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Home My WebLink AboutCT 2021-0005; CHINQUAPIN COASTAL HOMES; HYDROLOGY STUDY; 2023-04-01 HYDROLOGY STUDY FOR TENTATIVE TRACT MAP / MINOR SITE DEVELOPMENT PLAN / COASTAL DEVELOPMENT PERMIT CHINQUAPIN COAST HOMES - 330 CHINQUAPIN AVENUE CT 2021-0005 / PUD 2021-0010 / CDP 2021-0067 CITY OF CARLSBAD, CA PREPARED FOR: 330 CHINQUAPIN, LLC 5315 AVENIDA 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 __________________________________________________ Bryan A. Knapp, PE #86542 DATE Final: April 2023 04/06/2023 -~ No. 86542 ex: Exp. 03/31/2 C/V\L TABLE OF CONTENTS SECTION Executive Summary 1.0 Introduction 1.1 Existing Conditions 1.2 Proposed Project 1.3 Conclusions 1.4 References 1.5 Methodology 2.0 Introduction 2.1 County of San Diego Criteria 2.2 Runoff Coefficient Determination 2.3 Hydrology & Hydraulic Model Output 3.0 Pre-Developed Hydrologic Calculations (100-Year Event) 3.1 Post-Developed Hydrologic Calculations (100-Year Event) 3.2 Pre-Developed vs. Post-Developed Peak Flows (100-Year Event) 3.3 Detention Analysis 3.4 Preliminary Hydraulics Analysis 3.5 Appendix 4.0 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 PLSA 3729-01 Page 1 of 15 1.0 EXECUTIVE SUMMARY 1.1 Introduction This Preliminary Hydrology Study for the proposed development at 330 Chinquapin Avenue, 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 Avenue, 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 Avenue, 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 corner of the property to the southeast, discharging to the Chinquapin Avenue 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 Avenue, 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- PLSA 3729-01 Page 2 of 15 hour storm event for the onsite drainage basin. Table 1 below summarizes the results of the Rational Method calculations. EXISTING DRAINAGE FLOWS DRAINAGE AREA DRAINAGE AREA (ACRES) Q100 (CFS) I100 (IN/HR) 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 with 0.224 acres of impervious area 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 corner 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 corner of the site to the Chinquapin Avenue 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 Avenue. Previous pavers located on the east side of the site server to reduce the impervious area and the sites weighted runoff coefficient. Infiltration testing shows the underlying soil has an infiltration rate of 1.1 in/hr, which is suitable for infiltration. The pavers will not require a linear but will have a 4-inch PVC subdrain that connects into a brooks box. Infiltration will be allowed adjacent to footings if the deepened edge adjacent to the pavers and building footing is extended to match the depth PLSA 3729-01 Page 3 of 15 of the building footing; additionally the separation between pavers and footings is great enough to prevent infiltration near the footing. 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. PROPOSED DRAINAGE FLOWS DRAINAGE AREA DRAINAGE AREA (ACRES) Q100 (CFS) I100 (IN/HR) 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. PLSA 3729-01 Page 4 of 15 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. 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 PLSA 3729-01 Page 5 of 15 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: I = 7.44 x P6 x D-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: Q = CIA Where: 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 PLSA 3729-01 Page 6 of 15 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. 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 PLSA 3729-01 Page 7 of 15 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. PLSA 3729-01 Page 8 of 15 3.0 HYDROLOGY MODEL OUTPUT 3.1 Pre-Developed Hydrologic Model Output (100-Year Event) Pre-Development: Q = CIA *Rational Method Equation P100 = 2.5 *100-Year, 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 P6 x D-0.645 *Rainfall Intensity Equation I = 7.44 x 2.5 x 5.0-0.645 ≈ 6.59 in/hr Q100 = 0.493 x 6.59 in/hr x 0.493 Ac = 1.44 cfs PLSA 3729-01 Page 9 of 15 3.2 Post-Developed Hydrologic Model Output (100-Year Event) Post-Development (without considering HMP/BMP treatment): Q = CIA *Rational Method Equation P100 = 2.5 *100-Year, 6-Hour Rainfall Precipitation Basin PR-1 Total Area = 19,247 sf  0.442 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 5.0-0.645 ≈ 6.59 in/hr Q100 = 0.580 x 6.59 in/hr x 0.442 Ac = 1.69 cfs PLSA 3729-01 Page 10 of 15 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 corner to Chinquapin Avenue 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 corner to Chinquapin Avenue Total Q100 = 1.69 cfs Pre-Development vs. Post-Development (Discharge Leaving Site): Pre-Development Post-Development Delta Q100 = 1.44 cfs Q100 = 1.69 cfs +0.25 cfs 3.4 Detention Analysis 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. PLSA 3729-01 Page 11 of 15 3.4.1 Static (No Routing) Detention Calculation Pre-Development: 100-Year Event (Basin EX-1) Volume = C*P6*A *Equation 6-1 of SDCHM 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 = 515 CF 515 CF of storage in gravel layers under pervious paver driveway. PRE- VERSUS POST- VOLUME ANALYSIS: Δ V100 = 349 CF Storage Provided= 515 CF > 349 CF No additional storage required to mitigate the post-development 100-yr stormwater volume onsite. 6" X 16" PCC FLUSH CURB\\ OR DEEPENED G-1 CURB APPROVED PERVIOUS PAVERS W/MIN j• VOID VOIOFILLER-i° TO!"(N0.8) AGGREGATE IN VO/OS BEDDING COURSE-2" THICK OF j • :"-r TOi°(NO.B)AGGREGATE ~ • s. • • •... _ CHOKERCOURSE-4"THICKOFj·-· '11 1 i rot /N0.57/ CRUSHED ROCK ,;:.: . • 111 M/N.6"THICKOF¾"__.,...,.. -11 1-1 CRUSHEDROCK ::.ll ~'~'.:::::::IJ SOIL SUBGRADE ------ NO.TE: -All AGGREGATE MUST BE CLEAN/WASHED AND FREE OF FINES (SAND, SILT, ETC.) -THE PAVERS SHALL NOT BE SEALED ONCE THE VOID FILLER HAS BEEN ADDED -EACH COURSE SHALL BE VIBRATORY COMPACTED BEFORE PLACEMENT OF NEXT COURSE -NO IMPERVIOUS LINER OR FILTER FABRIC IS TO BE USED -SPECIAL APPROVAL REQUIRED FOR USE IN HIGHLY EXPANSIVE S0/L-SUBDRAIN MAY BE REQUIRED PERVIOUS PAVERS-TYPICAL DETAIL NOTTO SCALE PLSA 3729-01 Page 12 of 15 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 with the peak flow leaving each minor basin shown at each node. The peak flow rate through each minor basin is also shown at the final pipe run before reaching the nodes at the final inlet of each minor basin. 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. Flow capacity calculations for varying pipe sizes and slopes as well as the concrete ribbon gutter and modified D-25 curb outlet are included in Appendix C. Basin PR-1 – A1 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 D-0.645 *Rainfall Intensity Equation I = 7.44 x 2.5 x 5.0-0.645 ≈ 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 0.7% slope. Basin PR-1 – A2 Total Area = 4,073 sf  0.094 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 D-0.645 *Rainfall Intensity Equation I = 7.44 x 2.5 x 5.0-0.645 ≈ 6.59 in/hr Q100 = 0.58 x 6.59 in/hr x 0.094 Ac = 0.36 cfs QTotal = 0.1 + 0.36 = 0.46 cfs PLSA 3729-01 Page 13 of 15 **Q at Node PR-102 in southwest corner of property, end 6” PVC private storm drain at 0.7% slope and begin 6” PVC private storm drain at 1.3% slope. Basin PR-1 – A3 Total Area = 2,514 sf  0.058 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 D-0.645 *Rainfall Intensity Equation I = 7.44 x 2.5 x 5.0-0.645 ≈ 6.59 in/hr Q100 = 0.58 x 6.59 in/hr x 0.058 Ac = 0.23 cfs QTotal = 0.1 + 0.36 + 0.23 = 0.69 cfs **Q at Node PR-103, end 6” PVC private storm drain at 0.7% slope and begin 6” PVC private storm drain at 1.3% slope. Basin PR-1 – A4 Total Area = 344 sf  0.008 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 D-0.645 *Rainfall Intensity Equation I = 7.44 x 2.5 x 5.0-0.645 ≈ 6.59 in/hr Q100 = 0.58 x 6.59 in/hr x 0.008 Ac = 0.03 cfs QTotal = 0.1 + 0.36 + 0.22 + 0.03 = 0.72 cfs **Q at Node PR-103, end 6” PVC private storm drain at 1.3% slope and begin 6” PVC private storm drain at 2.0% slope. PLSA 3729-01 Page 14 of 15 Basin PR-1 – B1 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 D-0.645 *Rainfall Intensity Equation I = 7.44 x 2.5 x 5.0-0.645 ≈ 6.59 in/hr Q100 = 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 D-0.645 *Rainfall Intensity Equation I = 7.44 x 2.5 x 5.0-0.645 ≈ 6.59 in/hr Q100 = 0.58 x 6.59 in/hr x 0.246 Ac = 0.95 cfs **Q at Node PR-104 in gutter entering brooks box. PLSA 3729-01 Page 15 of 15 4.0 APPENDIX IL__·-----_--_I .L I I I I I . . . . . . . . • . -) . ,-. ' ' . : . . . ,, .,,. . . -... ·, "~ ~ ~ . I I I I I · . --- . . -~ . . . . . . . . ,=' ·- --. . . . . . . . ' ~ e,a\H'1'Y 0 ~i.NDIEc;o • I -······_--___JI DPW ~GIS [lep:I.J""iJ7ient Di P11Mc Works Grn,r,..•pfll/,; /11furrr,.itiw1 &rv,t r.i-:; 10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 0.5 0.4 0.3 0.2 0.1 ' ' " .... ' "r-.. ' ' .... i, .... .... ' • ' .... , ........ .... I'-,. 'r-. r-,, ' ... ... 'r-.. ' ' ..... .... , .... ,. ... • ' ' ' .... "r-,. ' ' ' ... ' .... , ' ' • ' 'r-.. ... ..... ' .... ,. ' ' .... , ' , .. ' 5 6 7 8 9 10 ·, .... • r-.., ·, ... , ·, .... , r-.r-. .. r-' ' ~ .. .. I" I'-"-""" , .. .. ~ ~ r-.r-, "'i-. '~ ~ .. .. .. , ... , .. 'i-. ~ ~ r-.,. '~ .. .. r-. I", .. .. "r-~ ....... .. ,. 'r-.. ... .. ~ .. 1'-i-,. ,, "", .. 15 20 30 Minutes .. .. '"" .... .. .... .. ~r-.. .. ~ ~ .. .. .. .. ~ .. ~ ~ ~ '"" ~ .. .. .. ""~ 40 50 Duration I = I = p6 = D = EQUATION 7.44 P6 D-0.645 Intensity (in/hr) 6-Hour Precipitation (in) Duration (min) 'i', ... ' ... , .... i', ,i-.. ' ~ i', .... 'i-.. 1, 'i-.. 'r-- Ir-. ... , , ... 'i-.. ' I'-, 'i' '-i-.. 2 ', '' .. ' .... '' ' .. .. ""· ', ', ' ~ "" '' . .... , . .... , .. , ' I" .. ', '"" I" I" 3 Hours .. .. .. .. .. .. .. ~ ~ .. .. .. 4 5 6 O> i 0 ~ 7J ro 0 6.0 R 5.5 ~ 5.0 g 4.5 5' 0 4.0 ~ 3.5 ~ 3.0 2.5 2.0 1.5 1.0 Intensity-Duration Design Chart -Template Directions for Application: (1) From precipitation maps determine 6 hr and 24 hr amounts for the selected frequency. These maps are included in the County Hydrology Manual (10, 50, and 100 yr maps included in the Design and Procedure Manual). (2) Adjust 6 hr precipitation (if necessary) so that it is within the range of 45% to 65% of the 24 hr precipitation (not 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 . Application Form: (a) Selected frequency ___ year p (b) p6 = ---in., P24 = ---'P 6 = %(2J 24 (c) Adjusted p6<2l = ___ in. (d) tx = __ min . (e) I = __ in./hr . Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. I 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 10.60 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 1.08 1.62 2.15 2.69 3.23 3.77 4.31 4.85 5.39 5.93 6.46 -25 0.93 1.40 1.87 2.33 2.80 3.27 3.73 4.20 4.67 5.13 5.60 30 0.83 1.24 1.66 2.07 2.49 2.90 3.32 3.73 4.15 4.56 4.98 ~ 0.69 1.03 1.38 1.72 2.0~ 2.41 2.76_ 3.10 3.45 3.79 c---4.13 50 0.60 0.90 1.19 1.49 1.79 2.09 2.39 2.69 2.98 3.28 3.58 60 0.53 0.80 ,_~ 1.33 1.59 1.86 2.12 2.39 2.65 2.92 3.18 90 0.41 0.61 0.82 1.02 TI3 1.43 1.63 1.84 2.04 2.25 2 .45 120 0.34 0.51 0.613_ 0.85 ~ 1.19 1.36 1.53 1.70 1.87 2.04 --f--150 0.29 0.44 0.59 0.73 0.88 1.03 1.18 1.32 1.47 1.62 1.76 180 0.26 0.39 0.52 0.65 0.78 0.91 1.04 1.18 1.31 1.44 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 0.28 0.38 0.47 0.56 0.66 0.75 0.85 0.94 1.03 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 ~ San Diego County Hydrology Manual Section: 3 Date: June 2003 Page: 6 of 26 Table 3-1 RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use Runoff Coefficient “C” Soil Type NRCS Elements County Elements % IMPER. A B C D Undisturbed Natural Terrain (Natural) Permanent Open Space 0* 0.20 0.25 0.30 0.35 Low Density Residential (LDR) Residential, 1.0 DU/A or less 10 0.27 0.32 0.36 0.41 Low Density Residential (LDR) Residential, 2.0 DU/A or less 20 0.34 0.38 0.42 0.46 Low Density Residential (LDR) Residential, 2.9 DU/A or less 25 0.38 0.41 0.45 0.49 Medium Density Residential (MDR) Residential, 4.3 DU/A or less 30 0.41 0.45 0.48 0.52 Medium Density Residential (MDR) Residential, 7.3 DU/A or less 40 0.48 0.51 0.54 0.57 Medium Density Residential (MDR) Residential, 10.9 DU/A or less 45 0.52 0.54 0.57 0.60 Medium Density Residential (MDR) Residential, 14.5 DU/A or less 50 0.55 0.58 0.60 0.63 High Density Residential (HDR) Residential, 24.0 DU/A or less 65 0.66 0.67 0.69 0.71 High Density Residential (HDR) Residential, 43.0 DU/A or less 80 0.76 0.77 0.78 0.79 Commercial/Industrial (N. Com) Neighborhood Commercial 80 0.76 0.77 0.78 0.79 Commercial/Industrial (G. Com) General Commercial 85 0.80 0.80 0.81 0.82 Commercial/Industrial (O.P. Com) Office Professional/Commercial 90 0.83 0.84 0.84 0.85 Commercial/Industrial (Limited I.) Limited Industrial 90 0.83 0.84 0.84 0.85 Commercial/Industrial (General I.) General Industrial 95 0.87 0.87 0.87 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 Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/29/2021 Page 1 of 4 36 6 7 7 2 0 36 6 7 7 3 0 36 6 7 7 4 0 36 6 7 7 5 0 36 6 7 7 6 0 36 6 7 7 7 0 36 6 7 7 8 0 36 6 7 7 9 0 36 6 7 8 0 0 36 6 7 8 1 0 36 6 7 7 2 0 36 6 7 7 3 0 36 6 7 7 4 0 36 6 7 7 5 0 36 6 7 7 6 0 36 6 7 7 7 0 36 6 7 7 8 0 36 6 7 7 9 0 36 6 7 8 0 0 36 6 7 8 1 0 468100 468110 468120 468130 468140 468150 468160 468170 468100 468110 468120 468130 468140 468150 468160 468170 33° 8' 55'' N 11 7 ° 2 0 ' 3 1 ' ' W 33° 8' 55'' N 11 7 ° 2 0 ' 2 8 ' ' W 33° 8' 51'' N 11 7 ° 2 0 ' 3 1 ' ' W 33° 8' 51'' N 11 7 ° 2 0 ' 2 8 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 20 40 80 120Feet 0 5 10 20 30Meters Map Scale: 1:503 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. USDA = MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography 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. Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/29/2021 Page 2 of 4USDA = □ D D D D D D D D ,,..,,,. ,,..,,,. □ ■ ■ □ □ ,,..._., t-+-t ~ tllWI ,..,,. ~ • Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI MlC Marina loamy coarse sand, 2 to 9 percent slopes B 0.5 100.0% Totals for Area of Interest 0.5 100.0% 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 (A/D, B/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 (A/D, B/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 Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/29/2021 Page 3 of 4USDA = Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/29/2021 Page 4 of 4~ I ) I --I ,, ---/ -., I \I LEGEND PROPERTY BOUNDARY CENTERLINE OF ROAD ADJACENT PROPERTY LINE PUBLIC RIGHT-OF-WAY MAJOR BASIN BOUNDARY FLOW LINE IMPERVIOUS AREA EXISTING 2 S""ORY BUii.DiNG EXISTING 1 STORY BUILDING X 52.6 ---------- &\\\\I YE V BASIN EX-1 -AREA CALCULATIONS TOTAL SITE AREA BASIN EX-1 TOTAL AREA BASIN EX-1 IMPERVIOUS AREA BASIN EX-1 PERVIOUS AREA % IMPERVIOUS en TIME OF CONCENTRA T/ON 19,247 SF (0.442 AC) 19,247 SF (0.442 AC) 7, 186 SF (0.165 AC) 12,061 SF (0.277 AC) 37% 0.49 5.0 MINUTES (PER SDCHM) EXISTING 2 STORY BUILDING • • . • ,,, • . V ,,, . • , • . • "' • V ,,, • • • . • V ,,, • 0 . V • • I ,= .. .::::> I ~ I , L=-.u.u, / / / / ® I • EXISTING HYDROLOGY EXIHIBT 10 CH/NQUAPIN COAST HOMES -330 CH/NQUAPIN AVE 30 SCALE: 1' = 10' CARLSBAD, CA 92008 PREPARED BY, PASCO LAREY SUITER t ffi\~~IQltC!ffi\llE~ San Diego I Solana Beach I Orange County Phone 858.259.8212 I www.plsaengineering.com X XXXXXX X X X XXXXX X X X X X EXISTING 2 STORY BUILDING EXISTING 2 STORY BUILDING EXISTING 2 STORY BUILDING EXISTING 2 STORY BUILDING EXISTING 1 STORY BUILDING EXISTING 1 STORY BUILDING EXISTING 1 STORY BUILDING SHED 3' WOOD FENCE 8' WROUGHT IRON FENCE 6' WOOD FENCE6' WOOD FENCE6' WOOD FENCE 6' WOOD FENCE 6' WOOD FENCE 6' WOOD FENCE 3' WOOD FENCE 6' WOOD FENCE X X X X X 53 53 52 52 52 52 52 51 51 51 5 1 51 50 50 50 50 50 49 49 49 49 49 49 48 48 48 48 48 48 48 4 8 47 47 47 47 47 47 46 46 46 46 46 45 4545 45 44 44 44 44 43 42 FL=48.49 FL=48.27 FL=47.40 FL=46.20 FL=46.14 FL=45.30 FL=44.59 FL=44.45 FL=43.98 FL=43.34 FL=42.92 FL=42.66 TC=48.95 TC=48.74 TC=47.85 TC=46.26 TC=46.68 TC=45.38 TC=44.74 TC=44.90 TC=44.14 TC=43.48 TC=43.08 TC=43.11 OE OE OE OE OE OE OE OE OE OE OE COMM POST SI D E W A L K DR I V E W A Y EN T R A N C E DR I V E W A Y EN T R A N C E WA L K W A Y WALKWAY WALKWAYWA L K W A Y PATIO PATIO BLDG OVERHANG BLDG OVERHANG 42.7 42.3 42.7 42.8 42.7 43.4 45.9 46.747.247.748.2 48.5 48.5 48.8 48.8 48.7 49.4 49.4 49.4 49.4 49.5 49.1 49.1 49.4 49.5 49.4 49.7 49.4 49.4 49.4 49.3 49.3 49.4 49.4 49.2 48.9 49.0 51.4 51.3 51.5 51.4 51.3 51.2 51.2 51.8 51.6 51.2 50.8 50.4 49.7 49.4 48.7 48.3 48.6 48.3 52.3 52.5 52.3 52.6 52.2 52.2 51.5 51.3 51.7 51.4 51.7 51.3 51.8 51.4 51.6 51.5 50.5 50.7 50.3 50.6 50.3 50.7 50.3 50.8 50.4 50.6 50.2 49.7 49.2 49.8 49.3 49.6 49.4 49.8 49.3 49.7 49.2 49.7 48.7 48.7 48.7 48.7 48.6 48.5 51.8 47.2 49.4 OE OE OE OE X X X X X X X X X X X X X X X X X X X X XXXXXXXXXXXXXXXXXXXXXXXXXX X X X X X X X X X X X X XX X X X X X X X XXXXXXXXXXXXXXXXX X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X XXXX X X X XX X X X X X W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W W G G G G G G G G G G G G G G G G G G W W W SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD SD G G G G S S S S S W SUBBASIN PR-1-A AREA = 8,165 SF (0.187 AC) Cn = 0.58 BASIN PR-1 (TOTAL) AREA = 19,247 SF (0.442 AC) Cn = 0.58 SUBBASIN PR-1-B AREA = 11,907 SF (0.273 AC) Cn = 0.58 GR A D E B R E A K GR A D E B R E A K GR A D E B R E A K MINOR BASIN PR-1-B1 AREA = 3,524 SF Cn = 0.58 MINOR BASIN PR-1-A1 AREA = 1,234 SF Cn = 0.58 BASIN PR-1 (TOTAL) AREA = 19,247 SF (0.442 AC) Cn = 0.58 MINOR BASIN PR-1-A3 AREA = 2,514 SF Cn = 0.58 MINOR BASIN PR-1-B2 AREA = 10,713 SF Cn = 0.58 NODE PR-100 49.8 HP 49.38 FL NODE PR-200 48.32 FL Q100= 0.3 CFS 49.44 FS NODE PR-102 44.43 FL Q100= 1.69 CFS QCAP=2.39 CFS 49.50 FS 48.43 FS NODE PR-104 Q100 IN DWY = 0.95 CFS Q100 IN SD = 0.72 CFS Q100 OUT = 1.69 CFS NODE PR-103 47.2 TG 46.4 IE Q100= 0.7 CFSNODE PR-101 49.4 TG 48.7 IE Q100 IN = 0.1 CFS NODE PR-104 47.0 TG 45.5 IE Q100= 0.72 CFS (48.5) FG (48.2) FG 48.2 TW@EG 47.5 TW@FS (46.3 BW@FG) (48.7 TW@EG) 47.3 TW@FG (45.8 BW@EG) (48.4 TW@EG) 47.0 TW@FS (45.6 BW@EG) (53.4) FG (53.8) FG (54.0) FG (54.2) FG (54.3) FG (54.3) FG (54.3) FG (54.1) FG(54.3) FG 49.29 FS 48.51 TC 48.01 FL 48.15 TC 47.65 FL 52.4 TW 52.0 TW@FG 48.7 BW 47.7 TF 49.7 TW 49.4 TW@FG 47.7 BW 46.3 TF 51.7 TW 51.5 TW@FG 48.5 BW 47.7 TF 48.0 TW@EG 48.0 TW@FS (47.0 BW@FG) 6-IN PVC PVT SD @ 0.7% 6-IN PVC PVT SD @ 2.0% MODIFIED D-25 CURB OUTLET (2' WIDE) @ 2.0% CH I N Q U A P I N A V E MIN5.0% MI N 5.0 % MI N 5.0 % MI N 5.0 % MI N 5.0 % MI N 5.0 % MI N 5.0 % MI N 5.0 % MIN 5.0 % MI N 5.0 % MIN 5.0% 70 . 0 0 ' N 5 5 ° 5 8 ' 2 7 " E 274.76'N 34°00'09" W 274.78'N 34°00'09" W 70 . 0 0 ' S 5 5 ° 5 9 ' 0 3 " W 6-IN PVC PVT SD @ 1.3% MINOR BASIN PR-1-A2 AREA = 4,073 SF Cn = 0.58 NODE PR-102 48.1 TG 47.5 IE Q100 IN = 0.46 CFS MINOR BASIN PR-1-A4 AREA = 344 SF Cn = 0.58 Q100=0.62 CFS QCAP=0.64 CFS Q100=0.34 CFS QCAP=0.46 CFS Q100=0.71 CFS QCAP=0.79 CFS LEGEND PROPERTY BOUNDARY CENTERLINE OF ROAD ADJACENT PROPERTY LINE PUBLIC RIGHT-OF-WAY BASIN PR-1 - AREA CALCULATIONS TOTAL SITE AREA 19,247 SF (0.442 AC) BASIN PR-1 TOTAL AREA 19,247 SF (0.442 AC) BASIN PR-1 IMPERVIOUS AREA 9,776 SF (0.224 AC) BASIN PR-1 PERVIOUS AREA 9,471 SF (0.217 AC) % IMPERVIOUS 50.8% Cn 0.58 TIME OF CONCENTRATION 5.0 MINUTES (PER SDCHM) 0 10 20 30 SCALE: 1" = 10' PROPOSED HYDROLOGY EXIHIBT CHINQUAPIN COAST HOMES - 330 CHINQUAPIN AVE CARLSBAD, CA 92008MAJOR BASIN BOUNDARY SUB-BASIN BOUNDARY MINOR BASIN BOUNDARY AT POINT OF ANALYSIS FLOW LINE IMPERVIOUS AREA PLAN VIEW - PROPOSED HYDROLOGY SCALE: 1" = 10' PLSA 3729J:\ACTIVE JOBS\3729 RINCON 330 CHINQUAPIN\CIVIL\REPORTS\HYDROLOGY\FINAL\APPENDIX\3729-CV-HYDD.DWG I I 7' ix \ J a I I -- X X X ------- ' • ' " ' ' < lie ' ' --- \ X -- ' ' I ' t. 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'I • ' .• ' ; ;;:::=========71 A -===·· =·===;==· =::::::::::::::=::::::!::::::::·="'=--T. °'---------=· =· =· ::::::!!:::::=. ="'==-'f=:::::::::::·=="'====·====J/:::::::::::::::::::::::::::·=====-=j'.::::. =j==:::::::::==:::::::::::::::~~,, --l • ---• --ID . ·... -~--I-" -t-• I I· I I I I V I 11 I I I I I • I I I I I I ,,, I I I I I I • I I I I \ I • I ' I I ' - ---------- ~\\\\I --- / I PREPARED BY: PASCO LAREY SUITER & ASSOCIATES San Diego Encinitas Orange County Phone 858.259.8212 I www.plsaengineering.com Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Tuesday, Feb 15 2022 330 CHINQUAPIN: DWY RIBBON GUTTER User-defined Invert Elev (ft) = 99.45 Slope (%) = 1.00 N-Value = 0.013 Calculations Compute by: Known Q Known Q (cfs) = 0.30 (Sta, El, n)-(Sta, El, n)... ( 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, 0.013) Highlighted Depth (ft) = 0.10 Q (cfs) = 0.300 Area (sqft)= 0.27 Velocity (ft/s)= 1.11 Wetted Perim (ft) = 6.82 Crit Depth, Yc (ft) = 0.10 Top Width (ft)= 6.82 EGL (ft)= 0.12 -2 0 2 4 6 8 10 12 14 16 18 20 22 Elev (ft)Depth (ft)Section 98.50 -0.95 99.00 -0.45 99.50 0.05 100.00 0.55 100.50 1.05 101.00 1.55 Sta (ft) 48.3 FL @ NODE PR-200 0.1' ----.......~ ---.............. ............... -~""""---V \__ Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Wednesday, Aug 24 2022 6-IN PVC @ 0.7% Circular Diameter (ft) = 0.50 Invert Elev (ft) = 100.00 Slope (%) = 0.70 N-Value = 0.013 Calculations Compute by: Known Depth Known Depth (ft) = 0.50 Highlighted Depth (ft) = 0.50 Q (cfs) = 0.469 Area (sqft)= 0.20 Velocity (ft/s)= 2.39 Wetted Perim (ft) = 1.57 Crit Depth, Yc (ft) = 0.35 Top Width (ft)= 0.00 EGL (ft)= 0.59 0 1 Elev (ft)Section 99.75 100.00 100.25 100.50 100.75 101.00 Reach (ft) --\- ) ~ __/ - Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Wednesday, Aug 24 2022 6-IN PVC @ 1.3% Circular Diameter (ft) = 0.50 Invert Elev (ft) = 100.00 Slope (%) = 1.30 N-Value = 0.013 Calculations Compute by: Known Depth Known Depth (ft) = 0.50 Highlighted Depth (ft) = 0.50 Q (cfs) = 0.639 Area (sqft)= 0.20 Velocity (ft/s)= 3.26 Wetted Perim (ft) = 1.57 Crit Depth, Yc (ft) = 0.41 Top Width (ft)= 0.00 EGL (ft)= 0.66 0 1 Elev (ft)Section 99.75 100.00 100.25 100.50 100.75 101.00 Reach (ft) --\- ) ~ __/ - Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, May 4 2022 6-in PVC Storm Drain @ 2.0% Circular Diameter (ft)= 0.50 Invert Elev (ft) = 46.00 Slope (%)= 2.00 N-Value = 0.013 Calculations Compute by:Known Depth Known Depth (ft) = 0.50 Highlighted Depth (ft)= 0.50 Q (cfs)= 0.793 Area (sqft)= 0.20 Velocity (ft/s)= 4.04 Wetted Perim (ft) = 1.57 Crit Depth, Yc (ft) = 0.45 Top Width (ft)= 0.00 EGL (ft)= 0.75 0 1 Elev (ft)Section 45.75 46.00 46.25 46.50 46.75 47.00 Reach (ft) --\- ) ~ __/ - Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Wednesday, Feb 8 2023 10-INCH PVC PIPE @1.0% Circular Diameter (ft) = 0.83 Invert Elev (ft) = 100.00 Slope (%) = 1.00 N-Value = 0.013 Calculations Compute by: Known Depth Known Depth (ft) = 0.83 Highlighted Depth (ft) = 0.83 Q (cfs) = 2.167 Area (sqft) = 0.54 Velocity (ft/s) = 4.00 Wetted Perim (ft) = 2.61 Crit Depth, Yc (ft) = 0.66 Top Width (ft) = 0.00 EGL (ft) = 1.08 0 1 Elev (ft)Section 99.75 100.00 100.25 100.50 100.75 101.00 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Wednesday, Feb 8 2023 MODIFIED D-25 CURB OUT LET 3-INCH X 2-FEET Rectangular Bottom Width (ft) = 2.00 Total Depth (ft) = 0.25 Invert Elev (ft) = 100.00 Slope (%)= 2.00 N-Value = 0.015 Calculations Compute by:Known Depth Known Depth (ft) = 0.25 Highlighted Depth (ft)= 0.25 Q (cfs)= 2.394 Area (sqft)= 0.50 Velocity (ft/s)= 4.79 Wetted Perim (ft) = 2.50 Crit Depth, Yc (ft) = 0.25 Top Width (ft)= 2.00 EGL (ft)= 0.61 0 .5 1 1.5 2 2.5 3 Elev (ft)Depth (ft)Section 99.75 -0.25 100.00 0.00 100.25 0.25 100.50 0.50 100.75 0.75 101.00 1.00 Reach (ft) ~ ~ -= ~