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HomeMy WebLinkAboutMS 2020-0004; ADAMS STREET HOMES; FINAL HYDROLOGY & HYDRAULIC STUDY FOR ADAMS STREET HOMES; 2022-04-01 FINAL HYDROLOGY & HYDRAULIC STUDY FOR ADAMS STREET HOMES GRADING PERMIT / PARCEL MAP DWG 534-5A (MS 2020-0004 / CDP 2020-0043) CITY OF CARLSBAD, CA PREPARED FOR: RREG INVESTMENTS SERIES, LLC SERIES I044 5315 AVENIDA ENCINAS, SUITE 200 CARLSBAD, CA 92008 PH: (888) 357-3553 PREPARED BY: PASCO LARET SUITER & ASSOCIATES, INC. 535 N. HIGHWAY 101, SUITE A SOLANA BEACH, CA 92075 PH: (858) 259-8212 Prepared: October 2021 Revised: January 2022 Revised: April 2022 __________________________________________________ TYLER G. LAWSON, RCE 80356 DATE PLSA 3339 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 City of Carlsbad Standards 2.3 Runoff Coefficient Determination 2.4 Hydrology & Hydraulic Model Output 3.0 Pre-Developed Hydrologic Model Output (100-Year Event) 3.1 Post-Developed Hydrologic Model Output (100-Year Event) 3.2 Detention Analysis (100-Year Event) 3.3 Hydromodification Analysis 3.4 Storm Water Pollutant Control 3.5 Appendix 4.0 Appendix A: Hydrology Support Material Appendix B: 100-Year Storm Event Detention Analysis Appendix C: Hydraulic Calculations PLSA 3339 Page 1 of 20 1.0 EXECUTIVE SUMMARY 1.1 Introduction This Final Hydrology Study for the proposed development at 3745 Adams Street 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 west of Adams Street between Magnolia Avenue to the north, and Tamarack Ave to the south. The site is adjacent to residential properties directly to the north and east, New Song Church to the west, and commercial structures to the south. The existing site consists of mostly natural vegetation with no structures. Recently the site was cleared of a single-family home and other residential improvements typical to adjacent properties. Natural vegetation onsite is made up of several trees, low shrubs, and bare soil. The property is located within the Carlsbad watershed, and, more specifically, the Agua Hedionda Hydrologic Area. The existing site is comprised of approximately 1.105 gross acres owned-in-fee out to the Adams Street centerline. Based on a study of the existing topography, most of the site generally drains from east to west, towards the western property line. A portion of the site drains to a local low point towards the middle of the site, where it can be assumed ponding occurs before drainage ultimately continues to the western property boundary. To take the most conservative approach in the calculation of peak runoff leaving the property as well as in the sizing of onsite detention mitigation measures, this area (broken out as Basin EX- 2) has been removed from the drainage study and has been assumed to not leave the site. There does not appear to be any existing storm drain infrastructure located onsite to convey drainage, and runoff sheet flows through the site toward the western property boundary, evenly discharging across the extent of the boundary. Just offsite on the property to the west exists a wall that partly retains and is majority freestanding. In a rain event, drainage appears to eventually make its way through this wall by means of weepholes or local low spots to continue west through the adjacent property towards Pio Pico. Once in Pio Pico, runoff enters an existing storm drain curb inlet in front of the New Song Church and is conveyed toward the outlet in the Agua Hedionda Lagoon in the buried pipe network. Separately, a portion of the Adams Street right-of-way also drains onto the site across the eastern property line as there does not exist curb, gutter, or berm surface improvements to keep run-on within the limits of the right-of-way. The subject property can be assumed to have one discharge location from the site in the existing condition from the western property line. The total analyzed area is approximately 1.105 acres in size and roughly 3% impervious. To be conservative, the portion of the site PLSA 3339 Page 2 of 20 draining towards a local sump in the middle of the site mentioned above has been delineated and is assumed to not drain to the western property boundary. Basin EX-1, discharging along the western property line, and Basin EX-2, draining towards the low point on site and ultimately infiltrating, are 0.781 and 0.324 acres respectively. Per the Web Soil Survey application available through the United States Department of Agriculture, the area is generally categorized to have group B soils. Based upon soil type B and the amount of existing impervious area onsite, a runoff coefficient of 0.27 was calculated for the analyzed area using the methodology described in section 3.1.2 of the San Diego County Hydrology Manual and the formula provided therein. 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 drainage basin for the 100-year, 6-hour storm event. 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 0.781 0.94 4.47 EX-2 0.324 0.51 5.78 Table 1. Existing Condition Peak Drainage Flow Rates The peak flow rate for the 100-year, 6-hour storm for Basin EX-1 was determined to be 0.94 cfs with a time of concentration of 9.7 minutes, leaving the site and discharging the western property line. To conservatively size the onsite storm water mitigation facilities, it is assumed the 0.51 cfs generated within Basin EX-2 does not leave the subject property after reaching the local sump onsite. Refer to pre-development hydrology calculations included in section 3.1 of this report for detailed analysis and the pre-development hydrology map in Appendix A of this hydrology report for existing drainage basin delineation and discharge locations. 1.3 Proposed Project The proposed project includes the clearing of all onsite vegetation and the construction of four (4) single-family residential structures and additional-dwelling units on each of the four (4) proposed parcels. Each parcel also proposes various hardscape and landscape improvements. Site grading along with drainage and utility improvements typical of this type of residential development will also be constructed. Runoff from the proposed development is to be collected by a series of storm drains and will be directed to two separate biofiltration BMPs with partial retention for treatment and detention. As in the existing site condition, storm water will be directed generally from Adams Street right-of-way to the east towards the west. Private catch basins, trench drains, and drain pipes will be located on each parcel allowing for storm water to be conveyed to PLSA 3339 Page 3 of 20 a biofiltration basin located in between parcel 3 and 4 near the western property line of the site, and in the front yard of parcel 3. Storm water leaving the basin will be directed westerly through several parallel pipes that will outlet along the western property line onto a rip rap dissipator that will spread the runoff and will mimic the existing conditions. The onsite biofiltration basin was designed using Storm Water Management Model (SWMM) software in conjunction with the City of Carlsbad’s BMP Design Manual. Refer to section 3.4 of this report for a more detailed SWMM analysis. The total approximate area of the onsite biofiltration basins is 975 square feet. Additionally, widening along Adams Street is proposed to satisfy the requirements of the City of Carlsbad’s engineering department and comply with the ultimate road cross-section per the City’s public road standards. As such, curb and gutter is proposed that will convey runoff south to north and ultimately to Magnolia Avenue within the right-of-way. This eventually heads west on Magnolia Avenue where it enters an existing curb inlet at the intersection with Pio Pico. To provide some mitigation for the additional runoff entering the Magnolia system, the project proposes tree well BMP’s that contain storage within the structural soil layer as well as on the surface. Additionally, it is assumed that the increase to the Magnolia Street system can be considered negligible and that ultimately the downstream infrastructure is adequately sized as water is not diverted from reaching the curb inlet in Pio Pico. In an effort to comply with City of Carlsbad’s storm water standards for Priority Development Project requirements, the project site will also implement source control and site design BMP’s where feasible and applicable in accordance with the City of Carlsbad’s BMP Design Manual. Aside from the proposed biofiltration basin, the site will also implement minimized hardscape areas and runoff dispersion through landscaped swales. Similar to the existing condition, the analyzed watershed can be categorized into one major drainage basin with one eventual discharge location from the subject property sheet flowing from the western property line. Basin PR-1 is 0.97 acres in size and is approximately 51% impervious. Basin PR-1 can further be broken down into three smaller sub-basins based on which portion of the site is tributary to each of the biofiltration basins, as well as the portion of the Lot 3 and 4 side slopes that are self-mitigating and discharge directly offsite. Based upon soil type B and the amount of proposed impervious area onsite, a runoff coefficient of 0.56 was calculated for the entire site using the methodology described in section 3.1.2 of the San Diego County Hydrology Manual and the formula provided therein. 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 post- development 100-year, 6-hour storm event. Table 2 below summarizes the results of the Rational Method calculations. PLSA 3339 Page 4 of 20 PROPOSED DRAINAGE FLOWS DRAINAGE AREA DRAINAGE AREA (ACRES) Q100 (CFS) I100 (IN/HR) PR-1.1 0.65 2.52 6.59 PR-1.2 0.22 0.84 6.59 PR-1.3 0.10 0.37 6.59 *PR-2 0.135 0.44 - Table 2. Proposed Condition Peak Drainage Flow Rates (Undetained Condition) *Basin PR-2 contains the portion of Adams Street in the right-of-way that is part of the proposed widening and will discharge to Magnolia Avenue as opposed to the western property line in the existing condition. For discussion and analysis of the Magnolia Avenue existing infrastructure, refer to Section 3.6. The peak flow rate for the 100-year, 6-hour storm for the entire Basin PR-1 was determined to be 3.73 cfs with a time of concentration of 5.0 minutes (minimum time of concentration per San Diego County Hydrology Manual used to calculate rainfall intensity since calculated Tc was less than 5.0 minutes) discharging from the site. Basin PR-1.1 discharges into the central biofiltration basin between parcels 3 and 4, and Basin PR-1.2 discharges to the biofiltration basin in the front yard of parcel 3. Once treated and detained in each BMP, runoff that doesn’t infiltrate into the underlying soil continues west to a flow- spreader system consisting of rock rip rap and an embedded concrete sill running the length of the western boundary. This prevents concentrated discharge leaving the site and generates an evenly distributed sheet flow condition from the project to match the existing condition. 1.4 Conclusions Based upon the analysis included in this report, the proposed onsite drainage system design is adequate to capture and convey runoff from the proposed project and discharge via sheet flow methods across the western property boundary, as it does in the existing condition, while complying with local and state level water quality regulations. There is no diversion of flows onsite, and water leaving any portion onsite eventually is conveyed through the neighboring wall in the same methods that exist currently. Once drainage passes through the adjacent wall via weepholes or local low spots, it continues further downstream through the adjacent property to the west to enter the City’s public storm drain system by means of an existing curb inlet located on Pio Pico. Table 3 below summarizes the results of the detained peak flow conditions. PLSA 3339 Page 5 of 20 COMPARISON DRAINAGE FLOWS DRAINAGE AREA DRAINAGE AREA (ACRES) Q100 (CFS) I100 (IN/HR) EX-1 0.78 0.94 4.33 PR-1.1 0.65 0.21 - PR-1.2 0.22 0.01 - PR-1.3 0.10 0.37 - PR-1 (Det) 0.97 0.59 - Table 3. Proposed Condition Peak Drainage Flow Rates (Detained Condition) As mentioned in previous sections, there is a small diversion of water along the frontage of the property in the post-project condition compared to the pre-project condition as a result of the ultimate frontage improvements along Adams Street. A study of the larger drainage basin reaching the curb inlet at the intersection of Magnolia Avenue and Pio Pico resulted in determining the existing curb inlet is adequately sized to intercept and convey flows resulting from the ultimate frontage improvements adjacent the subject property along Adams Avenue. 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 “Engineering Standards, Volume 5: Carlsbad BMP Design Manual”, revised February 2016, City of Carlsbad Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. Web Soil Survey. Available online at http://websoilsurvey.nrcs.usda.gov. PLSA 3339 Page 6 of 20 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 Rational Method formula estimates the peak rate of runoff based on the variables of area, runoff coefficient, and rainfall intensity, and is the preferred method for drainage basins up to one square mile in size. 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 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. PLSA 3339 Page 7 of 20 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. 2.3 City of Carlsbad Standards The City of Carlsbad requires a Preliminary Hydrology Study be completed for projects larger than 1-acre per Form P-2: Development Permits. The City of Carlsbad has additional requirements for hydrology reports which are outlined in the Grading and Erosion Control Ordinance. Please refer to this manual for further details. 2.4 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 at the end of this section, categorizes the land use, the associated development density (dwelling units per acre) and the percentage of impervious area. PLSA 3339 Page 8 of 20 2.5 AES Rational Method Computer Model The Rational Method computer program developed by Advanced Engineering Software (AES) satisfies the County of San Diego design criteria, therefore it is the computer model used for this study. The AES hydrologic model is capable of creating independent node- link models of each interior drainage basin and linking these sub-models together at confluence points to determine peak flow rates. The program utilizes base information input by the user to perform calculations for up to 15 hydrologic processes. The required base information includes drainage basin area, storm water facility locations and sizes, land uses, flow patterns, and topographic elevations. The hydrologic conditions were analyzed in accordance with the 2003 County of San Diego Hydrology Manual criteria as follows: Design Storm 100-year, 6-hour 100-year, 6-hour Precipitation 2.6 inches Rainfall Intensity Based on the 2003 County of San Diego Hydrology Manual criteria Runoff Coefficient Weighted Runoff Coefficients per Section 3.1, 3.2 of this report and Table 3-2 of SDHDM 2.5.1 AES Computer Model Code Information 0: Enter Comment 2: Initial Subarea Analysis 3: Pipe/Box/Culvert Travel Time 5: Open Channel Travel Time 7: User-Specified hydrology data at Node 8: Addition of sub-area runoff to Main Stream 10: Copy Main Stream data onto a Memory Bank 11: Confluence Memory Bank data with Main Stream 13: Clear the Main Stream PLSA 3339 Page 9 of 20 3.0 HYDROLOGY MODEL OUTPUT 3.1 Pre-Developed Hydrologic Model Output (100 Year Event) Pre-Development: Q = CIA *Rational Method Equation P100 = 2.6 in *100-Year, 6-Hour Rainfall Precipitation Total Disturbed Area Total Area = 48,138 sf ➔ 1.105 Acres Impervious Area = 1,333 sf ➔ 0.031 Ac Pervious Area = 46,805 sf ➔ 1.074 Acres Cn, Weighted Runoff Coefficient, - 0.25, Cn value for natural ground, Type B Soils *Per San Diego County Hydrology Manual (SDCHM) Section 3.1.2 - 0.90, Cn value for developed/impervious surface *Per SDCHM Section 3.1.2 Cn = 0.25 x 46,805 + .9 x 1,333 sf = 0.27 48,138 sf Basin EX-1 Total Area = 34,042 sf ➔ 0.781 Acres Initial Slope ~5%, Land Use = 1 DU / AC zoning Ti = 8.0 mins *Table 3-2 per SDCHM Tt = {[11.9*(170 ft / 5,280 ft/mile)^3]/6.1 ft}^0.385 = .024 hours = .024 hours * 60 = 1.5 mins Tc = 8.7 + 1.5 = 9.7 min Tc = 9.7 min P6 = 2.6 I = 7.44 x P6 x D-0.645 I = 7.44 x 2.6 x 9.7-0.645 ≈ 4.47 in/hr I100 ≈ 4.47 in/hr Q100 = C*I*A Q100 = 0.27 x 4.47 in/hr x 0.78 Ac = 0.94 cfs **Discharging via sheet flow across the western property line PLSA 3339 Page 10 of 20 Basin EX-2 Total Area = 14,096 sf ➔ 0.324 Acres Initial Slope ~10%, Land Use = 1 DU / AC zoning Ti = 6.4 mins *Table 3-2 per SDCHM Tt = {[11.9*(10 ft / 5,280 ft/mile)^3]/1 ft}^0.385 = .002 hours = .002 hours * 60 min / hr = 0.1 min Tc = 6.4 + 0.1 = 6.5 min Tc = 6.5 min P6 = 2.6 I = 7.44 x P6 x D-0.645 I = 7.44 x 2.6 x 6.5-0.645 ≈ 5.78 in/hr I100 ≈ 5.78 in/hr Q100 = C*I*A Q100 = 0.27 x 5.78 in/hr x 0.324 Ac = 0.51 cfs **Draining to local sump / low point in property and assumed to infiltrate / not drain to the western property line for the purpose of this analysis PLSA 3339 Page 11 of 20 3.2 Post-Developed Hydrologic Model Output (100-Year Event) Post-Development: Q = CIA *Rational Method Equation P100 = 2.6 in *100-Year, 6-Hour Rainfall Precipitation Total Site (Onsite Drainage Basin – Prior to Biofiltration Treatment) Total Area = 42,290 sf ➔ 0.97 Acres Impervious Area = 20,050 sf ➔ 0.460 Ac Pervious Area = 22,240 sf ➔ 0.511 Ac Cn, Weighted Runoff Coefficient, - 0.25, Cn value for natural ground, Type B Soils *Per San Diego County Hydrology Manual (SDCHM) Section 3.1.2 - 0.90, Cn value for developed/impervious surface *Per SDCHM Section 3.1.2 Cn = 0.9 x 20,050 sf + 0.25 x 22,240 sf = 0.56 42,290 sf Basin PR-1.1: Node 108 (Tributary to BMP-1 between parcels 3 and 4) Total Area = 28,465 sf ➔ 0.65 Acres Q = Cn x I100 x A Tc = 5.0 min (see attached AES calculations) Q100 = 2.52 cfs (see attached AES calculations) Basin PR-1.2 (Tributary to BMP-2 in front yard of parcel 3) Total Area = 9,555 sf ➔ 0.22 Acres Q = Cn x I100 x A Tc = 5.0 min (see attached AES calculations) Q100 = 0.84 cfs (see attached AES calculations) PLSA 3339 Page 12 of 20 Basin PR-1.3 (Side Slopes on Lots 3 and 4 draining directly offsite) Total Area = 4,270 sf ➔ 0.10 Acres Cn = 0.56 Tc = 5.0 min (see attached AES calculations) Q100 = 0.37 cfs (see attached AES calculations) Basin PR-1 (Entire Drainage Basin) Tc = 5.0 min (see attached AES calculations) Q100 = 2.52 cfs + 0.84 cfs + 0.37 cfs Q100 = 3.73 cfs (see attached AES calculations) Basin PR-2 (Frontage Improvements along Adams Street) Total Area = 5,848 sf ➔ 0.13 Acres Impervious Area = 5,397 sf ➔ 0.12 Ac Pervious Area = 451 sf ➔ 0.01 Ac Cn, Weighted Runoff Coefficient, - 0.25, Cn value for natural ground, Type B Soils *Per San Diego County Hydrology Manual (SDCHM) Section 3.1.2 - 0.90, Cn value for developed/impervious surface *Per SDCHM Section 3.1.2 Cn = 0.9 x 5,397 sf + 0.25 x 451 sf = 0.85 5,848 sf Ti = 9.6 mins *Per SDCHM table 3-2 Tt = {[11.9*(140/5280)^3]/1.5}^0.385 = .034 hours = .034 hours * 60 = 2.01 mins Tc = 9.6 + 2.0 = 11.6 mins P6 = 2.6 I = 7.44 x P6 x D-0.645 I = 7.44 x 2.6 x 11.6-0.645 ≈ 3.98 in/hr Q100 = C*I*A Q100 = 0.85 x 3.98 in/hr x 0.13 Ac = 0.44 cfs **Discharging from northern end of Adams Street along the property frontage and entering the Magnolia Street system PLSA 3339 Page 13 of 20 Pre-Development vs. Post-Development (Undetained Runoff from Western PL) Pre-Development (Basin EX-1) Post-Development (Basin PR-1) Q100 = 0.94 cfs Q100 = 3.73 cfs = 2.52 cfs (PR-1.1) + 0.84 cfs (PR-1.2) + 0.37 (PR-1.3) Delta 2.8 cfs *Total overall site runoff increased in proposed condition from pre-development site. Refer to the following section, Section 3.3, of this report for a discussion of detention system proposed to mitigate site to existing conditions. Also refer to the Appendix of this report for existing and proposed condition hydrology node maps showing discharge locations from the subject property. PLSA 3339 Page 14 of 20 3.3 Detention Analysis The onsite biofiltration basins and raised planters provide pollutant control as well as mitigation of the 100-year, 6-hour storm event peak flow rate. A routing analysis was performed for the proposed biofiltration facilities to confirm peak flow will be detained and slowly released to match existing conditions. HydroCAD-10 has the ability to route the 100-year, 6-hour storm event inflow hydrograph (generated and modeled using RatHydro, which is a Rational Method Design Storm Hydrograph software that creates a hydrograph using the results of the Rational Method calculations) through each biofiltration facility. Based on the BMP cross-sectional geometry, stage-storage and outlet structure data, HydroCAD-10 has the ability to perform a dynamic / routing analysis and calculate the detained peak flow rate as well as detained time to peak. The results of this analysis can be found in Appendix B of the report. COMPARISON DRAINAGE FLOWS DRAINAGE AREA DRAINAGE AREA (ACRES) Q100 (CFS) I100 (IN/HR) EX-1 0.78 0.94 4.33 PR-1.1 0.65 0.21 - PR-1.2 0.22 0.01 - PR-1.3 0.10 0.37 - PR-1 (Det) 0.97 0.59 - Table 3. Comparison of Peak Drainage Flow Rates – Detained Condition Table 3 above lists a summary of the results of the detention analysis as compared to the pre-project and post-project unmitigated peak flows. Based on the results of the HydroCAD-10 analysis, it was determined that the biofiltration basin facilities provide mitigation for the 100-year, 6-hour storm event peak flow rate by detaining the proposed condition to 0.59 cfs, which is below the existing condition Q100 of 0.94 cfs leaving the property to the west via sheet flow methods. For additional information, refer to Appendix A of this Hydrology Report for the pre-and- post-developed project hydrologic node maps. Lastly, refer to Appendix B of this report for the HydroCAD-10 detailed output, which shows the dynamic routing of the 100-year, 6-hour storm event through the biofiltration basins and the resulting mitigated peak discharge leaving the subject property. PLSA 3339 Page 15 of 20 3.4 Hydromodification Analysis Refer to the project Storm Water Quality Management Plan (SWQMP) prepared by Pasco, Laret, Suiter & Associates under separate cover for discussion of hydromodification management strategy and compliance to satisfy the requirements of the MS4 Permit. 3.5 Storm Water Pollutant Control To meet the requirements of the MS4 Permit, the HMP biofiltration facility is designed to treat onsite storm water pollutants contained in the volume of runoff from a 24-hour, 85th percentile storm event by slowly infiltrating runoff through an engineered soil layer. Refer to the project Storm Water Quality Management Plan (SWQMP) prepared by Pasco, Laret, Suiter & Associates under separate cover for discussion of pollutant control. 3.6 Supplemental Calculations for Determination of Downstream Facilities Capacity As mentioned in previous sections of the report, the proposed frontage improvements along Adams Street adjacent the subject property are shown as requested by the City of Carlsbad engineering department in accordance with the City’s public road standards. This results in a slight diversion of water from the existing condition, as the post-project condition routes a portion of Adams Street north towards Magnolia Avenue, where it continues west to a curb inlet near the intersection of Pio Pico. As such, an analysis was performed for the overall drainage basin ultimately draining to this inlet – including the improved portion of Adams Street in the post-project condition – to confirm if sufficient capacity exists to convey the 100-year, 6-hour design storm event. This curb inlet appears to be in a local sump condition at the low spot of Magnolia Avenue. The Rational Method was used to quantify the peak flow rate The analysis of the resulting depth of flow in the existing curb and gutter along Magnolia Avenue - due to the slight increase in runoff leaving the subject property - was performed using Hydraflow Express – Civil 3D extension. The curb depth at the inlet was determined from a Caltrans as-built and was used to calculate the resulting flow capacity of the existing curb inlet using the Curb Inlets in Sag equation per San Diego County Hydraulic Design Manual, Section 2.3.2.1. Based on the results of the analysis, the existing curb inlet on Magnolia Avenue appears to be sized appropriately to adequately intercept and convey the increase in peak flow generated by the proposed project during the 100-year, 6-hour storm event. Basin Area = 614,637 sf *Includes portion of Adams Street widening = 14.18 Ac adjacent subject property Runoff Coeff C= 0.45 *Value for Medium Density Residential (4.3 DU/A or less), Type ‘B’ soils *Per San Diego Hydrology Design Manual (SDHDM) Section 3.1.2 PLSA 3339 Page 16 of 20 Tc = Ti + Tt Ti @ 70’ = 1% R-4 per Land Use Element => 9.6 min from Table 3-2 Tt => L = 2,147’ ΔE = 98.0’ Tt= [{11.9(L/5,280)^3}/ΔE]^0.385 Tt= [{11.9(2,147/5,280)^3}/98.0]^0.385 = 0.157 0.157 x 60 = 9.42 Min. Tc = 9.6 + 9.4 = 19.0 Min P6 = 2.6 I = 7.44 x P6 x D-0.645 I = 7.44 x 2.6 x 19.0-0.645 ≈ 2.89 in/hr Q100 = C*I*A Q100 = 0.45 x 2.89 in/hr x 14.18 Ac = 18.44 cfs Total Q100 = Post Project including Adams Street widening Total Q100 = 18.44 cfs Check Capacity at Curb Inlet: Curb Inlets in Sag *Per San Diego County Hydraulic Design Manual Section 2.3.2.1 Q = Cw Lw d3/2 Where… Q = inlet capacity (ft3/s); Cw = weir discharge coefficient = 3.0 (per Table 2-1) Lw = weir length (feet) = 16 ft (per Carlsbad utility GIS) D = flow depth (feet) = 0.66 ft (per Caltrans DWG 802-7, Pg. 39) Q = 3.0 x 16 ft x (7.9/12 ft)3/2 Q = 25.64 cfs Street Flow (18.44 cfs) < Downstream Curb Inlet Flow Capacity (25.64 cfs), therefore, the downstream facilities are equipped to convey the slight increase in peak Q100 flow resulting from the Adams Street public improvements. PLSA 3339 Page 17 of 20 3.7 Supplemental Calculations for Determination of Pipe and Grate Capacity The storm drain system pipe capacity was determined by delineating the site into sub- areas that would contribute to the system as shown in the Storm Drain Capacity exhibit in Appendix C. Once the site was delineated into sub-areas the maximum flow rate was calculated using the rational method. After determining the minimum pipe slope in a sub-area the pipe capacity was calculated using the Civil 3D extension hydroflow express as shown in Appendix C. Sub-areas with a minimum pipe slope of one percent or more will compare the pipe flow of a six-inch pipe at one percent against the maximum flow rate for the sub-area. Sub-areas that have pipes that are sloped at less than 1 percent or are larger than six-inches will compare the minimum pipe size and slope in the sub-area to the maximum flow rate that sub area will receive. Finally, the brow ditch on the south side of the project with a depth of 0.2 feet was modeled as a pipe with a flow depth of 0.2 feet. The brow ditch flow rate at a depth of 0.2 feet was compared against the maximum flow rate the brow ditch would receive. The grate capacity was determine using the methodology from chapter 2 of the San Diego County Hydraulic Design Manual (September, 2014). The grate capacity was checked assuming 50 percent clogging in orifice and weir conditions shown in Appendix C. The storm drain system has been proven to have capacity for the 100-year storm and the grate inlets at 50 percent clogging will not flood up to pad elevation. PLSA 3339 Page 18 of 20 4.0 APPENDIX IL__·-----_--_I 10.0 9.0 8,0 7.0 6.0 5.0 4.0 3.0 2.0 0.6 0,5 0.4 0.3 0.2 0,1 ' . ' ......... ' ""'I'-,, ' ' ..... 1, ..... ' . ' ...... , .......... ......... ""r-. I""._ I", .... .... "i--.. ...... r-,r-, ,'""' ....... ' ' .... ...... , ""'" ..... .. I' . ' """' --.... ~ .. ' • ""' ~" ' ..... ""'I'-,, "" ,., I', " I", ' ' .......... ! .. --~ ~ "" .... " ' ..... , I= 3.2 in/hr ...... "' " ' ~ ~" -,_ .... .... " ..... ......... I', .... .... " " ' ..... " .. l'o ~ ' ...... 'l'o, "~ ' ...... , I " ' "l'o "~ , ... 'l'o ......... ~" ...... " ,, .. .. "' " " tc = 20 min I I I I 11 I 111 ' 5 6 7 8 9 10 15 20 30 Minutes " .. "" "• " "• " ~ .. .. " ~ .. " " "• " " "· "• " " '" I 40 50 Duration EQUATION I = 7.44 P5 D-0.645 I = Intensity (in/hr) P5 = 6-Hour Precipitation (in) D = Duration (min) 'I',, .... ' ..... '' I'-,, , .... ... , ,, ... ' 1, ""' r-... ' .... ...... .. ~" l'r-..._ , .. ,, "" " 1, "'r-. ...... :--....., .. l'o " :--.I',, ,, " ·~ " ..... ... " .... , ....... :-,... ,., ""' ~ :--., ' .. " ....... " 1, "'"' " ' I'"" 1,._. " :-,...r-... I', :--....., " " 2 3 4 Hours I I 5 6 C)} ± 0 ~ -0 ~ s.o t 5.5 g, 5.0 :, 4.5 '§' 0 4.0 ~ 3.5 !!!.. 3,0 2.5 2.0 1.5 1.0 Intensity-Duration Design Chart -Example 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 (1 O, 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 = _3_ in., p24 ::;: ~ .~ ::;: ~ %(2) 24 (c) Adjusted p6(2) = _3_ in . (d) Ix= 20 min . {e) J = ~ in./hr. Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. 5-5.5 -6 ~ 1 1.5 r~ 2.5 J-3:-5 -4 4.5' I Ouralion 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 2.124 ~.18 _i.?415.3Q_ 6.36_U£ jl.48-9.54 J 0.60 11.:,6_6_ J.2.72 __ 10 1.68 2.53 3.37 4.21 5.~ 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 1.00 I, .6212.,sfu~ 3.23 3.11 4.31 4.85 5.39 5.93 '5.45 --25 0.93 1 .40 1.87 2.33 2.80 3.27 3.73 4.20 4.67 5. ~ 5.60 --30 0.83 1.24 1.661 2,07 2.49 2,90 3,32 3.73 4.15 4.56 ,..i-98 --. -_-40 0.69-:-1.03 1.38 1.72 2.07 2.41 2.76 3.10 3.45 3.79 4.13 50 o.6_f o.oo T 19-1.49 I 1.19~()~ ..J,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 2.9~ 3.18 ~ o::fi 0.61 0.02 1.02 123 1.43 1.63 1.84 2.04 2.25 ~2A5 ----rio 0.34 0.51 0.68 0.85 1.02 1.19 1.36 1.53 1.70 1fil 2.04 7 so 0.29 0.44 0.59 0.7310.88 1.03 1.18.....J.12 1.47 1.62 1.76 180 .9.26 ~r-5g_ 0.65 0.78 0.91 1.Q!J 1.18 1.31 1.44 1.57 240 0.22 0.33 0.43 0.540.651·0.76 0~87 j 0.98 1.08 1.~ 1.30 300 0.19 0.28 0.38 0.470:56 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 I 0.75 0.84 0.92 1.00 Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 4/30/2020 Page 1 of 43668480366849036685003668510366852036685303668540366855036685603668570366858036684803668490366850036685103668520366853036685403668550366856036685703668580468620468630468640468650468660468670468680468690468700468710468720468730468740468750468760468770468780 468620 468630 468640 468650 468660 468670 468680 468690 468700 468710 468720 468730 468740 468750 468760 468770 468780 33° 9' 20'' N 117° 20' 11'' W33° 9' 20'' N117° 20' 5'' W33° 9' 16'' N 117° 20' 11'' W33° 9' 16'' N 117° 20' 5'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 35 70 140 210Feet 0 10 20 40 60Meters Map Scale: 1:778 if printed on A landscape (11" x 8.5") 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 14, Sep 16, 2019 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jan 23, 2020—Feb 13, 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 4/30/2020 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 1.2 100.0% Totals for Area of Interest 1.2 100.0% 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 4/30/2020 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 4/30/2020 Page 4 of 4~ /////////////////////////////////////////////XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXS 92 9292 929292 92 929191 9 1 91 91 91 9191919190 9 0 90 90 90 90909090 8989898989 89 89 89 8989 8888 888888 88 888888 88 8787 87 87 878787 87 878 7 87 8786 86 86 86 8686868 686 8686 86 85 85 85 85 85 85 8585858585 858 5 858484 84 84 8 4 84 84 8 4848484 84 84 83 83 83 8383 8383838383 82 82 8 2 82828 2 8 2 82 8181818181818 1 8080 X X X X XXXXXXXXXXXXXXXXXXXXXXXXDENSE OVERGROWTH REQUIRES CLEARING FOR A MORE ACCURATE SURFACE DENSE OVERGROWTH REQUIRES CLEARING FOR A MORE ACCURATE SURFACE SHIPPING CONTAINER ADAMS STREETNODE 1.3 (FG = 80.9) Q100 = 0.94 CFS NODE 1.1 (FS = 91.8) DISTURBED AREA AREA= 48,138 SF Cn = 0.27 APN: 205-270-13-00APN:205-270-43-00APN: 205-270-24-00 APN: 205-270-27-00 APN: 205-270-12-00 APN: 205-270-23-00 BASIN EX-2 AREA= 14,096 SF Cn = 0.27 BASIN EX-1 AREA= 34,042 SF Cn = 0.27 NODE 1.2 (FG = 87.0)L1 =100'L1 = 100'NODE 2.1 (FS = 91.9) NODE 2.2 (FG = 82.0) NODE 2.3 (FG / LP = 81.0) Q100 = 0.51 CFS L2 =170' EXISTING EDGE OF PAVEMENT LEGEND BASIN EX-1 - AREA CALCULATIONS TOTAL BASIN AREA 34,042 SF (0.781 AC) Cn 0.27 Q100 0.94 CFS TC 9.7 MIN PROPERTY BOUNDARY CENTERLINE OF ROAD ADJACENT PROPERTY LINE / RIGHT-OF-WAY EXISTING CONTOUR LINE EXISTING PATH OF TRAVEL EXISTING DIRECTION OF FLOW EXISTING MAJOR DRAINAGEBASIN BOUNDARY EXISTING DRAINAGE BASIN BOUNDARY TO SUMP IN SITE EXISTING IMPERVIOUS AREA PRE-DEVELOPMENTHYDROLOGIC NODE MAP 3745 ADAMS STREET CITY OF CARLSBAD 10 20 30 GRAPHIC SCALE: 1" = 10' 010 J:\ACTIVE JOBS\3339 3745 ADAMS STREET\CIVIL\REPORTS\HYDROLOGY\FINAL ENGINEERING\APPENDIX\3339-CV-HYDE.dwg 64 PLSA 3339-01 DISTURBED AREA - AREA CALCULATIONS TOTAL BASIN AREA 48,138 SF (1.105 AC) BASIN EXISTING IMPERVIOUS AREA 1,333 SF (0.00 AC) BASIN EXISTING PERVIOUS AREA 46,805 SF (0.97 AC) % IMPERVIOUS ~3% Cn 0.27 BASIN EX-2 - AREA CALCULATIONS TOTAL BASIN AREA 14,096 SF (0.324 AC) Cn 0.27 Q100 0.51 CFS TC 6.5 MIN / / / / / / / / / 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 "- I \ I \ I \ I I I I I \ I I \ J \ 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 I I I I I I I / I 7 ----- / / 1 ---, 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 \ 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 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 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 I I / / I I / I 1 r (\ I \ I \ I \ ,I \ ----- I --- I I I \ -----. \ \ \ ...._ ...... \ \ \ \ \ \ \ \ \ ' ...... ...._ ...._ ...._ / \~ / \ ..., ,I / / I \ \ i I I 10 \ \ \ \ I I I I d I I q I I I I I I I I I I\ I \ I \ I \ I ', \ \ I \ I I I I I -------- f77Z7ZZ/21/ZZ/Z PASCO LARET SUITER I ~~~(C))tl~llE~ San Diego I Solana Beach I Orange County Phone 858.259.8212 I www.plsaengineering.com XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXS 92 9292 929292 92 929191 9 1 91 91 91 91919191909090 90 90 90909090 898989898989 89 89 898 989 8888 8 88888 88 88888 8 8 8 8787 87 87 878787 87 878787 8786 8 6 86 86 8686868686 868 6 86 85 85 85 85 85 85 8585858585 858 5 858484 84 848484 84 84848484 84 84 83 8383 8383 8383838383 82 82 8 2 82 828 2 8 2 82 8181818181818 1 8080 X X X X XXXXXXXXXXXXXXXXXXXXXXXXXDENSE OVERGROWTH REQUIRES CLEARING FOR A MORE ACCURATE SURFACE DENSE OVERGROWTH REQUIRES CLEARING FOR A MORE ACCURATE SURFACE SHIPPING CONTAINER / / / // //////////////////////////////////////////////XXXXXXXXXXXXXXXXXXXXXXXX X X X X X X X XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 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 XXXXXXXXXX84 85 86 87 83 88 89 909188 89 90 87 8684 85 83 828182929192918990889291 9292 / / / // //////////////////////////////////////////////XXXXXXXXXXXXXXXXXXXXXXXX X X X X X X X XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 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 XXXXXXXXXX84 85 86 87 83 88 89 909188 89 90 87 8684 85 83 828182929192918990889291 9292SDSDSDSDSDSDSDSDS DSDSD SDSDSDS D S D SDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSD SD SDSDSD SD SD SD SD SD SD SD SD APN: 205-270-13-00 NODE 1.3 IE = 81.5 UNMIT Q100 = 3.57 CFS; MIT Q100 = X CFS ADAMS STREETAPN:205-270-43-00APN: 205-270-24-00 APN: 205-270-27-00 APN: 205-270-12-00 NODE 100 FS=91.6 BMP OUTLET 82.5 IE UNMITIGATED Q100 = 2.52 CFS; MITIGATED Q100 = 0.21 CFS FLOW SPREADER DEVICE AND RIP RAP FG = 85.5 (81.5 IE OUT) APN: 205-270-23-00 FG = 86.0 BMP OUTLET; 83.0 IE UNMITIGATED Q100 = 0.84 CFS; MITIGATED Q100 = 0.01 CFS FLOW SPREADER DEVICE AND RIP RAP BMP-1 BMP-2 4" PVC DRAIN PIPE TO DISCHARGE THROUGH WALL 6" X 24" PCC SILL NODE 1.5 IE = 81.5 Q100 = 3.74 CFS; Q100 = 0.59 CFS (DET) 6" X 24" PCC SILL BASIN PR-1.2-7 AREA= 2,153 SF Cn = 0.56 BASIN PR-1 AREA= 42,290 SF Cn = 0.56 NODE 101 TG=90.6 IE=88.1 NODE 102 IE=87.55 NODE 103 IE=87.3 NODE 104 IE=87.15 NODE 105 IE=86.7 NODE 106 IE=86.55 L= 15' BASIN PR-1.1-7 AREA= 7,250 SF Cn = 0.56 BASIN PR-1.1-6 AREA= 4,197 SF Cn = 0.56 BASIN PR-1.1-8 AREA= 13,350 SF Cn = 0.56 BASIN PR-1.2-1 AREA= 1,150 SF Cn = 0.56 BASIN PR-1.2-2 AREA= 767 SF Cn = 0.56 BASIN PR-1.2-3 AREA= 544 SF Cn = 0.56 BASIN PR-1.2-4 AREA= 460 SF Cn = 0.56BASIN PR-1.2-5 AREA= 410 SF Cn = 0.56 BASIN PR-1.2-8 AREA= 3,566 SF Cn = 0.56 BASIN PR-1.2-6 AREA = 429 SF Cn = 0.56 NODE 200 FS=91.6 L= 16' NODE 201 TG = 91.4 IE = 88.5 NODE 202 IE = 88.0 NODE 203 IE = 87.8 NODE 204 IE = 87.6 NODE 205 IE = 87.15 NODE 206 IE = 86.9 NODE 207 IE = 86.75 NODE 208 IE = 86.0 Q100 IN = 0.52 CFS BASIN PR-1.1-1 AREA= 1,143 SF Cn = 0.56 BASIN PR-1.1-2 AREA= 789 SF Cn = 0.56 BASIN PR-1.1-3 AREA= 502 SF Cn = 0.56 BASIN PR-1.1-4 AREA= 400 SF Cn = 0.56 BASIN PR-1.1-5 AREA= 591 SF Cn = 0.56 NODE 107 IE=85.6 NODE 108 IE=85.5 Q100 IN = 1.3 CFS NODE 300 FS = 92.4 NODE 301 FS = 92.3 NODE 302 FS=90.8 Q100=0.44 CFS L= 140'L= 70'BASIN PR-2 AREA= 5,848 SF Cn = 0.85 BASIN PR-1.3 AREA= 4,270 SF Cn = 0.56 APPROX. ROOF LINE PER BLDG PLANS Q100 = 3.74 CFS; Q100 = 0.59 CFS (DET) LEGEND BASIN PR-1.1 - AREA CALCULATIONS TOTAL BASIN AREA 28,814 SF (0.661 AC)Cn 0.56 TIME OF CONCENTRATION 5.0 MINUTES (PER SDCHM) PROPERTY BOUNDARY CENTERLINE OF ROAD ADJACENT PROPERTY LINE / RIGHT-OF-WAY EXISTING CONTOUR LINE PROPOSED CONTOUR LINE PROPOSED PATH OF TRAVEL PROPOSED DIRECTION OF FLOW PROPOSED MAJOR DRAINAGEBASIN BOUNDARY PR-1 PROPOSED MAJOR DRAINAGE BASIN BOUNDARY PR-2 PROPOSED MINOR DRAINAGE BASIN BOUNDARY PR-1-2 PROPOSED DRAINAGE SUB-BASIN BOUNDARY EXISTING IMPERVIOUS AREA 10 20 30 GRAPHIC SCALE: 1" = 10' 010 64 64 PLSA 3339-01J:\ACTIVE JOBS\3339 3745 ADAMS STREET\CIVIL\REPORTS\HYDROLOGY\FINAL ENGINEERING\APPENDIX\3339-CV-HYDD.dwg POST-DEVELOPMENTHYDROLOGIC NODE MAP 3745 ADAMS STREETCITY OF CARLSBAD TOTAL SITE - AREA CALCULATIONS TOTAL BASIN AREA 42,290 SF (0.97 AC) BASIN PROPOSED IMPERVIOUS AREA 20,050 SF (0.460 AC) BASIN PROPOSED PERVIOUS PAVEMENT 0 SF (0.00 AC) BASIN PROPOSED PERVIOUS AREA 22,240 SF (0.511 AC) % IMPERVIOUS 50.6% Cn 0.56 TIME OF CONCENTRATION X MINUTES (PER SDCHM) BASIN PR-1.2 - AREA CALCULATIONS TOTAL BASIN AREA 9,511 SF (0.218 AC)Cn 0.56 TIME OF CONCENTRATION 5.0 MINUTES (PER SDCHM) BASIN PR-2 - AREA CALCULATIONS TOTAL BASIN AREA 5,848 SF (0.134 AC) Cn 0.85 TIME OF CONCENTRATION 5.0 MINUTES (PER SDCHM) BASIN PR-1.3 - AREA CALCULATIONS TOTAL BASIN AREA 3,965 SF (0.091 AC) Cn 0.56 TIME OF CONCENTRATION 5.0 MINUTES (PER SDCHM) \ \ \ \ ------- / \ \ / / / / / I I I I I I I 1•----11 I I I I. I I I / I I -'r ' ' I '\ I \ I \ I \ I I I I I I I \ I I \ I \ I \ / \ ---~~/--+----l \ / \ // '-/ ' / ' / ...._~ p 4 ----- \ \ I \ \ ' ' L ' \ I I \ \ -- / / I ---- 0 / / / I I ' ' '· ', , ... ' ' ' ' . ' ' ' ' '' ,,"' ' ' ' \ \ \ \ / / \ \ / / / / / / f\ I \ I \ I \ -~-4 ~--,:,, ,,: ~~~ tr' -,,; . ' ~" ~"' :-- I I I I ,-' " , ' ,,r-------.• ' --.. ~ ~-..... :_J _::L -- - - -- - - ------ IZ0Z7/2½1/ZZZl PASCO LARET SUITER t 11.SS!Ote ii.iii" !ES San Diego Solana Beach I Orange County Phone 858.259.82121 www.plsaengineering.com PLSA 3339 Page 17 of 18 APPENDIX B: HYDROCAD-10 SUPPORTING MATERIAL RATIONAL METHOD HYDROGRAPH PROGRAM COPYRIGHT 1992, 2001 RICK ENGINEERING COMPANY RUN DATE 1/3/2022 HYDROGRAPH FILE NAME Text1 TIME OF CONCENTRATION 5 MIN. 6 HOUR RAINFALL 2.6 INCHES BASIN AREA 0.66 ACRES RUNOFF COEFFICIENT 0.56 PEAK DISCHARGE 2.52 CFS TIME (MIN) = 0 DISCHARGE (CFS) = 0 TIME (MIN) = 5 DISCHARGE (CFS) = 0.1 TIME (MIN) = 10 DISCHARGE (CFS) = 0.1 TIME (MIN) = 15 DISCHARGE (CFS) = 0.1 TIME (MIN) = 20 DISCHARGE (CFS) = 0.1 TIME (MIN) = 25 DISCHARGE (CFS) = 0.1 TIME (MIN) = 30 DISCHARGE (CFS) = 0.1 TIME (MIN) = 35 DISCHARGE (CFS) = 0.1 TIME (MIN) = 40 DISCHARGE (CFS) = 0.1 TIME (MIN) = 45 DISCHARGE (CFS) = 0.1 TIME (MIN) = 50 DISCHARGE (CFS) = 0.1 TIME (MIN) = 55 DISCHARGE (CFS) = 0.1 TIME (MIN) = 60 DISCHARGE (CFS) = 0.1 TIME (MIN) = 65 DISCHARGE (CFS) = 0.1 TIME (MIN) = 70 DISCHARGE (CFS) = 0.1 TIME (MIN) = 75 DISCHARGE (CFS) = 0.1 TIME (MIN) = 80 DISCHARGE (CFS) = 0.1 TIME (MIN) = 85 DISCHARGE (CFS) = 0.1 TIME (MIN) = 90 DISCHARGE (CFS) = 0.1 TIME (MIN) = 95 DISCHARGE (CFS) = 0.1 TIME (MIN) = 100 DISCHARGE (CFS) = 0.1 TIME (MIN) = 105 DISCHARGE (CFS) = 0.1 TIME (MIN) = 110 DISCHARGE (CFS) = 0.1 TIME (MIN) = 115 DISCHARGE (CFS) = 0.1 TIME (MIN) = 120 DISCHARGE (CFS) = 0.1 TIME (MIN) = 125 DISCHARGE (CFS) = 0.1 TIME (MIN) = 130 DISCHARGE (CFS) = 0.1 TIME (MIN) = 135 DISCHARGE (CFS) = 0.1 TIME (MIN) = 140 DISCHARGE (CFS) = 0.1 TIME (MIN) = 145 DISCHARGE (CFS) = 0.1 TIME (MIN) = 150 DISCHARGE (CFS) = 0.1 TIME (MIN) = 155 DISCHARGE (CFS) = 0.1 TIME (MIN) = 160 DISCHARGE (CFS) = 0.1 TIME (MIN) = 165 DISCHARGE (CFS) = 0.1 TIME (MIN) = 170 DISCHARGE (CFS) = 0.1 TIME (MIN) = 175 DISCHARGE (CFS) = 0.1 TIME (MIN) = 180 DISCHARGE (CFS) = 0.1 TIME (MIN) = 185 DISCHARGE (CFS) = 0.1 TIME (MIN) = 190 DISCHARGE (CFS) = 0.1 TIME (MIN) = 195 DISCHARGE (CFS) = 0.2 TIME (MIN) = 200 DISCHARGE (CFS) = 0.2 TIME (MIN) = 205 DISCHARGE (CFS) = 0.2 TIME (MIN) = 210 DISCHARGE (CFS) = 0.2 TIME (MIN) = 215 DISCHARGE (CFS) = 0.2 TIME (MIN) = 220 DISCHARGE (CFS) = 0.2 TIME (MIN) = 225 DISCHARGE (CFS) = 0.3 TIME (MIN) = 230 DISCHARGE (CFS) = 0.3 TIME (MIN) = 235 DISCHARGE (CFS) = 0.5 TIME (MIN) = 240 DISCHARGE (CFS) = 0.7 TIME (MIN) = 245 DISCHARGE (CFS) = 2.52 TIME (MIN) = 250 DISCHARGE (CFS) = 0.4 TIME (MIN) = 255 DISCHARGE (CFS) = 0.3 TIME (MIN) = 260 DISCHARGE (CFS) = 0.2 TIME (MIN) = 265 DISCHARGE (CFS) = 0.2 TIME (MIN) = 270 DISCHARGE (CFS) = 0.2 TIME (MIN) = 275 DISCHARGE (CFS) = 0.1 TIME (MIN) = 280 DISCHARGE (CFS) = 0.1 TIME (MIN) = 285 DISCHARGE (CFS) = 0.1 TIME (MIN) = 290 DISCHARGE (CFS) = 0.1 TIME (MIN) = 295 DISCHARGE (CFS) = 0.1 TIME (MIN) = 300 DISCHARGE (CFS) = 0.1 TIME (MIN) = 305 DISCHARGE (CFS) = 0.1 TIME (MIN) = 310 DISCHARGE (CFS) = 0.1 TIME (MIN) = 315 DISCHARGE (CFS) = 0.1 TIME (MIN) = 320 DISCHARGE (CFS) = 0.1 TIME (MIN) = 325 DISCHARGE (CFS) = 0.1 TIME (MIN) = 330 DISCHARGE (CFS) = 0.1 TIME (MIN) = 335 DISCHARGE (CFS) = 0.1 TIME (MIN) = 340 DISCHARGE (CFS) = 0.1 TIME (MIN) = 345 DISCHARGE (CFS) = 0.1 TIME (MIN) = 350 DISCHARGE (CFS) = 0.1 TIME (MIN) = 355 DISCHARGE (CFS) = 0.1 TIME (MIN) = 360 DISCHARGE (CFS) = 0.1 TIME (MIN) = 365 DISCHARGE (CFS) = 0 RATIONAL METHOD HYDROGRAPH PROGRAM COPYRIGHT 1992, 2001 RICK ENGINEERING COMPANY RUN DATE 1/3/2022 HYDROGRAPH FILE NAME Text1 TIME OF CONCENTRATION 5 MIN. 6 HOUR RAINFALL 2.6 INCHES BASIN AREA 0.22 ACRES RUNOFF COEFFICIENT 0.56 PEAK DISCHARGE 0.84 CFS TIME (MIN) = 0 DISCHARGE (CFS) = 0 TIME (MIN) = 5 DISCHARGE (CFS) = 0 TIME (MIN) = 10 DISCHARGE (CFS) = 0 TIME (MIN) = 15 DISCHARGE (CFS) = 0 TIME (MIN) = 20 DISCHARGE (CFS) = 0 TIME (MIN) = 25 DISCHARGE (CFS) = 0 TIME (MIN) = 30 DISCHARGE (CFS) = 0 TIME (MIN) = 35 DISCHARGE (CFS) = 0 TIME (MIN) = 40 DISCHARGE (CFS) = 0 TIME (MIN) = 45 DISCHARGE (CFS) = 0 TIME (MIN) = 50 DISCHARGE (CFS) = 0 TIME (MIN) = 55 DISCHARGE (CFS) = 0 TIME (MIN) = 60 DISCHARGE (CFS) = 0 TIME (MIN) = 65 DISCHARGE (CFS) = 0 TIME (MIN) = 70 DISCHARGE (CFS) = 0 TIME (MIN) = 75 DISCHARGE (CFS) = 0 TIME (MIN) = 80 DISCHARGE (CFS) = 0 TIME (MIN) = 85 DISCHARGE (CFS) = 0 TIME (MIN) = 90 DISCHARGE (CFS) = 0 TIME (MIN) = 95 DISCHARGE (CFS) = 0 TIME (MIN) = 100 DISCHARGE (CFS) = 0 TIME (MIN) = 105 DISCHARGE (CFS) = 0 TIME (MIN) = 110 DISCHARGE (CFS) = 0 TIME (MIN) = 115 DISCHARGE (CFS) = 0 TIME (MIN) = 120 DISCHARGE (CFS) = 0 TIME (MIN) = 125 DISCHARGE (CFS) = 0 TIME (MIN) = 130 DISCHARGE (CFS) = 0 TIME (MIN) = 135 DISCHARGE (CFS) = 0 TIME (MIN) = 140 DISCHARGE (CFS) = 0 TIME (MIN) = 145 DISCHARGE (CFS) = 0 TIME (MIN) = 150 DISCHARGE (CFS) = 0 TIME (MIN) = 155 DISCHARGE (CFS) = 0 TIME (MIN) = 160 DISCHARGE (CFS) = 0 TIME (MIN) = 165 DISCHARGE (CFS) = 0 TIME (MIN) = 170 DISCHARGE (CFS) = 0 TIME (MIN) = 175 DISCHARGE (CFS) = 0 TIME (MIN) = 180 DISCHARGE (CFS) = 0 TIME (MIN) = 185 DISCHARGE (CFS) = 0 TIME (MIN) = 190 DISCHARGE (CFS) = 0 TIME (MIN) = 195 DISCHARGE (CFS) = 0.1 TIME (MIN) = 200 DISCHARGE (CFS) = 0.1 TIME (MIN) = 205 DISCHARGE (CFS) = 0.1 TIME (MIN) = 210 DISCHARGE (CFS) = 0.1 TIME (MIN) = 215 DISCHARGE (CFS) = 0.1 TIME (MIN) = 220 DISCHARGE (CFS) = 0.1 TIME (MIN) = 225 DISCHARGE (CFS) = 0.1 TIME (MIN) = 230 DISCHARGE (CFS) = 0.1 TIME (MIN) = 235 DISCHARGE (CFS) = 0.2 TIME (MIN) = 240 DISCHARGE (CFS) = 0.2 TIME (MIN) = 245 DISCHARGE (CFS) = 0.84 TIME (MIN) = 250 DISCHARGE (CFS) = 0.1 TIME (MIN) = 255 DISCHARGE (CFS) = 0.1 TIME (MIN) = 260 DISCHARGE (CFS) = 0.1 TIME (MIN) = 265 DISCHARGE (CFS) = 0.1 TIME (MIN) = 270 DISCHARGE (CFS) = 0.1 TIME (MIN) = 275 DISCHARGE (CFS) = 0 TIME (MIN) = 280 DISCHARGE (CFS) = 0 TIME (MIN) = 285 DISCHARGE (CFS) = 0 TIME (MIN) = 290 DISCHARGE (CFS) = 0 TIME (MIN) = 295 DISCHARGE (CFS) = 0 TIME (MIN) = 300 DISCHARGE (CFS) = 0 TIME (MIN) = 305 DISCHARGE (CFS) = 0 TIME (MIN) = 310 DISCHARGE (CFS) = 0 TIME (MIN) = 315 DISCHARGE (CFS) = 0 TIME (MIN) = 320 DISCHARGE (CFS) = 0 TIME (MIN) = 325 DISCHARGE (CFS) = 0 TIME (MIN) = 330 DISCHARGE (CFS) = 0 TIME (MIN) = 335 DISCHARGE (CFS) = 0 TIME (MIN) = 340 DISCHARGE (CFS) = 0 TIME (MIN) = 345 DISCHARGE (CFS) = 0 TIME (MIN) = 350 DISCHARGE (CFS) = 0 TIME (MIN) = 355 DISCHARGE (CFS) = 0 TIME (MIN) = 360 DISCHARGE (CFS) = 0 TIME (MIN) = 365 DISCHARGE (CFS) = 0 1L Inflow to BMP-1 6P BMP-2 Alt6 7L Inflow to BMP-2 8P BMP-1 Alt6 Routing Diagram for 3339 Prepared by Pasco Laret Suiter & Associates, Printed 1/4/2022 HydroCAD® 10.10-7a s/n 10097 © 2021 HydroCAD Software Solutions LLC Subcat Reach Pond Link __ ____j~ 0 D 6 [j .------___J 3339 Printed 1/4/2022Prepared by Pasco Laret Suiter & Associates Page 2HydroCAD® 10.10-7a s/n 10097 © 2021 HydroCAD Software Solutions LLC Summary for Link 1L: Inflow to BMP-1 Inflow =2.52 cfs @ 4.08 hrs, Volume=0.085 af Primary =2.52 cfs @ 4.08 hrs, Volume=0.085 af, Atten= 0%, Lag= 0.0 min Routed to Pond 8P : BMP-1 Alt6 Primary outflow = Inflow, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs DISCHARGE Imported from BMP-1 RatHydro adjusted.csv Link 1L: Inflow to BMP-1 Inflow Primary Hydrograph Time (hours) 95908580757065605550454035302520151050Flow (cfs)2 1 0 DISCHARGE Imported from BMP-1 RatHydro adjusted.csv 2.52 cfs 2.52 cfs D 3339 Printed 1/4/2022Prepared by Pasco Laret Suiter & Associates Page 6HydroCAD® 10.10-7a s/n 10097 © 2021 HydroCAD Software Solutions LLC Summary for Pond 8P: BMP-1 Alt6 Inflow =2.52 cfs @ 4.08 hrs, Volume=0.085 af Outflow =0.21 cfs @ 4.33 hrs, Volume=0.085 af, Atten= 92%, Lag= 14.8 min Discarded =0.01 cfs @ 0.16 hrs, Volume=0.040 af Primary =0.20 cfs @ 4.33 hrs, Volume=0.045 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 101.53' @ 4.33 hrs Surf.Area= 1,287 sf Storage= 2,703 cf Plug-Flow detention time= 828.9 min calculated for 0.085 af (100% of inflow) Center-of-Mass det. time= 829.1 min ( 1,035.6 - 206.5 ) Volume Invert Avail.Storage Storage Description #1 97.00'3,360 cf Custom Stage Data (Conic) Listed below (Recalc) Elevation Surf.Area Voids Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(%)(cubic-feet)(cubic-feet)(sq-ft) 97.00 700 0.0 0 0 700 98.50 700 95.0 998 998 841 100.00 700 20.0 210 1,208 981 101.50 1,275 100.0 1,460 2,667 1,580 102.00 1,500 100.0 693 3,360 1,814 Device Routing Invert Outlet Devices #1 Primary 97.00'8.0" Round Culvert L= 17.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 97.00' / 96.50' S= 0.0294 '/' Cc= 0.900 n= 0.013, Flow Area= 0.35 sf #2 Device 1 97.00'0.5" Vert. Orifice C= 0.600 Limited to weir flow at low heads #3 Device 1 101.50'36.0" x 36.0" Horiz. Grate C= 0.600 in 36.0" x 36.0" Grate (100% open area) Limited to weir flow at low heads #4 Discarded 97.00'0.705 in/hr Exfiltration over Surface area below 97.00' #5 Device 2 97.00'5.000 in/hr Exfiltration over Surface area below 100.00' Discarded OutFlow Max=0.01 cfs @ 0.16 hrs HW=97.05' (Free Discharge) 4=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.20 cfs @ 4.33 hrs HW=101.53' (Free Discharge) 1=Culvert (Passes 0.20 cfs of 4.02 cfs potential flow) 2=Orifice (Orifice Controls 0.01 cfs @ 10.22 fps) 5=Exfiltration (Passes 0.01 cfs of 0.08 cfs potential flow) 3=Grate (Weir Controls 0.18 cfs @ 0.54 fps) t_ 3339 Printed 1/4/2022Prepared by Pasco Laret Suiter & Associates Page 7HydroCAD® 10.10-7a s/n 10097 © 2021 HydroCAD Software Solutions LLC Pond 8P: BMP-1 Alt6 Inflow Outflow Discarded Primary Hydrograph Time (hours) 95908580757065605550454035302520151050Flow (cfs)2 1 0 Peak Elev=101.53' Storage=2,703 cf 2.52 cfs 0.21 cfs 0.01 cfs0.20 cfs D 3339 Printed 1/4/2022Prepared by Pasco Laret Suiter & Associates Page 5HydroCAD® 10.10-7a s/n 10097 © 2021 HydroCAD Software Solutions LLC Summary for Link 7L: Inflow to BMP-2 Inflow =0.84 cfs @ 4.08 hrs, Volume=0.018 af Primary =0.84 cfs @ 4.08 hrs, Volume=0.018 af, Atten= 0%, Lag= 0.0 min Routed to Pond 6P : BMP-2 Alt6 Primary outflow = Inflow, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs DISCHARGE Imported from BMP-2 RatHydro adjusted.csv Link 7L: Inflow to BMP-2 Inflow Primary Hydrograph Time (hours) 95908580757065605550454035302520151050Flow (cfs)0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 DISCHARGE Imported from BMP-2 RatHydro adjusted.csv 0.84 cfs 0.84 cfs :~ D J / ]vv ~v V i V :~ V ~ V ~V V 1vv -v V ~v v = V ~~/ = V ]~v : / 1vv ✓, ~v /, 1 '//,'~~,,,,_;,///, ~ 'I//. 'II 'I ,¼0 z~;,,~ ~ ;,///~;,,~ .#/////2 -1//./2: ~/V/////2"~fff:~ ~ ,,,,,~,,~~/~:,,,,. 1// 3339 Printed 1/4/2022Prepared by Pasco Laret Suiter & Associates Page 3HydroCAD® 10.10-7a s/n 10097 © 2021 HydroCAD Software Solutions LLC Summary for Pond 6P: BMP-2 Alt6 Inflow =0.84 cfs @ 4.08 hrs, Volume=0.018 af Outflow =0.01 cfs @ 4.57 hrs, Volume=0.018 af, Atten= 98%, Lag= 29.5 min Discarded =0.00 cfs @ 3.25 hrs, Volume=0.009 af Primary =0.01 cfs @ 4.57 hrs, Volume=0.009 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-96.00 hrs, dt= 0.01 hrs Peak Elev= 100.70' @ 4.57 hrs Surf.Area= 436 sf Storage= 721 cf Plug-Flow detention time= 567.6 min calculated for 0.018 af (100% of inflow) Center-of-Mass det. time= 567.7 min ( 804.3 - 236.6 ) Volume Invert Avail.Storage Storage Description #1 97.00'1,157 cf Custom Stage Data (Conic) Listed below (Recalc) Elevation Surf.Area Voids Inc.Store Cum.Store Wet.Area (feet)(sq-ft)(%)(cubic-feet)(cubic-feet)(sq-ft) 97.00 275 0.0 0 0 275 98.50 275 95.0 392 392 363 100.00 275 20.0 83 474 451 101.00 515 100.0 389 863 701 101.50 665 100.0 294 1,157 857 Device Routing Invert Outlet Devices #1 Primary 97.00'6.0" Round Culvert L= 25.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 97.00' / 96.60' S= 0.0160 '/' Cc= 0.900 n= 0.013, Flow Area= 0.20 sf #2 Device 1 97.00'0.4" Vert. Orifice C= 0.600 Limited to weir flow at low heads #3 Device 1 101.00'36.0" x 36.0" Horiz. Grate C= 0.600 in 36.0" x 36.0" Grate (100% open area) Limited to weir flow at low heads #4 Discarded 97.00'0.705 in/hr Exfiltration over Surface area below 97.00' #5 Device 2 97.00'5.000 in/hr Exfiltration over Surface area below 100.00' Discarded OutFlow Max=0.00 cfs @ 3.25 hrs HW=97.05' (Free Discharge) 4=Exfiltration (Exfiltration Controls 0.00 cfs) Primary OutFlow Max=0.01 cfs @ 4.57 hrs HW=100.70' (Free Discharge) 1=Culvert (Passes 0.01 cfs of 1.68 cfs potential flow) 2=Orifice (Orifice Controls 0.01 cfs @ 9.24 fps) 5=Exfiltration (Passes 0.01 cfs of 0.03 cfs potential flow) 3=Grate ( Controls 0.00 cfs) t_ 3339 Printed 1/4/2022Prepared by Pasco Laret Suiter & Associates Page 4HydroCAD® 10.10-7a s/n 10097 © 2021 HydroCAD Software Solutions LLC Pond 6P: BMP-2 Alt6 Inflow Outflow Discarded Primary Hydrograph Time (hours) 95908580757065605550454035302520151050Flow (cfs)0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Peak Elev=100.70' Storage=721 cf 0.84 cfs 0.01 cfs 0.00 cfs 0.01 cfs 1/1 L_ ,~: ~~ ~v :~~ :~~;,;'; ;;;; ;;; ,,,,,, 'I ,,,,. ,,,. ,,,,. V///////p .,. ·////J::;,"//./4 ~~~ ~~ ~ ~~ ~ ~ ~~ ½ "/J ½ ;l'.fi r/J ;l'.fi ,,,,,,. ,,,, V/. ,,,,,, ½ v~ ·11//-'//////,. 'h D PLSA 3339 Page 18 of 18 APPENDIX C: HYDRAULIC CALCULATIONS MAGNOLIA AVENUE CURB INLET – SUPPORT MATERIAL ODE 102 (74.0f:S) ~)8'88 CFS ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~1. 0 0 D 0 J:'.4CTIVE JOBSl3339 3745ADAMS S7REE71CIVIL\REPORTSIHYOROLOGYIFINAL ENGINEERING'.4PPENDIXl3339-GV-HYDO-EXTN.dwg Q 0 STREET FLOW NODE MAP EXHIBIT ADAMS STREET HOMES-3745ADAMS STREET " Ar/ 1111 , - d 0 Cl I \ 0 MAG~OLIA AVENU ~ I s Q BASIN 1 AREA= 617,637 SF =14.18AC Cn = 0.45 • PLAN VIEW -STREET FLOW NODE MAP SCALE: 1''=80' ; ) f C sl 11 ' . g _ ~ ~ Q ::n: ·O LEGEND PROPERTY BOUNDARY CENTERLINE OF ROAD ADJACENT PROPERTY LINE I RIGHT-OF-WAY EXISTING CONTOUR LINE EXISTING PATIi OF TRAVEL EXISTING MAJOR DRAINAGE BASIN BOUNDARY ------ 64 ••• ----l~ --- BASIN-AREA CALCULATIONS TOTAL BASIN AREA /. Cn 614,637 SF (14.18AC) 0.45 I _,...,-:;:; TTME OF CONCENTRATION 19.0 MINUTES 80 GRAPHIC SCALE: 1" = 80' 0 80 160 STREET FLOW HYDROLOGIC NODE MAP 3745ADAMS STREET CITY OF CARLSBAD 240 PASCO LARET SUITER ----• I ~SSOJtCl~ii'[S San Diego I Solana Beach I Orange County Phone 858.259.82121 www.plsaengineering.com PLSA 3339-01 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Wednesday, Apr 27 2022 MAGNOLINA AVENUE STREET FLOW Gutter Cross Sl, Sx (ft/ft) = 0.020 Cross Sl, Sw (ft/ft) = 0.083 Gutter Width (ft) = 1.50 Invert Elev (ft) = 100.00 Slope (%) = 5.30 N-Value = 0.015 Calculations Compute by: Known Q Known Q (cfs) = 18.44 Highlighted Depth (ft) = 0.39 Q (cfs) = 18.44 Area (sqft)= 2.31 Velocity (ft/s)= 7.97 Wetted Perim (ft) = 15.38 Crit Depth, Yc (ft) = 0.60 Spread Width (ft) = 14.97 EGL (ft)= 1.38 0 5 10 15 20 25 30 35 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) "V ~ __,,- __,,. ~ ~ ~ Chapter 2. Street Drainage and Inlets Page 2-6 San Diego County Hydraulic Design Manual September 2014 LT = length of clear opening of inlet for total interception (ft). For the minimum required efficiency of E=0.85, this general equation reduces to the following expression: 0.85 0.65ETLL (2-5) Step 3. Calculate the amount of flow intercepted by the inlet and the bypass flow, and apply to the bypass flow to the roadway flow calculations and inlet capacity calculations downstream. INTERCEPT APPRROACH QEQ (2-6) 1BYPASS APPROACH INTERCEPT APPROACH QQ Q EQ (2-7) Curb Inlets in Sag Curb inlets in sags or sump locations operate as weirs at shallow depths, and operate as orifices as water depth increases. The designer shall estimate the capacity of the inlet under each condition and adopt a design capacity equal to the smaller of the two results. When designing the size of a facility, the designer shall use the larger of the sizes obtained by solving for the two conditions. Inlets in sumps act as weirs for shallow depths, which can be described using Equation 2-8: 3/2WWQCLd (2-8) where ... Q = inlet capacity (ft3/s); CW = weir discharge coefficient (see Table 2-1) LW = weir length (ft); and d = flow depth (ft). Table 2-1 presents appropriate weir coefficient values and lengths for various inlet types. At higher flow depths, curb inlets operate in a manner more typical of an orifice (Equation 2-9). 1/20.67 (2 )oQhLgd (2-9) where ... Q = inlet capacity (ft3/s); h = curb opening height (ft); L = curb opening length (ft); g = gravitational acceleration (ft2/s); and do = effective depth of flow at curb face (ft). Chapter 2. Street Drainage and Inlets San Diego County Hydraulic Design Manual Page 2-7 September 2014 The effective depth of flow at the curb face includes the curb depression, and must be adjusted for the curb inlet throat configuration. The San Diego Regional Standard curb inlet opening (SD- RSD No. D-12) has an inclined throat, and therefore the effective depth of flow at the curb face is given by the expression: ()sin2o hdya (2-10) where ... y = depth of flow in adjacent gutter (ft); a = curb inlet depression (ft); (/2)sinh = adjustment for curb inlet throat width (h) and angle of throat incline (). For a standard 6-inch curb inlet opening with a 4-inch depression (SD-RSD No. D-12), (/2)sinh =3.1 inches (0.26 ft). Table 2-2 presents appropriate orifice coefficient values and lengths for various inlet types. In general, if an inlet is functioning as an orifice, the depth of flow is very deep and it is recommended that the design of the inlet be re-considered to avoid this condition. 2.3.2.2 Grated Inlets Grated Inlets on Grade The capture efficiency of grated inlets on grade depends on the width and length of the grate and the velocity of the flow approaching the grate. When the approaching flow velocity is slow and the flow width does not exceed the grate width, the grate inlet might be able to intercept all of the approaching flow. In cases where the width of the approaching flow exceeds the grate width, very little of the approaching flow that exceeds the grate width will be intercepted by the inlet. When the velocity of the approaching flow is too high, the flow will “splash over” the grate. Both these phenomena contribute to flow bypass of grate inlets, which is analogous to the bypass flow discussed in relation to curb opening inlets on grade. Table 2-1 Weir Coefficients for Inlets in Sag Locations Inlet Type Coefficient Weir Length Equation Valid WC WL Grate Inlet Against Curb 3.00 2L W (1) 1.79oWdAL Grate Inlet, Flow from All Sides 3.00 2( )LW(1) 1.79oWdAL Curb Opening Inlet 3.00 L dh Depressed Curb Opening Inlets Less than L'=12 ft(2) 3.00 1.8LW dh Slotted Inlets 2.48 L (1) 0.2dft (1) Weir length shall be reduced by 50% to account for clogging. (2) “Depressed Curb Opening Inlets” refers to curb inlets with depression larger the width of the gutter (for example, SD-RSD No. 20, “Concrete Apron for Curb Inlet”). The width (W) of the curb opening depression is measured perpendicular to the face of the curb opening. I I ONSITE GRATED INLET SIZING – SUPPORT MATERIAL XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXS 92 9292 929292 92 929191 9 1 91 91 91 91919191909090 90 90 90909090 898989898989 89 89 898 9 8888 8 88888 88 88888 8 8 8 8787 87 87 878787 87 878787 8786 8 6 86 86 8686868686 868 6 86 85 85 85 85 85 85 8585858585 858 5 858484 84 848484 84 84848484 84 84 83 8383 8 383 8383838383 82 82 8 2 82 828 2 8 2 82 8181818181818 1 8080 X X X X XXXXXXXXXXXXXXXXXXXXXXXXDENSE OVERGROWTH REQUIRES CLEARING FOR A MORE ACCURATE SURFACE DENSE OVERGROWTH REQUIRES CLEARING FOR A MORE ACCURATE SURFACE SHIPPING CONTAINER / / / // //////////////////////////////////////////////XXXXXXXXXXXXXXXXXXXXXXXX X X X X X X X XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 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 XXXXXXXXXX84 85 86 87 83 88 89 909188 89 90 87 8684 85 83 828182929192918990889291 9292 / / / // //////////////////////////////////////////////XXXXXXXXXXXXXXXXXXXXXXXX X X X X X X X XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 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 XXXXXXXXXX84 85 86 87 83 88 89 909188 89 90 87 8684 85 83 828182929192918990889291 9292SDSDSDSDSDSDSDSDS DSDSD SDSDSDS D S D SDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSDSD SD SDSDSD SD SD SD SD SD SD SD SD ADAMS STREETAPN:205-270-43-00APN: 205-270-24-00 APN: 205-270-27-00 APN: 205-270-12-00 NODE 100 FG = 85.5 APN: 205-270-23-00 FG = 86.0 BMP-1 BMP-2 NODE 101 Q100=0.12 CFS 6" PVC NODE 102 Q100 IN =0.1 CFS 6" INLET NODE 103 Q100 IN=0.05 CFS 6" INLET NODE 104 Q100=0.05 CFS 6" INLET NODE 105 Q100=0.05 CFS 6" INLET NODE 106 Q100=0.4 CFS 12"X12" INLET NODE 200 NODE 201 Q100=0.1 CFS 6" PVC NODE 202 Q100=0.1 CFS 6" INLET NODE 203 Q100=0.05 CFS 6" INLET NODE 204 Q100=0.05 CFS 6" INLET NODE 205 Q100=0.05 CFS 6" INLET NODE 206 Q100=0.33 CFS 6" PVC NODE 207 Q100=0.2 CFS 12"X12" INLET Q100=0.52 CFS 6" PVC @ 1.0% NODE 107 Q100=0.64 CFS 12"X12" INLET NODE 108 Q100=2.52 CFS 36"X36" INLET Q100=0.6 CFS 12X12 INLET Q100=0.6 CFS 12X12 INLET AREA = 13,350 SF (X.X AC) Q100=0.2 CFS 6" PVC @ 1.0% Q100=0.23 CFS 6" PVC @ 1.0% Q100=0.27 CFS 6" PVC @ 1.0%Q100=0.32 CFS 6" PVC @ 1.0% Q100=0.6 CFS 10" PVC @ 1.0% Q100=1.3 CFS 10" PVC @ 1.0% Q100=0.17 CFS 6" PVC @ 1.0% Q100=0.21 CFS 6" PVC @ 1.0% Q100=0.26 CFS 6" PVC @ 1.0% Q100=0.3 CFS 6" PVC @ 1.0% NODE 207 Q100=0.52 CFS 6" PVC @ 1.0% NODE 208 Q100=0.84 CFS 36"X36" INLET LEGEND PROPERTY BOUNDARY CENTERLINE OF ROAD ADJACENT PROPERTY LINE / RIGHT-OF-WAY EXISTING CONTOUR LINE PROPOSED CONTOUR LINE PROPOSED PATH OF TRAVEL PROPOSED DIRECTION OF FLOW PROPOSED MAJOR DRAINAGE BASIN BOUNDARY PR-1 PROPOSED MINOR DRAINAGE BASIN BOUNDARY PR-1.2 PROPOSED DRAINAGESUB-BASIN BOUNDARY EXISTING IMPERVIOUS AREA 10 20 30 GRAPHIC SCALE: 1" = 10' 010 64 64 PLSA 3339-01J:\ACTIVE JOBS\3339 3745 ADAMS STREET\CIVIL\REPORTS\HYDROLOGY\FINAL ENGINEERING\APPENDIX\3339-CV-HYDD Q-PIPESIZING.dwg POST-DEVELOPMENTHYDROLOGIC NODE MAP 3745 ADAMS STREETCITY OF CARLSBAD '\ \ \ 7 / / / / \ \ -,---=--=---- / / \ \ / / / I I I I I I I I I I ✓----/ ----....... I ..._ ' I "-I \ I \ I \ I \ I I I I I I \ I \ I \ / \ ~~L/ __ +----, '\. / '-// ' / ' / '-/ ----- p ------7 ( '\. I \ I \ I I \ J.1 \ I '----... \ ------------ l \ \ I / / 0 I I I / / / '-'- A ): ' r I,, == ·, ,.,_,,"-""' -______... I I / \ \ "~,, ... , ... ,,, ', ' ' ,,,,,' ~ I I I I I I \ I \ \ , / / I / , ' ' ,,·,, ',, ', ''-"'~'@, "'"' ' ' ' ..,,,,.,,--...... ............ I I / /~I 1' ( ,_ M M :--ii / -., ', ·,, ,::,.,.,,.,. :,.,_,_,, -.~,.,,.,,,, ' ', -, ' ·, , ... ' ' -----------,, ' I / / / I ;,-';------i---c---,-:-~c--''L.--;-~~--i· ! (// -_··, :.1\:\:)~-.··1 . /, );:·M-...._O~;---- I I ------/ I ,--·-...;.--- ~""--'-, ~I .!_;', I ~-----"/ /....._, / / ;!,~"" / '1 / /....._ ....._ , -0 /. "I /....._/....._ I I I I '-~---------) ....._ I. I....._ . I I ....._ '; \j ' ~,-.J ------_ , ___ --------·---,, ' '-~~ ' \--___ p - \ \ \ I / / I I / / I 'I /....._ I , . d I I I I\ I \ I '-I \ -~ ~ ~ 3c ~ -r ~ I - :g_ _:.-~ '"",.,..--'i -- ~ I -· ~~~ -. ..;.::--,- ..:.- ; -~ -J ;::::...-,- ' ,v ' . .. ,,.·-' ... ' ' ' I L __ -- - - - ------ PASCO LARET SUITER t 11.SS!Ote ii.iii" !ES San Diego I Solana Beach I Orange County Phone 858.259.82121 www.plsaengineering.com 6-in Grated Inlet in Sag (Assumed 50% Clogging) Cw 3 Unitless L 0.5 ft Pe 1.00 ft W 0.5 ft C0 0.67 Unitless Ae 0.125 *Pe assumes 50% clogging Weir Orifice Q (cfs) d (ft)Q (cfs) d (ft) 0.02 0.25 0.34 0.25 0.19 0.5 0.48 0.5 0.63 0.75 0.58 0.75 1.5 1 0.67 1 2.93 1.25 0.75 1.25 5.06 1.5 0.82 1.5 Step 1. Calculate the capacity of a grate inlet operating as a w eir, using the weir equation (Equation 2-16) with a length equivalent to perimeter of the grate. When the grate is located next to a curb, disregard the length of the grate against the curb. O=C Pd312 ~ W e (2-16) w he.re ... Q = Cw = P e d inlet ,capacity of the grated inlet (ft3/s); weir coefficient (CF3 .. 0 for U .S. Traditional Units); effective grate perimeter length (ft); and. flow deptl1 approaching inlet (ft). To account for the effects of clogging of a grated inlet operating as a w eir, a clogging factor of fifty percent (CI=0.50) shall be applied to the actua l (uncfogged) perimeter of the grate (P): Step 2. Calculate the capacity of a grate inlet operating as an orifice. Use the o rifice equation (Equation 2-1 8), assuming the clear opening of the grate reduced by a clogging factor CA=0 .50 (Equation 2-1 9). A San Diego Regional Standard No. D-I 5 1 1 1 • r 4 A ,-, r.2 "T"'l1 ..-, 1 1 "1' "1''" 1 w here ... Q Co g grate has an actual c lear opening ot A=4:t tt~. The l<ecteral Highway Administration's Urban Drainage Design Manual (HEC-22) provides guidance for other grate types and configurations. inlet capacity of the grated inlet (ft3/s); orifice coefficient (C0 =0.67 for U.S. Traditional Units); gravitational acceleration (ft/s2); (2-18) (2-19) d = A e flow depth above inlet (ft); effective (clogged) grate area (ft2); CA A area c logging factor (CA=0.50); and actual opening area of the grate inlet (i.e., the total area less the area of bars or vanes). The actual opening area for a San Diego Regional Standard No. D-15 grate is A=4.7 ft2. The Federal Highway Administration's Urban Drainage Design Manual (HEC-22) provides guidance for other grate types and configurations. 12-in Grated Inlet in Sag (Assumed 50% Clogging) Cw 3 Unitless L 1 ft Pe 2.00 ft W 1 ft C0 0.67 Unitless Ae 0.5 *Pe assumes 50% clogging Weir Orifice Q (cfs) d (ft)Q (cfs) d (ft) 0.05 0.25 1.34 0.25 0.38 0.5 1.90 0.5 1.27 0.75 2.33 0.75 3 1 2.69 1 5.86 1.25 3.01 1.25 10.13 1.5 3.29 1.5 Step 1. Calculate the capacity of a grate inlet opet-ating as a w eir, using the w eir equation (Equation 2-16) w ith a length equiYalent to perimeter of the grate . When the g1·ate is located next to a curb ,. disrega rd the length of the grate against the curb. 0 = C Pd312 (2-16 1 ~ W e '/ w here ... Q = inlet capacity of the grated inlet (ft3/s); Cw weir coefficient (Cw=3.0 for U .S. T raditional U nits); effectiYe g1-ate perimeter length (ft); and Pe = d = flow depth approaching inlet (ft). To account for the effects of clogging of a grated inlet operating as a w e ir, a clogging factor of fifty percent (CL=0 .50) shaU be applied to the actual (undogged) perimeter of the grate (P ): Step 2. Calculate the capacity of a grate inlet operating as an orifice. Use the orifi ce equation (Equation 2-1 8), assuming the clear opening of the grate reduced by a clogging factor CA=0.50 (Equation 2-19). A San D iego Regional Standard No. D-15 ___ ..__ 1___ __.._ __ 1 _t ______________ ..£" ,1 A.,.., ..o...2 'T"1 __ T""_..J ____ t '1 T:_1_ _____ _ grate has an actual clear openmg ot A=4. I tr. l he red.eral Highway Administration's Urban Drainage D esign Manual (HEC-22) provides guidance for other grate types and configurations. where ... Q Co g d = A e CA = A inlet capacity of the grated inlet (ft3/s); orifice coefficient (C0 =0.67 for U.S. Traditional Units); gravitational acceleration (ft/s2); flow depth above inlet (ft); effective (clogged) grate area (ft2); area clogging factor (CA=0.50); and (2-18) (2-19) actual opening area of the grate inlet (i.e., the total area less the area of bars or vanes). The actual opening area for a San Diego Regional Standard No. D-15 grate is A=4.7 ft2• The Federal Highway Administration's Urban Drainage Design Manual (HEC-22) provides guidance for other grate types and configurations. Trench Grate-in Grated Inlet in Sag (Assumed 50% Clogging) Cw 3 Unitless L 0.5 ft Pe 19.50 ft W 19 ft C0 0.67 Unitless Ae 4.75 *Pe assumes 50% clogging Weir Orifice Q (cfs) d (ft)Q (cfs) d (ft) 0.46 0.25 12.77 0.25 3.66 0.5 18.06 0.5 12.34 0.75 22.12 0.75 29.25 1 25.54 1 57.13 1.25 28.55 1.25 98.72 1.5 31.28 1.5 Step 1. Calculate the capacity of a grate inlet opet-ating as a w eir, using the w eir equation (Equation 2-16) w ith a length equiYalent to perimeter of the grate . When the g1·ate is located next to a curb ,. disrega rd the length of the grate against the curb. 0 = C Pd312 (2-16 1 ~ W e '/ w here ... Q = inlet capacity of the grated inlet (ft3/s); Cw weir coefficient (Cw=3.0 for U .S. T raditional U nits); effectiYe g1-ate perimeter length (ft); and Pe = d = flow depth approaching inlet (ft). To account for the effects of clogging of a grated inlet operating as a w e ir, a clogging factor of fifty percent (CL=0 .50) shaU be applied to the actual (undogged) perimeter of the grate (P ): Step 2. Calculate the capacity of a grate inlet operating as an orifice. Use the orifi ce equation (Equation 2-1 8), assuming the clear opening of the grate reduced by a clogging factor CA=0.50 (Equation 2-19). A San D iego Regional Standard No. D-15 ___ ..__ 1___ __.._ __ 1 _t ______________ ..£" ,1 A.,.., ..o...2 'T"1 __ T""_..J ____ t '1 T:_1_ _____ _ grate has an actual clear openmg ot A=4. I tr. l he red.eral Highway Administration's Urban Drainage D esign Manual (HEC-22) provides guidance for other grate types and configurations. where ... Q Co g d = A e CA = A inlet capacity of the grated inlet (ft3/s); orifice coefficient (C0 =0.67 for U.S. Traditional Units); gravitational acceleration (ft/s2); flow depth above inlet (ft); effective (clogged) grate area (ft2); area clogging factor (CA=0.50); and (2-18) (2-19) actual opening area of the grate inlet (i.e., the total area less the area of bars or vanes). The actual opening area for a San Diego Regional Standard No. D-15 grate is A=4.7 ft2• The Federal Highway Administration's Urban Drainage Design Manual (HEC-22) provides guidance for other grate types and configurations. ONSITE STORM DRAIN SIZING – SUPPORT MATERIAL I I I I p 4 -----1 AREAl 0.074AC -\--\- -\--\- -\--\- -\--\- -\- -\- 4 " "' ~ . BMP 1 Q100 (UNMIT) = 2.52 CFS " p 4 --··- p I I I I I I I I I I -., ,ff \ ----- AREA 10 0.083AC " ' u,. ,□--□[ I __,.....,......,~_,j,.,._ ............. _· ----1 ---7 I AREA6 0.087 AC 4 4 p -====------- I ----=---~ -== - I AREA1----5 ~ : 0.024 AC I I I I I I 1----- rji~r -""'"~~" .. t I 1 I I I I I I I I 0 ' BMP2 Q100 (UNMIT) = 0.84 CFS ':" '~ '1: ·.• .... •:· . . . -~ •.. ,. .. -:-. ... : ~~ ·.,_ ~---~\~ '. ~ ;:-<' •. -i --- AREA 11 0.033AC I, r. CJ) 0 PLAN VIEW -STORM DRAIN CAPACITY SCALE: 1" = 10' J:IACT/\/E JOBSl3339 3745ADAMS STREETICML \REPORTS\HYDROLOGY\F/NAL ENGJNEER/NGIAPPEND/XJ3339-CV-APPENDIX C.DWG ' ,:,S CJ) 0 '"' " "' ' AREA2 0.10AC Os_ ------L ' AREA9 0.066AC - p ' ' ' ' AREA4 0.035AC , 4 p ___ _J as---as--as--as----- --r-:------=------.· as • A as as as ' 4 p d AREA3 0.14AC • r 1 l ,□ __ □j ' -p AREA 1 0.076AC as P' ef p ' 4 P' d 4 ' , 4 4 p 4 p 4 d 4 p ' ' ,1 I I; s II I i; I ' ,1 I '1 " I '1 . ' I • '1 ' '1 LEGEND PROPER7YBOUNDARY CEIVTERL/NE OF ROAD ADJACENT PROPER7Y LINE I RIGHT-OF-WAY -------- 64 EXISTING CONTOUR LINE PROPOSED CONTOUR LINE AREA CONTRIBUTING TO STORM DRAIN SUB AREA ----64---------- SUB-AREA 1 MAXIMUM RUN OFF FLOW RATE: MINIMUM PIPE SIZE AND SLOPE IN SUB-AREA SUB-AREA2 MAXIMUM RUN OFF FLOW RATE: MINIMUM PIPE SIZE AND SLOPE IN SUB-AREA SUB-AREA3 MAXIMUM RUN OFF FLOW RA TE: MINIMUM PIPE SIZE AND SLOPE IN SUB-AREA ' SUB-AREA4 MAXIMUM RUN OFF FLOW RATE: ADDITIONAL RUNOFF FROM SUB-AREA 3: , MAXIMUM PIPEFLOW THROUGH AREA 4: MINIMUM PIPE SIZE AND SLOPE IN SUB-AREA SUB-AREAS MAXIMUM RUN OFF FLOW RATE: MINIMUM PIPE SIZE AND SLOPE IN SUB-AREA SUB-AREA6 MAXIMUM RUN OFF FLOW RATE: MINIMUM PIPE SIZE AND SLOPE IN SUB-AREA SUB-AREA 7 MAXIMUM RUN OFF FLOW RATE: MINIMUM PIPE SIZE AND SLOPE IN SUB-AREA.· SUB-AREAB MAXIMUM RUN OFF FLOW RATE: MINIMUM PIPE SIZE AND SLOPE IN SUB-AREA SUB-AREA 9 MAXIMUM RUN OFF FLOW RATE: ADD/TONAL RUNOFF FROM SUB-AREA 1 & 2: TOTAL FLOW RATE THROUGH PIPES: MINIMUM PIPE SIZE AND SLOPE IN SUB-AREA SUB-AREA 10 MAXIMUM RUN OFF FLOW RATE: ADDITIONAL RUNOFF FROM SUB-AREA 5: TOTAL FLOW RATE THROUGH PIPES: MINIMUM PIPE SIZE AND SLOPE IN SUB-AREA SUB-AREA 11 MAXIMUM RUN OFF FLOW RATE: DRAINAGE DITCH DIAMETER AND SLOPE: Q=CIA =(0.56)(6.85)(0.076) =0.29CFS 6" AT 0.7% = 0.47 CFS' 0.47 > 0.29 OK Q=CIA =(0.56)(6.85)(0.10) =0.38CFS 6"AT 1.0% = 0.561 CFS' 0.56 > 0.38 OK Q=CJA =(0.56)(6.85)(0.14) =0.54 CFS 6"AT 1.0% = 0.561 CFS' 0.561 > 0.54 OK Q=CIA =(0.56)(6.85)(0.035) =0.13CFS 0.54 CFS =0.54 + 0.13 =0.67CFS 6" AT 2.0% = 0.79 CFS' 0.79 > 0.67 OK Q=CJA =(0.56)(6.85)(0.024) =0.09CFS 6"AT 1.0% = 0.561 CFS' 0.561 > 0.09 OK Q=CIA =(0.56)(6.85)(0.087) =0.33CFS 6"AT2.1% = 0.561 CFSH 0.561 > 0.33 OK Q=CIA =(0.56)(6.85)(0.074) =0.28 CFS 6"AT3.2% = 0.561 CFStt 0.561 > 0.28 OK Q=CIA =(0.56)(6.85)(0.096) =0.37CFS 6"AT 0.46% = 0.38 CFS' 0.38 > 0.37 OK Q=CIA =(0.56)(6.85)(0.066) =0.25CFS 0.67CFS =0.25 + 0.67 =0.92CFS 10"AT 1.0% = 2.17 CFS' 2.17>0.92OK Q=CIA =(0.56)(6.85)(0.083) =0.32CFS 0.09CFS =0.32+0.09 =0.41 CFS 10"AT 1.0% = 2.17 CFS' 2.17>0.41 OK Q=CJA =(0.56)(6.85)(0.033) =0.13CFS 2'AT2.0% = 0.56 CFS' 0.58 > 0.13 OK • BMP 1 MAXIMUM RUN OFF FLOW RATE: MINIMUM PIPE SIZE AND SLOPE IN SUB-AREA BMP2 MAXIMUM RUN OFF FLOW RATE: MINIMUM PIPE SIZE AND SLOPE IN SUB-AREA Q100 (UNM/1) = 2.52 CFS 10"AT 2.7% = 3.56 CFS' 3.56 > 2.52 OK Q100 (UNM/1) = 0.84 CFS 8" AT 1.0% = 1.22 CFS' 1.22 > 0.84 OK STORM DRAIN DATA TABLE PIPE SEGMENT PIPE DIAMETER LENGTH SLOPE MAX FLOWRA TE MIN. SD CAPAC/7¥ 1 6"PVC 36' 0.9% 0.29CFS 0.47CFS 2 6"PVC 71' 1.2% 0.29CFS 0.47CFS 3 6"PVC 15' 1.0% 0.29CFS 0.47CFS 4 6"PVC 46' 1.0% 0.29CFS 0.47CFS 5 6"PVC 22' 0.7% 0.29CFS 0.47CFS 6 10" PVC 72' 1.3% 0.67CFS 2.17CFS 7 10" PVC 7' 1.4% 1.33 CFS 2.17 CFS 8 6"PVC 44' 1.1% 0.54CFS 0.56CFS 9 6"PVC 21' 1.0% 0.54CFS 0.56CFS 10 6"PVC 16' 1.3% u . ..,...vrv 0.56CFS 11 6"PVC 44' 1.0% 0.54CFS /J_:m u-r.:::. 12 6"PVC 22' 1.1% 0.54CFS 0.56CFS 13 6"PVC 14' 1.1% 0.54CFS 0.56CFS 14 6"PVC 60' 1.3% 0.54CFS 0.56CFS 15 6"PVC 14' 2.1% 0.67CFS 0.79 CFS 16 6"PVC 12' 2.1% 0.67CFS 0.79 CFS 17 6"PVC 10' 2.0% 0.67CFS 0.79 CFS 1~ 6"PVC 21' 0.46% 0.37CFS 0.38CFS '" 6"PVC 16' 0.63% 0.37CFS 0.38CFS ,, b" 7' 0.7% 0.37CFS 0.38 CFS 21 6"PVC 21' 1.0% 0.37CFS 0.38CFS ,, 6"PVC 23' 2.0% 0.09CFS 0.56CFS 23 6"PVC 5' 1.0% 0.09CFS 0.56CFS 24 10" PVC 7' 1.4% 0.41 CFS 2.17CFS 25 6"PVC 10' 1.4% 0.38CFS 0.56CFS 26 6"PVC 14' 1.1% 0.38CFS 0.56CFS Z7 6"PVC 19' 2.1% 0.28CFS 0.56CFS 28 6"PVC 19' 3.2% 0.33CFS 0.56CFS 29 B"PVC 26' 1.5% 0.64CFS 1.22CFS 30 B"PVC 66' 1.4% 0.64CFS 1.22CFS 31 6"PVC 17' 2.7% 2.52CFS 3.56CFS 32 B"PVC 160' 'SEE APPENDIX FOR STORM DRAIN CAPACITIES "STORM DRAJN SLOPE ALLOWS FOR HIGHER CAPAC/7¥ THEN CAPAC/7¥ STATED AT 1 % EXHIBIT-STORM DRAIN CAPACITY PASCO LARET SUITER ~ #:l~~©llCl#:11[~ San Diego I Solana Beach I Orange County Phone 858.259.82121 www.plsaengineering.com PLSA 3339-01 Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Tuesday, Mar 29 2022 <Name> Circular Diameter (ft) = 0.50 Invert Elev (ft) = 100.00 Slope (%) = 0.46 N-Value = 0.013 Calculations Compute by: Known Depth Known Depth (ft) = 0.50 Highlighted Depth (ft) = 0.50 Q (cfs) = 0.380 Area (sqft)= 0.20 Velocity (ft/s)= 1.94 Wetted Perim (ft) = 1.57 Crit Depth, Yc (ft) = 0.32 Top Width (ft)= 0.00 EGL (ft)= 0.56 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.Tuesday, Mar 29 2022 <Name> 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® AutoCAD® Civil 3D® by Autodesk, Inc.Monday, Dec 20 2021 <Name> Circular Diameter (ft) = 0.50 Invert Elev (ft) = 100.00 Slope (%) = 1.00 N-Value = 0.013 Calculations Compute by: Known Depth Known Depth (ft) = 0.50 Highlighted Depth (ft) = 0.50 Q (cfs) = 0.561 Area (sqft)= 0.20 Velocity (ft/s)= 2.86 Wetted Perim (ft) = 1.57 Crit Depth, Yc (ft) = 0.39 Top Width (ft)= 0.00 EGL (ft)= 0.63 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.Monday, Apr 4 2022 <Name> Circular Diameter (ft) = 0.67 Invert Elev (ft) = 100.00 Slope (%) = 1.00 N-Value = 0.013 Calculations Compute by: Known Depth Known Depth (ft) = 0.67 Highlighted Depth (ft) = 0.67 Q (cfs) = 1.224 Area (sqft) = 0.35 Velocity (ft/s) = 3.47 Wetted Perim (ft) = 2.10 Crit Depth, Yc (ft) = 0.53 Top Width (ft) = 0.00 EGL (ft) = 0.86 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, Jan 19 2022 10-in PVC @ 1.0% Circular Diameter (ft) = 0.83 Invert Elev (ft) = 86.00 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 85.75 86.00 86.25 86.50 86.75 87.00 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Monday, Apr 4 2022 <Name> Circular Diameter (ft) = 0.83 Invert Elev (ft) = 100.00 Slope (%) = 2.70 N-Value = 0.013 Calculations Compute by: Known Depth Known Depth (ft) = 0.83 Highlighted Depth (ft) = 0.83 Q (cfs) = 3.560 Area (sqft) = 0.54 Velocity (ft/s) = 6.58 Wetted Perim (ft) = 2.61 Crit Depth, Yc (ft) = 0.79 Top Width (ft) = 0.00 EGL (ft) = 1.50 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.Tuesday, Apr 5 2022 Modified Drainage Ditch with .2' depth Circular Diameter (ft) = 2.00 Invert Elev (ft) = 100.00 Slope (%) = 2.00 N-Value = 0.015 Calculations Compute by: Known Depth Known Depth (ft) = 0.20 Highlighted Depth (ft) = 0.20 Q (cfs) = 0.584 Area (sqft)= 0.16 Velocity (ft/s)= 3.55 Wetted Perim (ft) = 1.29 Crit Depth, Yc (ft) = 0.27 Top Width (ft)= 1.20 EGL (ft)= 0.40 0 1 2 3 4 Elev (ft)Depth (ft)Section 99.50 -0.50 100.00 0.00 100.50 0.50 101.00 1.00 101.50 1.50 102.00 2.00 102.50 2.50 103.00 3.00 Reach (ft) ~ ......... / " / L ' \ ) ~ L '-..._ ,. / ......... -= =-~