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Home My WebLink AboutCT 02-25; NORTHPARK AT LA COSTA; HYDROLOGY/HYDRAULIC ANALYSIS; 2004-01-06EWROLOGY/HWRAmC ANALYSIS FOR Carlsbad Tract No, 02-25 NortbPHTkatLa Costa Dated: 09/19/03 Revised 01/06/04 SfniggBm-Ogge 8348 Center Drive, Suite G La Mesa, CA 91942-2910 (619) 697-9234, Fax (619) 460-2033 JobNo. CA1133 TOUCHSTONE COMMUNITY TM File: CA1131 8/23/2002 SUMMARY PROJECT DESCRIPTION: THE PROJECT PROPOSES TO DEVELOP 14 LOTS TO INCLUDE 12 LOTS WITH DWELLING UNITS AND 2 COMMON LOTS FOR ACCESS DRIVEWAY AND LANDSCAPE COMMON AREA ONTO TWO (2) VACANT LOTS, LOT 227 AND 228 OF SUBDIVISION MAP NO. 7457. CURRENT SITE CONDITIONS: THE SUBJECT SITE IS LOCATED ON AN ELEVATED PAD WITH THE TOPOGRAPHY SLOPING AWAY IN ALL DIRECTIONS. IT IS BOUND TO THE EAST AND THE SOUTH BY LA COSTA AVENUE AND LEVANTE STREET RESPECTIVELY; TO THE fcMESL /T IS BOUND BY MULTI-FAMILY RESIDENTIAL AND SINGLE- FAMILY ^ESIDEITAL TO THE NORTH, THE RUNOFF FROM THE PROPERTY SHEET-FUDWS~~SOUTHERLY DISCHARGING INTO PUBLIC RIGHT-OF-WAY, LEVANTE STREET. NO OFF-SITE RUNOFF DISCHARGES ONTO THE SUBJECT SITE. EXISTING RUNOFF: THE SUBJECT SITE HAS PREVIOUSLY GRADED INTO 2 PADS AND FLOWS FROM THE NORTHEAST CORNER OF THE SITE TO THE SOUTHWEST CORNER OF THE SITE WHICH IS THE LOW POINT THE RUNOFF FROM THE SUBJECT SITE IN THE CURRENT CONDITION IS 4.04 CFS IN THE 100-YEAR, 6-HOUR STORM. POST-DEVELOPMENT RUNOFF: THE POST-DEVELOPED SITE DIVIDES THE SITE INTO 2 DRAINAGE BASINS, NORTHERLY BASIN AND SOUTHERLY BASIN, 0.92 ACRES AND 0.55 ACRES, RESPECTIVELY. THE NORTHERLY HALF OF THE SITE INCLUDES THE PROPOSED LOTS 1 TO 7, 14 AND PORTION OF LOT 13 OF THE PROPOSED TENTATIVE MAP. SURFACE DRAINAGE FROM THE NORTHERLY BASIN SHEET FLOWS TO A DETENTION BASIN, WHICH IS LOCATED AT THE SOUTHWEST CORNER OF THE PROJECT SITE THEN DISCHARGING TO THE PUBLIC RIGHT- OF-WAY LEVANTE STREET, BY A CURB OUTLET. THE SOUTHEASTERLY HALF OF THE SITE INCLUDES LOTS 8 TO 12 AND PORTION OF LOT 13 OF THE PROPOSED TENTATIVE MAP. SURFACE DRAINAGE SHEET FLOWS TO PUBLIC RIGHT-OF-WAY, LEVANTE STREET. THE ATTACHED DETENTION BASIN DESIGN CALCULATIONS SHOW THAT THE POST DEVELOPMENT RUNOFF DISCHARGE SHALL NOT EXCEED THE PRE- DEVELOPMENT RUNOFF DISCHARGE IN THE 100-YEAR, 6-HOUR STORM. Prepared By: Drainage-Summaiy.doc Snipes-Dye Associates i HYDROLOGYJ mCANALYSIS Carlsbad Tract No. 02^ North Park at La Costa 834ai.CenterDfive, Suite G La MIstka, CA 91942-2910 ($19) 697-^^, Fax (619) 460-2033 William A. Snipes R.C.E. 50477 W HYDROLOGY/HYDRAVUC ANALYSIS FOR Carlsbad Tract No, 0, North Park at La Costa Dated: 09/19/03 Snlfmrn-Oyie 8348 Center Drive, Suite G La Mesa, CA 91942-2910 (619) 697-9234, Fax (619) 460-2033 Job No. CAll32 HYDROLOGY/BYDRAVUC ANALYSIS FOR Carlsbad Tract No, 02-25 North Paric at La Costa », SuSe G 1942-2910 ax (619) 460-2033 j William A. Snipes R.C.E. 50477 NORTHPARK AT LA GOSTA TM File: CA1133 1/6/04 SUMMARY PROJECT DESCRIPTION: THE PROJECT PROPOSES TO DEVELOP 14 LOTS TO INCLUDE 12 LOTS WITH DWELLING UNITS AND 2 COMMON LOTS FOR ACCESS DRIVEWAY AND LANDSCAPE COMMON AREA ONTO TWO (2) VACANT LOTS, LOT 227 AND 228 OF SUBDIVISION MAP NO. 7457. CURRENT SITE CONDITIONS: THE SUBJECT SITE IS LOCATED ON AN ELEVATED PAD WITH THE TOPOGRAPHY SLOPING AWAY IN ALL DIRECTIONS. IT IS BOUND TO THE EAST AND THE SOUTH BY LA COSTA AVENUE AND LEVANTE STREET, RESPECTIVELY; TO THE WEST IT IS BOUND BY MULTI-FAMILY RESIDENTIAL AND SINGLE- FAMILY RESIDENTIAL TO THE NORTH. THE RUNOFF FROM THE PROPERTY SHEET-FLOWS SOUTHERLY DISCHARGING INTO PUBLIC RIGHT-OF-WAY, LEVANTE STREET. NO OFF-SITE RUNOFF DISCHARGES ONTO THE SUBJECT SITE. EXISTING RUNOFF: THE SUBJECT SITE HAS PREVIOUSLY GRADED INTO 2 PADS AND FLOWS FROM THE NORTHEAST CORNER OF THE SITE TO THE SOUTHWEST CORNER OF THE SITE, WHICH IS THE LOW POINT THE RUNOFF FROM THE SUBJECT SITE IN THE CURRENT CONDITION IS 4.04 CFS IN THE 100-YEAR, 6-HOUR STORM. POST-DEVELOPMENT RUNOFF: THE POST-DEVELOPED SITE DIVIDES THE SITE INTO 2 DRAINAGE BASINS, NORTHERLY BASIN AND SOUTHERLY BASIN, 0.92 ACRES AND 0.55 ACRES, RESPECTIVELY. THE NORTHERLY HALF OF THE SITE INCLUDES THE PROPOSED LOTS 1 TO 7, 14 AND PORTION OF LOT 13 OF THE PROPOSED TENTATIVE MAP. SURFACE DRAINAGE FROM THE NORTHERLY BASIN SHEET FLOWS TO A DETENTION BASIN, WHICH IS LOCATED AT THE SOUTHWEST CORNER OF THE PROJECT SITE THEN DISCHARGING TO THE PUBLIC RIGHT- OF-WAY, LEVANTE STREET, BY A CURB OUTLET. THE SOUTHEASTERLY HALF OF THE SITE INCLUDES LOTS 8 TO 12 AND PORTION OF LOT 13 OF THE PROPOSED TENTATIVE MAP. SURFACE DRAINAGE SHEET FLOWS TO PUBLIC RIGHT-OF-WAY, LEVANTE STREET THE ATTACHED DETENTION BASIN DESIGN CALCULATIONS SHOW THAT THE POST DEVELOPMENT RUNOFF DISCHARGE SHALL NOT EXCEED THE PRE- DEVELOPMENT RUNOFF DISCHARGE IN THE 100-YEAR, 6-HOUR STORM. Prepared By: Drainage-Summary.doc Snipes-Dye Associates i TOUCHSTONE COMMUNITY TM ^%n9l2002 SITE PEAK FLOW DETENTION (100-YEAR) DETERMINE VOLUME OF INCREASED RUNOFF FROM THE DEVELOPED SITE IN THE 6-HOUR, 100-YEAR STORM: 1. DETERMINE WEIGHTED SITE RUNOFF COEFFICIENT FOR CURRENT SITE 2. DETERMINE WEIGHTED SITE RUNOFF COEFFICIENT FOR DEVELOPED SITE 3. DETERMINE PEAK RUNOFF FROM THE CURRENT SITE AND THE DEVELOPED SITE IN THE 6-HOUR, 100-YEAR STORM. 4. PREPARE SITE HYDROGRAPH FOR THE DEVELOPED SITE. 5. DETERMINE VOLUME FOR INCREASED RUNOFF FROM THE DEVELOPED SITE 6. DETERMINE RETENTION BASIN WITH INCREASED RUNOFF VOLUME 1. CALCULATE WEIGHTED RUNOFF COEFFICIENT ICI FOR THE CURRENT STTE: I 1= 1.37 ACRES (Al = 1.37 ACRES, ASSUME 01 = 0.55) I 1= 0.18 ACRES (A2 = 0.18 ACRES, ASSUME 02 = 0.70) A=A1 +A2 C = {A1(C1)+A2(C2)}/A 0 = {1.37(0.55) + 0 18(0.70)} ^ 1.54 C = 0.57 2. CALCULATE WEIGHTED RUNOFF COEFFICIENT Kl FOR THE DEVELOPED STTE: 1 1= 0.58 ACRES (A3 = 0.58 ACRES, ASSUME 03 = 0.40) I 1= 0.06 AORES (A4 = O06 ACRES ASSUME 04 = O70) ^^3= 0.91 ACRES (A5 = 0.91 ACRES, ASSUME 05 = 0.95) A=A3+A4 + A5 0 = {A3(C3) + A4(C4) + A5(C5)}/A 0 = (058(0.40) + 0.06(0.70) + 0.91(0.95)} rr 1.54 0 = 0.74 Prepared by: 100-YR Calculations Snipes-Dye Associates ' TOUCHSTONE COMMUNITY TM CA1131 9/19/2003 3. CALCULATE PEAK DISCHARGE OF CURRENT STTE: ASSUME Tc = 10 MINUTES FOR CURRENT AND DEVELOPED SITE. UTILIZE FIGURE 3-1 INTENSITY/DURATION CURVE AND ISOPLUVIALS OF 100-YEAR 6-HOUR PRECIPITATION READ INTENSITY (I) = 4.6 INCH/HOUR Q = CIA 0 = 0.57, / = 4.6 in/hr, A = 1.54 acres 0^0.57(4.6)1.54 Q = 4.04 cfe 4. CALCULATE PEAK DISCHARGE OF DEVELOPED SITE: Q = CIA 0 = 0.74,1 = 4.6 in/hr, A = 1.54 acres 0 = 0.74(4.6)1.54 Q= 5.24 cfs Prepared by: . . Snipes-Dye Associates 2 100-YR Calculabons TOUCHSTONE COMMUNITY TM File: CA1131 9/19/2003 5. CALCULATE VOLUME OF INCREASED RUNOFF FROM DEVELOPED SITE: DEVELOPED SITE HYDROGRAPH Q (cfe; 5.24 4.04 x=1.15 A h=1.20 • r 4 • 7c (MINUTES) AREA UNDER SHADED AREA = VOLUME OF DISCHARGE FROM DEVELOPED SITE VOLUME = 1.15(1.20)(60) = 82.80 CU. FT. (MIN. VOLUME OF STORMWATER TO RETAIN) TOTAL PRE-DEVELOPMENT DISCHARGE FROM SITE (Qex): Qex =4.04 cfs TOTAL POST-DEVELOPMENT DISCHARGE FROM STTE (Qpr): Qpr = 5.24 cfs THE POST-DEVELOPMENT DISCHARGE RUNOFF THROUGH RETENTION BASIN (Qin): Qin= 2.91 cfs (See attaclied calculations) THE POST-DEVELOPMENT DISCHARGE RUNOFF NOT THROUGH RETENTION BASIN (Qnr): Qnr = Qpr - Qin = 5.24 cfe - 2.91 cfe Qnr = 2.33 cfs ^ THE MAX. ALLOWABLE POST-DEVELOPMENT DISCHARGE RUNOFF PRIOR TO RETAIN (Q r): Qr = Qex - Qnr = 4.04 cfe - 2.33 cfe Qr = 1.71 cfs Utilize 2-4 inch PVC pipes for the proposed retention basin outlet: 4" pipe's discharge capacity = 0.84 cfe (See attached calculations) 2-4- pipes = 2 x 0.84= 1.68 cfs <Qr THE TOTAL POST-DEVELOPMENT RUNOFF = Qnr+Q (two 4" pipes) = 2.33 cfs * 1.68 cfs = 4.01 cfs 4.01 cfs (the total post-development runoff) is less than 4.04 cfs (the total pre-development runoff) Prepared by: Snipes-Dye Associates 100-YR Calculations TOUCHSTONE COMMUNITY TM 6. OESfGN RETENTION STRUCTURE WTTH MINIMUM VOLUME OF 82 CUBIC FEET: (See attached detail) RETENTION VOLUME (V) = CROSS-SECTION BASIN AREA (A) X WIDTH OF BASIN (W) A = 1/2 X WATER LEVEL HEIGHT (H) X LENGTH OF WATER SURFACE (L) File: CA1131 9/19/2003 6" OVERFLOW PIPE RETENTION BASIN DIMENSIONS: W = 4.17 FEET H = 0.67 FEET H/L = 1/100 L = 100(H) = 67 FEET V = A(W) = 1/2L(H)(W) V = (67 FT)(0.67 FT)(4.n FT)/2 V=94 CU. FT. > 82 CU. FT. DETERMINE THE OVERFLOW PIPE: Utilize one 6"pipe for tfie retention basin overflow pipe 6" overflow pipe's discharge capacity = 2.55 cfs (See attached calculations) Q(enter) - Q (two 4" pipes) = Q(min. overflow pipe) 2.91 cfs - 1.68 cfs = 1.23 cfs < 2.55 cfe (The capacity of a 6" overflow pipe is greater than the required runoff discharge.) CONCLUSION: THE TWO 4" PVC PIPE OUTLET AT THE BOTTOM OF THE LOW-END OF THE PROPOSED RETENTION BASIN AND ONE 6" PVC OVERFLOW PIPE. WHICH HAS AN INVERT ELEVATION AT 8" ABOVE THE BOTTOM OF THE LOW-END ARE SUFFICIENT TO RETAIN THE REQUIRED VOLUME OF STORM WATER AND DRAIN THE DEVELOPED SITE DURING A PEAK FLOW, 100-YEAR STORM EVENT. Prepared by: Snipes-Dye Associates 100-YR Calculations 6" PVC OVERFLOW PIPE ^ 2-4" PVC PIPES DISCHARGE TO CURB OUTLET QDiBcn«Hee"l-68 CFS •RETBslTION VOLUME (V) - I05 CU. FT. -RETAINING WALL PS? GRADING F^-AN (TYP.) SECTION A-A NO SCALE • DRAINAGE PIPES DISCHARGE K TO CURB (XITLET o. IMPROVEMENT PLANS (TYPJ O RETAINING WALL PER GRADING F>LAN OTP.) 4' PVC PIPE to d 70' PLAN VIEW - RETENTION BASIN DETAIL NO SCALE HYDRAULIC ELEMENTS - I PROGRAM PACKAGE (C) Copyright 1982-99 Advanced Engineering Software (aes) Ver. 8.0 Release Date: 01/01/99 License ID 1305 Analysis prepared by: Snipes-Dye Associates 8348 Center Drive, Suite G La Mesa, CA 91942-2910 Fax (619)460-2033 Phone (619)697-9234 TIME/DATE OF STUDY: 11:52 8/ 7/2002 DISCHARGE CAPACTTY OF A 4" PIPE **********************************************************************^ »»PIPEFL0W HYDRAULIC INPUT INFORMATION«« PIPE DIAMETER(FEET) = 0.330 FLOWDEPTH(FEET) = 0.330 PIPE SLOPE(FEET/FEET) = 0.4900 MANNINGS FRICTION FACTOR = 0.020000 »»> NORMAL DEPTH FLOW(CFS) = 0.84 HYDRAULIC ELEMENTS - I PROGRAM PACKAGE (C) Copyright 1982-99 Advanced Engineering Software (aes) Ver. 8.0 Release Date: 01/01/99 License ID 1305 Analysis prepared by: Snipes-Dye Associates 8348 Center Drive, Suite G La Mesa, CA 91942-2910 Fax (619)460-2033 Phone (619)697-9234 TIME/DATE OF STUDY: 8:11 8/ 8/2002 DISCHARGE CAPACITY FO A 6" PIPE **************************************************************************** »»PIPEFLOW HYDRAULIC INPUT INF0RMATI0N«« PIPE DIAMETER(FEET) = 0.500 FLOWDEPTH(FEET) = 0.500 PIPE SLOPE(FEET/FEET) = 0.4900 MANNINGS FRICTION FACTOR = 0.020000 »»> NORMAL DEPTH FLOW (CFS) = 2.55 TOUCHSTONE COMMUNITY ''"^9A9/2003 RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 1985,1981 HYDROLOGY MANUAL (c) Copyright 1982-99 Advanced Engineering Software (aes) Ver. 1.5A Release Date: 01/01/99 License ID 1305 Analysis prepared by: Snipes-Dye Associates 8348 Center Drive, Suite G La Mesa, CA 91942-2910 Fax (619)460-2033 Phone (619)697-9234 LEVANTE STREET TENTATIVE MAP POST-DEVELOPMENT CONDITIONS TOUCHSTONE COMMUNITY FILE NAME: CA1131.DAT TIME/DATE OF STUDY: 14:49 8/27/2002 USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: 1985 SAN DIEGO MANUAL CRITERIA USER SPECIFIED STORM EVENT(YEAR) = 100.00 6-HOUR DURATION PRECIPITATION (INCHES) = 2.700 SPECIFIED MINIMUM PIPE SIZE(INCH) = 3.00 SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE =0.95 SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED NOTE: ONLY PEAK CONFLUENCE VALUES CONSIDERED **************************************************************************** FLOW PROCESS FROM NODE 1.00 TO NODE 2.00 IS CODE = 21 »»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««< *USER SPECIFIED(SUBAREA): MULTI-UNITS DEVELOPMENT RUNOFF COEFFICIENT = .7400 INITIAL SUBAREA FLOW-LENGTH = 495.00 UPSTREAM ELEVATION = 295.45 DOWNSTREAM ELEVATION = 284.33 ELEVATION DIFFERENCE = 11.12 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 11.008 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.276 SUBAREA RUNOFF(CFS) = 2.91 TOTAL AREA(ACRES) = 0.92 TOTAL RUNOFF(CFS) = 2.91 Post-Dev.doc TOUCHSTONE COMMUNITY File: CA1131 9/19/2003 ^t+************************************************************************** FLOW PROCESS FROM NODE 2.00 TO NODE 3.00 IS CODE = 4 »»>COMPUTE PIPEFLOW TRAVELTIME THRU SUBAREA««< »»>USING USER-SPECIFIED PIPESIZE««< DEPTH OF FLOW IN 6.0 INCH PIPE IS 3.9 INCHES PIPEFLOW VELOCITY(FEET/SEC.) = 21.5 UPSTREAM NODE ELEVATION = 287.00 DOWNSTREAM NODE ELEVATION = 279.60 FLOWLENGTH(FEET) = 15.00 MANNING'S N = 0.013 GIVEN PIPE DIAMETER(INCH) = 6.00 NUMBER OF PIPES = 1 PIPEFLOW THRU SUBAREA(CFS) = 2.91 TRAVEL TIME(MIN.) = 0.01 TC(MIN.) = 11.02 *^t************************************************************************** FLOW PROCESS FROM NODE 4.00 TO NODE 5.00 IS CODE = 21 »»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««< *USER SPECIFIED(SUBAREA): MULTI-UNITS DEVELOPMENT RUNOFF COEFFICIENT = .7400 INITIAL SUBAREA FLOW-LENGTH = 200.00 UPSTREAM ELEVATION = 294.00 DOWNSTREAM ELEVATION = 286.78 ELEVATION DIFFERENCE = 7.22 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 5.974 *CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. TIME OF CONCENTRATION ASSUMED AS 6-MINUTES 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.325 SUBAREA RUNOFF(CFS) = 1.17 TOTAL AREA(ACRES) = 0.25 TOTAL RUNOFF(CFS) = 1.17 **************************************************************************** FLOW PROCESS FROM NODE 6.00 TO NODE 7.00 IS CODE = 21 »»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««< *USER SPECIFIED(SUBAREA): MULTI-UNITS DEVELOPMENT RUNOFF COEFFICIENT = .7400 INITIAL SUBAREA FLOW-LENGTH = 100.00 UPSTREAM ELEVATION = 291.00 DOWNSTREAM ELEVATION = 285.00 ELEVATION DIFFERENCE = 6.00 URBAN SUBAREA OVERLAND TIME OF FLOW(MINUTES) = 3.566 *CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. TIME OF CONCENTRATION ASSUMED AS 6-MINUTES 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.325 SUBAREA RUNOFF(CFS) = 1.40 TOTAL AREA(ACRES) = 0.30 TOTAL RUNOFF(CFS) = 1.40 END OF RATIONAL METHOD ANALYSIS Post-Dev.doc 40 50 1 Duration 3 4 Hours Directions for Application: (1) From precipitation maps determine 6 hr and 24 hr amounts for the selected frequency. These maps are included in the County Hydrology Manual (10, 50, and 100 yr maps included in the Design and Procedure Manual). (2) Adjust 6 hr precipitation (if necessary) so that it is within the range of 45% to 65% of the 24 hr precipitation (not appllcaple to Desert). (3) Plot 6 hr precipitation on the right side of the chart. (4) Draw a line through fhe point parallel to the plotted lines. (5) This line is the intensity-duration curve for Ihe location being analyzed. to %(2) 24 Application Form: (a) Selected frequency J_^0^_ year (b) Pg = 2^1_ in., P24 = h3__ , (c) Adjusted Pg'^) = in. (d) tj^ = _i 0 min. (e) I = in./hr. Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. P6 1 1.5 '2 2.5 3 3.5 4 4.5 5 5.5 6 Duration 1 •|'" i 1 i 1 i 1 1 1 1 5 263 3.95 527 659 790 922 10 54 11 86 13 17 14 49 1581 7 2.12 3.18 4.24 i 5.30 a 36 7.42 8 48 9.54 10 60 11,66i 12.72 10 iTei" 2.53 3 37 4.21 5^65 5.90; 6.74 758 8 42 9 27 10 11 15 1 30 1.9512 59 324 3.89 4.54 5.19 5.84 6 49 7.13 7 78 20 1.08 1.62 2.15 2.69 323 3 77 4 31 4 85 5.39 593 646 " 25 0.93 1.40 1.87 233 280 327 3 73 4 20 4 67 5 13 5 60 30 o:83 l!24 1 66 2.07 2.49 2 90 3 32 3 73 4 15 4 56 4 98 40 6.69 1 03 1 38 1.72 2.07 2.41 2.76 3 10 3 45 3 79 4 13 SO 0.60 0.90 1.19 1 49 1 79 2.09 2 39 2.69 2.98 3 28 3 58 60 0.53 0.80 1.06 1.33 1.59 1 86 2.12 239 265 2 92 3 18 90 0^41 0.61 082 1.02 1.23 1.43 1.63 1.84 204 2.25 2.45 126 034 0.51 0.68 0.85 1.02 1.19 1 36 1.53 1 70 1 87 204 ISO 0.29 6^44 0.59 0.73 0.88 1 03 1 18 1.32 1 47 1 62 1 76 iiui 0.26 6.39 0.52 0.65 0.78 091 1.04 1.18 1 31 • 1 44 1 57 240 '0.22' 0.33 0.43 0.54 10.65 0.76 0.87 0.98 1.08 1.19 1.30 300 0.19 0.28 6.38 047 6.56 6.66 0.75 0.85 0.94 i 1^03 1.13 360 6.17 6;25 6.33 0 42 OSO 6.58 067 0.75 0.84 i 092 1 00 Intensity-Duration Design Chart - Template HazMat/Counly. , jgeology Manual/lnLDur Design Chart.FHB 3-1 FIGU R E C|^Y OF SAN DIEGO DWRTHEHT OF SANITATION £. FLOOD CONTROL lOO-YEAETS-HOUlI PJ?ECIP!TATIOij ^IW-y ISOPLUVIALS pnECiFiTATion in 33 OF 100-YEAR 6-HOUR EHTMS or AM i;:c!i Prepn U.S. DEPARTMEN NATIONAL OCEANIC AND AT." SPECIAL STUDIES URA.SCll, OFFICE OF II OF SAN DIEGO DEPAHTHENT OF SANITATION S- FLOOD CONTROL 'i5 33' 30' 15 h5' U.S. DEPARTMEN NATIONAL OCEANIC AND AT:. SPECIAI. STUDIES UKANCII. OFI ICE Ot II 100-YEAn%-[IOl n PRECIPITATIOM ^2Q-^ISGPLU\/iALS OF 100-YEAR 24-imUR PRECIPITATION IN ENTHS OF AN INCH 30' — nil •i by r OF COMMERCE OSPIIEKIC AD.MINISTRATIUN UUOLOCY, NATIONAL WEATIIEK SEKVICE /,ljl 30' jr. I 17' 30' If-,' no- INSERT MAP HERE