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Home My WebLink AboutCT 2021-0005; CHINQUAPIN COAST HOMES; PRELIMINARY HYDROLOGY STUDY; 2022-05-05------------- -- 1111111 -... .. ... .. .. ... -.. ... .. .. ,. 11111 ,. 11111 PRELIMINARY HYDROLOGY STUDY FOR TENTATIVE TRACT MAP I MINOR SITE DEVELOPMENT PLAN/ COASTAL DEVELOPMENT PERMIT CHINQUAPIN COAST HOMES -330 CHINQUAPIN A VENUE CT 2021-0005 / PUD 2021-0010 / CDP 2021-0067 CITY OF CARLSBAD, CA PREPARED FOR: 330 CHINQUAPIN, LLC 5315 A VENIDA ENCINAS, SUITE 200 CARLSBAD, CA 92008 PREPARED BY: PASCO LARET SUITER & ASSOCIATES, INC . 1911 SAN DIEGO AVE, SUITE 100 SAN DIEGO, CA 92110 PH: (858) 259-8212 Prepared: November 2021 Revised: May 2022 Bryan A. Knapp, PE #86542 5-5-22 DATE --... --... -... ... ... .. ... .. ----... .. ... ... -.. ---... -... ... 11111 ... ... -... Executive Summary Introduction Existing Conditions Proposed Project Conclusions References Methodology Introduction TABLE OF CONTENTS County of San Diego Criteria Runoff Coefficient Determination Hydrology & Hydraulic Model Output Pre-Developed Hydrologic Calculations (100-Year Event) Post-Developed Hydrologic Calculations (100-Year Event) Pre-Developed vs. Post-Developed Peak Flows (100-Year Event) Detention Analysis Preliminary Hydraulics Analysis Appendix Isopluvial Maps Intensity Duration Design Charts Runoff Coefficients Hydrologic Soil Group -USDA Web Soil Survey Pre-Development Hydrology Node Map Post-Development Hydrology Node Map SECTION 1.0 1.1 1.2 1.3 1.4 1.5 2.0 2.1 2.2 2.3 3.0 3.1 3.2 3.3 3.4 3.5 4.0 .... -.. ... ... .. ... ... ... .. ... ... ... -.. .. .. .. - ... .. ---... -... ... ... .. .. .. ... .. PLSA 3729-01 1.0 EXECUTIVE SUMMARY 1.1 Introduction This Preliminary Hydrology Study for the proposed development at 330 Chinquapin A venue, has been prepared to analyze the hydrologic and hydraulic characteristics of the existing and proposed project site. This report intends to present both the methodology and the calculations used for determining the runoff from the project site in both the pre- developed ( existing) conditions and the post-developed (proposed) conditions produced by the 100-year, 6-hour storm . 1.2 Existing Conditions The subject property is located along Chinquapin A venue, northeast of the intersection of Chinquapin Avenue and Garfield Street, in the City of Carlsbad. The site is bound by a combination of existing single-family and multi-family developments to the west, north, and east, as well as Chinquapin A venue, a public road, to the south. The existing site consists of a single-family residence, driveway, walkways, landscaping, and miscellaneous improvements typical of this type of development. The project site is located in the Agua Hedionda Hydrologic Area, and, more specifically, the Los Monos Hydrologic Sub-Area (904.31) of the Carlsbad watershed . The subject property has an approximate area of 0.442 acres and is approximately 37.3% impervious in the existing condition. Per the Web Soil Survey application available through the United States Department of Agriculture, the basin is generally categorized to have type B hydrologic soils. Based on the existing impervious area and land use type, a pre-development weighted runoff coefficient of 0.49 was calculated for the subject property using the methodology described in section 3.1.2 of the San Diego County Hydrology Manual and the formula provided therein . After review of the site edge conditions, existing topography, and adjacent developments, it was determined that there is no additional offsite runon entering the site from the neighboring properties. The existing site can be categorized into one (1) major drainage basin, with one ( 1) primary discharge location leaving the property. Drainage basin EX-1 consists of the entirety of the project site and primarily drains from the northwest comer of the property to the southeast, discharging to the Chinquapin A venue right-of-way by surface and sheet flow methods. Once in the Chinquapin Avenue right-of-way, runoff leaving the site travels northeast towards existing storm water infrastructure. An existing sidewalk underdrain is on the north side of Chinquapin A venue, which conveys runoff into the public right-of-way. Surface flows entering the sidewalk underdrain ultimately are conveyed south to outlet in the Agua Hedionda Lagoon prior to entering the Pacific Ocean . Using the Rational Method Procedure outlined in the San Diego County Hydrology Manual, a peak flow rate and time of concentration was calculated for the 100-year, 6- Page 1 of 13 -------... -... ---... ... -... ... -.. .. ... -... .. ... --... ... -... ... ... -... ... PLSA 3729-01 hour storm event for the onsite drainage basin. Table 1 below summarizes the results of the Rational Method calculations. EXISTING DRAINAGE FLOWS DRAINAGE Q100 DRAINAGE lioo AREA AREA (CFS) (IN/HR) (ACRES) EX-1 0.442 1.44 6.59 Table 1. Existing Condition Peak Drainage Flow Rates Refer to pre-development hydrology calculations included in Section 3 .1 of this report for a detailed analysis of the existing drainage basin, as well as a pre-development hydrology node map included in the appendix of this report for pre-development drainage basin delineation and discharge locations . 1.3 Proposed Project The proposed project includes the demolition of all existing onsite improvements and the construction of three (3) new multi-family detached unit blocks, each containing three (3) attached units, creating a total of nine (9) units. The project proposes a driveway to provide vehicular access to the proposed garages consisting of pervious pavers. Three private onsite parking stalls interior to the site are also shown for site residents and guest parking. Site grading, drainage and utility improvements typical of this type of multi- family residential development will also be constructed as can be seen on the Preliminary Grading Plan prepared by Pasco, Laret, Suiter & Associates under separate cover. The subject property is approximately 50.8% impervious in the proposed condition. Based on the proposed impervious area and land use type, a post-development weighted runoff coefficient of 0.58 was calculated for the subject property using the methodology described in section 3 .1.2 of the San Diego County Hydrology Manual and the formula provided therein. The proposed site consists of one (1) major drainage basin, with one ( 1) primary discharge location from the northwest comer of the property similar to the existing condition. Drainage basin PR-1 consists of the entirety of the site and will continue to convey runoff generally from a high point in the northwest comer of the site to the Chinquapin A venue right-of-way by means of surface flow. A concrete ribbon gutter located at the center of the pervious paver driveway will also serve to capture and convey drainage to the proposed curb and gutter along Chinquapin A venue . Using the Rational Method Procedure outlined in the San Diego County Hydrology Manual, a peak flow rate and time of concentration were calculated for the 100-year, 6- hour storm event for the onsite drainage basin. Table 2 below summarizes the results of the Rational Method calculations in the post-developed condition . Page 2 of13 ,,,. -... -.. -.. -... ---.. ... ... ... ... .. ... .. ... ... ... .. ... ... ... .. .. .. ... ... ... .. PLSA 3729-01 PROPOSED DRAINAGE FLOWS DRAINAGE DRAINAGE Q100 lioo AREA AREA (CFS) (IN/HR) (ACRES) PR-1 0.442 1.69 6.59 Table 2. Proposed Condition Peak Drainage Flow Rates Refer to post-development hydrology calculations included in Section 3.2 of this report for a detailed analysis of the proposed drainage basin, as well as a post-development hydrology node map included in the appendix of this report for post-development drainage basin delineation and discharge locations. In an effort to comply with the City of Carlsbad storm water standards, the proposed site has incorporated LID design techniques to optimize the site layout. Runoff from proposed roofs and new or removed and replaced hardscape areas will be directed to landscaped areas or pervious pavers to disperse drainage to pervious surfaces. The landscaped areas will assist to remove sediment and particulate-bound pollutants from storm water. In addition, the storage layers of the pervious pavers will help to mitigate peak runoff by providing detention volume as well as slightly increasing the site's overall time of concentration. Refer to Section 3.4 of the report for a static detention analysis showing that the increase in overall volume generated by the slight increase in hardscape is accounted for in the gravel storage layer of the pervious pavers . 1.4 Conclusions Based upon the analysis included in this report, there is an increase of ~0.25 cfs in peak runoff as a result of the proposed development due to the 2,590 square feet of increased hardscape in the proposed condition as compared the existing site. Similar to the existing condition, the project will discharge from the northwest corner of the property to the southeast and onto the Chinquapin Avenue right-of-way. Thus, water will not be diverted away from existing drainage patterns, and the runoff produced by the proposed development will not have an adverse effect on the downstream watershed. Although there is no increase is storm water volume, the inherent detention characteristics and storage volume provided in the gravel layers of the pervious pavers will assist to detain and mitigate peak runoff to pre-project conditions. The proposed project will be exempt from hydromodification compliance requirements as it does not qualify as a Priority Development Project as defined in the Regional Municipal Separate Storm Sewer System (MS4) Permit and the San Diego County Model BMP Design Manual. Page 3 of 13 ---------... ---.. --... ---... ... - .. ----.. ... .. - -... ~ .. PLSA 3729-01 1.5 References "San Diego County Hydrology Manual", revised June 2003, County of San Diego, Department of Public Works, Flood Control Section. "San Diego County Hydraulic Design Manual", revised September 2014, County of San Diego, Department of Public Works, Flood Control Section "City of Carlsbad Engineering Standards, Volume 5: Carlsbad BMP Design Manual (Post Construction Treatment BMPs) ", revised February 2016 "Low Impact Development Handbook-Stormwater Management Strategies", revised July 2014, County of San Diego, Department of Public Works Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. Available online at http://websoilsurvey.nrcs.usda.gov . Accessed September 2, 2020 Page 4 of13 ---------- -- -.. ... .... JIii ... ---... --- - ,.. --.. ... PLSA 3729-01 2.0 METHODOLOGY 2.1 Introduction The hydrologic model used to perform the hydrologic analysis presented in this report utilizes the Rational Method (RM) equation, Q=CIA. The RM formula estimates the peak rate of runoff based on the variables of area, runoff coefficient, and rainfall intensity. The rainfall intensity (I) is equal to: 1 = 7.44 x P6 x o-0·645 Where: I= Intensity (in/hr) P6 = 6-hour precipitation (inches) D = duration (minutes -use Tc) Using the Time of Concentration (Tc), which is the time required for a given element of water that originates at the most remote point of the basin being analyzed to reach the point at which the runoff from the basin is being analyzed. The RM equation determines the storm water runoff rate (Q) for a given basin in terms of flow (typically in cubic feet per second (cfs) but sometimes as gallons per minute (gpm)). The RM equation is as follows: Where: Q=CIA Q = flow (in cfs) C = runoff coefficient, ratio of rainfall that produces storm water runoff (runoff vs. infiltration/evaporation/absorption/etc) I= average rainfall intensity for a duration equal to the Tc for the area, in inches per hour. A = drainage area contributing to the basin in acres. The RM equation assumes that the storm event being analyzed delivers precipitation to the entire basin uniformly, and therefore the peak discharge rate will occur when a raindrop that falls at the most remote portion of the basin arrives at the point of analysis. The RM also assumes that the fraction of rainfall that becomes runoff or the runoff coefficient C is not affected by the storm intensity, I, or the precipitation zone number. Page 5 of 13 - Ill -----------.. -... - ... ... -... -.. -111111 --... .. ... .. ... ... .. PLSA 3729-01 2.2 County of San Diego Criteria As defined by the County Hydrology Manual dated June 2003, the rational method is the preferred equation for determining the hydrologic characteristics of basins up to approximately one square mile in size. The County of San Diego 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 anticipated from a given storm event (i.e. 100-year, 6-hour storm). One of the variables of the RM equation is the runoff coefficient, 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 Coefficients for Urban Areas to be applied to basin located within the County of San Diego. The table categorizes the land use, the associated development density ( dwelling units per acre) and the percentage of impervious area. Each of the categories listed has an associated runoff coefficient, C, for each soil type class. The County has also illustrated in detail the methodology for determining the time of concentration, in particular the initial time of concentration. The County has adopted the Federal Aviation Agency's (FAA) overland time of flow equation. . This equation essentially limits the flow path length for the initial time of concentration to lengths under 100 feet, and is dependent on land use and slope. The time of concentration minimum is 5 minutes for purposes of calculating rainfall intensity per the County of San Diego Hydrology Manual requirements. 2.3 Runoff Coefficient Determination As stated in section 2.2, the runoff coefficient is dependent only upon land use and soil type and the County of San Diego has developed a table of Runoff Coefficients for Urban Areas to be applied to basin located within the County of San Diego. The table, included in the Appendix of this report, categorizes the land use, the associated development density ( dwelling units per acre) and the percentage of impervious area. For this study, a weighted runoff coefficient was used for both the pre-project and post- developed site in accordance with the equation provided in Section 3 .1.2 of the County of San Diego Hydrology Manual. The weighted runoff coefficient is a function of the total impervious and pervious surface areas in the existing and proposed conditions . Page 6 of13 ---... -------- 11111 -.. ... ... -... -... ... ------ JIii ... ... 11111 .. ... 111111 PLSA 3729-01 3.0 HYDROLOGY MODEL OUTPUT 3.1 Pre-Developed Hydrologic Model Output (100-Year Event) Pre-Development: *Rational Method Equation Q=CIA P100= 2.5 * 100-Y ear, 6-Hour Rainfall Precipitation Basin EX-1 Total Area= 19,247 sf-+ 0.442 Acres Impervious Area = 7, 186 sf-+ 0.165 Acres Pervious Area= 12,061 sf-+ 0.277 Acres Cn, Weighted Runoff Coefficient -0.25, Cn value for natural ground, Type B soils * Per San Diego Hydrology Design Manual (SDHDM) Section 3.1.2 -0.9, C value for developed/ impervious surface * Per SDHDM Section 3.1.2 Cn = 0.9 x 7,186 sf+ 0.25 x 12,061 sf= 0.493 19,247 sf Tc= 5.0 Min *Minimum Tc for Rainfall Intensity per SDHDM I = 7.44 x P 6 x D-0-645 *Rainfall Intensity Equation I= 7.44 X 2.5 X 5.o-0·645 ::::; 6.59 in/hr Q100 = 0.493 x 6.59 in/hr x 0.493 Ac = 1.44 cfs Page 7 of 13 -----------... --.. ---... -... ... .... -.. .. ---- ... ... ... ... ... PLSA 3729-01 3.2 Post-Developed Hydrologic Model Output (100-Year Event) Post-Development (without considering HMP/BMP treatment): *Rational Method Equation Q=CIA P100= 2.5 * 100-Y ear, 6-Hour Rainfall Precipitation Basin PR-1 Total Area = 19,247 sf -+ 0 .44 2 Acres Impervious Area= 9,776 sf-+ 0.224 Acres Pervious Area= 9,471 sf-+ 0.217 Acres Cn, Weighted Runoff Coefficient -0.25, Cn value for natural ground, Type B soils * Per San Diego Hydrology Design Manual (SDHDM) Section 3.1.2 -0.9, C value for developed/ impervious surface * Per SDHDM Section 3.1.2 Cn = 0.9 x 9,776 sf+ 0.25 x 9,471 sf= 0.580 19,247 sf Tc= 5.0 Min *Minimum Tc for Rainfall Intensity per SDHDM I= 7.44 x P6 x D-0·645 *Rainfall Intensity Equation I= 7.44 X 2.5 X 5.o-0·645 ::::; 6.59 in/hr Q100 = 0.580 x 6.59 in/hr x 0.442 Ac = 1.69 cfs Page 8 of 13 ----- ... --- --.. .. -,,,. ... ... .. .. 111111 .. --... -.. -.. .. .. ... - 111111 ... 3.3 Pre-Developed vs. Post-Developed Peak Flows (100-Year Event) Total Pre-Development (Discharge Leaving Site) Basin EX-1 Q100 = 1.44 cfs *Discharging from the site at the southeast comer to Chinquapin A venue Total Q100 = 1.44 cfs Total Post-Development (Discharge Leaving Site) Basin PR-1 Q100 = 1.69 cfs *Discharging from the site at the southeast comer to Chinquapin A venue Total Q100 = 1.69 cfs Pre-Development vs. Post-Development (Discharge Leaving Site): Pre-Development Q100 = 1.44 cfs 3.4 Detention Analysis Post-Development Q100 = 1.69 cfs Delta +0.25 cfs PLSA 3729-01 The 100-year, 6-hour storm event detention analysis was performed in accordance with Chapter 6 of the San Diego County Hydrology Manual (SDCHM). The results of the analysis provide a static detention requirement by comparing the total volume produced by the 100-year, 6-hour storm in the existing and post-project conditions. The total volume can be calculated after producing a hydrograph for each event (pre-and post- developed) with the results of the Rational Method analysis. Calculations and results of this analysis can be shown below. The proposed pervious pavement driveway provides mitigation of the 100-year, 6-hour storm event peak flow rate. Underneath the paver units and bedding layer is a 6-inch gravel storage layer that provides sufficient detention volume to offset the increase in total volume generated in the proposed condition due to the increase in overall hardscape. See sections 3.4.1 and 3.4.2 below for the results of these calculations. Page 9 of 13 -.. -------... --... -- ,,,. --.. ... -... -----... ... .. .. .. ... 3.4.1 Static (No Routing) Detention Calculation Pre-Development: 100-Year Event (Basin EX-1) PLSA 3729-01 Volume= C*P6*A *Equation 6-1 ofSDCHM Volume= 0.493 * (2.5 in* 1 ft/ 12 in)* (19,247 SF)= 1,977 CF Post-Development: 100-Year Event (Basin PR-1) Volume= C*P6*A *Equation 6-1 of SDCHM Volume= 0.580 * (2.5 in* 1 ft/ 12 in)* (19,247 SF)= 2,326 CF Required Detention Volume = Total Post-Development-Total Pre-Development = Basin PR-1 -Basin EX-1 = 2,326 CF-1,977 CF= +349 CF 3.4.2 Pervious Pavement Drive Aisle -Storage Detention Volume Provided = Driveway Area x 6" Gravel Layer x 40% Voids = 2,576 SF * (6 in * 1 ft/ 12 in) * 0.40 APPROVED PERVIOUS PAVERS WI MIN f' VOID 6' X 16'PCCFLUSH CURB\ OR DEEPENED G-1 CURB VOID FILLER-/' TOj"(N0.8/ AGGREGATE IN VOIDS BEDDING COURSE-2" TIIICK OF j • = 515 CF TOj'(N0.8/AGGREGATE ~ r.l.ii"-i'iiiiiirr;..~~ CIIOKERCOURSE-4"TIIICKOFi·-· : I 1=1 NOTE. TOJ • (N0.571 CRUSHED ROCK _:;; • 1 -111: -All AGGREGATE MUST BE CLEAN/WASHED AND FREE OF FINES (SAND, SILT, ETC.) f ..------_--THEPAVERS SHALL NOT BE SEALED ONCE THE VOIDFILLERHASBEENADDED MIN S"THICKOF • -=I 11=1 -EACHCOURSESHALLBEVIBRATORYCO/.IPACTf.DBEFOREPLACEMENTOFNEXTCOURSE CRUSIIEDROCK -mi m-~ '' 1---:1 I 1--NOIMPERVIOUSLJNERORFILTf.RFABR/CISTOBEUSED SOIL SUBGRADE ---------SPECIAL APPROVAL REQUIRED FOR USE IN HIGHLY EXPANSNE SOIL-SUBDRAIN MAY BE REQUIRED PERVIOUS PAVERS -TYPICAL DETAIL NOTTO SCALE 515 CF of storage in gravel layers under pervious paver driveway. PRE-VERSUS POST-VOLUME ANALYSIS: ~ V100 = 349 CF Storage Provided= 515 CF> 349 CF No additional storage required to mitigate the post-development 100-yr stormwater volume onsite . Page 10 of 13 -.. ---.. --... - .. -.. ... -,,. --... --,,. ... .. --... - ,,. ... ,,. ... .. .. .. PLSA 3729-01 3.5 Preliminary Hydraulics Analysis A preliminary hydraulics analysis was performed for the 100-year, 6-hour design storm event to check proposed onsite storm drain facility capacity. The analysis was performed by first delineating the site into minor drainage basins at desired points of analysis to determine peak flow conveyed by the proposed infrastructure using the Rational Method (minimum time of concentration of 5.0 minutes was used in accordance with the San Diego County Hydrology Manual for use in the rainfall intensity equation to conservatively size the facilities). The minor basin areas as shown below can be seen graphically on the proposed hydrology node map included in the Appendix of the report. Capacity was calculated utilizing the Hydraflow Express extension in AutoCAD Civil 3D to model the peak flows generated through a cross-section using open channel flow . Basin PR-1 -Al Total Area= 1,234 sf-+ 0.028 Acres Cn = 0.58 *Runoff Coefficient for Site Tc= 5.0 Min *Minimum Tc for Rainfall Intensity per SDHDM I = 7.44 x P6 x o-0-645 *Rainfall Intensity Equation I= 7.44 X 2.5 X 5.o-0·645 ::::: 6.59 in/hr Q100 = 0.58 x 6.59 in/hr x 0.028 Ac= 0.1 cfs **Q at Node PR-101 in northwest corner of property, begin 6" PVC private storm drain at 1.0% slope. Basin PR-1 -A2 Total Area= 7,848 sf-+ 0.180 Acres Cn = 0.58 *Runoff Coefficient for Site Tc= 5.0 Min *Minimum Tc for Rainfall Intensity per SDHDM I = 7.44 x P6 x o-0·645 *Rainfall Intensity Equation I= 7.44 X 2.5 X 5.o-0·645 ::::: 6.59 in/hr Q100 = 0.58 x 6.59 in/hr x 0.18 Ac= 0.7 cfs **Q at Node PR-102 in southwest corner of property, end 6" PVC private storm drain at 1.0% slope and begin 6" PVC private storm drain at 2.0% slope . Page 11 of 13 -.. --.. ----... - 1111111 - .... ... -- ... -- -- -... .. .. ... ... ... .. PLSA 3729-01 Basin PR-1-Bl Total Area= 3,524 sf-+ 0.081 Acres Cn = 0.58 *Runoff Coefficient for Site Tc= 5.0 Min *Minimum Tc for Rainfall Intensity per SDHDM I= 7.44 x P6 x o-0-645 *Rainfall Intensity Equation I= 7.44 X 2.5 X 5.o-0·645 ::::; 6.59 in/hr Qrno = 0.58 x 6.59 in/hr x 0.081 Ac = 0.3 cfs **Q at Node PR-200 in ribbon gutter prior to 6" curb and gutter flow. Per ribbon gutter cross-section, slope, and capacity, depth of flow= 0.1' at Node PR-200. Flow is contained within drive aisle section. Basin PR-1 -B2 Total Area= 10,713 sf-+ 0.246 Acres Cn = 0.58 *Runoff Coefficient for Site Tc= 5.0 Min *Minimum Tc for Rainfall Intensity per SDHDM I = 7.44 x P6 x o-0·645 *Rainfall Intensity Equation I= 7.44 X 2.5 X 5.o-0·645 ::::; 6.59 in/hr Qrno = 0.58 x 6.59 in/hr x 0.246 Ac = 0.95 cfs **Q at Node PR-103 in gutter entering brooks box. Page 12 of 13 --... -------... --... ... ... ,.. ... -... ,,. .. .. ... ... ... -... -... ... -... .. .. .. .. .. PLSA 3729-01 4.0 APPENDIX Page 13 of 13 33°00' I I 32°45' 32°30' I 0 ('I) 0 r--..... ..... 0 ('I) 0 r--..... ..... () ro ..... 0 r--..... ..... ro ..... 0 r--..... ..... 0 0 0 r--..... ..... 0 0 0 r--..... ..... . . ro "<f" 0 <O ..... ..... ro "<f" 0 <O ..... ..... .. ... -.. --.... . . . ........... ,... . ;•": .... ,.,, ...... ~ ... #• I M e X . ' C 0 ('I) 0 (0 .,... ..... 0 ('I) 0 <O ..... ..... .. . . . . . ........... " .. ti \• ..... ro ..... 0 (0 ..... ..... .. ·· .. ·. ·. ·· .. . . . . .-----... . . . . . . ' ' . . ... ..... ,' ',, ~;;liila-,:=,::f. __ """ ' ...... ro ..... 0 (0 ..... 33°30' 3°00' 3 ""O CD ~-0) 2°45' 32°30' County of San Diego Hydrology Manual Rainfall Isopluvials 100 Year Rainfall Event-6 Hours lsopluvial (inches) DPW ~GIS Dtor.Jr•"'I' of Put,:;c Wm.a ~lrfo,ftal,;,r~ s1IG1s W'c Hav..: San Dil.-go Covered! THIS MAP IS PROVIDED WITHOUT WARRANTY OF Am KIND, EITHER EXPRESS OR IMPUEO. INClUOING, BUT NOT LIMITED TO. THE IMPLIED WARRANTIES OF MERCHANTASll llY ANO FITNESS FOR A PARTICULAR PURPOSE . Cop,,ightSanGIS./>JRlglu ReoeM,d . This products may corna;n --from lhe SANOAG Reg;onal Information System which cannot be reproduced wi1houl lhe written permission d SA.NOAG. This product may c.ontain infcnnation which has been reproduced with po,mission g,antod by Thomas 8-Maps. Miles I 32°45' 32°30' 0 (Y') 0 ,.._ ...... ...... 0 (Y') 0 ,.._ ...... ...... io ...... 0 ,.._ ...... ...... io ...... 0 ,.._ ...... ...... 0 0 0 ,.._ ...... ...... 0 0 0 ,.._ ...... ...... io s;t 0 (0 ...... ...... Riverside County .............. ... \. ~ i <l;:i . . ..... ~-· .. · so· , .. •· . ' , .. , .. . ' . . . .. . >···•. .. .. .. . ............. ,,........ .. ......... / A~•. ! /\ . . . ... . . ' . ' . M e X io s;t 0 (0 ,... ...... C 0 (Y') 0 CD ...... ...... 0 (Y') 0 CD ...... ,... io ...... 0 CD ,,.. ...... io ...... 0 CD ...... ...... . . . . . . ................. 33°30' . ·' . ' . 3°00' 3 "O CD 0) () 0 C: :::, -'< 2°45' 32°30' County of San Diego Hydrology Manual Rainfall lsopluvials 100 Year Rainfall Event-24 Hours lsopluvial (inches) DPW ~GIS o.o.trtr.-.r'f~PwlicWOl'XI ~~ . ..tr,,,~ S-:iGIS We Hav..: San Diego Cc,vcrcd! Tl-flS MAP JS PROVIDED WJTl-fOUT WARRANTY Of' ANY KIND, EITl-fER EXPRESS OR lw>LIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY ANO FITNESS FOR A PARTlaJLAR PURPOSE. Copyright SanGIS. All Rights Re$eM>d. This p,oduds may a>ntain mlonnation fn,m Jho SANDAG Regk>nal Information System vmic::h cannot be reproduced wtthout the written permission of SANOAG. This p,oduct may~-.., which has been ,_uced with pem,1$SiOng,anledbyThomasl!rolhet>Maps. Miles 10.0 9.0 8.0 7.0 I 6.0 5.0 4.0 3.0 2.0 £ c: 1.0 ~0.9 -~0.8 fo.1 0.6 0.5 0.4 0.3 0.2 0.1 I I 1' "r-,... ........ .............. I "' ........ ... '""" . .... .... i X . ' ""r-,... .... r.... 1-...1",,. r,, ... """' N. ' .... r....r.... ...... ...... i.. "" i ' i-..... .. ..... "'" I -.... !'. r-..." ........ .. .. /"" ! I . ' """ I!'. .. "'"' i..,. .. " ' ... .. r.... ..... ~ ' r...., ,.. ... " ' i..... ... r-..... .. ~"" N,.. .... , I" ..... ~ "" .. r,,... ...... .. ,.. ~" .... " .. I . ' r....r.... "'" " .. "" " ~ .. .... ""!",, .. ,.." "~ .. ...... ""~ " ~ .,...., .... " """' ~" .... I ' ...... ""~ i " ' ' .. i .. ! .... , '" "" .. .. r,,... r-.., I '"" """ : " " .... I",, ~"" ...... ' ~" ; .... ... ,.. ... ,.. i " ~ I " ~ .. : '"~ I .... I " I i i i -----· . -f-----·-~->-· i --+---·-· .... -~---,-- 5 6 7 8 9 10 15 20 30 Minutes 40 50 Duration I I I I I I I I I I I I EQUATION I = 7.44 P5 D-0.645 I = Intensity (in/hr) P5 = 6-Hour Precipitation (in) D = Duration (min) : I :,-., ! I I ' .... ,r-... ; . , ,, ...... ' .. ! ... ' !• .. "i.. ' ,, I" "" .. .. " I ...... ; 1, I",, • I"'.., .. . .... " .. l 'r--. ...... ... ,.. ~ " ,·, .. '""" ...... " ~ la .. .. • ... , "'"' .. I;' ... , "'"' !' ' ,...., " .,. ,. 'r.... ... ...,.. ~"" r I"" ..... " ... ,.. r-,. '., ,1 r.... -a- - 2 I•._ ,-- ..... " .. '"" 3 Hours " 1' I r " ' ' T I " i : I i ' i 4 5 6 Cf' ::c 0 !:; " ~ 6.0 "§: 5.5 ![ 5.o ~r 4.5 g 4.0 i 3.5 .!!!. 3.0 2.5 2.0 1.5 1.0 Directions for Appllcatlon: (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 induded 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 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 the location being analyzed. Appllcatlon Fonn: (a) Selected frequency __ year p (b) P5 = __ in., P24 = --'P 6 = __ %<2J 24 (c) Adjusted P6<2> = __ in. (d) tx = __ 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 I I I I I . I . I I I I I 5 2.63 3.95 5.27 6.59 7.90 9.22 10.54 11.86 13.17 14.49 15.81 7 2.12 ·3.18,4.24 5.30 6.36 7.42 8.48. 9.54 10.00·11.66 12.72 10 1.68 ·2.53·3.37 4.21 5.05·5_90· 6.74 · 7.58 · 8.42 · 9.27 ·10.11 15 1.30 1.95 2.59 3.24 ·3.89 4.54· 5.19 5.84 6.49. 7.13. 7.78 20 1.oa 1.62· 2.15 2.69 · 3.23 · 3.n · 4.31 4.85 · 5.39 · 5.93 · 6.46 25 0.93 1.40 1.87 233 2.80.327 3.73. 4.20. 4.67. 5.13 5.60 30 o.83 1241.66 2.01 2_49·2.00· 3.32 3.73 · 4.15 · 4.56 4.98 40 0.69 1.03 1.38 1.72 207 2.41. 2.76 3.10 3.45 3.79. 4.13 50 0.60 ·0.001.19· 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 2.39 2.65 . 2.92 3.18 90 o.41 ·0.61 o.82 1.02 1.23 1 43 1.63 1.84 2.04 · 2.25 · 2.45 120 0.34 . 0.51 0.68. 0.85 1.02 1 19. 1.36 1.53 . 1.70 . 1.87 2.04 150 o.29 ·o.«·o.59. o.73 o.ea 1.03 1.18 · 1.32 · 1.47 1.62 1.16 1eo 0.26 ·039·0.52 065 0.18 o.91 1.04 · 1.18 · 1.31 · 1.« · 1.57 240 0.22 . 0.33. 0.43. 0.54 0.65 0. 76 0.87 0.98 . 1.08 1.19 . 1.30 300 0.19 ·028·038 o.47 o.56 o.66 015 0.85 · o.94 · 1.00 · 1.13 360 0.17 . 0.25 0 33. 0.42 0.50 0.58 0.67 _ 0. 75 . 0.84 0.92 . 1.00 FIGURE Intensity-Duration Design Chart• Template / 3-1 l I I J I J I I I I I I I J I J I I I I I I I J San Diego County Hydrology Manual Date: June 2003 Table 3-1 Section: Page: RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use I Runoff Coefficient "C" Soil Type NRCS Elements Coun Elements % IMPER. A B Undisturbed Natural Terrain (Natural) Permanent Open Space 0* 0.20 0.25 Low Density Residential (LOR) Residential, 1.0 DU/ A or less 10 0.27 0.32 Low Density Residential (LOR) Residential, 2.0 DU/A or less 20 0.34 0.38 Low Density Residential (LOR) Residential, 2.9 DU/A or less 25 0.38 0.41 Medium Density Residential (MOR) Residential, 4.3 DU/A or less 30 0.41 0.45 Medium Density Residential (MOR) Residential, 7.3 DU/A or less 40 0.48 0.51 Medium Density Residential (MOR) Residential, 10.9 DU/A or less 45 0.52 0.54 Medium Density Residential (MOR) Residential, 14.5 DU/A or less 50 0.55 0.58 High Density Residential (HOR) Residential, 24.0 DU/A or less 65 0.66 0.67 High Density Residential (HOR) Residential, 43.0 DU/A or less 80 0.76 0.77 Commercial/Industrial (N. Com) Neighborhood Commercial 80 0.76 0.77 Commercial/Industrial (G. Com) General Commercial 85 0.80 0.80 Commercial/Industrial (O.P. Com) Office Professional/Commercial 90 0.83 0.84 Commercial/Industrial (Limited I.) Limited Industrial 90 0.83 0.84 Commercial/Industrial (General I.) General Industrial 95 0.87 0.87 C 0.30 0.36 0.42 0.45 0.48 0.54 0.57 0.60 0.69 0.78 0.78 0.81 0.84 0.84 0.87 3 6 of26 D 0.35 0.41 0.46 0.49 0.52 0.57 0.60 0.63 0.71 0.79 0.79 0.82 0.85 0.85 0.87 *The values associated with 0% impervious may be used for direct calculation of the runoff coefficient as described in Section 3.1.2 (representing the pervious runoff coefficient, Cp, for the soil type), or for areas that will remain undisturbed in perpetuity. Justification must be given that the area will remain natural forever (e.g., the area is located in Cleveland National Forest). DU/A= dwelling units per acre NRCS = National Resources Conservation Service 3-6 I I I I I I I I I I I I I I l J l J I J I I l I I J l I I J l J I I l I I J 3JOB'SS"N 3JOB'S!"N Hydrologic Soil Group-San Diego County Area, California 46813:l 468140 468100 468110 <16812) 46813:l <168140 Map Scale: 1: 503 f printed on A portrait (8.5" X 11 ") sheet N ---===-----=====Meters 0 5 10 2l l) A ---===------=======Feel: o 2l ~ oo m Map projection: Web Mercator Comer roordinates: WGS84 Edge tics: lJTM ZOne 11N WGS84 USDA Natural Resources :iiiiii Conservation Service Web Soil Survey National Cooperative Soil Survey 468150 468150 468100 468100 468170 468170 ~ Ill i::: ~ 11/29/2021 Page 1 of 4 3JO 8' 55" N 3JO B'Sl"N USDA ~ Hydrologic Soil Group-San Diego County Area, California MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons D A D ND D B D BID D C D CID D D D Not rated or not available Soil Rating Lines .-A ,...,,. ND ,...,,. B ,...,,. B/D C ,...,,. CID ,...,,. D .. ,. Not rated or not available Soil Rating Points ■ A ■ ND ■ B ■ BID Natural Resources t_ -,-vatic---,vice C • C CID ■ D □ Not rated or not available Water Features Streams and Canals Transportation H--+ Rails ,,w, Interstate Highways _._, US Routes Major Roads Local Roads Background • Aerial Photography Web Soil Survey N~'---<;Cooic:.::i Soil(··-·1y 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: Coordinate 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. Soil Survey Area: San Diego County Area, California Survey Area Data: Version 16, Sep 13, 2021 Soil map units are labeled (as space allows) for map scales 1 :50,000 or larger. Date(s) aerial images were photographed: Jan 24, 2020--Feb 12,2020 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. 11/29/2021 0 ~1e 2 o,f.-• Hydrologic Soil Group-San Diego County Area, California Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI MIC Marina loamy coarse B 0.5 sand, 2 to 9 percent slopes Totals for Area of Interest 0.5 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, 8/D, and C/D). 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, 8/D, or C/D), 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 D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition USDA Natural Resources ,.,,.._ Conservation Service Web Soil Survey National Cooperative Soil Survey 100.0% 100.0% 11/29/2021 Page 3 of 4 Hydrologic Soil Group-San Diego County Area, California Component Percent Cutoff: None Specified Tie-break Rule: Higher USDA Natural Resources --.a Conservation Service Web Soil Survey National Cooperative Soil Survey 11/29/2021 Page 4 of 4 .I '\..._ 3' WOOD FENCE l I Ji I I I ii I I I LEGEND PROPERTY BOUNDARY CENTERLINE OF ROAD ADJACENT PROPERTY LINE PUBLIC RIGHT-OF-WAY MAJOR BASIN BOUNDARY FLOW LINE IMPERVIOUS AREA X4S.2 X 49.7 xs,1 X 52 5 ! ( e' WOOD FENCE EXISTiNS 1 STORV BUILDING ---------- &\\\\I X 5:.3 " " 50.3 X 50.7 X SC 8 514 X 51.7 / X 51 1 BASIN EX-1 (TOTAL)- AREA = 19,247 SF /0.442 AC) en= 0.49 ---- X 50.S X 51 3 / X 51 e X 49.7 / X 51.5 X I -----------~~-----I X 52.2 ! ----------- X 52.2 (543)/ ' " e.woocF:NcE ----5.?-- \ C -. ~FG 1---'------'-'~--~----------~---- BASIN EX-1 -AREA CAL GULA T/ONS TOTAL SITE AREA BASIN EX-1 TOTAL AREA BASIN EX-1 IMPERVIOUS AREA BASIN EX-1 PERVIOUS AREA % IMPERVIOUS en 19,247 SF (0.442 AC) 19,247 SF /0.442 AC} 7,186 SF (0.165AC) 12,061 SF /0.277 AC) 37% 0.49 X I TIME OF CONCENTRATION 5.0 MINUTES (PER SDCHM) X 50.4 X 51.2 X 5,._6 X Si.8 N 34°00'09' W -_ _; \- X 51.4 X 51.3 X 51.5 --- A 45.9 - - X 51.4 ~ EXISTING 2 STORY BUILDING f X 49.2 - EXIST NG 2 STORY B.JlLD NG , - / X4S., - X 49.1 ~- I I' I 82 • DCXl X4S.5 X49.4 EX STlcJG . $ OR Bl lLD NG I I \ \ I 1-<' X'19A I ' X49.4 X 49 3 6' WOOD FENCE . .. · I a• wROUG!-'.-r;"1RoNI' '7' ..... --::_ -.... '7 ,,. FENCE .. J=I --1G X 49.5 X49.4 X 49.7 I I I I [ w 0 w 0 7C-.17 85 11 t-L=41.4"8 / / / / / / TC=48.7L L=-.u.Lf w ' ., 0 -I EXISTING HYDROLOGY EXIHIBT 0 10 CHINQUAPIN COAST HOMES -330 CHINQUAPIN AVE 30 SCALE: 1' = 10' CARLSBAD, CA 92008 PREPARED BY, PASCO LAREY SUITER ~ ffe.$${Q)t I ffe. f IE$ San Diego I Solana Beach Orange County Phone 858.259.8212 I www.plsaengineering.com t I " • 0:0% ¾// I ~/ ~o\o::i "✓-~"' X 52.5 ' EXISTING 2 STORY BUILDING "<,..:... .. ....r--~-~--l - MINOR BASIN PR-1-B1 AREA = 3,524 SF I en =0.58 50. XS.4 ' X5 .3 MINOR BASIN PR-1-A1 51 AREA = 1,234 SF I Cn = 0.58 J ' -.._ 7~~\ NOD P R 1 1 ';10DE P , 100 4f4 7\G \' 9.8 P ' 48.71 · Q00/=.1 CS SD GI SD X42 7 so. BASIN PR-1 (TOTAL) AREA = 19,247 SF (0.442 AC) Cn =0.58 X .7 SD X 42.3 • X 5 .4 I SD < 4S.·· ~ \' • 0 • • 50. _.,. X _ 7 SD SD JI F r------ 1 ;,._,= ,~,;m./ /' . f , ----------------------(54-.3) -(54.3) ,1------t---~--- i I I I I LEGEND PROPERTY BOUNDARY CENTERLINE OF ROAD ADJACENT PROPERTY LINE PUBLIC RIGHT-OF-WAY EXISTING 1 STORY '3UILDING ---------- FG FG MAJOR BASIN BOUNDARY SUB-BASIN BOUNDARY MINOR BASIN BOUNDARY AT POINT OF ANALYSIS FLOW LINE IMPERVIOUS AREA (54.3) FG ~\\\\I .. \ · \ , a ; \ X 0.6 so SD ~.,.1 SUBBAS/N PR-1-B AREA= 11,907 SF (0.273AC) Cn =0.58 \ 50. , EXISTING 2 STORY BUILDING 49. SUBBAS/N PR-1-A ~ X J----+c-+--+- AREA = 8, 165 SF (0.187 AC) x , X 1.2 en =0.58 X s □,,,,,-SD • 48.7 TW, EG 47.3TW@FG (45.8 BW@EG) X45.9 i 48 . J, II EXISTING 2 STORY BUILDING NODBPR-03 X 9 4 4-1:IJ-'~G L-;t-,1++~'r-+--+--+~ ¥55 E 0100-0. 72 C •S 0 "' , I I X O '. !!!!!!!!!!!!!!!!!!!!!!!!•-\--\~+-l-+-+-H++-1-++-1-+-+-H-H-+-\-++-t++-rr-,n1"""1 t· ~ I MINOR BASIN PR-1-A2 AREA = 7,848 SF Cn =0.58 I XI Tl 1 ST qy UI DI G 61._N pYC ~VT Slii @2.0% , . ,:0 \ \ I , : i NODE f' -102 i f~'·TG f6 is o 0= 1c 15_s 1 , \ ., i X4 4 1 X4 4 " " < 49.4 ~ 49.7 , !, I I ' I : • j '-0 ----r CJ -_.,. w fJ ~ • .. I • I I - _ _:...•- CJ T..C"4Lllj j;C=4f. '1 '1 CJ _.,y _.,. r-1) _.,. J -_.,.s'Y _.,. _.,. ;;: I J ;;: ===ii s SD SD SD SD- ~-·: 1,, ;/// I -0/ w I ✓ ~-1 • w 1 "ifowksT W ~ ;;: '5, WOOD FENCE /-1 I' ' (54.2) ...-,:'.l !M.Q}_/ --~ ~ WOOD FENCE ,T • 8' WROUti~J-iT'RONI -• // "-274:76' ... •· ,. • , •• •· I-,., -, • --.._ :::_ _ _ 1· ~->-E, ·p ,j , -;\ ___.e-, . . c9 ·t '"---•-----\-~-F-'-G-------~---• ___ F,:_G ____ \-----------•--"'--FG. ____ _.:_ _______ __:.'!-F-E_N_tf'-1----...L_-,. fl-.._-.._ 1G] ~ ' J"" , 52.4 TW 52.0 TW@FG 48.7 BW 47.7 TF BASIN PR-1 -AREA CALCULATIONS TOTAL SITE AREA BASIN PR-1 TOTAL AREA BASIN PR-1 IMPERVIOUS AREA BASIN PR-1 PERVIOUS AREA % IMPERVIOUS Cn TIME OF CONCENTRATION 19,247 SF (0.442 AC) 19,247 SF (0.442 AC) 9,776 SF (0.224 AC) 9,471 SF (0.217 AC) 51% 0.58 5. 0 MINUTES (PER SDCHM) 51.7TW 515TW@FG 48.5BW 47-}lffiNG 2 STORY BJILD!NG 49.?TW 49.4 TW@FG 47.?BW 46.3 TF (53.4) FG ,. ! 1 I I . I • I I I \ < ' \ ' w 0 • w ' -" 0 w 0 - 'f' ;;: ;;: CJ j CJ / I ~4 L=4 4 CJ PROPOSED HYDROLOGY EXIHIBT 0 10 --w I -M CHINQUAPIN COAST HOMES -330 CHINQUAPIN AVE 30 SCALE: 1" = 10' CARLSBAD, CA 92008 PREPARED BY, PASCO LARET SUITER ~ ~~~(O)(C!~11E~ San Diego I Solana Beach I Orange County Phone 858.259.8212 I www.plsaengineering.com Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. 330 CHINQUAPIN: DWY RIBBON GUTTER User-defined Invert Elev (ft) Slope(%) N-Value Calculations Compute by: Known Q ( cfs) (Sta, El, n)-(Sta, El, n) ... = 99.45 = 1.00 = 0.013 Known Q = 0.30 Highlighted Depth (ft) a (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Grit Depth, Ye (ft) Top Width (ft) EGL (ft) Tuesday, Feb 15 2022 = 0 .10 = 0 .300 = 0.27 = 1.11 = 6.82 = 0.10 = 6.82 = 0.12 ( 0.00, 100.00)-(12.50, 99.50, 0.013)-(13.50, 99.45, 0.013)-(14.50, 99.50, 0.013)-(19.50, 99.57, 0.01 3) Elev (ft) 101 .00 100.50 100.00 99.50 99.00 98.50 -2 0 ---.......... ~ r---.._ ~ 2 4 6 Section ------...... --~ , --. ~ 8 10 12 Sta (ft) Depth (ft) 1.55 1.05 0.55 0.1' V - 0.05 ' \_4 .3 FL (f i NODI p ~-200 -0.45 -0.95 14 16 18 20 22 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. 6-in PVC Storm Drain @ 1.0% Circular Diameter (ft) Invert Elev (ft) Slope(%) N-Value Calculations Compute by: Known Depth (ft) Elev (ft) 0 = 0.50 = 46.00 = 1.00 = 0.013 Known Depth = 0.50 Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth , Ye (ft) Top Width (ft) EGL (ft) Wednesday, May 4 2022 = 0.50 = 0.561 = 0.20 = 2.86 = 1.57 = 0.39 = 0.00 = 0.63 Section Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. 6-in PVC Storm Drain @ 2.0% Circular Diameter (ft) Invert Elev (ft) Slope(%) N-Value Calculations Compute by: Known Depth (ft) Elev (ft) 0 = 0.50 = 46.00 = 2.00 = 0.013 Known Depth = 0.50 Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Grit Depth, Ye (ft) Top Width (ft) EGL (ft) Wednesday, May 4 2022 = 0.50 = 0.793 = 0.20 = 4.04 = 1.57 = 0.45 = 0.00 = 0.75 Section Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 30® by Autodesk, Inc. 1.5-ft Wide Modified D-25 @ 2.0% Rectangular Bottom Width (ft) Total Depth (ft) Invert Elev (ft) Slope (%) N-Value Calculations Compute by: Known Q ( cfs) Elev (ft) 45.00 44.75 44 .50 44.25 44.00 0 = 1.50 = 0.26 = 44.40 = 2.00 = 0.015 Known Q = 1.69 l..olllll ...... .5 Section V -- 18-in 1 Reach (ft) Hi hli hted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Ye (ft) Top Width (ft) EGL (ft) .... .,,,. 1.5 2 Wednesday, May 4 2022 = 0.25 = 1.690 = 0.38 = 4.51 = 2.00 = 0.26 = 1.50 = 0.57 2.5 Depth (ft) 0.60 0.35 0.10 -0.15 -0.40