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Home My WebLink AboutCDP 05-21; KELLAS RESIDENCE; HYDROLOGY REPORT KELLAS; 2006-01-26Keilas R^idence Hydrology Study HYDROLOGY REPORT for Kellas Residence 4410 Highland Drive City of Carlsbad, California r'reparea lor: Bill and Laurie Kellas 621 Saltgrass Ave, Carisbad, CA 92009 W.O. DL 2005-11 January 26, 2006 REVISED; June 13, 2006 Doii^Logan, RtC.E. 39726 President, Logan Engineering JC:jc D:\Hydrotogy\Logan EngineeringV20(^11\Hm04.doc w.o. 2005-11 m 4/2006 8:23:00 AM Kellas Residence Hydrology Study TABLE OF CONTENTS SECTION Executive Sumnnary 1.0 Introduction 1.1 Existing Conditions 1.2 Proposed Project 1.3 Summary of Results and Conditions 1.4 Conclusions 1.5 References 1.6 Methodology 2.0 Introduction 2.1 County of San Diego Criteria 2.2 RunofT coefficient determination 2.3 Hydrology Model Output 3.0 Pre-Developed Hydrologic Model Output {100-yr 6-h(Mjr) 3.1 Post-Developed Hydrologic Model Output (100-yr S-hoiw) 3.2 Existing Condition Hydrology Map Fhroposed Condition Hydrology Map (pocket) (pocket) JC:ic D:U^ydrok>gy\LoganEi^ineering\2005-11\HYD-O4.doc w.o. 2005-11 6A13/200611:11.^)0 AM Kellas Residence Hydrology Study 1.0 EXECUTIVE SUMMARY 1.1 introduction This Hydrology Study for Kellas Residence has been prepared to analyze the hydrok^ic characteristics of the existing an6 proposed project site. This report intends to present the methodology and Vne cateiicrtnns used for determining the rufKjff from the project site In tx)th the pre-devetoped (ejdsting) conditk)ns and the po^-devekiped (propesed) conditions, as as offsite areas, produced by the 100 year 6 hotr storm. 1.2 Existing Conditioi» The project stte is kx:^ed on fhe ^ist side Hl^^and Drive, south of Carisbad Village Drive, in the City of Carlsbad, CaMofraa. The fxvject is kx^t^ in tfie Cartsbad watershed arxj the Endnas hydrctog^ irMt 904.40. The afea is composed of existing residmtial (^ekxpgn&nL The esos^ng corxtitions cf the projx»sed f^-c^ect ^e ccfisi^ of a yacart paicei fli^ is neariy retibanguiar in configuration, and encofnpasses alnriost .35 acres. 71% majority of the sile is a pre-existif^ graded pad. The terraHi vales frcxn ^itly kxtr^ to mod^M^y ste^ siang me east- and soL#i-tac^ sk^ses. Elev^k^ ^e the order of 165 to 145 feet akxrife meati sea teyel. Existing drainage of the site is facHrtated she^ fiow in a southeaslQly directi(Mi across the psH'cei. . 1.3 Proposed ProJ^ Conditions The project is a single family resident^. Ttie prciposed dev^opnnern indudes grading oS a driveway, a pad suitat^ for txikfr^ costsSnxbon, w^kmiQ ^t/^ls and utilities. The proposed project design will not divert fiow from the existing drainage course. 1.4 Sunmiary of Results The project site in both the existing axiditiai and de^^k^sed condttk)n wi^e fUKxieied with sionn water disdiarge at two kicalions. The ir^kciogic anafy^ of existing condition can be found in S^:^CMIS 3.1 .The piopt^ed project cie»gn, vnH nc^ iBie e^d^r^ drmnage. Ansa ct^^is ane fxoj30sed to dnan ar^s b^ind waUs, ixA are rxA inl^ided as a skxm <km\ sysksnt The proposed development will increai ttie k^ ^CKTH w^^cfi^tiar^d by 0.03 cfs yiJhen ttie disc3iarges 1n»n Ix^ Sre fffe-de^^oped and de^oped coTK^&xn for th» Uvo pcMits (rf (fisctwge are cx)n^>ar»i c&vm^fi^^^. The p^( Sows in ^ W1B.2Q0&-11 enaiKOe 11:11:00 AM Kellas Residence Hydrology Study existing condition hydrologic model were found to be 0.70 cfs with a Time of Concentration of 6.00 minutes and a 0.3 acre watershed for the northerly sub- basin, and 0.30 cfs with a Time of Concentratbn of 6.00 minutes and a 0.13 acre watershed for the northeriy sub-basin, and at the ultimate point of discharge (node 1) the peak 100-year 6-hour discharge from the site is found to be 0.97 cfs with a Time of Concentration of 7.51 minutes and a 0.43 acre total watershed area. The developed condition model maintains the same watershed limits that the pre- devetoped condition model was prepared with, and the watershed consists of approximately 0.43 acres. The developed condition model also maintains similar points of discharge. The hydrologic analysis of the devetoped condition Indtoates that the 100-yea 6 hour storm wouM produce an antidpated peak flow dischage of 0.88 cfe wfth a Time of Concentratton of 6.00 minutes and a 0.34 acre watershed for the northeriy sub-basin, 0.16 cfe wfth a Time of Concentratton of 11.25 minutes and a 0.09 acre watershed fbr the northeriy sub4>aski, and at the ultifTi^ pc»rt erf cfischage (node 1) the peak 1C»ifea 6-hour cBscharge from the site is found to be 1.00 cfe ^ a Tane of Concsndiatton of 7.39 minutes and a 0.43 acre tcrf^ watershed area. 1.5 Conclusions The proposed development will increase the amount of runoff from the prpject site as compared to the runoff from the sfte in the existing concjftions for all storms modeled by only 0.03 cfe (1.0 - 0.97 = 0.03). This increase in mnoff is n^rigSite aid based CXI ate wste the incaease wfll riot cause any problems to the downstream system. The northeriy sub-bastfi will experience a 0.18 cSs increase in dischage as compared to the existing condftton. TWs st4)-basin cSscharges into Highland Drive, and Hiland msie VMB be capatie of s^ely conveying the increase in peak disctiarge erf 0.18 cfe ch^kig Qie 100-year 6 hour ^xm. The southeriy basin will exhibft a decrease in peak runolf dischage of 0.14 cfe. Additionally cross lot drainage has l>een kter^ied on Ihis project site. The sou»ierty ^-bastn, tn bd&\ the pr&<levek)ped and devetoped condftton. drains across the property limits akxig the soirtherly fx^operty line. However, the peak discharge wiH be decreased by 0.14 cfe as compared to tie existing concStkxi peak discharge. This decrease is primarily fhe resu» of a cJecrease in area of 0.04 acres in the dev^c^»d ccxxfi&xi ccxil^ixi&ig to fhe saUSiesfy baskn as a result <rf the proposed residents, /wkfitionaly, the time of eoncenlratiusi for tte southeriy basin in the devetoped condfficxi m kicreased because 8ie ftow path is exl^ided atiu &!« of rw "fOw pawi *s s^^^eai^iy feckiced due fe the design of a grass fined BUP sufaie. JCqc DiVHydrologyUjogw Engineciintf«200S-11\HYI>4Mitoc w.o. 2005-11 «n3V20061ini«)MI Kellas Residence Hydrology Study In (X)ndusion. it is the opinion of Logan Engineering that the proposed devetopment will not significantly impact any downstream natural or manmade storm drain systems and the proposed drainage fadlities will fc>e c:apable erf collecting and safely conveying all runcrff generated on the project site by the 100-yea 6 hour stcxm event. 1.6 References "San Diego County Hydrology Manuar, revised June 2003, County of San Diego, Department of Public Works, Flood Control Section. JC:jc O:\Hydrology\LoganEngineeflng\2005-11\HYD-04.doc w.o. 2005-11 6/13/200611:11:00 AM Kellas Residence Hydrology Study 2.0 METHODOLOGY 2.1 Introduction The hydrologic model used to perform the hydrologic analysis presented in this report utilizes the Ration Method (RM) equation, Q=CIA. The RM formula estimates the peak rate of runoff based on the variables of area, runcrff coefficient, and rainfall intensity. The rainfall intensity (I) is equal to: I = 7.44 X Pe X D-°^^ Where: I = Intensity (in/hr) Pe = 6-hour predpitation (inches) D = duration (minutes - use Tc) Using the Time of Concentration (Tc), which is the time required fex a given element of water that originates at the most remote point of the t>asin being analyzed to reach tfie point at which the runcrff from the basin is being analyzed. The RM equation determines the storm water runcrff rate (Q) for a given basin in terms erf flow (typically in exibic feet per seccxid (cfs) but sometimes as gallcxis per minute (gpm)). The RM equatiexi is as follows: Q = CIA Where: Q= flow (in cts) C = runoff coeffident, ratio erf rainfall that |XOCkic;es storni water runoff (runoff vs. infiltration/evaporation/absorption/etc) I = average rainfall intensity fex a duratiexi equal to the Tc for the area, in inches per hour. A = drainage area exxitributir^ to tie t>asin in acres. The RM equatiexi assumes that the stexm event being analyzed delivers predpftatkxi to the entire basin unifcxmiy, and therefcxe the peak disctiarge rate will ocxxir when a raindrop that falls at the most remcrfe pcxtion erf the t>asin amves at tie point erf analysis. The RM sriso assumes tiat tie firactton of ranferii that beexxnes runcrff cx the runoff cx)effident C is not affected by the stexm intensity, I, cx thffi predpitation zcxie numb^-. In acktiticxi to tie atx)ve Raticxi Methcxl assumptions, the conservative assumprfton that eril nxicrff ex>effictents utilized for this report ae based on type "D" soils. 2.2 County of San Diego Criteria As defined by the County Hydrology Manual dated June 2003, the raticxial methcxj is the preferred ec:|uatiexi fex cjetermining the hydroto^ ctiarateristtos erf basins up to approximately cxie square mile in size. The Ccxinty erf San Diego JC:jC 0:\Hydrok)gy\Log«)En9neera«V2005-11Vm>-04.doc W.0.200S-U 6/13/200611:11:00 AM Kellas Residence Hydrology Study has developed its own tables, nomographs, and methodologies for analyzing storm water runoff for areas within the county. The County has also developed precipitation isopluvial contour maps that show even lines of rainfall antidpated from a given storm event (i.e. 100-year, 6-fiour storm). One of the variables of the RM equation is the runoff cx)effident, C. The runoff coefficient is dependent only upon land use and soil type and the County of San Diego has developed a table of Runoff Coeffidents fex Uri^an Areas to t>e applied to basin located within the County of San Diego. The table categorizes the land use, the asscxaated development density (dwelling units per acre) and the perc^entage of impervious area. Each erf the categories listed has an asscxriated runcrff cx)effident, C, for eacti soil type dass. The County has also illustrated in detail the methodology for determining the time of concentration, in particular the initial time of concrentraticxi. The County has adopted the Federal Aviaticxi Agency's (FAA) overiand time of flow equation. This equatton essentially limits the flow path length for the initial time of ccxic»ntation to lengths of 100 feet or less, arxj is dependent on land use and slope. 2.3 Runoff Coefficient Determination As stated in section 2.2, the runoff coeffident is dependent only upon land use and soil type and the County of San Diego has ctov^oped a tabie of Runoff Coeffidents for Urban Areas to be applied to basin Icxrated within the County of San Diego. The table, induded at the erxl of this section, crategorizes the land use, the asscxtated development density (dwelling units per acre) and the percentage erf imperviexjs area. Fex the proposed development the total number of dwellings proposed is 1 residential buikling, and is most costly asscx^ated with the NRCS Element Low Density Residential and tie County Element Residential 1.0 Du/A ex less in Table 3-1 of the County Hydrology manual. Therefore the runcrff coefficient of 0.41 was primarily utilized in tie developed ccxxliticxi model. For the existing conditicxis, runcrff coeffidents were selected based upexi the impervious percentage and land use. TT^ primary coefTxtent utilized was 0.37, and this was derived from a calculaticxi of the existing impervious surfaces (rcxjgtiiy 3.3% erf the existing project site is impervious). JCrjc O:\Hydrology\LoganEn9ineefingV2005-11\HYD-04.doc w.o. 2005-11 6/13/200611:11«) AM Kellas Residence Hydrology Study 3.0 Hydrology Model Output 3.1 Pre-Developed Hydrologic Model Output (100-yr 6-hour) RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 2003,1985,1981 HYDROLOGY MANUAL (c) Copyright 1982-2005 Advanced Engineering Software (aes) Ver. 2.0 Release Date: 06/01/2005 License ID 1574 Analysis prepared by: **-ifjfDESCRIPTION OF STUDY ************************** * HYDROLOGY STUDY FOR THE lOO-YEAR 6 HOUR STORM EVENT FOR: * * KELLAS RESIDENCE - EXISTING CONDITION * * * ************************************************************************** FILE NAME: C:\AES\KELLAS\100-EX.DAT TIME/DATE OF STUDY: 10:25 06/13/2006 USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: 1985 SAN DIEGO MANUAL CRITERIA USER SPECIFIED STORM EVENTIYEAR) = 100.00 6-HOUR DURATION PRECIPITATION (INCHES) = 2.7 00 SPECIFIED MINIMUM PIPE SIZE(INCH) = 18.00 SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.90 SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD NOTE: ONLY PEAK CONFLUENCE VALUES CONSIDERED *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n) 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS: 1. Relative Flow-Depth = 0.80 FEET as (Maximum Allowable Street Flow Depth) - (Top-of-Curb) 2. (Depth)*(Velocity) Constraint = 10.0 (FT*FT/S) *SIZE PIPE WITH A FLOW CAPACITY GREATER THAN OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.* **************************************************************************** FLOW PROCESS FROM NODE 11.00 TO NODE 10.00 IS CODE = 21 »»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««< *USER SPECIFIED(SUBAREA): SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .3700 S.C.S. CURVE NUMBER (AMC II) = 0 INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00 UPSTREAM ELEVATIONIFEET) = 162.20 DOWNSTREAM ELEVATION(FEET) = 147.10 ELEVATION DIFFERENCE(FEET) = 15.10 URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.317 *CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NCMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. TIME OF CONCENTRATION ASSUMED AS 6-MIN. JC:jc D:\Hyclrology\Logan Englneering\2005-11\HYD-04.doc w.o. 2005-11 6/13/2006 11:11:00 AM Kellas Residence Hydrology Study 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.325 SUBAREA RUNOFF (CFS) = 0.7 0 TOTAL AREA(ACRES) = 0.30 TOTAL RUNOFF(CFS) = 0.70 **************************************************************************** FLOW PROCESS FROM NODE 10.00 TO NODE 1.00 IS CODE = 51 »»>COMPUTE TRAPEZOIDAL CHANNEL FLOW««< »»>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)««< ELEVATION DATA: UPSTREAM(FEET) = 147.10 DOWNSTREAM(FEET) = 144.00 CHANNEL LENGTH THRU SUBAREA(FEET) = 165.00 CHANNEL SLOPE = 0.0188 CHANNEL BASE(FEET) = 2.00 "Z" FACTOR = 2.000 MANNING'S FACTOR = 0.030 MAXIMUM DEPTH(FEET) = 0.25 CHANNEL FLOW THRU SUBAREA(CFS) = 0.7 0 FLOW VELOCITY(FEET/SEC.) = 1.83 FLOW DEPTH(FEET) = 0.16 TRAVEL TIMEIMIN.) = 1.51 Tc(MIN.) = 7.51 LONGEST FLOWPATH FROM NODE 11.00 TO NODE 1.00 = 265.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 1.00 TO NODE 1.00 IS CODE = 1 »»>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE«<« TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = 7.51 RAINFALL INTENSITY(INCH/HR) = 5.47 TOTAL STREAM AREA(ACRES) = 0.30 PEAK FLOW RATE(CFS) AT CONFLUENCE = 0.7 0 **************************************************************************** FLOW PROCESS FROM NODE 21.00 TO NODE 20.00 IS CODE = 21 »»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««< *USER SPECIFIED(SUBAREA): SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .3700 S.C.S. CURVE NUMBER (AMC II) = 0 INITIAL SUBAREA FLOW-LENGTH{FEET) = 100.00 UPSTREAM ELEVATIONIFEET) = 164.00 DOWNSTREAM ELEVATION{FEET) = 14 8.00 ELEVATION DIFFERENCE(FEET) = 16.00 URB/W SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.215 *CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. TIME OF CONCENTRATION ASSUMED AS 6-MIN. 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.325 SUBAREA RUNOFF(CFS) = 0.30 TOTAL AREA(ACRES) = 0.13 TOTAL RUNOFF(CFS) = 0.30 **************************************************************************** FLOW PROCESS FROM NODE 20.00 TO NODE 1.00 IS CODE = 52 »»>COMPUTE NATURAL VALLEY CHANNEL FLOW««< »»>TRAVELTIME THRU SUBAREA««< ELEVATION DATA: UPSTREAM(FEET) = 148.00 DOWNSTREAM(FEET) = 144.00 CHANNEL LENGTH THRU SUBAREA(FEET) = 4 0.00 CHANNEL SLOPE = 0.1000 NOTE: CHANNEL FLOW OF 1. CFS WAS ASSUMED IN VELOCITY ESTIMATION CHANNEL FLOW THRU SUBAREA(CFS) = 0.30 FLOW VELOCITY(FEET/SEC) = 4.7 4 (PER LACFCD/RCFCSWCD HYDROLOGY MANUAL) TRAVEL TIME(MIN.) = 0.14 Tc(MIN.) = 6.14 LONGEST FLOWPATH FROM NODE 21.00 TO NODE 1.00 = 140.00 FEET. FLOW PROCESS FROM NODE 1.00 TO NODE 1.00 IS CODE = 1 »»>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE««< »»>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES««< JC:jc D:\Hyclrology\Logan Engineering\2005-11\HYD-04.doc w.o. 2005-11 6/13/2006 11:11:00 AM Kellas Residence Hydrology Study TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE: TIME OF CONCENTRATION(MIN.) = 6.14 RAINFALL INTENSITY(INCH/HR) = 6.23 TOTAL STREAM AREA (ACRES) = 0.13 PEAK FLOW RATE(CFS) AT CONFLUENCE = 0.30 ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) 1 0.70 7.51 5.474 0.30 2 0.30 6.14 6.231 0.13 RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY NUMBER (CFS) (MIN.) (INCH/HOUR) 1 0.92 6.14 6.231 2 0.97 7.51 5.474 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = TOTAL AREA(ACRES) = 0 LONGEST FLOWPATH FROM NODE 0. 97 43 11 Tc(MIN.) = 00 TO NODE 7.51 1.00 = 265.00 FEET. END OF STUDY SUMMARY: TOTAL AREA(ACRES) PEAK FLOW RATE(CFS) 0.43 0. 97 TC{MIN.) = 7.51 END OF RATIONAL METHOD ANALYSIS JC:jc D:\Hydrology\Logan Engineering\2005-11\HYD-04.doc w.o. 2005-11 6/13/2006 11:11:00 AM Kellas Residence Hydrology Study 3.2 Post-Developed Hydrologic Model Output (100-yr 6-hour) **************************************************************************** RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 2003,1985,1981 HYDROLOGY MANUAL (c) Copyright 1982-2005 Advanced Engineering Software (aes) Ver. 2.0 Release Date: 06/01/2005 License ID 1574 Analysis prepared by: ************************** DESCRIPTION OF STUDY ************************** * HYDROLOGY STUDY FOR THE 1OO-YEAR 6 HOUR STORM EVENT FOR: * * KELLAS RESIDENCE * * DEVELOPED CONDITIONS * FILE NAME: C:\AES\KELLAS\100-PR-2.DAT TIME/DATE OF STUDY: 10:18 06/13/2006 USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: 1985 SAN DIEGO MANUAL CRITERIA USER SPECIFIED STORM EVENT(YEAR) = 100.00 6-HOUR DURATION PRECIPITATION (INCHES) = 2.7 00 SPECIFIED MINIMUM PIPE SIZE(INCH) = 18.00 SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE =0.90 SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD NOTE: ONLY PEAK CONFLUENCE VALUES CONSIDERED *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GECMETRIES: MANNING WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n) 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS: 1. Relative Flow-Depth = 0.80 FEET as (Maximum Allowable Street Flow Depth) - (Top-of-Curb) 2. (Depth)*(Velocity) Constraint = 10.0 (FT*FT/S) *SIZE PIPE WITH A FLOW CAPACITY GREATER THAN OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.* **************************************************************************** FLOW PROCESS FROM NODE 11.00 TO NODE 10.00 IS CODE = 21 »»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««< *USER SPECIFIED(SUBAREA): SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .4100 S.C.S. CURVE NUMBER (AMC II) = 0 INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00 UPSTREAM ELEVATION(FEET) = 162.20 DOWNSTREAM ELEVATION(FEET) = 147.00 ELEVATION DIFFERENCE(FEET) = 15.20 URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.014 *CAUTION: SUBAREA SLOPE EXCEEDS COUNTY NOMOGRAPH DEFINITION. EXTRAPOLATION OF NOMOGRAPH USED. JC:jc D:\Hydrology\Logan Engineering\2005-11\HYD-04.doc w.o. 2005-11 6/13/2006 11:11:00 AM Kellas Residence Hydrology Study TIME OF CONCENTRATION ASSUMED AS 6-MIN. 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.325 SUBAREA RUNOFF(CFS) = 0.88 TOTAL AREA (ACRES) = 0.34 TOTAL RUNOFF (CFS) = 0.88 **************************************************************************** FLOW PROCESS FROM NODE 10.00 TO NODE 1.00 IS CODE = 51 »»>CCWPUTE TRAPEZOIDAL CHANNEL FLOW««< »»>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)««< ELEVATION DATA: UPSTREAM(FEET) = 147.00 DOWNSTREAM(FEET) = 144.00 CHANNEL LENGTH THRU SUBAREA(FEET) = 165.00 CHANNEL SLOPE = 0.0182 CHANNEL BASE(FEET) = 2.00 "Z" FACTOR = 2.000 MANNING'S FACTOR = 0.030 MAXIMUM DEPTH(FEET) = 0.25 CHANNEL FLOW THRU SUBAREA(CFS) = 0.88 FLOW VELOCITY(FEET/SEC.) = 1.98 FLOW DEPTH(FEET) = 0.19 TRAVEL TIME(MIN.) = 1.39 Tc(MIN.) = 7.39 LONGEST FLOWPATH FROM NODE 11.00 TO NODE 1.00 = 265.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 1.00 TO NODE 1.00 IS CODE = 1 »»>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE««< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = 7.39 RAINFALL INTENSITY(INCH/HR) = 5.53 TOTAL STREAM AREA(ACRES) = 0.34 PEAK FLOW RATE(CFS) AT CONFLUENCE = 0.88 **************************************************************************** FLOW PROCESS FROM NODE 22.00 TO NODE 21.00 IS CODE = 21 »»>RATIONAL METHOD INITIAL SUBAREA ANALYSIS««< *USER SPECIFIED(SUBAREA): SINGLE FAMILY DEVELOPMENT RUNOFF COEFFICIENT = .4100 S.C.S. CURVE NUMBER (AMC II) = 0 INITIAL SUBAREA FLOW-LENGTH(FEET) = 100.00 UPSTREAM ELEVATION(FEET) = 161.4 0 DOWNSTREAM ELEVATION(FEET) = 160.00 ELEVATION DIFFERENCE(FEET) = 1.4 0 URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = 11.102 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.252 SUBAREA RUNOFF(CFS) = 0.16 TOTAL AREA(ACRES) = 0.09 TOTAL RUNOFF(CFS) = 0.16 **************************************************************************** FLOW PROCESS FROM NODE 21.00 TO NODE 1.00 IS CODE = 52 »»>COMPUTE NATURAL VALLEY CHANNEL FLOW««< »>»TRAVELTIME THRU SUBAREA««< ELEVATION DATA: UPSTREAM (FEET) = 148.00 DOWNSTREAM ( FEET) = 144.00 CHANNEL LENGTH THRU SUBAREA(FEET) = 40.00 CHANNEL SLOPE = 0.1000 NOTE: CHANNEL FLOW OF 1. CFS WAS ASSUMED IN VELOCITY ESTIMATION CHANNEL FLOW THRU SUBAREA(CFS) = 0.16 FLOW VELOCITY(FEET/SEC) = 4.74 (PER LACFCD/RCFC&WCD HYDROLOGY MANUAL) TRAVEL TIME(MIN.) = 0.14 Tc(MIN.) = 11.24 LONGEST FLOWPATH FROM NODE 22.00 TO NODE 1.00 = 140.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 1.00 TO NODE 1.00 IS CODE = 1 »»>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE««< »»>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES««< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE: JC:jc D:\Hydrology\Logan Engineering\2005-11\HYD-04.doc w.o. 2005-11 6/13/2006 11:11:00 AM Kellas Residence Hydrology Study TIME OF CONCENTRATION(MIN.) = 11.24 RAINFALL INTENSITY(INCH/HR) = 4.22 TOTAL STREAM AREA(ACRES) = 0.09 PEAK FLOW RATE(CFS) AT CONFLUENCE = 0.16 ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) 1 0.88 7.39 5.528 0.34 2 0.16 11.24 4.218 0.09 RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY NUMBER (CFS) (MIN.) (INCH/HOUR) 1 1.00 7.39 5.528 2 0.83 11.24 4.218 COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 1.00 Tc(MIN.) = 7.39 TOTAL AREA (ACRES) = 0.43 LONGEST FLOWPATH FROM NODE 11.00 TO NODE 1.00 = 265.00 FEET. END OF STUDY SUMMARY: TOTAL AREA (ACRES) 0.43 TC(MIN.) = 7.39 PEAK FLOW RATE (CFS) 1.00 END OF RATIONAL METHOD ANALYSIS JC:jc D:\Hydrology\Logan Engineerlng\2005-11\HYD-04.doc w.o. 2005-11 6/13/2006 11:11:00 AM