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HomeMy WebLinkAboutCDP 2022-0051; ANDERSON ADU; HYDROLOGY STUDY; 2023-05-16• CL W No. 1557-D Hydrology Study High Ridge Avenue ADU 1877 High Ridge A venue Carlsbad, CA 92008 Prepared For: Construction With Pride Jessica Brandt 7040 A venida Encinas Ste I 04 Carlsbad, CA 92011 760-420-7051 Prepared By: Civil l!andworks Civil Landworks Corporation 110 Copperwood Way Suite P, Oceanside CA, USA 92058 760-908-8745 May 16, 2023 TABLE OF CONTENTS Section INTRODUCTION .......................................................................................................................... I DESIGN CRITERIA AND ASSUMPTIONS ................................................................................ I DISCUSSION ................................................................................................................................. 2 Proposed Conditions ................................................................................................................... 2 CONCLUSION ............................................................................................................................... 3 DECLARATION OF RESPONSIBLE CHARGE ......................................................................... 3 REFERENCES ............................................................................................................................... 4 ATTACHMENTS ATTACHMENT I -LOCATION MAP ATTACHMENT 2-PRECIPITATION MAPS AND SOIL MAP ATTACHMENT 3 -PROPOSED HYDROLOGY CALCULATIONS ATTACHMENT 4 -HYDROLOGY MAP -PROPOSED CONDITIONS Civil l!andworks INTRODUCTION Drainage Study High Ridge Avenue ADU Carlsbad, CA Determine storm water runoff site drainage and curb outlet capacity for a 100-year storm event for a proposed new ADU on a site with an existing single family residence in the City of Carlsbad, California. The project site is located near the intersection of High Ridge A venue and Telescope Avenue on High Ridge Avenue in Carlsbad. The project is 0.195 acres. The current site is developed with a single family residence. The proposed site development consists of clearing and grubbing the rear of the site for the construction of a new ADU. Improvement associated with the project includes new hardscape, storm system, and landscaping. Site elevations range from approximately 259 to 285 feet above mean sea level. See Attachment 1 for the Site Location and Vicinity Maps. DESIGN CRITERIA AND ASSUMPTIONS 1. Per NRCS, the site soil classification as hydrologic soil type B. See Attachment 2. 2. Per the San Diego County Hydrology Manual (2003) Rainfall Isopluvial Map (See Attachment 2): • 100 Year Rainfall Event-6 hours P6= 2.60 inches/hour • 100 Year Rainfall Event -24 hours P24= 4. 70 inches/hour 3. Hydrologic calculations were performed using the CIVILCAD/CIVILDESIGN Engineering software version 7.6 per methods as outlined within the San Diego Hydrology Manual (2003). The hydrology calculations for proposed conditions may be found within the hydrology calculations section of this report. Page 1 Civil l!andworks PROPOSED CONDITION$ DISCUSSION Drainage Study High Ridge Avenue ADU Carlsbad, CA The proposed conditions will consist of 6 drainage areas, see Attachment 6 for proposed drainage patterns. Storm water from drainage areas (PRl-A, PR-1B, PR-IC and PR-ID) will be collected via modified brow ditches and catch basin inlets, then piped northeast to discharge through a curb outlet into High Ridge Avenue. Storm water from drainage area (PR-2A and PR- 2B) sheet flows northeast off onto High Ridge Avenue. The drainage areas on the site will maintain a similar drainage pattern to that of the existing site. The proposed hydrologic conditions are summarized below: TABLE 2: 100 YEAR POST-DEVELOPMENT CRITERIA Tc I Area Node C £Min.) (in/hr) /acre) Q!O0 /cfs) VIO0 /ft/s) 113 0.77* 4.60 6.850 0.141 0.541 2.63 203 0.77* 4.15 6.850 0.053 0.223 TOTAL 0.194 0.764 NIA *Multiple drainage areas end up at Node 110 and 303 with different "C" values. The above hsted "C" value indicated the highest that is found in all the different drainage areas. With the construction of the new ADU, the peak flow exiting the site will be QI00 = 0.764 CFS. The site will implement disconnect impervious areas by draining all impervious toward landscape areas prior to discharge offsite to the maximum extent practical. Due to the existing 3" curb underdrains being overloaded for the current 100 year storm event, a curb outlet, constructed per SDRSD D-25, will be installed at the north existing curb underdrain location. The proposed site drainage is designed to mimic the existing sheet flow pattern. Page 2 Civil Uandworks CONCLUSION Drainage Study High Ridge Avenue ADU Carlsbad, CA A hydrologic analysis has been conducted for the subject property for a 100-year storm event. The project site peak flow was calculated to be QlO0 = 0.764 CFS, and the proposed curb outlet draining the property was determined to be adequately sized. The project falls under a standard project and LID features are implemented to help with storm water treatment and slowing down peak flows. The proposed development will mimic the drainage patterns similar to the existing conditions. DECLARATION OF RESPONSIBLE CHARGE I, hereby declare that I am the Engineer of Work for this project, that I have exercised responsible charge over the design of the project as defined in section 6703 of the business and professions code, and that the design is consistent with current standards. I understand that the check of project drawings and specifications by the County of San Diego is confined to a review only and does not relieve me, as Engineer of Work of my responsibility for project design. ENGINEER OF WORK: Civil Landworks Corporation 110 Copperwood Way, Suite P Oceanside CA, USA 92058 David V. Caron R.C.E. 70066 Exp. 9-30-24 5-16-23 Date 2' .C070066 09/J0/2 IV\\. Page 3 Civil Uandworks REFERENCES I. San Diego County Hydrology Manual (June 2003). 2. San Diego County Drainage Design Manual (July 2005). Drainage Study High Ridge Avenue ADU Carlsbad, CA 3. Web Soil Survey, San Diego Area, California. United States Natural Resource Conservation Service. 4. CIVILCADD/CIVILDESIGN Engineering Software, © 1991-2006 Version 7.6. San Diego County Control Division 2003 Manual Rational Hydrology Study. 5. AutoCAD Civil 3D Hydraflow Hydrogrpahs Extension for AutoCAD Civil 3D 2015 Version 10.4 by Autodesk, Inc. Page 4 ATTACHMENT 1 LOCATION MAP SITE LOCATION MAP 1877 HIGH RIDGE A VENUE -Ir: S. PERKS °"" 5/4/202J """" ,s SHOWN SITE VICINITY MAP 1877 HIGH RIDGE AVENUE ,_., S. PERKS ATTACHMENT 2 PRECIPITATION MAPS AND SOIL MAP 32°45' ,s2•30• 0 M . ,.._ ..-,... SITE LOCATION P6=2.6 g ~ ~ .... ii) ... i.. .... .... 8 ~ ,... ... 8 • ,... ... ... Riverside County ~ . co ..... ... Mex g U) .... ... 0 M re ... .... . . . . . ii) :--co ... ... ii) ... . co T"' .... l Councy of San Diego Hydrology Manual Rainfall /sop/uvials 100 Year Rainfall Event-6 Boun lsopluvial (inches) DPW ~GIS _,,,...._ --- N + s T>IS-IS-llfflMQUTWl#WfTYOf'Nf<IQOCl,-,illCl'AUS 011-.iEI), ~. Ill\' NOT I.MTm TO, 'l!E ..-..mw-. Of'IEOWffMUIY NIOl'ITIEU-APA!mCIANll'UAl'OS£. ~-,.. ..... -_,,_ ____ ... .,._.,,_..... -~--.. ---.. _,__ .. _ -..---------· ..-,,_., __ _ 3 0 ~ 3 MIies g r.... .... .... in .... . ,-.. ..... .... 8 r.... .... ..... in ..,. to .... .... 0 C"l U) 'r' .... in .... <D ..... .... 33•30, Orange ~ • .-· ,--~ • I • · 1 • I • I I Cotinty l 1 : .. • •.• !J ,._., , • • :• -/ •' :, :,,<;.t....{, 33•30• 33•15• ... 1 1 I 1 , I " I I•.... / • . / c:/::i•' i ."1 • ... ~ .ltd/ :..A #1 " ~ • ''" •v.· • "-i. ..... ..-.,_,. ,,:,~: 1 ·(!;),,,,' • ,. ........ ~ .. :::-.-:::::·•' ,/ ~---:-~; ... / ... -..;,. ..... ,, . ' .• J SITE LOCATION P24=4.7 ·•... '--·& ... ~ ····-e=~::--=~:.-··· \..,;, . •V ••••....._,~•,. •• ~ ····•)'o."•.;•~'Q ..-··•........... ·l9 ···~ '., \ ,••••·••A \ ', . ... !. ~~().~ ;-· .. ., : .. . .... ·, \ .... ·\ .. 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Q)' . .~· -,,,:•' ~-. .. ~-~ I .. ,t ,/ / l._ .. •• ., ... -···· ~ \ •""' "\u. -.. -.,,/ .. \ ~ . \. "-\ .!.. .. ·• ti' \,, .... . .. • ·... .. . .. ....... _ ..... ..... . ... .. ..., • • •.• ~ ~. 4 , ~-•. , . ..,, .. ,, .. . , . •." ............. • •• ... "r..... .. ....... • .... --""' ! . \ ................. ?!i ·~,~ . ...., ! . -. -.. ·-.... .. .... ...... 't ~ ~-• ... ~ ..-"' .. . .. ·..... ...... ·... •• \ -~L.. "'•~ . ~ ·:~•········•. • • -r •• .. t ... ' .. -···:.~:~--~: ,/', '· . , .... ~ . . \ . · ..•. ·~ ', \ ", •, . \ "' .. 1 • • \ \ .. • ' t ......... ·-". ~-"-•, I I • • I I '" • . ; .. '-"-\_ •. . .,:~ :-·· M e X in -:, <O ... ..... . ~ .... .... in .... U) ..... .... ___ ,, ..... .,. ... ,. :·•"""'• ...... . . . . . . ·, . .. -. 0 0 C ::J -'< ..... ~ \ ... ... 82°45' .. . . ,. . .. .. ;;. ... ~ ',, ' ,'"'"'•~ .......... : ·0 .. _ ··~ •·. ·., 32'30' County of San Di~go Hydrology Manual ~ -!4. • ' '1 • ... \ t-~~ ~) Rainfal/ lsopluvials 100 Year Rainfall Event -24 Hours lsopluvial (inches) DPW -CGIS _,,..__ --- N afi\jIS We H.l~~ "'-in Dic-~1 C.o,·cr<d! + --•-wmo.trWl>AIW(NOf'IH(ICMl,--.SS <JIIIMPlE),IIICWDINQ,_,,.NOTLMm>TD, --WARIWfflES Of'"'910WfT-1n' AIOfflNESS >ORA PM'TIC::IUII ,._. _..,._,......,_ ______ .............. _ ____ .. __ ... -------------· ,..__., __ _ 3 0 3 MIies ~ lJO 9' tl"N lJ09'TH Hydrologic Soil Group-San Diego County Area, California Map Scale: 1 :532 If r:nu,j on A portrait (8.5"' X 11'') sheet ---==:;:::,o-----=====M81:r.; 0 5 10 Zl :Jl ----=====--------=======lfeet o ~ ~ m ~ Map projettion: Web Mel1::alllr ComerOla'd!naCl!s: WGS84 Edge lies: lJTM Zone 11N WGS84 Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 3: b !!:: ~ 5/4/2023 Page 1 of 4 lJO 9' ll"N lJ09'TH Hydrologlc Soll Group-San Diego County Area, Callfomia MAP LEGEND MAP INFORMATION Area of lntarut (AOI) D Area of Interest (AOI) Solla Soll Rating Polygon• 0 A □ A/0 0B D BID 0 C 0 CID D D D Not rated or not available Soll R1tl119 Lina■ -A -AID -B -BID -C CID -D .. Not rated Of not available Soll Rating Points II A ■ AID ■ B ■ BID Natural R.esources Conservation Service D C D CID D D a Not rated or not available W■tar Features Streams and Canals Transportation +-+-+ Raus -Interstate Highways -US Routes Major Roads Local Roads B■ck9round • Aerial Photography Web Soll Survey National Cooperative Soll Survey The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: COOf'dinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product Is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soll Survey Area: San Diego County Area, California Survey Area Data: Version 18, Sep 14, 2022 Soil map units are labeled (as space allows) for map scales 1 :50,000 or larger. Date(s) aerial images were photographed: Mar 14, 2022-Mar 17,2022 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background Imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident 514/2023 Page 2 of 4 Hydrologic Soll Group-San Diego County Area, California Hydrologic Soil Group ' I Map unit symbol ..... Acres lnAOI Percot of AOI I CbE Carlsbad gravelly loamy B · I sand,15to30percent slopes ----~ ----~ , 3 Totals for Area of Interest Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (AID, B/D, and CID). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (AID, BID, or CID), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group Dare assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 100.0% 100.0% 5/412023 Page 3 of 4 Hydrologic Soil Group-San Diego County Area, California Component Percent Cutoff: None Specified Tie-break Rule: Higher Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 5/4/2023 Page4 of4 ATTACHMENT 3 PROPOSED HYDROLOGY CALCULATIONS AREA CAL CUL.A TIONS PROPOSED HYOROLOGIC BASINS Baaln SollTypa Pervlous , .. , , .. , Natural lmparvloue L•nd1cap11 Pervlous % CV■lu■ % Frac:tlon CVelue cv.1 ... Runoff ... • •• P■vera lmparviou• W•lght9d .... Fractlon RM, Coefllc:l,nt " k•• " " " " PR·1A A 0.20 0 0000 0 0 0 0 . 0.16 0% 0.00 . • 0.25 2,435 0,056 0 "' 1,908 0 . 0.20 ,00% 0,0 . ' 0.30 0 0,000 0 0 0 0 . 0.24 0% 000 . 0 0.35 0 0 000 0 0 0 0 0.27 0% 0.00 . Total . 2.435 00,0 0 "' 1.908 0 21.62% . 100% 0.20 .,,, Baaln Soll T)'JNI P•rvloue , .. , , .. , Natural lmparvlous Landsc:■PI' Pervlou• % CVelue % Fraction CV■lu■ CV■lue Runoff A,u ... ·-· 1m..-rvloua Welght..:t . ... Fraction Fln■I Coefllci.nt " Ac:n,■ " " " " PR-1B A 0.20 0 0.000 0 0 0 0 . 0.08 0% 0.00 . • 0.25 2,298 0.053 0 1.369 -~ 0 . 0.10 '"" 0.10 . ' o.~ 0 0.000 0 0 0 0 0.12 0% 0.00 . 0 0.35 0 0.000 0 0 0 0 . 0.14 0% 0.00 . , .. , . 2,298 0.053 0 1,369 "' 0 59.55% . 100% 0.10 ..,, Baaln Soll TYJN! Pervloul , .. , , .. , Naturel Impervious Landscapa ....... % CV■lue % Fraction C Velu■ CV■lue Runoff -... Psven, lmparvlous Weighted .... Frectlon Final Coefllc141nt " Acn,■ " " " " PR-1C A 0.20 0 0.000 0 0 0 0 . O.M 0% 0.00 ' 0.25 1.067 0.024 0 "' "' 0 0.0, 100% 0.06 . ' 0.30 0 0.000 0 0 0 0 . 0"' 0% 0.00 . 0 0.35 0 0.000 0 0 0 0 . 0"' 0% 0.00 '""' . 1,067 0.024 0 '" "' 0 77.76% . 100% 0.00 .,., a .. 1n Soll Typa Pervloul , .. , , .. , Natural Impervious Landsc:ap,o Pervlou. % CVelu■ % Fraction C Value CVelu■ '""°" ... ... PSYera lmp,orvlous Welghllld .... Fractlon RM, C...t'llc141nt " k"' " " " " PR-1D A 0.20 0 0 000 0 0 0 0 . 0.,0 0% 0,00 . ' 0.25 "' 0.00B 0 0 aM 0 . 0.25 100% 0.25 . ' 0.30 0 0.000 0 0 0 0 . 0.30 0% 0.00 . 0 0.35 0 0.000 0 0 0 0 . 0.35 0% 0.00 . '""' . aM 0.008 0 0 aM 0 0.00% . 100% 0.25 ""' a .. 1n Soll Type Pervlous ,_ , .. , Natural Impervious .......... hrvloua % CVelue % Fraction C Value cv,, ... Runoff ••• ·-p...,, .. lmp,orvlous Welght9d .... Fractlon Flnel C...t'llcl■nt " k•• " " " " ""·'-' A 0.20 0 0.000 0 0 0 0 . 00, 0% 000 . ' 0.25 1.192 0.027 0 ,oo "' 0 . 0.07 ,00% 0.07 . ' 0,30 0 0,000 0 0 0 0 . 0.08 0% 000 . 0 0,35 0 0,000 0 0 0 0 . 0.10 0% 0.00 . , .. , 1,192 0.027 0 "' "' 0 72.85% 100% 0.07 om ... ," SollTypa hrvlou■ , .. , , .. , Natural 1m.,.rv1ous L■nd•UIM Pervlous % CVelue %F.-.cllon CV■lu■ CV■lu■ Runoff -••• ·-· Impervious Weighted .... Fraction Flnal Coeflldent " k•• " " " " PR-26 A 0.,0 0 0.000 0 0 0 0 . 0.14 0% 0.00 . ' 0.25 1.148 0.026 0 "' "' 0 . 0.18 ,oo, 0.18 . ' 0.30 0 0 000 0 0 0 0 . o,, 0% 0,00 . 0 0.35 0 0.000 0 0 0 0 . o,s 0% 000 . , .. , . 1,148 0.026 0 "' "' 0 29.32% 100% 0.18 -· 1557PR1.out San Diego County Rational Hydrology Program CIVILCADD/CIVILDESIGN Engineering Soft~are,(c)1991-2012 Version 7,9 Rational method hydrology program based on San Diego County Flood Control Division 2003 hydrology manual Rational Hydrology Study Date: 05/15/23 Hydrology Study Control Information•••••••••• Program License Serial Number 6313 Rational hydrology study storm event year is English (in-lb) input data Units used Map data precipitation entered: 6 hour, precipitation(inches) = 2.600 24 hour precipitation(inches) • 4.700 P6/P24 = 55. 3% San Diego hydrology manual 'C' values used 100.0 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 101.000 to Point/Station 102.000 •••• INITIAL AREA EVALUATION•••• Oecimal fraction soil group A Decimal fraction soil group B Oecimal fraction soil group C Decimal fraction soil group D [LOW DENSITY RESIDENTIAL (2.9 DU/A or Less ) I!llpervious value, Ai= 0.250 Sub-Area C Value• 0.410 0.000 1.000 0.000 0.000 Initial subarea total flow distance ll.000(Ft.) Highest elevation = 284.600(Ft.) Lowest elevation" 27B.000(Ft.) Elevation difference 6.600(Ft.) Slope• 60.000 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 100.00 {Ft) for the top area slope value of 60.00 %, in a development type of 2.9 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration 3.17 minutes TC= [1.8*(1.1-C)•distance{Ft.)A,S)/(% slopeA(l/3)] Tc = [1.s•(1.1-0.4100)•( 100.000A.s)/( 60.000A(1/3)J= 3.11 Calculated TC of 3.173 minutes is less than 5 minutes, resetting TC to 5.0 minutes for rainfall intensity calculations Rainfall intensity (I) = 6.850(In/Hr) for a 100.0 year storm Effective runoff coefficient used for area (Q•KCIA) is C = 0.410 Subarea runoff • 0.1S7(CFS) Total initial stream area= 0.056(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 102.000 to Point/Station 106.000 ••0 IRREGULAR Cl-JANNEL FLO,,,i TRAVEL TIME uu Depth of flow= 0.172(Ft.), Average velocity S.320(Ft/s) ••••••• Irregular Channel Oata ••••••••••• ----------------------------------------------------------------- Information entered for subchannel number 1 : Page 1 1557PR1.out Point number 'X' coordinate 'Y' coordinate 1 0.00 0.50 ' 0.50 0.00 3 ,.,. 0.50 Manning's .,. friction factor 0.013 Sub-Channel flow s 0.157(CFS) flow top width= 0.344(Ft.) velocity= 5.320(Ft/s) area = 0.030(Sq.Ft) Froude number = 3. 198 Upstream point elevation= Downstream point elevation Flow length= 64.000(Ft.) Travel time • 0.20 min. 278.000(Ft.) 272.200(Ft.) Time of concentration = 3. 37 min. Depth of flow= 0.172(Ft.) Average velocity • S.320(Ft/s) Total irregular channel flow• Irregular channel normal depth Average velocity of channel(s) 0.157(CFS) above invert elev. 5.320(Ft/s) 0.172(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++t-+++-t-+++++++++++++++ Process from Point/Station 102.000 to Point/Station 106.000 **** CONFLUENCE OF MAIN STREAMS**** The follO\<oling data inside Main Stream is listed: In Main Stream number: l Stream flow area• 0.056(Ac.) Runoff from this stream= 0.157(CFS) Time of concentration= 3.37 min. Rainfall intensity • 6.850(In/Hr) Program is now starting with Main Stream No. 2 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 103.000 to Point/Station 104.000 **** INITIAL AREA E\IALUATION **** Decimal fraction soil group A• 0.000 Decimal fraction soil group B = 1.000 Decimal fraction soil group C • 0.000 Decil'lill fraction soil group D = 0.000 [HIGH DENSITY RESIDENTIAL (24.0 DU/A or Less ) Impervious value, Ai= 0.650 Sub-Area C 1/alue • 0.670 Initial subarea total flow distance 11.000(Ft.) Highest elevation = 283. 70El(Ft.) Lowest elevation= 278.200{Ft.) Elevation difference= 5.500(Ft.) Slope= 50.000 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 100.00 (Ft) for the top area slope value of 50.00 %, in a development type of 24.0 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration 2.10 minutes TC= [1.8*(1.l-C)*distance(Ft.)A.5)/(% slopeA(l/3)] TC= [1.8*(1.1-0.6700)*( 100.000A.5)/( S0.000A(l/3)]= 2.10 Calculated TC of 2.101 minutes is less than S minutes, resetting TC to 5.0 minutes for rainfall intensity calculations Rainfall intensity (I) = 6.850(In/Hr) for a 100.0 year storm Effective runoff coefficient used for area (Q•KCIA) is C = 0.670 Subarea runoff = 0.243(CFS) Total initial stream area= 0.053(Ac.) Page 2 1SS7PR1.out ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 104.000 to Point/Station 105.000 uu IRREGULAR CrlANNEL FLOW TRAVEL TIME **** Depth of flow= 0.160(Ft.), Average velocity 9.534(Ft/s) ••••••• Irregular Channel Data••••••••••• Information entered for subchannel number 1 : Point number l ' 3 'X' coordinate 0.00 0.50 1.00 'Y' coordinate 0.50 0.00 0.50 Manning's 'N' friction factor 0.013 Sub-Channel flow 0.243(CF5) flow top width= 0.319(Ft.) velocity= 9.534(Ft/s) area= 0.026(5q.Ft) Froude number = 5.945 Upstream point elevation• Downstream point elevation Flow length= 19.000(Ft.) Travel time 0.03 min. 278.200(Ft.) 272.100(Ft.) Time of concentration ~ 2.13 min. Depth of flow= 0.160(Ft.) Average velocity = 9.534(Ft/s) Total irregular channel flow= Irregular channel normal depth Average velocity of channel(s) 0.243(CFS) above invert elev. 9.534(Ft/s) 0.160(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 105.000 to Point/Station 106.000 **** PIPEFLOW TRAVEL TIME (Program estimated size)**** Upstream point/station elevation = 270. 600( Ft.) Downstream point/station elevation 269. 900(Ft.) Pipe length 67.00(Ft.) Slope 0.0104 Manning's N 0.013 No. of pipes= 1 Required pipe flow 0.243(CFS) Nearest computed pipe diameter 6.00(In.) Calculated individual pipe flow 0.243(CFS) Normal flow depth in pipe = 2. 72(In.) Flow top width inside pipe= 5.97(In.) Critical Depth • 2.98(In.) Pipe flow velocity = 2.80(Ft/s) Travel time through pipe = 0. 40 min. Time of concentration (TC) = 2.53 min. +++++++++++++++t++t+++++++++++++++++++++++++++t+++++t+++++++++++++t+++ Process from Point/Station 105.000 to Point/Station 106.000 0 •• CONFLUENCE OF MAIN STREAMS **** The following data inside Main Stream is listed: In Hain Stream number: 2 Stream flow area = 0.053(Ac.) Runoff from this stream 0.243(CFS) Time of concentration • 2. 53 min. Rainfall intensity • 6.850(In/Hr) Sunwr,ary of stream data: Stream No. Flow rate (CFS} TC (min) Rainfall Intensity (In/Hr) Page 3 1557PR1.out 1 0.157 3.37 6.850 , 0.243 2.53 6.850 Qmax(l) 1.000 • 1.000 • 0.157) • 1.000 • 1.000 • 0.243) • 0.401 Qmax(2) 1.000 • 0. 751 • 0.157) • 1.000 • 1.000 • 0.243) • 0.361 Total of 2 main streams to confluence: Flow rates before confluence point: 0.157 0.243 Maximum flow rates at confluence using above data: 0.401 0.361 Area of streams 0.056 before confluence: 0.053 Results of confluence: Total flow rate = 0.401(CFS) Time of concentration 3.373 min. Effective stream area after confluence 0.109(Ac.) ++++++++++++++tt+++++++++ttt+++t++tt+++++++++tt++++++++++t++++++++++++ Process from Point/Station 106.000 to Point/Station 108.000 nn PIPEFL()l,j TRAVEL TIME (Program estimated size) ••0 Upstream point/station elevation= 269.900(Ft.) Downstream point/station elevation 26S.900(Ft.) Pipe length 63.00(Ft.) Slope 0.0635 Manning's N 0.013 No. of pipes• 1 Required pipe flow 0.401(CFS) Nearest computed pipe diameter 6.00(In.) Calculated individual pipe flow 0.401(CFS) Normal flow depth in pipe= 2.18(In.) Flow top width inside pipe= 5.77(In.) Critical Depth~ 3.86(In.) Pipe flow velocity= 6.20(Ft/s) Travel time through pipe = 0. 17 min. Time of concentration (TC) • 3.54 min. ++++++++++tt+++++++++++t+++++++++++++++ttt++++++++++++t++++++++++++++t Process from Point/Station 106.000 to Point/Station 108.000 un CONFLUENCE OF MAIN STREAMS •o• The following data inside Main Stream is listed: In Main Stream number; 1 Stream flow area= 0.109(Ac.) Runoff from this stream 0,401(CFS) Time of concentration• Rainfall intensity= Program is now starting 3.54 min. 6.850(In/Hr) with Main Stream No. 2 +++t++++++++t++++++++++++++++++++t+++++++++++++++++++++++tt+++++++++++ Process from Point/Station 107.000 to Point/Station 108.000 •~•• INITIAL AREA EVALUATION**** Decimal fraction soil group A 0, 000 Decimal fraction soil group B 1.000 Decimal fraction soil group C 0.000 Decimal fraction soil group 0 0.000 [HIGH OENSITY RESIDENTIAL (43.0 DU/A or Less I Impervious value, Ai " 0.800 Page 4 1557PR1.out Sub-Area C Value= 0.770 Initial subarea total flow distance 48.000(Ft.) Highest elevation= 271.900(Ft.) Lowest elevation~ 268.900(Ft.) Elevation difference 3.000(Ft.) Slope= 6.250 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland floo1 distance is 95.00 (Ft) for the top area slope value of 6.25 %, in a development type of 43.0 OU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration 3.14 minutes TC= [1.8•(1.1-c)•distance(Ft.)A.S)/(% slopeA(l/3)] TC= [1.8*(1.1-0.7700)"( 95.000A.5)/( 6.250A(l/3)]-3.14 Calculated TC of 3.143 minutes is less than S minutes, resetting TC to 5.0 minutes for rainfall intensity calculations Rainfall intensity (I) = 6.850(In/Hr) for a 100.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0. 770 Subarea runoff = 0.127(CFS) Total initial stream area= 0.024(Ac.) +++++++++++++++t+++++++++++t+++++t+++++++++++++t+-++++++t++t++++++tt++t Process from Point/Station 107.000 to Point/Station 108.000 **** CONFLUENCE OF MAIN STREAMS uu The following data inside Main Stream is listed: In Main Stream number: 2 Stream flow area= 0.024(Ac.) Runoff frOl't'I this stream 0.127(CFS) Time of concentration= 3.14 min. Rainfall intensity = 6.8S0{In/Hr) Summary of stream data: Stream Flow rate " Rainfall Intensity "· (CFS) (min) (In/Hr) 1 0.401 3.54 6.850 2 0.127 3.14 6.850 Qmax(l) 1.000 • 1.000 • 0.401) • 1.000 • 1.000 • 0.127) • 0.S27 Qmax(2) • 1.000 • 0.887 • 0.401) t 1.000 • 1 000 * 0.127) •• 0.482 Total of 2 main streams to confluence: Flow rates before confluence point: 0.401 0.127 Maximum flow rates at confluence using above data: 0.S27 0.482 Area of streams before confluence: 0.109 0.024 Results of confluence: Total floo1 rate = 0.527(CFS) Time of concentration 3. S43 min. Effective stream area after confluence 0.133(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process frOl't'I Point/Station 108. 000 to Point/Station 111. 000 **** PIPEFL(1w TRAVEL TIME (Program estimated size) **** Upstream point/station elevation= Downstream point/station elevation 265.900(Ft.) 264.000{Ft.) 1557PR1.out Pipe length 24.00(Ft.) Slope= 0 0792 Manning's N 0.013 No. of pipes 1 Required pipe flow 0.527(CFS) Nearest computed pipe diameter 6.00(In.) Calculated individual pipe flow 0.S27(CFS) Normal flow depth in pipe~ 2,39(In.) Flow top width inside pipe= S.87(In.) Critical Depth -4.44(In.) Pipe flow velocity= 7.24(Ft/s) Travel time through pipe = 0.06 min. Time of concentration (TC) = 3.60 min. ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 108.000 to Point/Station 111.000 *"'** CONFLUENCE OF MAIN STREAMS "**"' The following data inside Main Stream is listed: In Main Stream number: 1 Stream flow area = 0 .133 (Ac.) Runoff from this stream 0.527(CFS) Time of concentration = 3.60 min. Rainfall intensity = 6.850(In/Hr) Program is now starting with Main Stream No. 2 tt+++++++++++t++++++++++++t++++++++++l-t+++++++++++t++++++++++t++++++++ Process from Point/Station 109.000 to Point/Station 110.000 "*** INITIAL AREA EVALUATION **** Decimal fraction soil group A Decimal fraction soil group B Decimal fraction soil group C Decimal fraction soil group D [UNDISTURBED NATIJRAL TERRAIN (Permanent Open Space ) Impervious value, Ai -0.000 Sub-Area C Value -0,2S0 0.000 1.000 0.000 0.000 Initial subarea total flow distance 4.000(Ft.) Highest elevation = 276. 700( Ft. ) Lowest elevation= 274.600(Ft.) Elevation difference 2.100(Ft.) Slope= S2.S00 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 100.00 (Ft) for the top area slope value of 52.50 %, in a development type of Permanent Open Space In Accordance With Figure 3-3 Initial Area Time of Concentration 4.09 minutes TC= [1.8*(1.1-C)*distance(Ft.)A.S)/(% slopeA(1/3)) TC= [1.8*(1.1-0.2500)*( 100.000A.SJ/( 52.500A(1/3)]= 4.09 Calculated TC of 4.086 minutes is less than S minutes, resetting TC to 5.0 minutes for rainfall intensity calculations Rainfall intensity (I) • 6.8S0{1n/Hr) -for a 100.0 year storm Effective runoff coefficient used for area (Q•KCIA) is C = 0.250 Subarea runoff = 0.014(CFS) Total initial stream area• 0.008(Ac.) ++++++++++++++++++++I-+++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 110.000 to Point/Station 111.000 **** IRREGULAR CHANNEL FLOW TRAVEL TIME**** Depth of flow = 0.064(Ft.), Average velocity 3.327(Ft/s) ******* Irregular Channel Data "*********" Information entered for subchannel Point number 'X' coordinate 1 0.00 number 1 : 'Y' coordinate 0.50 Page 6 ' 3 0.50 1.00 1557PR1.out 0.00 0.50 Manning's 'N' friction factor 0.013 Sub-Channel flow 0.014(CFS) flow top width= 0.128(Ft.) velocity= 3.328(Ft/s) area= 0.004(Sq.Ft) Froude number = 3.274 Upstream point elevation= Downstream point elevation 274.600(Ft.) 26S.100{Ft.) Flow length = 72.000(Ft. Travel time 0.36 min. Time of concentration = 4.45 min. Depth of flow ~ 0.064(Ft.) Average velocity= 3.327(Ft/s) Total irregular channel flow= Irregular channel normal depth Average velocity of channel(s) 0.014(CFS) above invert elev. 3.327(Ft/s) 0.064(Ft.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 110.000 to Point/Station 111.000 **** CONFLUENCE OF r-\AIN STREAMS**** The following data inside Main Stream is listed: In Main Stream number: 2 Stream flow area• 0.008(Ac.) Runoff from this stream 0.014{CFS) Time of concentration ~ 4. 45 min. Rainfall intensity ~ 6.850(In/Hr) Surm1ary of stream data: Stream ,o. Flow rate (CFS) TC (min) Rainfall Intensity (In/Hr) ' 0.S27 3.60 6.850 ' 0 '" 4.45 6.850 l)nax(l) 1.000 • 1.000 • 0.527) • 1.000 • 0.809 • 0.014) • 0. 538 l)nax(2) 1.000 • 1.000 • 0.527) • 1.000 • 1.000 • 0.014) • 0. 541 Total of 2 main streams to confluence: Flow rates before confluence point: 0.527 0.014 Maximum flow rates at confluence using above data: 0.538 0.541 Area of streams 0.133 before confluence: 0.008 Results of confluence: Total flow rate ~ 0.541(CFS) Time of concentration 4.447 min. Effective stream area after confluence 0.141{Ac.) ++++++++++++++++++++++++++++-++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 111.000 to Point/Station 112.000 nu PIPEFLOW TRAVEL TIME (Program estimated size) uo Upstream point/station elevation• 264.000(Ft.) Page 7 1SS7PR1.out Downstream point/station elevation= 263.800(Ft.) Pipe length 13.00(Ft.) Slope= 0.0154 Manning's N 0.013 No. of pipes= 1 Required pipe flow 0.S41(CFS) Nearest computed pipe diameter = 6.00(In.) Calculated individual pipe flow = 0.541(CFS) Normal flow depth in pipe= 3.97(In.) Flo.i top .iidth inside pipe m S.68(In.) Critical Depth~ 4.50(In.) Pipe flow velocity n 3.92(Ft/s) Travel time through pipe = 0.06 min. Time of concentration (TC) = 4.50 min. +ttH+++++++++++++++++++H--t++++++++++++tttt+++++++++t++++++++++tt+t+++ Process from Point/Station 112.000 to Point/Station 113.000 ••H IRREGULAR CHANNEL FLOW TRAVEL TIME H** Depth of flow• 0.069(Ft.), Average velocity 2.629(Ft/s) ••••••• Irregular Channel Data••••••••••• Information entered for subchannel number 1 : Point number 1 'X' coordinate 0.00 'V' coordinate 0.25 2 0.00 3 3.00 • 3.00 Manning's 'N' friction factor 0.013 Sub-Channel flow = 0.541(CFS) 0.00 0.00 0.25 flow top width• 3.000(Ft.) velocity= 2.629(Ft/s) area= 0.206(Sq.Ft) Froude number • 1. 769 Upstream point elevation = Downstream point elevation Flow length= 1S.000(Ft.) Travel time ~ 0.10 min. 263.800{Ft.) 263.500(Ft.) Time of concentration • 4.60 min. Depth of flow= 0.069(Ft.) Average velocity = 2.629(Ft/s) Total irregular channel flow • 0.541(CFS) Irregular channel normal depth above invert elev. 0.069(Ft.) Average velocity of channel(s) = 2.629(Ft/s) End of computations, total study area= 0.141 (Ac.) Page 8 1557PR2.out San Diego County Rational Hydrology Program CIVILCADD/CIVILDESIGN Engineering Software,{c}1991-2012 Version 7.9 Rational method hydrology program based on San Diego County Flood Control Division 2003 hydrology manual Rational Hydrology Study Date: 05/15/23 Hydrology Study Control Information•••••••••• Program License Serial Number 6313 Rational hydrology study storm event year is English (in-lb) input data Units used Map data precipitation entered; 6 hour, predpitation(inches) = 24 hour precipitation(inches) = P6/P24 ~ 55. 3% 2.600 4.700 San Diego hydrology manual 'C' values used 100.0 ++++-t+++++++++++++-t++++++++++++++++++++++++++++t-++++++++++++++++++++++ Process from Point/Station 201.000 to Point/Station 203.000 **** INITIAL AREA EVALUATION no Decimal fraction soil group A Decimal fraction soil group B Decimal fraction soil group C Decimal fraction soil group D [HIGH DENSITY RESIDENTIAL (43.0 DU/A or Less ) Impervious value, Ai• 0.800 sub-Area C Value • 0. 770 0.000 1.000 0.000 0.000 Initial subarea total flow distance 41.000(Ft.) Highest elevation= 266.200(Ft.) Lowest elevation= 262.900(Ft.) Elevation difference 3.300(Ft.) Slope= 8.049 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS; The maximum overland flow distance is 100.00 (Ft) for the top area slope value of 8.05 %, in a development type of 43.0 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration 2.96 minutes TC= [l.8*(1.l-C)*distance(Ft.)A.5)/(% slopeA(l/3)] TC• [1.8*(1.1-0.7700)*( 100.000A.S)/( 8.049A(l/3)]= 2.96 Calculated TC of 2.964 minutes is less than 5 minutes, resetting TC to 5.0 minutes for rainfall intensity calculations Rainfall intensity {I) = 6.850(In/Hr) for a 100.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.770 Subarea runoff • 0.142(CFS) Total initial stream area= 0.027(Ac.) +t-+++++++++++++++++++++-t+++++++++++++++++++++-t+++++++++-t+t-++++++++++++ Process from Point/Station 201.000 to Point/Station 203.000 ***" CONFLUENCE OF MAIN STREAMS **** The following data inside Main Stream is listed: In Main Stream number; 1 Stream flow area 0.027(Ac.) Runoff frOl'II this stream ~ 0.142(CFS) Page 1 1557PR2.out Time of concentration = 2.96 min. Rainfall intensity = 6.8S0(In/Hr} Program is now starting with Main Str11am No. 2 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Proc11ss from Point/Station 202.000 to Point/Station 203.000 uu INITIAL AREA EVALUATION ••o D11cimal fraction soil group A• 0.000 D11cimal fraction soil group B = 1.000 D11cimal fraction soil group C = 0.000 Decimal fraction soil group D -0.000 [MEDIUM DENSITY RESIDENTIAL (4.3 DU/A or Less ) Imp11rvious valu11, Ai= 0.300 Sub-Area C value = 0.450 Initial subar11a total flow distance 42.000(Ft.) Highest elevation= 272.300(Ft.} Lowest 11l11vation K 262. 900(Ft.) Elevation differ11nce = 9.400(Ft.) Slope= 22.381 % INITIAL AREA TIME OF CONCENTRATION CALCULATIONS: The maximum overland flow distance is 100.00 (Ft) for the top area slope value of 22.38 %, in a dev11lopment typ11 of 4.3 DU/A or Less In Accordance With Figure 3-3 Initial Area Time of Concentration 4.15 minutes TC= [1.8*(1.l-C)•distance(Ft.)A,5)/(% slopeA(l/3)] TC• [l.8*{1.1-0.4S00)*( 100.000A.S)/( 22.381A(l/3)]= 4.15 Calculated TC of 4.152 minutes is less than S minutes, resetting TC to 5.0 minutes for rainfall intensity calculations Rainfall intensity (I) K 6,850(In/Hr) for a 100.0 year storm Effective runoff coefficient used for area (Q=KCIA) is C = 0.4S0 Subarea runoff = 0.080(CFS) Total initial stream area= 0.026(Ac.) ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Process from Point/Station 202. 000 to Point/Station 203. 000 •*** CONFLUENCE OF MAIN STREAMS **** The following data inside Hain Stream is listed: In Hain Stream number: 2 Stream flow area• 0.026(Ac.) Runoff from this stream -0.080(CFS) Time of concentration = 4.15 min. Rainfall intensity = 6.8S0(In/Hr) Surrmary of stream data: Stream Flow rate No. (CFS) TC (min) Rainfall Intensity (In/Hr) 1 0.142 2.96 6.850 2 0.080 4.15 6.850 Qmax(l) 1.000 • 1.000 • 0.142) • 1.000 • 0. 714 • 0.080) • ()'rlax(2) 1.000 • 1.000 • 0.142) + 1.000 • 1.000 • 0.080) • Total of 2 main streams to confluence: Flow rates before confluence point: 0.142 0,080 Maximum flow rates 0.200 at confluence using above data: 0.223 0.200 0.223 Page 2 Area of streams 0.027 before confluence: 0.026 Results of confluence; Total flow rate" 0.223(CF5) Time of concentration " 4 .152 min. Effective stream area after confluence End of computations, total study area " 1557PR2.out 0.053(Ac.) 0.053 (Ac.) Page 3 ATTACHMENT4 HYDROLOGY MAP -PROPOSED CONDITIONS