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29457.1 0 -a- 04 IE .1 0 -a- HYDROLOGY & HYDRAULICS Tract. 29457 Prepared by: WATSON & WATSON ENGINEERING, INC. 79440 Corporate Center Drive, Suite 107 La Quinta, CA 92253 August 16, 2005 Hydrology Tract 29457 -4 BACKGROUND Tract 29457 -4 is a subdivision of approximately five acres into seven residential lots. A retention basin is proposed for the south end of the site. The project is bounded on the east, west and south by existing subdivisions. The project site site has existing walls on the east, west and south sides. Due to the existing development around the project, we are assuming a zero percolation rate and are providing calculations that show the lowest pad elevation is above a 500 -year storm event. Also we are providing weep holes in the existing wall that will allow an outlet into a street in the adjacent subdivision. These are, however, unnecessary due to the conservative design. As was used for the Rancho La Quinta project, we used the following criteria: Soil Type: "A" 100-year 24 hour: 4.0" 100 -year 6 hour: 2.75" 100 -year 2 hour: 22" Development: %2 acre (1/4 acre for existing development) It should be noted that the hydrology report for.this tract. was previously approved by Berryman & Henigar on 10/9/02. • i R C F C a W C D HYDROLOGY 1\AANUAL RATIONAL METHOD CALCULATION FORM PR' 6J ECT -rk Z 995"i FREQUENCY !iQ/o 0 Sheet No. —I of I—Sheris Calculated by �!� - "5KT�__- Checked by •-----� -- --� --- DRAINAGE AREA �- ww . (,:Or C �.O'r q., LIMITATIONS: I. Maximum length =1000 Tc 2. Maximum area = 10 Acres 5— H 0 L) TC1 L c 100 1000 —90 —900 o —80 100 800 70 —700 CL E Ob a 30 9 > C 20 — E CL 5 0 K A —500' U. Undeveloped 0 Good Cover 2 35 Undeveloped 0 E 1.0 —400 0 30 14 0 a-350 Ca Poor Cover 25 �Single Fam 502 17 300 re) 0 Z omme 11 arcial 0 20 19 — 1z; (Pav 19 0- 18 17 1 7 ,-250 16. M r 15' ..0 0-200 13- C 12 1 O� 150 —9 8 —7 —6 C-100 L C �.O'r q., LIMITATIONS: I. Maximum length =1000 Tc 2. Maximum area = 10 Acres 5— H L4 R C FIC Ek WOO HYDROLOGY MANUAL 25 — KEY L••+i —Tc —K —Tc' 30— EXAMPLE*. (1) L =550', H =5.0, K =Single Family (1/4 Ac.) 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 0 L) 500 c 400 300 _—zoo 7— o w CL 100 aci so SO 60 8 CL E Ob a 30 9 > 0 0 ........... 20 — 10 K A II U. Undeveloped 0 Good Cover 2 Undeveloped 0 E 1.0 Fair Cover .8 .6 14 0 15 Ca Poor Cover �Single Fam 502 17 E re) 0 18 omme 11 arcial 0 19 — 1z; (Pav 20-- L4 R C FIC Ek WOO HYDROLOGY MANUAL 25 — KEY L••+i —Tc —K —Tc' 30— EXAMPLE*. (1) L =550', H =5.0, K =Single Family (1/4 Ac.) 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 Xl V (r7 `J' �v RAINFALL INTENSITY- INCHES PER HOUR CATHEDRAL CITY I CHERRY VALLEY 7 I CORONA I DESERT HOT SPRINGS I ELSINORE - YILDONAR DURATION FREQUENCY MINUTES 10 100 YEAR YEAR 5 4.14 6.76 6 3.73 6.08 7 3.41 S.S6 8 3.1S S.15 9 2.95 4.81 10 2.77 4.52 11 2.62 4.28. 12 2.49 4.07 13 2.36 3.88 14 2.28 3.72 IS 2.19 3.S8 16 2.11 3.44 17 2.04 3.32 IB 1.97 3.22 19 1.91 3.12 20 1.85 3.03 22 1.75 2.86 24 1.67 2.72 26 1.59 2.60 28 1.52 2.49 30 1.46 2.39 32 1.41 2.30 34 1.36 2.22 36 1.32 2.15 38 1.28 2.09 40 1.24 2.02 4S 1.16 1.89 50 1.09 1.78 55 1.03 1.68 60 .98 1.60 65 .94 1.53 70 .90 1.46 75 .86 1.41 80 .83 1.35 85 .80 1.31 SLOPE ■ .580 DURATION FREQUENCY MINUTES 6 2.96 4.53 10 100 4.21 YEAR YEAR 5 3.6S 5.49 6 3.30 497 7 3.03 4156 8 2.82 4:24 9 2.64- 3:97 10 2.49 3:75 11 2.36 3:S6 12 2.2S 3:39 13 2.16 3:25 14 2.07 3:12 15 1.99 3:00 16 1.92 2:90 17 1.86 2:80 18 1.80 2:71 19 1.75 2`64 20 1.70 2:56 22 1.61 2:43 24 1.54 2:32 26 1.4T 2:22 28 1.41 2:13 30 1.36 2405 32. 1.31 1:99 34 1.27 1:91 36 1.23 1:85 38 1.20 1:80 40 1.16 1:75 45 1.09 1:64 50 1.03 1:55 SS .98 1:47 60 .93 1:40 65 .89 1:34 70 .85 1:29 75 .82 1:24 80 .79 1:20 85 .77 1:16 SLOPE _ .550 .' a i s DURATION . FREQUENCY MINUTES 6 2.96 4.53 10 loo 4.21 YEAR YEAR 5 3.10 4.78 6 2.84 4.36 7 2.64 4.07 8 2.47 3.81 9 2.34 3.60 10 2.22 3.43 11 2.12. 3:27 12 2.04 3.14 13 1.96 3.02 14 1.89 2.92 15 1.83 2.02 16 1.77 2.73 17 1.72 2.66 IB 1.68 2.58 19 1.63 2.52 20 1.59 2.46 22 1.52 2.35 24 1.46 2.25 26 1.40 2.17 28. 1.36 2.09 30 1.31 2.02 32 1.27 1.96 34 1.23 1.90 36 1.20 1.85 38 1.17 1.81 40 1.14 1.76 4S 1.08 1.66 50 1.03 1.58 55 .98 1.51 60 .94 1.45 65 .90 1.40 70 .87 1.35 75 .84 1.30 80 .82 1.26 85 .80 1.23 SLOPE .480 DURATION FREQUENCY MINUTES 6 2.96 4.53 10 100 4.21 YEAR YEAR 5 4.39 6.T6 6 3.95 6.08 7 3.62 5.56 8 3.35 5.15 9 3.13 4.61 10 2.94 4.52 11 208 4.28 12 2.65 4.07 13 2.53 3.88 14 2.42 3.72 15 2.32 3.58 16 2.24 3.44 1? 2.16 3.32 18 2.09 3.22 19 2.03 3.12 20 1.97 3.03 22 1.86 2.86' 24 1.7T 2.72 26 1.69 2.60 28 1.62 2.49 30 1.55 2.39 32 1.50 2.30 34 1.45 2.22 36 1.40 2.15 38 1.36 2.09 40 1.32 2.02 45 1.23 1.89 50 1.16 1.78 55 1.09 1.68 60 1.04 1.60 65 .99 1.53 70 .95 1.46 15 .91 1.41 80 .88 1.35 85 .85 1.31 SLOPE a .580 DURATION FREQUENCY MINUTES 10 100 YEAR YEAR 5 3.23 4.94 6 2.96 4.53 7 2.75 4.21 8 2.58 3.95 9 2.44 3.73 10 2.32 3.54 11 2.21 3.39 12 2.12 3.25 13 2.04 3.13 14 1.97 3.02 15 1.91 2.92 16 1.05 2.83 17 1.60 2.75 18 1.75 2.67 19 1.70 2.60 20 1.66 2.54 22 1.59 2.43 24 1.52 2.33 26 1.46 2.24 28 1.41 2.16 30 1.37 2.09 32 1.33 2.03 34 1.29 1.97 36 1.25 1.92 38 1.22 1.87 40 1.19 1.82 4S 1.13 1.72 50 1.07 1.64 55 1.02 1.56 60 .98 1.50 65 .94 1.44 70 .91 1.39 75 .88 1.3S 80 .85 1.31 85 .83 1.27 SLOPE = .480 TRACT 29457 -4 24" Storm Drain 100 year W.S. in Retention Basin 24" S.D. from Catch Basin to Retention Basin Qioo = 10.72 CFS Sf = [ Q„ ] 2 = [ 10.72 (.012) ]2 = 0.0019 d'/3K' 6.3 5 (.463 ) Hf = 102 Sf = HGL @ U.S. End of Pipe Q =VA V =3.41 FPS 43.00 0.19 43.19 H,= V2/2g =.18 1.2H, = .22 100 Yr W.S. in C.B. 43.41 Determine C.B. Size Qioo = 10.72 CFS H = .83' From BPR Chart 1,073.03 Length of Opening = 10.72/2.3 = 4.66 Use 6.0' Opening h = .74' H/h = 1.12 Capacity = 2.3 CFS/FT �-5 J 4—i0 7.5 Li �•' : - .0 x,-5.5 -- •C ��w� •�' _ f -r u •� -� . ' E- Iz f L i = s I i LJ • .� • � 4 eVt � .2 LO.r -- _., _ uU -R�:AU OF PU7LIC ROADS f1tJa c�:C. Tr -P' C•d. /f c�.c�r ,�:..��.:.� 'F•'z. z_':;z �a - ,C..;:Y�t 1'1,,S;!•, D. C.. N O&tO GRA ?K FOR CAPACITY -OF CUR-3. - OPENING INLETS AT L.O l- PO;NTS f ' .2 5—S .03 tG c� .OS •, k LU .04 -, r G cl C U:�o • LOG L 0 -? ,fir - v ' ' LO.r -- _., _ uU -R�:AU OF PU7LIC ROADS f1tJa c�:C. Tr -P' C•d. /f c�.c�r ,�:..��.:.� 'F•'z. z_':;z �a - ,C..;:Y�t 1'1,,S;!•, D. C.. N O&tO GRA ?K FOR CAPACITY -OF CUR-3. - OPENING INLETS AT L.O l- PO;NTS f ' r M M 6t i0 l�7 n 3-HOUR RAINFALL STORM PATTERNS 6 -MUR STORM IN PERCENT 24-HOUR STORM TIME 5 -NIM IO -MIN 15 -MIN 30 -MIN TIME 5 -MIN 10 -MIN 15 -NIN 30 -MIN TIME 5-MIN TIME 15 -MIN 30 -MIN 60 -NIN TIME 15 -NIN \ PERIOD PERIOD PfRtOD PERIOD PERIOD PERIOD PERIOD PERIOD PERIOD PERIOD PERIOD PERIOD PERIOD PERIOD PERIOD PERI00 PERIOD PERIOD ^ 1 1.3 2.6 3.l B.5 1 .5 1.1 1.7 3.6 49 I.7 1 .2 .5 1.2 49 2.5 ` , 2 1.3 2.6 3.3 4.a 10.0 2 .6 1.2 1.9 ♦.3 50 1.8 2 .3 T 1.] 50 2.6 C ] 1.1 S.1 13.9 3 .6 1.3 2.1 4.0 51 1.9 3 .3 .6 1.B 51 2•0 v 4 1.5 ].3 4.9 17.1 + •6 �l.♦ 2.2 4.9 52 2.0 4 .♦ .T 2.1 52 2.9 ` 5 1.5 3.3 6.6 29.9 S .6 X1.4 2.b S.3 53 2.1 5 .] .8 2.0 53 3.4 )Y 6 1.8 3.4 7.3 20.3 6 .7 :1.5 2.4 5.B 54 2.1 6 .3 1.0 2.9 54 3.4 (- 7 1.5 4.1 8.4 7 .7 1.6 2.4 6.8 55 2.2 7 .3 1.0 3.8 55 2.3 B 1.8 4.2 9.0 B .i -1.6 2.5 9.0 56 2.3 B .4 1.1 4.6 56 2.3 9 1.8 S.] 12.3 9 .T 1.6 2.6 11.6 57 2.4 9 .4 1.3 6.] 51 2.7 10 1.5 5.1 17.b 10 .T i1.6 2.7 14.4 5s 2.4 10 .4 1.5 0.2 5s 2.6 11 1.6 6.♦ 16.1 Il .T 1.6 2.a 25.1 59 2.5 Il .5 1.3 T.0 59 2.6 12 1.8 5.9 ♦.2 12 .B ;.1.7 3.0 '4.4 60 2.6 12 .5 1.6 1.3 60 2.5 13 2.2 T.3 13 .8 1.7 3.2 61 3.1 13 .5 1.6 10.8 61 2.4 14 IS 2.2 2.2 B.5 14.1 14 15 .8 :1.6 3.6 .B :'I.B 4.3 62 3.6 14 15 .5 2.0 2.l 11.4' 10.4 62 2.3 16 2.0 !4.! l6 .B :I.B 4:7 67 6+ 3.9 +•2 16 .5 .6 2.S B.5 63 61 1.9 1.9 1T 2.6 3.6 I7 .a 2.0 5.4 6S 4.7 17 .6 3.0 1.4 65 .4 Is 2.7 2.4 10 .B ;2.0 6.2 66 5.6 IB .7 3.3 1.9 66 •4 19 2.4 19 .8 .2.1 6.9 67 1.9 19 .1 3.9 1.3 67 .3 20 21 2.7 3.3 20 21 .B 2.2 T.S .8 .2.5 l0.6 6B .9 20 21 .6 .6 ♦.3 3.0 1.2 1.1 6B .7 22 i 3.1 22 .B. i2.B 14.5 69 70 •6 .5 22 .T 4.0 1.0 69 TO .5 23 1 2.9 23 .9 '3.0 3.4 23 .B 3.8 .9 it .5 s 24 3.0 24 .9 X3.2 I.D. T2 :3 2 24 •B 3.5 .0 72 .4 25 3.1 25 .6 3.5 25 .9 5.1 73 .4 26 4.2 26 .9 i3.9 26 .9 5.7 74 .4 27 5.0 3.5 27 26 .9 14.2 .9 ♦:5 - 27 2s 1.0 1.0 6.11 4.6 T5 .1 .26 29 30 6.8 7.3 29 .'� .9' ��.e 29 1.0 5.3� 76 T7 .2 .3 I 30 .9• „ 5.1 30 1.1 5.1 7B ./ D 31 B.2 31 .9 f6.1 . 31 1.2 4.T 19 .3 Z 32 33 I 5.9 2.0 32 33 .9T,B.t 1.Oi'10�3 32 3] 1.3 1.5 3.a .6 80 at BI .2 .7 "•n 34 35 1.8 I.B 34 34 1.0. �: ;2:a 1.0' ll.l 3♦ - 35 1.5 1.6 .6 l.d a2 B3 .3 .3 D 36 .6 36 1.0: .i ;S 36 1.7 .9 64 .2 i 37 38 1.0 ,. .. I l.1 1 37 38 1.9 2.0 .d as .3 D fr-- 1 39 l.l_ ..l 39 2.1 .9 •t 86 •. 67 .2 .3 +0 41'• 1.1' 1:2_ 40 41 2.2 1.5 .5 a Be .2 �i - 42 43 1.3 42 43 1.5 2.0 .5 e9 90 .3 .2 i A I 44- 1 .4 ? I. 44 2.0 91 92 .2 .2 TBl •1; 43 46 1:5 1:5 45 46 1.9 1.9 .3 93 .2 7 • .--+ 4T. 1.6 ! 4T 1.7 .j •4 94 95 .2 .2 ray 48' 1 48 1.8 .4 96 .2. Al ... NOTES: ! I. 3 and 6 -hour patterns based on the India area thunderstorm of September 24,1939. 2. 24 -hour patterns based on the general storm of March 2 6 3,1938. SUBJECT: RANCHO LA QUINTA PAGE OF PROJECT: TRACT 29457 -4 JOB NO: LOCATION: LA QUINTA BY: LWW CLIENT: DATE: 2/13/06 FLOW IN STORM DRAIN TO RETENTION BASIN HYDROGRAPH: AREA IN TRACT NO. 29457 -4 USE RCFCD HYDROLOGY MANUAL PLATE E -5.9 FOR RAINFALL PATTERN. PLATE E -5.6 INDICATES 100 -YEAR 24 -HOUR PRECIPITATION = 4.0" (1) (2) (3) INCL. NET PERIOD RAINFALL Q VOL. PREV. STOR. PERC. CUM. STOR. (HOUR) % INS. (PER HR) C C.F.S. (C.F.) (C.F.) (C.F.) (C.F.) 1 1.2 0.048 0.374 0.084 304 304 38 266 2 1.3 0.052 0.375 0.092 330 596 38 558 3 1.8 0.072 0.378 0.128 460 1,018 38 980 4 2.1 0.084 0.380 0.150 540 1,520 38 1,482 5 2.8 0.112 0.386 0.203 731 2,214 38 2,176 6 2.9 0.116 0.387 0.211 760 2,935 44 2,891 7 3.8 0.152 0.392 0.280 1,008 3,899 48 3,851 8 4.6 0.184 0.398 0.344 1,239 5,091 48 5,043 9 6.3 0.252 0.410 0.486 1,748 6,791 64 6,727 10 8.2 0.328 0.420 0.647 2,331 9,058 64 8,994 11 7.0 0.280 0.414 0.545 1,961 10,955 78 10,877 12 7.3 0.292 0.415 0.570 2,050 12,927 78 12,849 13 10.8 0.432 0.422 0.857 3,085 15,934 95 15,839 14 11.4 0.456 0.440 0.943 3,395 19,234 95 19,139 15 10.4 0.416 0.433 0.847 3,048 22,187 119 22,068 16 8.5 0.340 0.423 0.676 2,433 24,501 119 24,382 17 1.4 0.056 0.376 0.099 356 24,738 119 24,619 18 1.9 0.076 0.379 0.135 487 25,107 119 24,988 19 1.3 0.052 0.375 0.092 330 25,318 119 25,199 20 1.2 0.048 0.374 0.084 304 25,502 119 25,383 21 1.1 0.044 0.373 0.077 278 25,661 119 25,542 22 1.0 0.040 0.372 0.070 252 25,794 119 25,675 23 0.9 0.036 0.371 0.063 226 25,901 119 25,782 24 .0.8 0.032 0.370 0.056 200 25,982 119 25,863 (1) RAINFALL = % OF TOTAL PRRCIPITATION (2) Q= RAINFALL x C x A (INS. PER HOUR) (3) V = Q x 3600 = c.f. / HR (4) PERC. RATE = .017' /HR G: /Administration /COST ESTIMATES /HYDROGRAPH.wb3 A = 4.7 C = COEFF. FOR 40 GL. -SGL FAM 1/2 AC. PLATE D -5.1 SOIL GROUP "A" SUBJECT: RANCHO LA QUINTA PAGE OF PROJECT: TRACT 29457 -4 JOB NO.: LOCATION: LA QUINTA BY: W. DUNCAN CLIENT: DATE: 7.05.05 HYDROGRAPH FLOW IN STORM DRAIN TO RETENTION BASIN USE RCFCD HYDROLOGY MANUAL PLATE E -5 -9 FOR RAINFALL PATTERN PLATE E -5.4 INDICATES 100 YEAR 6 - HOUR PRECIPITATION = 2.75" PERIOD (15- MIN.) % (1) RAINFALL INS.(PER HR) C (2) Q C.F.S. (3) VOL. C.F. INCL. PREY. ST C.F. PERC. RATE C.F. NET CUM. STOR. C.F. 1 1.7 0.047 0.373 0.082 74 515 0 515 2 1.9 0.052 0.374 0.092 83 598 0 598 3 2.1 0.058 0.374 0.102 91 689 0 689 4 2.2 0.061 0.375 0.107 96 785 0 785 5 2.4 0.066 0.376 0.117 105 890 0 890 6 2.4 0.066 0.376 0.117 105 995 0 995 7 2.4 0.066 0.376 0.117 105 1100 0 1100 8 2.5 0.069 0.376 0.121 109 1209 0 1209 9 2.6 0.072 0.377 0.127 114 1323 0 1323 10 2.7 0.074 0.377 0.132 118 1442 0 1442 11 2.8 0.077 0.378 0.137 123 1565 0 1565 12 3.0 0.083 0.378 0.147 132 1697 0* 1697 13 3.2 0.088 0.379 0.157 141 1838 0 1838 14 3.6 0.099 0.385 0.179 161 1999 0 1999 15 4.3 0.118 0.386 0.215 193 2192 0 2192 16 4.7 0.129 0.388 0.236 212 2404 0 2404 17 5.4 0.149 0.390 0.272 245 2649 0 2649 18 6.2 0.171 0.395 0.317 285 2934 0 2934 19 6.9 0.190 0.398 0.355 319 3254 0 3254 20 7.5 0.206 0.400 0.388 349 3603 0 3603 21 10.6 0.292 0.413 0.566 509 4112 0 4112 22 14.5 0.399 0.432 0.810 729 4840 0 4840 23 3.4 0.094 0.382 0.168 151 4992 0 4992 24 1.0 0.028 0.367 0.047 43 5034 0 .5034 (1) RAINFALL = % OF TOTAL PRECIPITATION A= 4.7 ACRES (2) Q= RAINFALL x C x A (INS. PER HOUR) C= COEFF. FOR 40 - S. F. - 1/2 Ac. (3) V = Q x 900 = C.F./ 15 -MIN. PLATE D 5.1 SOIL GROUP "A" (4) PERC. RATE = 0. " /HR. SUBJECT: RANCHO LA QUINTA PAGE OF 3ROJECT: TRACT 29457 -4 JOB NO.: - OCATION: LA QUINTA BY: W. DUNCAN CLIENT: DATE: 7.05.05 HYDROGRAPH FLOW IN STORM DRAIN TO RETENTION BASIN USE RCFCD HYDROLOGY MANUAL PLATE E -5 -9 FOR RAINFALL PATTERN PLATE E -5.2 INDICATES 100 YEAR 3 - HOUR PRECIPITATION = 2.2" PERIOD (15 -MIN) % (1) . RAINFALL INS.(PER HR) C (2) Q C.F.S. (3) VOL. C.F. INCL. PREY. ST C.F. PERC. RATE C.F. NET CUM. STOR. C.F. 1 3.7 0.081 0.376 0.144 129 0 0 0 2 4.8 0.106 0.384 0.191 172 301 0 172 3 5.1 0.112 0.387 0.204 184 485 0 355 4 4.9 0.108 0.386 0.196 176 661 0 531 5 6.6 0.145 0.388 0.265 238 899 0 770 6 7.3 0.161 0.395 0.298 268 1167 0 1038 7 8.4 0.185 0.398 0.346 311 1478 0 1349 8 9.0 0.198 0.399 0.371 334 1813 0 1683 9 12.3 0.271 0.410 0.521 469 2282 0 2152 10 17.6 0.387 0.427 0.777 699 2981 0 2852 11 16.1 0.354 0.425 0.708 637 3618 0 3489 12 4.2 0.092 0.380 0.165 149 3767 0 3637 100.0 2.200 (1) RAINFALL = % OF TOTAL PRECIPITATION A= 4.7 ACRES (2)-Q = RAINFALL x C x A (INS. PER HOUR) C= COEFF. FOR 40 - S.F. - 1/2 Ac. (3) V = Q x 900 = C.F./ 15 -MIN. PLATE D 5.1 SOIL GROUP "A" (4) PERC. RATE = 0 "/HR. I�� ��1]►��L17i�IJ�T1 S.F. VOLUME ACCUMULATIVE VOLUME 37 2,208 2,504 38 2,800 2,504 3,288 39 3,776 5,792 4,192 40 4,608 9,984 , 5,096 41 5,584 15,080 6,280 42 6,976 21,360 7,688 (25,863) 43 8,400 29,048 43 1 1,712 12,440 41,488 44 13,168 14,136 45 15,104 55,624 Required 100 year - 24 hour Volume: 25,863 CF 100 Year Water Surface Elevation = 42.59 Additional volume is available due to the design of the project. At elevation 45.0, the available storage is 48,768 CF. Elevation 45.0' is 1.9' below the lowest pad. Based upon point precipitation frequency estimates from NOAA Atlas 14, the estimated volume for a 500 year storm event would be 5.03/3.63 x 27,856 CF = 38,599 CF. The volume available at elevation 45.0' exceeds the storage required for a 500 year storm by 15,833 CF. Lloyd Watson From: "AMGENG" <amgeng @dc.rr.com> To: <LWWATSON @LWWENG.NET> Sent: Tuesday, January 04, 2005 5:26 PM Subject: Precipitation Frequency Data Server r x NOAA ! i x NWS LOGO POINT PRECIPITATION FREQUENCY ESTIMATES LOGO to ink i FROM NOAA ATLAS 14 to ink California 33.6167 N 116.2528 W -6 feet from "Precipitation- Frequency Atlas of the United States" NOAA Atlas 14, Volume 1, Version 3 G.M. Bonnin, D. Todd, B. Lin, T. Parzybok, M.Yekta, and D. Riley NOAA, National Weather Service, Silver Spring, Maryland, 2003 Extracted: Tue Jan 4 2005 on d nce mlts .,�..,, ' Se so lity c47 Ma ih ai rifofi Gn�ds Maps ;1 Help Do Precipitation Frequency Estimates (inches) ARI* 10 15 30 60 120 10 20 30 45 60 [12 24 Fqhr (years) min min min min mm min hr hr hr hr �� day day day day day day day �� 0.13 0.19 0.24 0.32 0.40 0.53 0.61 0.79 0.97 1.05 1.16 1.26 1.39 1.46 1.58 1.71 1.92 2.08 0 0.20 0.31 0.38 0.51 0.64 0.83 0.93 1.20 1.45 1.59 1.78 1.94 2.13 2.25 2.44 2.63 2.96 3.23 10 0.27 0.41 0.51 0.68 0.85 1.08 1.20 1.52 1.82 2.01 2.29 2.50 2.72 2.88 3.12 3.34 3.74 4.09 25 0.38 F67571 0.71 I 0.96 1.19 1.47 1.61 1.98 2.34 12 6-11 3.05 3.30 3.58 3.79 4.07 4.34 4.82 5.30 50 0.47 0.72 0.89 1.20 Efl 1.82 1.96 2.36 2.76 3.10 3.69 3.99 4.29 4.55 4.86 5.14 5.68 6.26 100 0.59 0.90 1.11 I I.50 1.85 2.22 2.35 Efl 3.21 3.63 4.42 4.76 5.07 5.38 5.71 6.01 6.59 7.29 200 0.72 F 1-01 1.37 1.84 2.28 2.68 2.80 3.25 3.69 4.21 5.22 5.61 5.92 6.29 6.63 E47.54 8.36 500 0.94 I 1.44 1.78 2.40 2.96 3.39 3.49 3.94 4.38 5.03 6.43 6.87 F7-16-] 7.63 7.95. 8.26 8.87 9.88 1000 1.14 1.74 2.16 2.90 3.59 4.03 4.08 4.51 4.95 5.72 7.47 7.95 8.2] 8.75 9.05 9.34 9.93 11.09 These precipitation frequency estimates are based on a partial duration series. ARI is the Average Recurrence Interval. t 4411. ersfo,of tableI please refer to the documentation for more information. NOTE: Formatting forces estimates near zero to appear as zero. j ] pf2_Jan20:33:204.png I !� pf Jan20:33:204.png L_ Confidence Limits - Page 1 of 3 1/5/2005 lI. J:j W & W DESIGN DEVELOPMENT, INC. 79440 CORPORATE CENTER DRIVE, SUITE 107 LA QUINTA, CALIFORNIA 92253 REPORT OF INFILTRATION TESTING TRACT 294574 RETENTION BASIN RANCHO LA QUINTA COUNTRY CLUB LA QUINTA, CALIFORNIA February 6, 2006 0 2006 Earth Systems Southwest Unauthorized use or copying of this document is strictly prohibited without the express written consent of Earth Systems Southwest. File No.: 07748 -17 06 -01 -877 Uzi tod rHk3t: nai nti Earth Systems Southwest 79 -8110 Country Club Drive Dcrmuda Dunes, CA 92203 (760) 345 -1588 (800) 924 -7015 FAX (760) 345 -7315 February 6, 2006 W & W Design Development, Inc. 79440 Corporate Center Drive, Suite 107 La Quinta, California 92253 Attention: Mr. Lloyd Watson Subject: Report of Infiltration Testing Project: Tract 29457 -4 Retention Basin Rancho La Quinta Country Club La Quinta, California Dear Mr.. Watson: File No.: 07748 -17 06 -01 -877 it is our pleasure to present this report of infiltration testing prepared for the referenced site, identified as Tract 29457 -4 retention basin and located within the Rancho La Quinta Country Club in the City of La Quinta, California. This report presents our findings and recommendations for storm water disposal. This report should stand as a whole and no part of the report should be excerpted or used to exclusion of any other part. This report completes our scope of services in accordance with our agreement, dated October 31, 2005, and authorized November 4, 2005. Other services that may be required, such as a plan . review, are additional services and will be billed according to the Fee Schedule in effect at the. time services are provided. Unless requested in writing, the client is responsible for distributing . this report, to the appropriate governing agency or other members of the design team. Project Description This report of infiltration testing has been prepared for the proposed storm water disposal of the Tract 29457 -4 retention basin, located within the Rancho La Quinta Country Club in the City of La Quinta, California. The purpose of our services was to evaluate the site soil conditions and to provide professional opinions and recommendations regarding the feasibility for storm water disposal on the site. The scope of work included the following: • A general reconnaissance of the site. • Two infiltration tests. An engineering evaluation of the acquired data from the exploration and testing. A summary of our findings and recommendations in this written report, including: o Discussions on subsurface soil conditions. o Discussions on soil infiltration testing. Not Contained in This Report: Although available through Earth Systems Southwest, the current scope of our services does not include: February 6, 2006 174/ -2- File No.: 07748 -17 06 -01 -877 • An environmental assessment. • An investigation for the presence or absence of wetlands, hazardous or toxic materials in the soil, surface water, groundwater, or air on, below, or adjacent to the subject property. • Geotechnical and geologic studies. Infiltration Testa Two infiltration tests were performed at the site for the proposed storm water disposal as shown on the attacbed figure. The tests were conducted within .8 -inch diameter augered boreholes made to a depth of 10 feet below existing ground surface. A head of water was applied to within about 4 feet from the ground surface so that the tests represent infiltration of soils from about 4 to 10 feet below grade. A 31/. -inch outside diameter perforated pipe was set in each borebole. Each pipe was surrounded full- length with % -inch gravel. Water was .injected at a relatively constant rate until a stabilized head of water was established. Based on the US Bureau of Reclamation methodology for a. constant head, pump -in test, the following hydraulic conductivity rates were obtained. Test Bottom of Hole Water Head Flow Rate hydraulic Conductivity ID feet feet rp roller al/sf /da I -1 (East) 10.0 5.5 0.17 0.3 1 4.4 I -2 West 10.0 6.2 0.10 0.2 3.2 The designer of the retention basin should decide on whether an appropriate factor of safety should be applied to these reported infiltration rates. Infiltration may be significantly less than: the values given over time because of siltation and development of a film from road oils from paved streets. A silt and oil trap placed at influent points may be considered to reduce the potential for reduction in the infiltration rates of soils. Some of the other factors that could affect the infiltration rates in basin areas are planting of ground cover vegetation, such as lawn; accumulated silts and road oil from continued use; wind blown sand or silt; and the length of time between scheduled routine maintenance. In order to increase the infiltration rates, a dry well may be installed underneath the basin. We appreciate the opportunity to provide our professional services. Please contact our office if there are any questions or comments concerning this report or its recommendations. Respectfully submitted, EARTH SYSTEMS 4­(� SOUTHWEST Hongbin Huo, Ph.D. Project Engineer .Lettcr/hh /sls /reh Distribution: 31W & W Design Development, Inc. 1/RC File 2 /BD .File Reviewed by, Shelton L. Stringer GE 2266 �1Z oPOFESS�p,I,� No ON L. ST9i l FL "T a 266 z z ni Exp. 630- EARTH SYSTEMS SOUTHWEST ' r �rfCNN�����r �\ F'�rF CA,1���'' 1Y. 1313 IOU -12YJ -!1311 CHRInJYJImmS FAUL b5 /ba 116017'15"W /16 "143A "W 114 °15'45 "W SWO 567000 568000 5600130 0 Ift 7 ej� +;% cc, -30 .-WIN A. vF wr -Piilk tit an C, COD ry MCI + wen M V r Q, p 336AW JL: pM 12 lip r N 0 VT R sip V J4 - - I G7 c. L cp + VA m=m— ir— or c2 566000 587000 568000 569000 + + J1 114 °17'!5'W 116*16'30"W 11015'45"W M 1.000 2.000 3.000 4,000 SODO Fast Figure I Site Location Map Rancho La Quinta Retention Basin LEGENQ Tract 294574 Rancho La Quinta Country Club La Quinta, California Site Boundary Ewth 318"m 0 02/06L Q6 Fits No.: 0 Z748-17 • E v a I OU -134:1 ( J J mmm 1 nJ T D I Glnz:> rHUt a 1/ t,ti 116* 1�i72 "W 116 ^/6'3"W 2 5e7seo 116016'3Z "w 116 °►nt[• -w o so 100 200 300 am Soo Fens e M Figure z LEGEND Boring Location Map Rancho La Quinta Retention Basin CO Infiltration Location Tract 29457 -4 Rancho La Quinta Country Club La Quinta, California 064m••me Earth Systems Site Boundary manf"""t: nspf%OM& I Cite Nn - n77AR_17 Shallow Pump -in Test by USSR Method for Unsaturated Sails above Groundwater Project: Tract 28457-4 Retention sasin,Rancho La 4uinta Country Club Project No.: 07748 -17 a,.,. Test Bottom o} Borehole Lb I Stabilized Depth of Water DW Borehole Diameter O Stabilized Flow Rate q Perforated Length of Pipe _ �„ Outside Diameter of Pipe OD __�__, Elapsed Tune since Start ,�_._: , Radius Active )toad of Length of Borehole Water Ratio Ratio Ratio q r1 La h1 191hl Lalri h1Jrl r..w.-% M nr1 rrantl tfaett Hydra ulic ConducCai Borehole Wetted Area s Capacity q Q Factor dlda 9aYatPd Q1k k k k k (fpm (mJsec) inlhr galhfrm Calculation of Flow Rate Trial Diameter of Container Lem) Change In Height crn) Volume of Container (gallons Time to Fill minutes sec Flow Rate q m 1 Lb•Dw h1 = 0.25 1 30 0.17 2 k (galisVday) It (inAhr)'15 0.25 2 40 0.09 3 4 V = d14'M9.483`7.48 (gallons) Reference: ganger, Cad (1953), Theory and Problems of water Percolation, Cnyu,ca1119 Monographs No. B, US Bureau of Reclamation (also USSR Drainage Manual) q (cfm) = q(gpm)17.48 rl (feet) = D(Inches))24 La = Lb•Dw h1 = Lb-Dw k(fpm) = q[ slnW '(Lafi1)- (lafhl)V(2zLa'(2hl -La) It (inft) = it (ipm)'720 k (galisVday) It (inAhr)'15 °zmmPm�12WR ODFO rr 210Z 02�0.m 000 ME Mmo mwTz K °wz_zz °W -0 o OZO OZ y A a. mm miy;m4m;j_ ME mD cz i as�o0rn��0 z0 NZ5 00m ��zm W� o OD Fn m U) m =�Z�00SOOMZm =D mm OF WCOMW m 00 A m g Az��m_vz -immoNODOOmzzDMm imo�ov)fcDf�mOp� oomc;pm0cMF mv0zz omo� �w0 m Xo >m �mcn- iv�vmiCo0r?ON� MM Dm --Oiom -i z={-i - �z z cmi>om 0 0OOmoo = °�O -400 0 58r>S- W;90D =m �mCmmmc;0GT _mm4Z 9°COmcR@Qzvcz >=0� zmm O cnrnDO10O z�—° -n IMOnODA =Xzmy m ccc� =00=N -Z7D~ 0 cc movmrnr-i* mC 00 C_ MT =0y oz -lul' moc ..0 �FFrr'111 ��SU1 �Mm��NAm0 v�"'o "ic�cmiNm®0O0�U1 m®oNCmn zc°n z 0 CQMAp00T,�00 0 z rn 6'o z z 0610 OQ020>; m_rnzco2ZCmo -,°c* d*Z tzj u�-98 NON oii XRZ>°m8tHA -p rnOin z '020=100W DO OOZZ�Z 2zO NpZrnA„t •.DD k��-1 �jjm,ij*r T(-in 9 W°OZDGA? 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