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Home My WebLink AboutCDP 2021-0053; GILBERT RESIDENCE; PRELIMINARY DRAINAGE REPORT; 2021-09-27PRELIMINARY DRAINAGE REPORT GILBERT RESIDENCE 2351 PIO PICO DRIVE CITY OF CARLSBAD Prepared for: Karen Elise Gilbert 2351 Pio Pico Drive Carlsbad, CA 92008 Prepared by: bltA, Inc. land planning, civil engineering, surveying 5115 Avenida Encinas, Suite L Carlsbad, CA 92008-4387 (760) 931-8700 SEP 3 0 2021 c: \-( ~\,· I..~~-.~\-· ,:·.1/-\ 1-': L ,: pl_A,,Ji,11:->JC..; 01\/i:-,i'_:S · September 27, 2021 w.o. 1142-1513-600 Table of Contents Chapter 1 -Discussion .................................................................................................................. 3 1.1 Vicinity Map ............................................................................................................... 4 1.2 Purpose and Scope .................................................................................................... 5 1.3 Project Description .................................................................................................... 5 1.4 Existing Conditions .................................................................................................... 5 1.5 Developed Conditions ............................................................................................... 6 1.6 Study Method ............................................................................................................. 6 1.7 Conclusions ................................................................................................................ 8 1.8 Declaration of Responsible Charge ......................................................................... 9 Chapter 2 -Existing & Developed Hydrolog)7 Maps ................................................................ 10 Chapter 3 -100-Year Peak Flow Calculations .......................................................................... 11 3.1 Existing Hydrology Calculations ............................................................................ 12 3.2 Developed Hydrology Calculations ....................................................................... 14 Chapter 4 -References ................................................................................................................ 16 4.1 Methodology -Rational Method Peak Flow Determination .............................. 17 Gilbert Residence Preliminary Drainage Report bkA, Inc. 2 L Gilbert Residence Preliminary Drainage Report Chapter 1 Discussion bltA, Inc. L 1.1 Vicinity Map Gilbert Residence Preliminary Drainage Report PIO PICO DR. VICINITY MAP NOT TO SCALE bltA, Inc. 4 L 1.2 Purpose and Scope The purpose of this report is to publish the results of hydrology and hydraulic computer analysis for the proposed "Gilbert Residence" project site in the City of Carlsbad. The scope of this study is to analyze the results of existing and developed condition hydrology calculations and provide recommendations as to the design and size of various hydraulic systems considered as mitigation of any potential adverse effects of the proposed project. The mitigation measures proposed will include minimizing impervious areas and dispersing runoff towards areas such as landscaping. The 100-year storm frequency will be analyzed. 1.3 Project Description The Gilbert Residence Project is a single-family residential redevelopment with associated improvements. The project is located in the City of Carlsbad (APN 156-351-04), San Diego County, California. The project site is a 0.40-acres developed lot and is located east of Interstate 5, south of Pio Pico Drive, and north of Esmat Way. Site location is shown on a Vicinity Map on page 4 of this report. The site consists of a relatively flat-lying, rectangular lot. The property is bounded by Pio Pico Drive to the north, existing residential existing residential property to the west, and newly constructed residential structures on the remaining sides. Access to property is via an existing private driveway from Pio Pico Drive to the property located on the south side of the private driveway. Existing improvements to the property consist of a single-story residence with a detached garage, pool in the rear, a small attached deck directly behind the existing residence, and concrete flatwork covering most of the rear yard. The existing buildings will demolished and the site will be prepared for the construction of a two-story single-family residential structure with an attached garage. The existing concrete flatwork and pool in the rear yard will remain. The Gilbert Residence project is a redevelopment. The project proposes to replace and minimize existing impervious areas on an existing developed lot. 1.4 Existing Conditions Topographically, the site elevations are 90 feet near the northwest corner to 93.5 near the southwest corner. Existing drainage is generally directed offsite to the west. Vegetation onsite consists of scattered trees, and other typical residential landscaping. The onsite soil classification is Type-B as determined from USDA Web Soil Survey (see References). Storm flows affecting the site are limited to the rainfall that lands directly on the property and approximately 56% of the site is impervious. In the existing condition, one (1) Point of Compliance (POC) has been identified. The Gilbert Residence Preliminary Drainage Report bltA, Inc. 5 L project site surface drains west towards POC-1, located on the west side of the property. From POC-1, the flow drains to Jefferson Street and eventually to the Buena Vista Lagoon. Table 1 summarizes the existing runoff information from the site. Refer to the Existing Hydrology Map for drainage patterns, areas, and POC. T bl 1 E . t' C d'f P k Fl a e -XIS mg on I 10n ea ows DISCHARGE DRAINAGE AREA 100-YEAR PEAK FLOW LOCATION IAC) {CFS\ POC-1 0.40 1.71 1.5 Developed Conditions The project proposes the construction of a two-story single-family residential structure with an attached garage. The existing concrete flatwork and pool in the rear yard will remain. The project is a redevelopment. The project proposes to replace and minimize existing impervious areas on an existing developed lot. Post-development the site will be approximately 52% impervious. Impervious surfaces and proposed grading have been minimized where feasible. Proposed drainage patterns will not alter the existing flow pattern and will discharge from the site to the historic discharge locations. Table 2 summarizes the developed condition runoff from the site. Refer to the Developed Hydrology Exhibit for drainage patterns, areas, and POCs. a e -eve ope on 1 10n ea T bl 2 D l d C d'f P k Fl ows DISCHARGE DRAINAGE AREA 100-YEAR PEAK FLOW LOCATION IAC\ (CFS\ POC-1 0.40 1.62 1.6 Study Method The method of analysis was based on the Rational Method according to the 2003 San Diego County Hydrology Manual (SDCHM). The Hydrology and Hydraulic Analysis were done on HydroSoft by Advanced Engineering Software 2014. The study considers the runoff for a 100-year storm frequency. Methodology used for the computation of design rainfall events, runoff coefficients, and rainfall intensity values are consistent with criteria set forth in the SDCHM. A more detailed explanation of methodology used for this analysis is listed in Chapter 4-References of this report. Gilbert Residence Preliminary Drainage Report bltA, Inc. 6 L Drainage basin areas were determined from the topography shown on the Existing and Developed Hydrology maps. The Rational Method for this project provided the following variable coefficients: Rainfall Intensity -Initial time of concentration (Tc) value of 5 minutes is based on Figure 3-3 of the SDCHM and the Federal Aviation Administration's time of concentration equation. Rainfall lsopluvial Maps from the SDCHM were used to determine P6 for 100- year storm, see References. P6 for 100-year storm =2.70 inches Runoff Coefficient -In accordance with the County of San Diego standards, runoff coefficients were based on land use and soil type. The site was modeled with Type-B soils, as determined from NRCS Web Soil Survey. Type-B soils have moderate infiltration rates when thoroughly wetted. An appropriate runoff coefficient (C) for each type of land use in the subarea was selected from Table 3-1 of SDCHM and multiplied by the percentage of total area (A) included in that class. The sum of the products for all land uses is the weighted runoff coefficient (l[CA]). For the existing and developed conditions, a runoff coefficient of 0.25 was selected for all landscape and pervious areas (0% impervious) and 0.87 for all concrete and roof areas (95% impervious). The Developed Hydrology Exhibit shows the on-site drainage areas, and nodal points. Table 4 summarizes the composite C-values calculated in the existing and developed conditions. Table 4 -Composite Runoff Coefficient Existing Hvdrology UP DOWN TOTAL AREA C1 A1 C2 A2 CcoMP NODE NODE (AC) (AC) (AC) 10 20 0.400 0.25 0.176 0.87 0.224 0.60 Notes: C-values taken from Table 3-1 of San Diego County Hydrology Manual, consistent with on-site existing soil types from the USDA Web Soil Survey. See References. Gilbert Residence Preliminary Drainage Report bkA, Inc. 7 L Proposed Hydrology UP DOWN TOTAL AREA C1 A1 C2 A2 CcoMP NODE NODE (AC) lAC\ (AC) 10 20 0.400 0.25 0.192 0.87 0.208 0.57 Notes: C-values taken from Table 3-1 of San Diego County Hydrology Manual, consistent with on-site existing soil types from the USDA Web Soil Survey. See References. See the comparison of existing condition hydrology and developed condition hydrology in Table 5 below. a e -T bl 5 S ummaryo fP kFl ea ows DRAINAGE AREA 100-YEAR PEAK FLOW (AC) (CFS) EXISTING CONDITION 0.40 1.71 DEVELOPED CONDITION 0.40 1.62 DIFFERENCE 0.00 -0.09 1. 7 Conclusion The proposed "Gilbert Residence" project will result in a net decrease of peak flow discharged from the project site by 0.09 cfs during a 100-year storm event. In addition, landscaping areas and impervious areas dispersion will slow runoff discharges, further decreasing runoff when compared to existing runoff. These small collection techniques foster opportunities to maintain the existing hydrology and provide a much greater range of retention practices. The Gilbert Residence Project satisfies the drainage requirements of the City of Carlsbad. Furthermore, the project will result in decreasing the 100-year storm peak discharge from 1.71 cfs to 1.62 cfs. Based on this conclusion, runoff released from the proposed project site will unlikely cause any adverse impact to downstream water bodies or existing habitat integrity. Sediment will likely be reduced upon site development. Gilbert Residence Preliminary Drainage Report bl-tA, Inc. 8 L 1.8 Declaration of Responsible Charge I hereby declare that I am the Engineer of Work for this project, that I have exercised responsible charge over the design of the project as defined in Section 6703 of the business and professions code, and that the design is consistent with current standards. I understand that the check of project drawings and specifications by the City of Carlsbad is confined to a review only and does not relieve me, as Engineer of Work, of my responsibilities for project design. Bruce L. Rice R.C.E. 60676 Gilbert Residence Preliminary Drainage Report 9-27-21 Date bltA, Inc. 9 L Chapter 2 Existing & Developed Hydrology Maps Gilbert Residence Preliminary Drainage Report bltA, Inc. L b 1n l! b Gilbert Residence Preliminary Drainage Report Chapter 3 100-Y ear Peak Flow Calculations bltA, Inc. 11 L 3.1 Existing Hydrology Calculations 100-YEAR STORM ************************************************************************************** RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 2003,1985,1981 HYDROLOGY MANUAL (c) Copyright 1982-2014 Advanced Engineering Software (aes) Ver. 21.0 Release Date: 06/01/2014 License ID 1459 Analysis prepared by: BHA Inc 5115 Avenida Encinas, Suite L Carlsbad, CA 92008 ************************** DESCRIPTION OF STUDY************************** * EXISTING 100-YEAR STORM HYDROLOGY * * GILBERT RESIDENCE * * 2351 PIO PICO DRIVE, CARLSBAD CA (JN 1142-1513-600) ************************************************************************** FILE NAME: K:\HYDRO\1513\1513E100.DAT TIME/DATE OF STUDY: 10:23 09/24/2021 USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: 2003 SAN DIEGO MANUAL CRITERIA USER SPECIFIED STORM EVENT(YEAR) = 100.00 6-HOUR DURATION PRECIPITATION (INCHES) = 2.700 SPECIFIED MINIMUM PIPE SIZE(INCH) = 3.00 SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE= 0.95 SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREET FLOW MODEL* * HALF-CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING WIDTH CROSS FALL IN-I OUT-/PARK-HEIGHT WIDTH LIP NO. (FT) (FT) SIDE I SIDE/ WAY (FT) (FT) (FT) ========= ========-=====-== ====== ====== 1 30.0 20.0 0.018/0.018/0.020 0. 67 2.00 0.0313 GLOBAL STREET FLOW-DEPTH CONSTRAINTS: 1. Relative Flow-Depth= 0.00 FEET as (Maximum Allowable Street Flow Depth) -(Top-of-Curb) 2. (Depth)*(Velocity) Constraint= 6.0 (FT*FT/S) *SIZE PIPE WITH A FLOW CAPACITY GREATER THAN OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.* HIKE FACTOR (FT) (n) ======= 0.167 0.0150 **************************************************************************** FLOW PROCESS FROM NODE 10.00 TO NODE 20.00 IS CODE= 22 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< *USER SPECIFIED(SUBAREA): USER-SPECIFIED RUNOFF COEFFICIENT= .6000 S.C.S. CURVE NUMBER (AMC II) 0 USER SPECIFIED Tc(MIN.) = 5.000 The Pointe at Lanai -Lanai Court Preliminary Drainage Report blu, Inc. 12 L 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.114 SUBAREA RUNOFF(CFS) 1.71 TOTAL AREA(ACRES) = 0.40 TOTAL RUNOFF(CFS) 1. 71 +--------------------------------------------------------------------------+ POC-1 +--------------------------------------------------------------------------+ END OF STUDY SUMMARY: TOTAL AREA(ACRES) PEAK FLOW RATE(CFS) 0. 4 TC (MIN. ) = 1. 71 END OF RATIONAL METHOD ANALYSIS Gilbert Residence Preliminary Drainage Report 5.00 blu, Inc. L 3.2 Developed Hydrology Calculations 100-YEAR STORM ************************************************************************************** RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 2003,1985,1981 HYDROLOGY MANUAL (c) Copyright 1982-2014 Advanced Engineering Software (aes) Ver. 21.0 Release Date: 06/01/2014 License ID 1459 Analysis prepared by: BHA Inc 5115 Avenida Encinas, Suite L Carlsbad, CA 92008 ************************** DESCRIPTION OF STUDY************************** * DEVELOPED 100-YEAR STORM HYDROLOGY * * GILBERT RESIDENCE * * 2351 PIO PICO DRIVE, CARLSBAD CA (JN 1142-1513-600) ************************************************************************** FILE NAME: K:\HYDR0\1513\1513Pl00.DAT TIME/DATE OF STUDY: 10:53 09/24/2021 USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: 2003 SAN DIEGO MANUAL CRITERIA USER SPECIFIED STORM EVENT(YEAR) = 100.00 6-HOUR DURATION PRECIPITATION (INCHES) = 2.700 SPECIFIED MINIMUM PIPE SIZE(INCH) = 3.00 SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE= 0.95 SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREET FLOW MODEL* * HALF-CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING WIDTH CROSS FALL IN-I OUT-/PARK-HEIGHT WIDTH LIP NO. (FT) (FT) SIDE I SIDE/ WAY (FT) (FT) (FT) ---------======----------= ====== ====== 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0. 0313 GLOBAL STREET FLOW-DEPTH CONSTRAINTS: 1. Relative Flow-Depth= 0.00 FEET as (Maximum Allowable Street Flow Depth) -(Top-of-Curb) 2. (Depth)*(Velocity) Constraint= 6.0 (FT*FT/S) *SIZE PIPE WITH A FLOW CAPACITY GREATER THAN OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.* HIKE FACTOR (FT) (n) ======= 0.167 0.0150 **************************************************************************** FLOW PROCESS FROM NODE 10.00 TO NODE 20.00 IS CODE= 22 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< *USER SPECIFIED(SUBAREA): USER-SPECIFIED RUNOFF COEFFICIENT= .5700 S.C.S. CURVE NUMBER (AMC II) 0 USER SPECIFIED Tc(MIN.) = 5.000 Gilbert Residence Preliminary Drainage Report blu, Inc. L 100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 7.114 SUBAREA RUNOFF(CFS) 1.62 TOTAL AREA(ACRES) = 0.40 TOTAL RUNOFF(CFS) 1. 62 +--------------------------------------------------------------------------+ POC-1 +--------------------------------------------------------------------------+ END OF STUDY SUMMARY: TOTAL AREA(ACRES) PEAK FLOW RATE(CFS) 0 . 4 TC (MIN. ) = 1. 62 END OF RATIONAL METHOD ANALYSIS Gilbert Residence Preliminary Drainage Report 5.00 bltA, Inc. 13 L The Pointe at Lanai -Lanai Court Preliminary Drainage Report Chapter 4 References bltA, Inc. L 4.1 Methodology -Rational Method Peak Flow Determination The Pointe at Lanai -Lanai Court Preliminary Drainage Report bltA, Inc. 17 L 9/23121, 4:30 PM (i) Precipitation Frequency Data Server NOAA Atlas 14, Volume 6, Version 2 Location name: Carlsbad, California, USA* Latitude: 33.173°, Longitude: -117.3459° Elevation: 94.5 ft** • source: ESRI Maps •• source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES San)a Perica, Sarah Dietz, Sarah Heim, LIiiian Hiner, Kazungu Mattarla, Deborah Martin, Sandra Pavlovic, lshani Roy, Cart Trypaluk, Dale Unruh, Fenglin Yan, Michael Yekta, Tan Zhao, Geoffrey Bonnin, Daniel Brewer, Li-Chuan Chen, Tye Parzybok, John Yarchoan NOAA, National Weather Service, Silver Spring, Maryland PF tabular I PF grai::2hical I M.ai::2s & aerials PF tabular I PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 !ourationll Average recurrence interval (years) 1 II 2 II 5 II 10 II 25 II 50 II 100 II 200 II 500 II 1000 I 5-min j 0.139 0.177 0.229 0.275 0.341 0.396 II 0.456 0.522 0.618 0.700 (0.117-0.167) (0.148-0.212) (0.192-0.276) (0.228-0.334) (0.273-0.430) (0.311-0.511) (0.348-0.603) (0.387-0.712) (0.438-0.881) (0.478-1.03) j 10-min I 0.199 0.253 0.328 0.394 0.489 0.568 0.654 0.748 0.886 1.00 (0.168-0.239) (0.213-0.304' (0.275-0.396) (0.327-0.479) (0.392-0.616) '0.445-0. 732) (0.499-0.865) (0.554-1.02) (0.628-1.26) (0.685-1.48) I15-min I 0.241 0.306 0.397 0.476 0.591 0.687 0.790 0.904 1.07 1.21 (0.203-0.290 0.257-0.368) (0.333-0.478 10.395-0.579 0.474-0.745 '0.538-0.886' (0.603-1.05) (0.670-1.23) (0.759-1.53) '0.828-1.79 I30-min I 0.342 0.433 0.562 0.674 0.837 0.973 1.12 1.28 1.52 1.72 (0.288-0.410) (0.364-0.521) (0.471-0.677 (0.560-0.820) (0.671-1.06) {0.762-1.25) (0.854-1.48) (0.949-1. 75) (1.08-2.16) (1.17-2.54) ! so-min J 0.457 0.579 0.751 0.901 1.12 1.30 1.50 1.71 2.03 2.30 (0. 384-0. 548 0.487-0.696 (0.630-0.906 (0.749-1.10) (0.897-1.41) (1.02-1.68) (1.14-1.98) (1.27-2.34) (1.44-2.89) (1.57-3.40) I I B 0.616 0.766 0.975 1.16 I p.1~~ 2 79) 11 p.19~:11i 11 p.:3~2 8 48) II 11.:a-~\1i I 2.52 I 11.:.&\9) I (0.518-0.739 0.644-0.920 (0.818-1.18) (0.961-1.41) (1.78-3.59) B 0.722 0.895 1.14 1.34 1.64 1.89 2.15 2.43 2.85 3.20 (0.607-0.866) (0. 752-1. 08) {0.951-1.37) (1.12-1.63) I (1.31-2.07) ( 1.48-2.43) (1.64-2.84) (1.80-3.32) (2.02-4.06) (2.18-4. 73) B 0.925 1.15 1.46 1.72 I (1 .:8~2 9 64) I 2.39 2.70 3.04 3.51 3.90 (0.779-1.11) (0. 968-1. 39) (1.23-1.76) (1.43-2.10) (1.87-3.08) (2.06-3.58) (2.25-4.14) (2.49-5.01) (2.66-5.77) ~ 1.15 I 11.~~~ni II (1.:8~2~28) II 11.:a~}12i II 12}/}41) I 3.07 3.45 I (2.;t5\3l II (3. ;;;23) I 4.79 (0. 969-1. 38) (2.41-3.96) (2.63-4.56) (3.27-7.08) 8 1.39 1.83 2.39 2.84 3.44 3.90 4.36 4.83 5.46 5.95 (1.23-1.61) (1.61-2.12) (2.10-2. 78) (2.48-3.32) (2.91-4.16) (3.23-4.80) (3.53-5.50) (3.81-6.25) (4.14-7.35) (4.37-8.27) I 2-day J 1.70 2.24 2.94 3.51 4.27 4.85 5.43 6.02 6.82 7.43 (1.50-1.96) (1.98-2.60) (2.59-3.42) (3. 06-4.11) (3.61-5.15) (4.02-5.97) (4.39-6.84) (4.75-7.79) (5.17-9.17) (5.45-10.3) I J-day JI (1.6~~;19) ll (2_;1~2~90) II (2.;0~3~83) J 3.94 4.81 I (4.:4~\5) II (4.:91\6) II (5.:ci."8\6) II (5.:~~-5) I 8.51 (3.44-4.61) (4.07-5.81) (6.24-11.8) GJ 2.05 2.72 3.59 4.31 5.27 6.02 6.77 7.55 8.61 9.43 (1.81-2.38) (2.40-3.15) (3.16-4.17) (3.76-5.04) (4.46-6.36) (4.99-7.41) (5.49-8.53) (5.96-9.77) {6.53-11.6) (6.92-13.1) I 7-day J 2.38 3.17 4.21 5.07 6.24 7.16 8.09 9.06 10.4 11.4 (2.10-2.75) (2.79-3.67) (3.70-4.89) (4.42-5. 93) (5.28-7.54) (5.93-8.81) (6.55-10.2) (7.15-11.7) (7.88-14.0) (8.39-15.9) I10-day I 2.63 3.53 4.71 5.69 I 7.04 I 8.10 9.19 10.3 11.9 13.1 (2.32-3.05) (3.11-4.08) {4.14-5.47) (4.96-6.66) : (5.95-8.50) : (6.71-9.97) (7.44-11.6) (8.14-13.4) {9.02-16.0) (9.63-18.2) I 20-day II (2.;;3~74) II (3.!.35~05) I 5.88 I 7.16 II 8.96 I 10.4 I 11.9 II 13.4 II 15.6 I 17.4 {5.17-6.83) (6.25-8.38) :: (7.57-10.8) : (8.60-12.8) : (9.61-14.9) :: (10.6-17.4) :: (11.9-21.0) : (12.8-24.2) I JO-day II (3.;s!\oi I 5.15 6.99 8.54 10.7 12.5 14.4 16.4 19.2 21.4 (4.54-5.96) (6.14-8.11) (7.45-9.99) (9.08-13.0) (10.4-15.4) (11.6-18.1) (12.9-21.2) (14.5-25.8) (15.7-29.8) I45-day j 4.51 6.09 8.28 10.1 12.8 15.0 17.3 19.8 23.4 26.3 (3.98-5.22) (5.37-7.05) (7.28-9.61) (8.85-11.9) (10.8-15.5) (12.4-18.5) (14.0-21.8) (15.6-25.6) {17.7-31.5) (19.3-36.6) I 60-day II (4.;:6\3) I 1.00 I 9.49 II 11.6 II 14.8 II 17.3 II 20.1 I 23.1 I 12/:3!.02 I 31.0 (6.17-8.10) : (8.34-11.0) :: (10.2-13.6) :: (12.5-17.8) :: (14.4-21.3) :: (16.3-25.3) : (18.2-29.8) (22.7-43.0) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to TOR PF graphical https://hdsc.nws. noaa.gov/hdsc/pfds/pfds_printpage. html?lat=33.1730&1on=-117 .3459&data=depth&units=english&series=pds I 1/4 9/23/21, 4:30 PM 35 30 ~ 25 £ 0. QI 20 "'O C 0 ·.c 15 .L1! :§. u e! II.. 10 5 0 C ·e Ji 35 30 £ 25 £ 0. ~ 20 C 0 ·.c ~ 15 0. ·u ~ 10 5 Precipitation Frequency Data Server PDS-based depth-duration-frequency (DDF) curves Latitude: 33.1730°, Longitude: -117.3459° . . . ' . ' ' . ' . ' ' . . ' . 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' ' ' . ...... -:-.......... -: -....... ! ........... :-....... -:-..... . 0 I I ' t 2 5 10 25 so 100 200 500 1000 Average recurre_nce interval (years) NOAA Atlas 14, Volume 6, Version 2 Created (GMT): Thu Sep 23 23:30:32 2021 Back to Top Maps & aerials Small scale terrain Average recurrence mteM I (years) -1 2 5 10 25 50 100 -200 600 1000 Duration 5-mln -2-day 1o-mtn -3-day 15-mln 4-day -Jo-min 7-day -6o-mln 1G-day -2-tir -2G-day -3-tlr -3G-day -6-tlr -45-day -12-tir -6G-day -24--hr https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage. html?lat=33.1730&Ion=-117 .3459&data=depth&units=english&series=pds 214 9/23/21 , 4:30 PM 3km I I 2ml Precipitation Frequency Data Server OE J,l!JNTAIRPO.R ~ f ,-, o~ans~~ Lar e scale terrain 60ml 100km •' 60ml • -a,villt , • ~.1,to ' :p f , .., CllfyO lnclo -P°am irt-V'-. eta ~ .~ ide ~ ~ fnsenada 0 Large scale aerial https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage. html?lat=33.1730&Ion=-117 .3459&data=depth&units=english&series=pds 3/4 9/23/21 , 4:30 PM Precipitation Frequency Data Server Back to Toi:2 ~partment of Commerce National Oceanic and Atmospheric Administration National Weather Service National Water Center 1325 East West Highway Silver Spring, MD 20910 Questions?: HDSC.Questions@noaa.gQJ! Disclaimer https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=33. 1730&1on=-117 .3459&data=depth&units=english&series=pds 4/4 !ii ~ en ~ f : SI ! ~ ! VIOll~g I . 33'30' ,..._ . •. . (' .. ::!-~:• .......... -,---t--------t---------+--------t---------+----33'30' C 'f,£;1;:::::'-O .... ~ .{ ,:•<.>···,...{ Riverside County cr······• ... ::::::::~~~~~>\J<>::-::;;~\ • , ..................... • ••• ·•.. ... \ \ ••• ··.j . ,<:·,.,. ;:/ ' \\ n,\ \ k ····<~l\· ..... ,•··-··-i •,, ·. · .... ) ··--.... ::_i~::::.) ·--· '\ ···-~-----·········· ·?.5-· I ........ : .,f·\ 33'1 • ., ,..__..., ••.• Project. '22" N• . ' ' Lat. 33 1 ~ ., W '--·p ; i ~---............. . 117"20 SO V i .1·, :,--../ • : l, . ·. '-'-i Long. , O ~ '1,-'--t~ · ; i'. \\j.._ l ...-·, 33w I : --., ,· ·n~ -:~~:':'. ;~~-(:'.~3)~~\\ 33"00' 0 c> '). . 3 'O ,f.f"' !!1 a, ~ -:> 32°45' I ~-\I•---~ ... ---1; ' ·.-~ '1 ----: ~I - ... -····~-~ ·----· 0 g ,.,I);?. _ .. -J . '< 32°45' 32°30' en ~ 32'30' !ii ~ ., f t ~ ~ ~ ! County of San Diego Hydrology Manual • Rainfall lsopluvials 100 Year lulaf1II Ennt -6 Hours ~,-, I P6=2.70" I DPW ~GJ.§ S"liGIS "'cli«.;'-ml~~ --- N ;_-,:.:==:.,~=:"-':.~=:..<:- * .,,.__ .. _, _______ _ c_,,.,.-...111 ........ ________ ........... I\: E =--=---=-·---------------------s 3 0 3Mlln ~ ~ "' i ~ "' ' t ~ ! 33' 33'30' ~O~r!!a!).n~e~~,.,,:.··"?--,"jJ•':· :::----f-------t---~~---:-_;_ ______ l _______ r~~~ c:;:;: :::iZ!fa'< ~t: .. <:\ ;;:;i~:~~::;.~r~~:~J~/~i\~,f f:;;y-:(1 1'. I . ..s:tt·· :fS:/1 / \ ;. . . .... ·-... . ... ..., :.. '<l0:-,:·-.. : : i . . it. : ..... ·· ... \,; ., \ : ............ _... , . ,.J .• >> .. :./ , . ,-T--C::·' . \ \ '· " " -· . . . \Y. '·'L·-,i \! • , ______ .,, ... ·:·::::·.::.,."" 33'15' I "t,_.,.~ Project Location Lat. 33°10'22" N ILong. 117°20'50" W .... Cl ,... -33°00' I ,... ~---..... I 1/· 1: '\!f-~ . 1·· Cl ... -. . ••••• ., .•. •· • -.' • 0 Cl GI (I} -::, 32'•5' I ~\P,W~P:::~,,d L.·...,.···,,_ ••• ~·--_···· d ·~. , •••. _ ~~_;1-_, •• u,· Me >< k ?:~~;~+::::~:,::,::::::-.... ...... . -~~ "O !!! §I ('") 0 C: ::, ~~-'< .······· ....... . ·\. 32"30' "' 32'30' ~ "' ~ "' !ii ~ € ~ ~ County of San Diego Hydrology Manual • Rainfall Jsop/11vialr 100 Year lulafall Event -24 Hours [···· ltcpwlal(lnchn) I P24=4.36" I DPW •GIS S1iGIS -=-~-=-°«c tu • .:.!ion l)l,q,J(..,.,m:J! N __ .. ,_,..,.._,.,.___,...,,~.,.oe.r-,..,.,... ~. -~~WfllOf\.#TUIION--•&........,1".S c>~n .. .--,._.."OII•~~ c......,. ........... ..__ _____ ...., .. ..-,,o_,.... E :=".,-::::.:;-•-----..., ________ _ -------s 3 0 3MIIH ~ 10.0 9.0 8.0 7.0 ' ,, 6.01 I', ,... '' ... " ' , ... ' .,.. "' I'..._ ... :-,. ':-,. ... ,... ... 5.0 , l'r-,. "" I" ... "4.01 I ,,... " ""' I" ,... " ~ ... ' "'" :-, rr ~ :-,."' ~r ' ~ ~ "' r~ "":--... ""' r r "r 3.0j " 'r,. I' ~r ) ..... "" ... 2.01 I I l1.1 ~O.! '!0.1 io: 0.1 O~i o., o.: ) I I r ' ; I I 0.21 ! "i", ' ""' ... "I', I',' I 0. • ' ' ' 5 6 78910 """ rr rr . ... ~ r I"":-,, "', ~~ r 1, 20 30 Minutes J •0 50 1 Ounlbon EQUATION I = 7.44 P5 o-0.64S I ,. Intensity (in/hr) P5 • 6-Hour Precipitation {in) 0 = Duration {min) ,, ... ""' , ... " ... "'"'~ ... ... I• ~ ~ "' ,"" ~ ~ ... ... I•~~~~ ""' ":--~"' ~r ~ ~~ ... ~ ... "' " r I" ... ~ I"~ ~ ~~ "" ,.,. r-,. I', , .... II 2 3 4 Hours I s 6 ... i l 6.0 'SZ. 5.5 i 5.0 g- 4_5-::, ~:~! 3.0 2.5 2.0 1.5 1.0 Intensity-Duration DNlgn Chart· Template Dlrectlona for Applk:atlon: (1) From precipitation maps detennne 6 hr and 24 hr amounts for the selected frequency. These maps are included in the County Hydrology Maroa! (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 IY precipitation {not applicaple to Desert). (3) Plot 6 hr precipitation on the right side of the chart. (4) Draw a line through the point paralel to the plotted lines. (5) This line is the intensity-G.iration curve for the location being analyzed. Appllcatlonfonn: {a) Selected frequency 100 year p {b) P6 .. 2, 70 in., P24 = 4.36 .~ = .....§L %<2> 24 (c) Adjusted p6t2l = __ In. {d) 'x = __ min. (e) I "' __ in.Jhr. Note: This chart replaces the lntensity-Ouratlon-Frequency curves used since 1965. ,~I-: t~ ~=:];s :-?;5 =~---.~-=:=r :::.5j5-= ■- 5 2. 13.95.5.27 6,5"1>17 . 11 .541 11.1161 13.17114.◄111 15.81 1 ·2~12 11aiu◄ 5.30i1.36·1.◄2 1 &481 e.s-t ·10.eoi1ua 12.12 10 ·u,··2.53'J.~i.21 iS:-osi5.90 ·1.1◄ 1.sa·-a.◄2 "9.z, 10.11 15 ·1.30 ·1.95_2.59_3.243.1114.$4-5. 19-5.84-5.49-7.13 • 7.78 211 _1.oa f1.112:2.1s_2~611""f3.23"T3.?7 _◄.311 ,.as=5.391s.93~ 1.46_ 0.93 ,uo 1.17 2.3312.10 327 3.73 . ◄.20 4.57 5.13 5.60 _0.13_j':24, 1.66i~!2A'.2.90' 3.32-3.73 ,-4.15 ~ ◄.56 4.911 .o.e&_[L03_1.38.!.b!:2•2.07!2.◄1,2;,~ ... 3.10 _3.◄5 3.711 ◄.13 0.60 10.9011.19 1 1.C9 I 1.7912.09 2.39 I 2.S, 2.911 3.21 3.58 ·0.53· o.eo··1.01·1.3311.s9·1.as 2.-121 2.39 . 2.as 2.92 · 3.18 ,_-= ·o.4q 0.11(0.a2[1.02:1.23, 1.43~1.s:, ... 1..,.1,(j 2.0t~.2S., 2.~1 1 0.3◄ 10.5110.6510.8511.02 1.19, l.36 11.53j 1.70 .1.17 ! 2.0t I -'. 0.29 io:-...~o.se10.n l o,ea[103J_1a ___ 1.32_~47 'u2 i 1.16 i 1 0.26 0.3910.52 0.65 0.78 0.91 · 1.0. · 1.11 . 1.31 1.44 1.57. -· ~o~~-~o.◄310:5410:asf o 11C-0:11 o.911_, 1.01_ ..!_111-"5.30; 0.19 _o,2&!0.38J.O..c!~.O~!o.e&l_o.1s_ o.as.:_0.M_1..oo _1.13 0.17 0.25 0.33 O.~_O.SO 0.51 0.67 OJS_0.8◄ 0.02 1 00 ~ Iii w LL ~ w (.) ~ en 0 w en a:: => ~ i EXAMPLE: Given: Watercourse Distance (D) = 70 Feet Slope (s) = 1.3% Runoff Coefficient (C) = 0.41 Overland Flow Time (T) = 9.5 Minutes SOURCE: Airport Drainage, Federal Aviation Administration, 1965 T= 1.8(1.1-C)VD 3Vs FIGU R E Rational Formula -Overland Time of Flow Nomograph 3.3 33" 10 23' N 33" 10'21'N Hydrologic Soil Group-San Diego County Area, California N Map Scale: 1:307f prirted on A pc,tral (8.5" X 11") sheet. ----====--------========Meters 0 4 9 ffl V A ---====------=====feet 0 W D ~ ~ Map p-ojeclion: We:J Mercator Canero:x:irmates: v.GS84 Edge tics: lJTM Zone llN v.GS84 Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 33" 1023'N 9/23/2021 Page 1 of 4 33" 10 21' N Hydrologic Soil Group-San Diego County Area, California MAP LEGEND MAP INFORMATION Area of Interest (AOI) D Area of Interest (AOI) Solis Soll Rating Polygons D A D ND D B □ B/0 D C D C/0 D D D Not rated or not available Soll Rating Lines .,..,,-A .,..,,_ ND .,..,,_ B .,..,,_ B/0 C .,..,,_ C/0 .,..,,_ D ,. ,, Not rated or not available Soll Rating Points ■ A ■ AID ■ B ■ B/0 USDA Natural Resources al■ Conservation Service D C ■ C/O ■ D □ Not rated or not available Water Features ,..._, Streams and Canals Transportation +++ _..,, _,,.,. --~ Rails Interstate Highways US Routes Major Roads Local Roads Background • Aerial Photography Web Soil Survey National Cooperative Soil Survey The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: 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 15, May 27, 2020 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. 9/23/2021 Page 2 of 4 Hydrologic Soil Group-San Diego County Area, California Hydrologic Soil Group Map unit symbol Map unit name Rating Acres lnAOI Percent of AOI MIC Marina loamy coarse B 0.4 sand, 2 to 9 percent slopes Totals for Area of Interest 0.4 Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (AID, BID, 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 near1y impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (AID, BID, or 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 Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 100.0% 100.0% 9/23/2021 Page 3 of 4 Hydrologic Soil GrouJr-5an Diego County Area, California Aggregation is the process by which a set of component attribute values is reduced to a single value that represents the map unit as a whole. A map unit is typically composed of one or more "components". A component is either some type of soil or some nonsoil entity, e.g., rock outcrop. For the attribute being aggregated, the first step of the aggregation process is to derive one attribute value for each of a map unit's components. From this set of component attributes, the next step of the aggregation process derives a single value that represents the map unit as a whole. Once a single value for each map unit is derived, a thematic map for soil map units can be rendered. Aggregation must be done because, on any soil map, map units are delineated but components are not. For each of a map unit's components, a corresponding percent composition is recorded. A percent composition of 60 indicates that the corresponding component typically makes up approximately 60% of the map unit. Percent composition is a critical factor in some, but not all, aggregation methods. The aggregation method "Dominant Condition" first groups like attribute values for the components in a map unit. For each group, percent composition is set to the sum of the percent composition of all components participating in that group. These groups now represent "conditions" rather than components. The attribute value associated with the group with the highest cumulative percent composition is returned. If more than one group shares the highest cumulative percent composition, the corresponding "tie-break" rule determines which value should be returned. The "tie-break" rule indicates whether the lower or higher group value should be returned in the case of a percent composition tie. The result returned by this aggregation method represents the dominant condition throughout the map unit only when no tie has occurred. Component Percent Cutoff: None Specified Components whose percent composition is below the cutoff value will not be considered. If no cutoff value is specified, all components in the database will be considered. The data for some contrasting soils of minor extent may not be in the database, and therefore are not considered. Tie-break Rule: Higher The tie-break rule indicates which value should be selected from a set of multiple candidate values, or which value should be selected in the event of a percent composition tie. Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 9/23/2021 Page 4 of 4 San Diego County Hydrology Manual Date: June 2003 Table 3-1 Section: Page: RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use I Runoff Coefficient ''C" SoilTYpC NRCS Elements Coun Elements %IMPER. A B Undisturbed Natural Terrain (Natural) Permanent Open Space o• 0.20 Im] Low Density Residential (LOR) Residential, 1.0 DU/ A or less 10 0.27 0.32 Low Density Residential (LOR) Residential, 2.0 DU/ A or less 20 0.34 0.38 Low Density Residential (LOR) Residential, 2.9 DU/A or less 25 0.38 0.41 Medium Density Residential (MOR) Residential, 4.3 DU/A or less 30 0.41 0.45 Medium Density Residential (MOR) Residential, 7.3 DU/A or less 40 0.48 0.51 Medium Density Residential (MOR) Residential, 10.9 DU/A or less 45 0.52 0.54 Medium Density Residential (MOR) Residential, 14.5 DU/A or less 50 0.55 0.58 High Density Residential (HOR) Residential, 24.0 DU/A or less 65 0.66 0.67 High Density Residential (HOR) Residential, 43.0 DU/A or less 80 0.76 0.77 Commercial/Industrial (N. Com) Neighborhood Commercial 80 0.76 0.77 Commercial/Industrial (G. Com) General Commercial 85 0.80 0.80 Commercial/Industrial (O.P. Com) Office Professional/Commercial 90 0.83 0.84 Commercial/Industrial (Limited I.) Limited Industrial 90 0.83 0.84 Commercial/Industrial (General I.) General Industrial 95 0.87 10.811 C 0.30 0.36 0.42 0.45 0.48 0.54 0.57 0.60 0.69 0.78 0.78 0.81 0.84 0.84 0.87 3 6of26 D 0.35 0.41 0.46 0.49 0.52 0.57 0.60 0.63 0.71 0.79 0.79 0.82 0.85 0.85 0.87 •Toe values associated with O"/o 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