 65 16:00 OA 0.080 0204 0.072 0.008 0.02 20,3 20.3 16371 66 16:15 OA 1 0,080 0.201 0.072 0.008 -' 0.02 20.3 20.3 15392 67 16:30 0.3 1 0.080 0.198 0.054 0.006 0.02 15.2 15.2 15407 68 16:45 0.3 1 0.060 0.195 0.054 0.006 0.02 15.2 15.2 15422 69 17:00 0.5 0.100 0.102 0.090 0.010 0.03 25.4 25,4 15448 70 17:15 0.5 0.100 0.188 0.090 0.010 0.03 25.4 25.4 15473 71 17:30 0.5 0.100 0.186 0.090 0.010 0.03 25.4 25.4 16498 72 17:45 0.4 0.080 0.163 0.072 0.008 0.02 20.3 20.3 15519 73 18:00 0.4 0.080 0.181 0.072 0.008 0.02 20,3 20.3 15539 74 18:15 0.4 0.080 0.178 0.072 0.008 0.02 20.3 20.3 15558 75 18:30 0.3 0.060 0.175 ' 0.054 0.006 0.02 15.2 152 15576 78 18:45 0.2 0.040 0.173 0.036 0.004 0.01 10.2 10.2 15585 77 191.00 0.3 0.060 0.171 0.054 0.008 0.02 15.2 15.2 15600 76 191.15 0.4 1 0.080 0.168 0.072 0.008 0.02 20.3 20.3 16820 79 19:30 0.3 0.080 0.168 0.054 0.008 0.02 15.2 15.2 15838 so 1$.45 0.2 0.040 0.164 0.038 0.004 0.01 10.2 10.2 16848 ' 81 20:00 0.3 0.080 0.181 0.054 0.006 0.02 15.2 15.2 15661 82 20:15 0.3 0.060 0.159 0.054 0.006 0.02 15.2 15.2 15878 83 20:30 03 0.060 0.157 0.054 0.006 0.02 15.2 15.2 15692 84 20:45 0.2 0.040 0.155 0.036 0.004 0.01 40.2 10.2 15702 95 21:00 0.3 0.080 0,154 0.054 0.008 0.02 15.2 152 15717 86 21:15 02 0.040 0.152 0.036 0.004 0.01 10.2 10.2 15727 87 21:30 03 0.060 0.150 0.054. 0.008 0.02 15.2 15.2 15742 80 21:45 0.2 0.040 0.149 0.038 ' 0.004 0.01 10.2 10.2 15753 89 22:00 0.3 0.080 0.147 0.054 0.008 0.02 15.2 15.2 15785 90 22'15 0.2 0.040 0.146 0.036 0.004 0.01 10.2 10.2 15778 91 22;30 01 0.040 0.145 0.038 0.004 0.01 10.2 10.2 16788 82 22:45 0.2 0.040 0.143 0.036 0.004 0.01 10.2 10.2 15798 03 23:00 0.2 0.040 0.142 0.038 0.004 0.01 10.2 10.2 15808 94 23:15 0.2 0.040 0.142 0.036 1 0.004 0.01 10.2 10.2 15519 95 23:30 0.2 0.040 0.141 0.036 0.004 0.01 101 10.2 15829 98 23:45 0.2 0.040 1 0.140 1 0.038 1 0.004 041 101 10.2 15839 ACTUAL IMPERVIOUS COVER Land Use. (1) Range- Percent Recommended Value 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 .20,000 S. F. ( Acre) Lots 30 -'45 40 7,200 - 10,000 S. F. Lots 45 55 C�) U5� Multiple Family Residential: Condominiums 45 - 70 65 Apartments 65 - 90 80 Mobile Home Park 60 - 85 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 impervious area 5 per- cent over the values recommended-in the table above. R C F C a W C D IMPERVIOUS COVER HYDROLOSY MANUAL FOR DEVELOPED AREAS PLATE E -6.3 E RUNOFF INDEX NUMBERS OF HYDROLOGIC SOIL -COVER COMPLEXES FOR PERVIOUS AREAS -AMC II. Cover Type (3) Quality of Soil Group A B 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 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 J 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 HYDROLOGY MANUAL FOR PERVIOUS AREAS PLATE E -6.1 (I of 2) TCB I AECOM P&D Consultants 8954 Rio San Diego Drive, Suite 610, San Diego, California 92108 D n n T 619.291.1475 F 619.291.1476 www.tcb.aecom.com 0 Vic JJAN. 32006. Transmittal Date: 1 -12 -06 To: Mr. Andrew Mogensen City of La Quinta — Community Development Department 78 -495 Calle Tampico La Quinta, CA 92253 Phone: 760 - 777 -7068 From: Bob Grable Project No.: 175846; City La Quinta Tract 33801 Transmitted Via: Fed EX Overnight We are sending you the following: Number of Copies Description 5 Revised Preliminary Hydrology Report — January 2006 21 Revised Tentative Map — dated January 12, 2006 Andrew, per our telephone conversation today, enclosed are revised Tentative Maps and Hydrology Reports. Could you please pass one:report and TM,to Bnan Ching ASAP After reviewing the hydrology report with Paul-Goble" oho 6 phone; he= said =he `wotild`quicklyrevlew It when it, came in. Thank you'very much for your help and please call if any questions or additional needs, BG a.v. o. :•tw .L,+,4fA• SITE DATA 1. ASSESSORS PARCEL NUMBERS- 766- 080 -009 2 SITE AREA: 258 ACRES J. BUILDING SETBACKS FRONT 20 FT. REAR: 20 FT. SIDE: 5 FT 4. ZONING EXIS77NG. RL PROPOSED: RL ADJACENT PROPERTIES' RL 5. GENERAL PLAN DESIGNATION EXISTING.• AGRICUL TURE PROPOSED. RESIDENTIAL LOW 6. EXISTING LAND USE AGRICUL 7URE (TWO EXISTING BUILDINGS) 7 PROPOSED LAND USE: SINGLE FAMILY RESIDENTIAL AND COMMON OPEN SPACE. 8. NUMBER OF PROPOSED LOTS: 8 RESIDENTIAL LOTS 3 LETTERED LOTS ( P RI VA TE STREET & 2 OPEN SPACE MAINTAINED BY HOA) 9. PUBLIC AGENCIES /UTILITIES SEWER. COACHELLA VALLEY WA 7ER DISTRICT WA 7ER. COACHELLA VALLEY WATER DISTRICT POLICE AND FIRE: COUNTY OF RIVERSIDE SCHOOLS: COACHELLA VALLEY UNIFIED SCHOOL DISTRICT ELECTRIC. • IMPERIAL IRRIGA77ON DIS7RICT GA 5- N/A 7ELEPHONE• VERION CABLE TV- 77ME WARNER 10. EAR7HWORK QUA N7777ES (RAW): CUT 1,200 C FILL: 3,100 C (OVER EXCAVATION NIC.) 11. SOURCE OF TOPOGRAPHY- FIELD SURVEY (MAY, 2005) GENERAL NOTES 1. ALL WORK WITHIN THE PUBLIC RIGHT OF WAY SHALL BE DONE IN ACCORDANCE WITH THE STANDARD SPECIFICA 77ONS FOR PUBLIC WORKS CONS7RUC710N AND 7HE DESIGN AND CONSTRUCTION STANDARDS OF THE CITY OF LA QUINTA. 2• THIS MAP PROPOSES SCHEDULE "A" IMPROVEMENTS FOR PUBLIC FACIL177ES J. PRI VA 7E STREETS ARE PROCEED WITH I GA 7ED EN7RY. 4. GRADING SHALL BE CONS7RUC7ED IN ACCORDANCE WITH THE COUNTY OF RIVERSIDE GRADING ORDINANCE. 5. GRADING SHOWN HEREON IS PRELIMINARY AND SUBJECT TO CHANGE IN FINAL DESIGN. 6. U77LI77ES SHALL BE UNDERGROUND. EASEMENTS TO BE PROVIDED AS NECESSARY. 7 SANITARY SEWER TO BE PROVIDED AND CONNECTED TO COACHELLA VALLEY WATER DISTRICT SEWER SYSTEM. SEWER MAINS ARE 8" MINIMUM AND SHALL BE INSTALLED IN ACCORDANCE WITH COACHELLA VALLEY WA7FR DISTRICT STANDARDS SEWER SHOWN IS PRELIMINARY AND IS SUBJECT TO MODIRCA77ON IN FINAL DESIGN. 8. WATER SYSTEM TO BE INSTALLED IN ACCORDANCE WITH THE STANDARDS OF THE COACHELLA VALLEY WATER DISTRICT AND SHALL BE MAINTAINED AND OPERA7ED BY SAID DIS7RICT. 9. 7HE FIRE HYDRANT LOCA77ONS AS SHOWN ARE PRELIMINARY AND SHALL BE INSTALLED IN ACCORDANCE WITH THE CITY OF LA QUINTA ENGINEERING DEPARTMENT AND SUBJECT TO APPROVAL BY THE FIRE DEPARTMENT. 10. SUBDIVIDER TO PROVIDE AND INSTALL APPROVED STREET LIGHT STANDARDS AND FIXTURES IN THE TYPE AND NUMBER REQUIRED BY THE CITY OF LA QUIINTA. 11. SPECIFIC METHODS OF HANDLING STORM DRAINAGE ARE SUBJECT TO APPROVAL BY 7HE CITY ENGINEER AT THE 77ME OF SUBMITTAL OF IMPROVEMENT AND GRADING PLANS DESIGN SHALL BE ACCOMPLISHED ON THE BASIS OF THE REQUIREMENTS OF THE APPROVED DRAINAGE /STORM WATER MANAGEMENT REPORT DRAINAGE EASEMENTS SHALL BE PROVIDED AS REQUIRED BY THE CITY ENGINEER. 12. DEVELOPER SHALL COMPL Y WI TH THE REQUIREMENTS OF THE NA 77ONAL POLLUTANT DISCHARGE ELIMINA77ON SYS7E-M (NPDES) PERMIT, LATEST VERSION. DEVELOPER SHALL PROVIDE IMPROVEMENTS C0NS7RUC7ED PURSUANT TO BEST MANAGEMENT PRAC77CES AS REFERENCED IN THE "CALIFORNIA STORM WATER BEST MANAGEMENT PRA C77CES HANDBOOK" TO REDUCE SURFACE POLLUTANTS TO AN ACCEPTABLE LEVEL PRIOR TO THE DISCHARGE TO SENS177VE AREAS. PLANS FOR SUCH IMPROVEMENTS SHALL BE SUBMITTED TO AND SUBJECT TO THE APPROVAL OF THE CITY ENGINEER. 13. MODEL UNITS MAY BE BUILT PRIOR TO FINAL MAP RECORDA 770N. 14. THIS MAP REPRESENTS ALL CON77GUOUS OWNERSHIP. LOT NUMBER l( PAD ELEVATION LAA 3I � 5' - rC` - I 5' Cs `; N � O STREET TYPICAL LOT GRADING NTS P/L ON -SITE MAX FLOOD DEPTH 5' TENTATIVE TR.ACT l P No 33801 AVERAGE 25' do 9' VARIES STORM pR�41 SAND FILTER AND LEACH LINE TYI CAL BASIN SECTION NTS R/W 110' R.O.W. R/W (EXISTING) 55 55 55' EXIST. R W 34' PROPOSD IMPROVEMENT EXISTIN IMPROVEMENTS 30' 18'f 16'f 16'± 20' 8" C RB JAC. OVERLAY �EXIS77NG PAVEMENT C PVM'T OVER TO REMAIN 20' LANDSCAPE APPROVED BASE EASEMENT (�— EXIST 30" WA TER EXIST. 12" 8' MEANDERING v (WEST OF MADISON ST CL IRRIG PIPE SIDEWALK AS SHOWN HEREON) (WEST OF MADISON ST AS SHOWN HEREON) MADISON STREET (LOOKING NORTH) NTS OFF- Sl7E PERIMETER WALL DETAIL NTS 36' 2, rL 32' rL 2, 10' 16' 16' 10' P. U. E. A. C. PA V'T. LINE P.U.E. AND BASE I f 2q 29,' CONC. D WATER CURB S OUTH 6' NORTH T SEWER PRIVATE INTERIOR STREET NTS u1j] 1� I- L-- I 7 8 ACT 33801 = � I PROP 8" VCP SEwER� EX. 30" WATEI PAIN EX. MH I 2Q INV. 448.60 , PROP. 24" WATER / R/W 24,. 1 1/2" �-- 3/4» EXISTING 30" PUBLIC HIGHWAY EASEMENT nr-n ArMll n in.IC lei M1 779 0/` 3ic;3 n j I i I \ i 71AC MF Nd M68 EX. 72" IRR MAIN ��r i ! l EX. 8" VCP SEWER EX. MH 19 CVWD DWG. NO. 33194 INV 447.58 - --I-w W �VEN& /mow —VV' w w w- OFF -SITE SEWER CONNECTION N.T.S STREET WIDTH SHOWN ON PLANS -1/4:1 BA T TER °3 /�8tR. ? I �_ 30" 6" WEDGE CURB NTS ENGINEER OF WORK LExp.6/30/07 P & D CONSULTANTS, INC. 8954 RIO SAN DI EGO DRIVE, SUITE 610 SAN DIEGO, CALIFORNIA 92108 TEL: (619) 291-1475 f4T�tTf2e or Date: 11/15/2005 PAULI R. KANt RCE 44016 F C E � V E D JAN 13 Zoos 0 40' 0' 40 80' 120' SCALE I)' - 40" LEGEND PROJECT BOUNDARY PROPOSED CONTOUR EXISTING CONTOUR PROPOSED SPOT ELEVA 77ON LOT LINE LOT NUMBER PAD ELEVATION T. C FS F. L. P. E. F. G. L. P. H.P. SLOPE (2:1 MAX) DIRECTION OF FLOW WITH GRADIENT PROPOSED STORM DRAIN PROPOSED WATER LINE PROPOSED SEWER LINE W TH MH FLOW DIRECTON 8' MEANDERING SIDEWALK -- -_"- 460 4� 3 4XX.X TOP OF CURB FINISHED SURFACE FLOW LINE PAD ELEVATION FINISHED GRADE LOW POINT HIGH POINT TENTATIVE MAP ~ TRACT NO. 3380' PRELIMINARY GRADING PLAN VICINITY MAP N. T. S J IiV THOMAS BROTHERS: D o 1998 EDITION MAP PAGE. • 5530 Elf Fred Waring Dr o CORRDINA TES. G -4 J'-__Ayeriue4 10 Pga West Resort Golf Course Lake 50th ig V) PREPARED BY: 01 P &D CONSULTANTS, INC. 8954 RIO SAN DIEGO DRIVE, SUITE 610 SAN DIEGO, CALIFORNIA 92108 TELE. (619) 291 -1475 FAX. 291 -1476 ASSESSOR'S PARCEL NO: 766 - 080 -009 LEGAL DESCRIPTION: THE NORTH HALF OF THE NORTH HALF OF THE SOUTHEAST QUARTER OF THE SOUTHEAST QUARTER OF SECTION 28, TOWNSHIP 6 SOUTH, RANGE 7 EAST, SAN BERNARDINO BASE AND MERIDIAN, IN THE CITY OF LA QUINTA, COUNTY OF RIVERSIDE, STATE OF CALIFORNIA OWNER /APPLICANT NAME BLAKE JUMPER ADDRESS 80553 JASPER PARK INDIO, CA 92201 TELEPHONE (760) 399 -7263 WJ 0 N °o 'a Thermal Municipal Airport Revision 9: Revision 8: Revision 7: Revision 6: Revision 5: Revision 4: Revision 3: Revision 2 : JAN. 12 2006 Revision 1 : NOV. 18, 2005 Original Date: JUNE 1, 2005 SHEET of PROJECT NO. 175846