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Home My WebLink AboutCT 02-25; NORTHPARK AT LA COSTA; HYDROLOGY/HYDRAULIC ANALYSIS; 2004-01-06 (2)HYDROLOGY/HYDRAVUC ANALYSES FOE Carlsbad Tract No. 02-25 North Park atLa Costa Dated: 09/19m Revised 01/06/04 Snlgmm-DsiB 8348 Center Drive, Suite G La Afesa, CA 91942-2910 (619) 697-9234, Fax (619) 460-2033 Job No. CA1133 cr o2~z^ TOUCHSTONE COMMUNITY TM ''''8^3/2002 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 SUE 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 WESL IT IS BOUND BY MULTI-FAMILY RESIDENTIAL AND SINGLE- FAMILY iREslDEflAL TO THE NORTH. THE RUNOFF FROM THE PROPERTY SHEET-FbDWS'~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 HYDROLOGY/HYDRAVUC ANALYSIS FOR Carlsbad Tract No. 02^ North Park at La Costa 834Bi.Centerbfive. Suite 6 La M^a, CA 91942-2910 (d[19) 697-^^, Fax (619) 460-2033 William A. Snipes R. C. E. 50477 ..if / 1- HYDROLOGY/HYDRAVUC ANALYSIS FOR or Carlsbad Tract No. OA North Park at La Costa Dated: 09/19/03 8348 Center Drive, Suite G La Mesa, CA 91942-2910 (619) 697-9234, Fax (619) 460-2033 Job No. CA1132 HYDROLOGY/HYDRAVUC ANALYSIS FOR Carlsbad Tract No. 02-25 North Park at La Costa : Center £»]p/e, SuUe 6 )1942-2910 , (61^) 697-92fhfax (619) 460-2q33 / William A. Snipes R.C.E. 50477 NORTHPARK AT LA COSTA 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 ''''%?9/2003 S/7-E PEAK FLOW DETENTION (lOO-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 Kl FOR THE CURRENT SUE: I \= 1.37 ACRES (A1 = 1.37 ACRES, ASSUME Cl = 0.55; 1= 0.18 ACRES (A2 = 0.18 ACRES. ASSUME C2 = 0.70) A=A1 +A2 C = {A1(C1)+A2(C2)}/A C = (1.37(0.55) + 0.18(0.70)} 1.54 C = 0.57 2. CALCULATE WEIGHTED RUNOFF COEFFICIENT fCI FOR THE DEVELOPED SITE: I 1= 0.58 ACRES (A3 = 0.58 ACRES ASSUME C3 = 0.40) 1= 0.06 ACRES (A4 = 0.06 ACRES, ASSUME 04 = 070) \^^= 0.91 ACRES (A5 = 0.91 ACRES, ASSUME C5 = 095; A=A3+A4 + A5 C = {A3fC3; + A4(C4) + A5fC5;;/A C = (0.58(0.40) + 0.06(0.70) + 0.91(0.95)} 1.54 0 = 0.74 Prepared by: 100-YR Calculations Snipes-Dye Associates TOUCHSTONE COMMUNITY TM 9/?9/2003 3. CALCULATE PEAK DISCHARGE OF CURRENT SITE: 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 C = 0.57,1 = 4.6 in/hr, A = 1.54 acres Q = 0.57(4.6)1.54 Q = 4.04 cfs 4. CALCULATE PEAK DISCHARGE OF DEVELOPED SITE: Q = CIA 0 = 0.74,1 = 4.6in/hr, A = 1.54acres 0 = 0.74(4.6)1.54 Q= 5.24 cfs Prepared by: 100-YR Calculations Snipes-Dye Associates ^ TOUCHSTONE COMMUNITY TM File: CA1131 9/19/2003 S. CALCULATE VOLUME OF INCREASED RUNOFF FROM DEVELOPED SITE: DEVELOPED SITE HYDROGRAPH Q(cfs) x=1.15 M 5.24 4.04 Tc (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 PREDEVELOPMENT DISCHARGE FROM SITE (Qex): Qex =4.04 cfs TOTAL POST-DEVELOPMENT DISCHARGE FROM SITE (Qpr): Qpr = 5.24 cfs THE POST-DEVELOPMENT DISCHARGE RUNOFF THROUGH RETENTION BASIN (Qm): Qm= 2.91 efs (See attached calcinations) THE POST-DEVELOPMENT DISCHARGE RUNOFF NOT THROUGH RETENTION BASIN (Qnr): Qnr = Qpr-Qin= 5.24 cfs - 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 ck Qr = 1.71 cfs Utilize 2-4 inch PVC pipes for ffie proposed retention basin outlet: 4" pipe's discharge capacity = 0.84 cfe (See attached calculations) 2-4" pipes = 2x0.84= 1.68 cfs <Qr THE TOTAL POST-DEVELOPMENT RUNOFF = Qnr+Q(two 4" pipes) = 2.33 cfe + f.6« cfe = 4.0f cfe 4.0f 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. DESIGN RETENTION STRUCTURE WITH MINIMUM VOLUME OF 82 CUBIC FEET: attached deUO) File: CA1131 9/19/2003 fSee 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) 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^^H)(W} V=(67 FT)(0.67 FT)(4.17 FT)/2 V= 94CU. FT. > 82 CU. FT. DETERMINE THE OVERFLOW PIPE: Utilize one 6"pipe Ibr the retention liasin overflow pipe 6" overflow pipe's tOscharge capacity = 2.55 cfs (See attadied cafcufatfons; Q(enter) - Q (two 4" pipes) = Q(mln. overflow pipe) 2.91 cfe - 1.68 cfs = 1.23 cfs < 2.55 cfs (The capacity ofa 6" overtteivpfpe is greater titan the reqimed 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 «" 480VE THE BOTTOM OF THE LOW-END ARE SUFFiaENT 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 ^ PVC PIPES DISCHARGE TO CURB OUTLET Q, 1.68 CFS -RETeslTION VOLUME (V) - I05 CU. FT -RETAINING WALL PB? GRADING PLAN (TYP.) SECTION A-A NO SCALE • DRAINAGE PIPES DISCHARGE TO CURB OUTLET PB5 IMPROVEMENT PLANS (TYPJ O RETAINING WALL PB2 GRADING PLAN CnrP.) 4' PVC PIPE K d gSSi fSiS^, IMS iMisSi 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 CAPACITY OFA 4" PIPE »»PIPEFLOW 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 ^f^,^,^,^,^,^r**************•k**•k* **************************************** »»PIPEFLOW HYDRAULIC INPUT INFORMATION«« 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 ^'^ntnm 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 **************************************************************************** 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 **************************************************************************** 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 O'VERLAND 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 2 3 4 5 Hours Directions for Application: (1) From precipitation maps determine 6 hr and 24 hr amounis for the selected frequency. These maps are included in Ihe 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 precipitalion (not applicaple to Desert). (3) Plot 6 hr precipitation on the right side of the chart. (4) Draw a line through the point parallel to the plotted lines. (5) This line is the intensity-duration curve for Ihe localion being analyzed. 24 Application Form: (a) Selected frequency \P_0__ year (b) PQ = 2^1_ in., P24 = ,p (c) Adjusted Pg(2) = _2._!jf- in. (d) tj^ = _i 0 min. (e) I = in./hr. Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. P6 Duration '5: 7 10 15 20 " 25 30 40 50 60 90 120 _^150 iiU) 240 300 360 3.95 3.18 2.53 1 95 1.62 1.40 1.24 1 03 0.90 0.80 0.61 0.51 6^44: 6.39 0.33 0.19 aaa 263 2.12 I'ei' 1 30 1.08 0.93 0;83 0.69 0.60 6.53 6A\ 0.34 0.29 6.26 '6.'22' 2.5 1 3.5 1 4.5 I 5.5 I 527 4.24 3 37 2.59 2.15 1.87 1.66 1 38 1.19 1.06 0.82 0.68 0.59 0.52 0.43 038 0.33 6 59 5.36 •4.21' 324 2.69 2.33 2.07 1.72 1.49 1.33 1.02 085 0.73 0.65 0.54 047 042 7.90 6 36 5.05 3.89 323 2.80 2.49 2.07 1 79 1.59 1.23 1.02 088 0.78 0.65 6.56 922 7.42 5'90 4.54 3 77 327 2.90 2.41 2 09 1.66 1.43 1.19 1.03 0.91 0.76 6.66 0.50! 0.58 1054 8 48 6.74 5.19 4.31 3 73 3.32 2.76 2 39 2 12 1.63 1 36 1 18 1.04 0,87 0.75 067 11.86 i 9.54 ; 7 58 • ' 5.84 ' ' 4.85 ' ; 4.20 ! 3.73 ! 3.10 ' i 2.69 ' j 2.39 ' I 1.84 ' i 1.53 ' j 1.32 , 1.18 10.98; I 0.85 I ! 075 I 13 17 10 60' 8 42 • 6 49 ' 5.39 • 4.67 i 4,15 ' 3 45 2 ,98 ' 2 65 ' 2.04 i 1 70 i 1.47 ; 1 31 • 1.08 1 0.94 I 0.84 i 14 49 1581 11,66j 12,72 9,27 \ 10,11 7.13 ! 7,78 5,93 \ 6,46 5 13 ; 4 ,56 ' 3 79 3 28 ' 2,92 ' 2,25 1 87 1 62 • 1 44 1.19 ' t03 i 0 92 i 560 4 98 4 13 3 58 3 18 2,45 204 1 76 1,57 1.30 1 13 1 00 Intensity-Duration Design Chart - Template HazMal/Counly. , ogeology Manual/lnl_Dur Design Chart.FHB 3-1 FIGUR E C|^Y OF SAN DIEGO DWRTHEHT OF SANITATION £. FLOOD CONTROL lOO-YEArS-HOUR PflECIPITATlOij 45' ISOPLUVIALS PnECiPITATIOn lil 30' 15' 33' i,5i OF 100-YEAR 6-IIOUR j'EnTiis or AM i;:cii Prepn U.S. DEPARTMEN NATIONAL OCEANIC AND AT.' SPECIAL STUDIES URA.NCII, OFFICE OF II 30' _ .'d by r OF COMMER OSPIIEKIC AOmiH UROLOGY. NATK CE ISTRATION 3NAL WEATHER S ERVICE 118' C(|^Y OF SAN DIEGO DEPARTMENT OF SANITATION S- FLOOD CONTROL 'i5 33' 30' 15 ii5' U.S. DEPARTMEN NATIONAL OCEANIC AND AT:. SPECIAI. STUDIES UKA.NCII. OFI ICE Of 11 30' 100-YEAR%-IIOl|R PRECIPITATIOM --2Q-^ISGPLUVIALS OF 100-YEAR 24-liOUR PRECIPITATION IN SAfI Cl ENTHS OF AN INCH J by r OF COMMERCE OSPIIEKIC AD.MINISTRATION UI.'OLOGY, NATIONAL HEATHER SEKVICE l-l I 111" 30' 17' V;i :in' ir. I