Appendix H Amanda Estates Drainage Study

Transcription

1 Appendix H Amanda Estates Drainage Study Hunsaker & Associates 2015

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3 Contents 1 Scope Existing Conditions Project Description Methodology Hydrology Hydraulics Results and Conclusions References Watershed Information Appendices List of Appendices Appendix 1 Soils Information Appendix 2 Hydrology Calculations and Exhibits Appendix 3 Detention Basin Analysis Appendix 4 Hydraulic Calculations Appendix 5 Gamble Lane Storm Drain Reference Plans

4 1 Scope The purpose of this study is to provide flood control calculations in support of a proposed subdivision of land for creation of 21 single family residential lots in the City of Escondido, CA. This report will provide preliminary calculations for existing and proposed runoff for the 50-year frequency storm event. 2 Existing Conditions The Amanda Estates project site is acres, located in the City of Escondido, California. The property is located west of the proposed extension of Amanda Lane, north of Gamble Lane, east of Greenwood Place, and south of Blackhawk Glen. See Vicinity Map below. The pre-project topography varies from 842 to 743 MSL. A hill is currently centrally located with a residential home at its peak. An access road to the home connects it to Amanda Lane. Drainage is radial down the slope. However, runoff from the eastern half of the site is eventually directed towards the southeast within both man-made and naturally occurring drainage channels. This runoff sheet flows in a southeasterly

5 direction and confluences with runoff generated by areas south and east of the project boundary. A riser located at the northwest corner of Gamble Lane and Eucalyptus Avenue collects this flow and directs it south within the existing 48 storm drain on Eucalyptus Avenue. The eastern portion of the site is within the Hamilton Lane storm drain basin as designated in the City of Escondido Drainage Master Plan. The western portion of the site slopes towards the west. Runoff from this area is collected by storm drain facilities located at the rear of two existing residential lots along Greenwood Place. Cumulative, both lots receive runoff from approximately 5.4 acres of the Amanda Estates project area. This area is part of the Del Dios Avenue Drainage Basin as designated in the City s Drainage Master Plan. The Existing Condition hydrologic model included within this report includes analysis of areas south of Gamble Lane. These areas were included to analyze the existing storm drain since developed flows from Amanda Estates are proposed to be added to the Gamble Lane storm drain system. Existing and proposed condition hydraulic analysis on the existing system is included in Appendix 4. Hydrologic and Geotechnical Characteristics; The project is situated at the divide of two drainage basin; Hamilton Lane and Del Dios Avenue. The Hamilton Lane Drainage Basin is tributary to Felicita Creek and Lake Hodges, as part of the San Dieguito Hydrologic Unit, Hodges Hydrologic Area, and the Felicita Creek Hydrologic Subarea (basin number ). The Del Dios Drainage Basin is tributary to the Escondido Creek within the Escondido Creek Hydrologic Area (basin number 904.6) within the Carlsbad Watershed. The site is mapped within a Zone X, described to be an area determined to be outside the 0.2% annual chance floodplain. According to the NRCS Web Spoil Survey website, the onsite soils consist of Fallbrook sandy loam which are within the hydrologic soil type C classification. The hydrologic calculations included herein assumed a more conservative type D soil which will result in higher runoffs.

6 3 Project Description The proposed development will create 21 single residential lots. Amanda Lane, which provides access to the site from Gamble Lane, will also be improved between the site and Gamble Lane. Project improvements will include sidewalks and streets as well as include storm drain facilities and utilities such as water and sewer. The site layout of Amanda Estates will have an interior looped street which connects to Amanda Lane. Additional offsite improvements associated with the site will include street improvements in the vicinity of the Gamble Lane- Amanda Lane intersection which includes storm drain, curb and street pavement. Drainage Routing and Improvements: The proposed onsite site design will cut and flatten the existing hill. Street grades will vary between 4-12% and slope towards the southwest corner of the site. A small portion of area which previously drained west is diverted east in the proposed design. Approximately 2.68 acres will be diverted from the west (Del Dios Drainage Basin) to the east (Hamilton Lane Drainage Basin). The reduction in area towards the west will reduce the amount of runoff currently flowing onto two residential lots along Greenwood Place. No impervious areas will be added to the westward-draining areas. On the other hand, the increase in acreage towards the east will increase the unmitigated peak flow amounts. Therefore, an onsite detention basin is proposed to attenuate the peak developed flows draining to the southeast corner of the site and will reduce them below existing condition. This basin will also serve water quality and hydromodification uses as described in the Major Stormwater Management Plans (SWMP) for Amanda Estates (February 2015). Currently, drainage from the areas west of Amanda Lane generally sheet flows across Amanda Lane towards the east then southeast till it reaches a riser located at the northwest corner of Gamble Lane and Eucalyptus Avenue. The improvements of Amanda Lane will slightly alter this existing drainage scenario. For example, offsite flows from the northern portion of existing Amanda Lane will be collected with catch basin inlets and be conveyed together with developed Amanda Estate flows south towards the existing storm drain on Gamble Lane. These offsite flows are from approximately 4 acres of land east of Amanda Lane. The drainage patterns associated with the southern portion of Amanda Lane will remain unaffected by the Amanda Estate project and continue to flow overland towards the northwest corner of Gamble Lane and Eucalyptus Avenue and continue downstream in the existing 48 storm drain. A small portion of Amanda Lane at the entrance to the developed site will include a bioretention swale along the east side of the road to collect and treat the 85 th percentile rainfall event as described in the SWMP for Amanda Estates.

7 The proposed onsite detention basin was sized to attenuate peak flows to below existing condition in order to insure that the existing downstream storm drain infrastructure along Gamble Lane and Eucalyptus Avenue was not compromised. Appendix 4 includes the preliminary hydraulic analysis for the Gamble Lane storm drain system. The analysis routes the proposed flows to verify adequacy of the existing system.

8 4 Methodology 4.1 Hydrology The Rational Method as described in the June 2003 San Diego County Hydrology Manual (SDCHM), Section 3, was used for the hydrologic calculations for this project. The Rational Method formula is expressed as follows: Q = C I A I = 7.44P 6 T c T c = T t + T i T t = (11.9*L 3 / ΔE) Where: Q = Peak discharge, in cubic feet per second (cfs). C = Runoff coefficient, proportion of the rainfall that runs off the surface. The C coefficient was obtained from Table 3-1 of the SDCHM. It has no units and is based on the soil group and the development type for the drainage sub-area. A = Drainage area contributing to the design location (ac). I = Average rainfall intensity (in/hr). The formula can be found on Figure 3-2 of the SDCHM. P 6 = 6-hour precipitation (in). This value was taken from the 6-hour isopluvial maps found in Appendix B of the SDCHM. T i = Initial time of concentration, from Table 3-2 of the SDCHM. T t = Travel time (min), from Figure 3-4 of the SDCHM. L = Longest flow path distance (mi). ΔE = Change in elevation along flowpath (ft). 4.2 Hydraulics In order to provide adequate flood control, increases in peak flow rates at the outfall location for this site were mitigated using the design of the proposed basin. Mitigation within the basin was modeled using RickRatHydro as an input to Hydraflow Hydrographs Extension for AutoCAD Civil 3D RickRatHydro was used to produce a hydrograph for the project drainage areas, based on the area, time of concentration, P6 value, runoff coefficient, and peak flow rate. The hydrograph was then imported into Hydraflow Hydrographs and was routed through the proposed basin by using an iteration of outlet structures, until the resulting outlet structure provided a flow rate to the outfall that was equal to or less than that during the existing condition, and the water surface elevation was below the top of the basin.

9 Storm drain analysis along Gamble Lane was prepared using a separate extension of AutoCAD Civil 3D 2011 named Storm Sewer. Pre and Post condition hydraulic analysis was prepared to verify storm drain adequacy. See Appendix 4 for results.

10 5 Results and Conclusions Table 1 Rational Method Results Existing Condition Location/Node #* Area (ac) 50-Year Peak Flow (cfs) Totals: Proposed Condition Location/Node #* Area (ac) 50-Year Peak Flow (cfs) Totals: *Nodes locations are shown the hydrology exhibits in Appendix 2. As illustrated above, development of the Amanda Estates project site will decrease the cumulative amount of peak flow by approximately 10 cfs. This reduction can be attributed to the site design and its inclusion of a detention to reduce peak flow amounts below existing condition. Therefore, the proposed drainage design and peak flow routing by the Amanda Estates project will not adversely affect the existing downstream infrastructures. Due to the addition of storm drain and flows from Amanda Estates and Amanda Lane, a portion of the existing upper reach of the Gamble storm drain system will be replace/relocated. Hydraulic analysis confirms that the downstream reaches of the existing Gamble Lane are adequate for the proposed flows.

11 6 References Plans for the Improvement of Escondido Tract No. 692, Manitou Engineering Company, September 3, Major Storm Water Management Plan for Amanda Estates, Hunsaker & Associates San Diego, Inc., February San Diego County Hydrology Manual, June City of San Diego Drainage Design Manual, April 1984 City of Escondido- Design Standards and Standard Drawings, April 2, FEMA Flood Insurance Rate Map (Firmette).

12 7 Watershed Information City of Escondido- Runoff intensity duration curves and runoff coefficients. FEMA Flood Insurance Rate Map (Firmette).

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15 8 Appendices

16 Appendix 1 - Soils Information

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21 Appendix 2 - Hydrology Calculations and Exhibits

22 EXISTING CONDITION

23 RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 2003,1985,1981 HYDROLOGY MANUAL (c) Copyright Advanced Engineering Software (aes) Ver Release Date: 07/01/2010 License ID 1239 Analysis prepared by: Hunsaker & Associates San Diego, Inc Waples Street San Diego, CA ************************** DESCRIPTION OF STUDY ************************** * Amanda Lane * * EXISTING CONDITION, 50 year return interval * * W.O , DLN 1166 * ************************************************************************** FILE NAME: R:\1166\HYD\CALCS\AES\50EX.DAT TIME/DATE OF STUDY: 10:49 02/11/2015 USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: USER SPECIFIED STORM EVENT(YEAR) = SPECIFIED MINIMUM PIPE SIZE(INCH) = SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.90 RAINFALL-INTENSITY ADJUSTMENT FACTOR = *USER SPECIFIED: NUMBER OF [TIME,INTENSITY] DATA PAIRS = 9 1) 5.000; ) ; ) ; ) ; ) ; ) ; ) ; ) ; ) ; SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD NOTE: ONLY PEAK CONFLUENCE VALUES CONSIDERED *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n) === ===== ========= ================= ====== ===== ====== ===== ======= /0.018/ 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.* FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< USER-SPECIFIED RUNOFF COEFFICIENT =.3500 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.25 TOTAL AREA(ACRES) = 0.18 TOTAL RUNOFF(CFS) = 0.25 FLOW PROCESS FROM NODE TO NODE IS CODE = 53 >>>>>COMPUTE NATURAL MOUNTAIN CHANNEL FLOW<<<<< >>>>>TRAVELTIME THRU SUBAREA<<<<<

24 ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = CHANNEL LENGTH THRU SUBAREA(FEET) = CHANNEL SLOPE = NOTE: CHANNEL FLOW OF 1. CFS WAS ASSUMED IN VELOCITY ESTIMATION CHANNEL FLOW THRU SUBAREA(CFS) = 0.25 FLOW VELOCITY(FEET/SEC) = 2.47 (PER LACFCD/RCFC&WCD HYDROLOGY MANUAL) TRAVEL TIME(MIN.) = 2.22 Tc(MIN.) = 8.49 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 81 >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<< 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.3500 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 2.71 SUBAREA RUNOFF(CFS) = 3.32 TOTAL AREA(ACRES) = 2.9 TOTAL RUNOFF(CFS) = 3.54 TC(MIN.) = 8.49 FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< USER-SPECIFIED RUNOFF COEFFICIENT =.3500 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.18 TOTAL AREA(ACRES) = 0.13 TOTAL RUNOFF(CFS) = 0.18 FLOW PROCESS FROM NODE TO NODE IS CODE = 53 >>>>>COMPUTE NATURAL MOUNTAIN CHANNEL FLOW<<<<< >>>>>TRAVELTIME THRU SUBAREA<<<<< ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = CHANNEL LENGTH THRU SUBAREA(FEET) = CHANNEL SLOPE = NOTE: CHANNEL FLOW OF 1. CFS WAS ASSUMED IN VELOCITY ESTIMATION CHANNEL FLOW THRU SUBAREA(CFS) = 0.18 FLOW VELOCITY(FEET/SEC) = 2.10 (PER LACFCD/RCFC&WCD HYDROLOGY MANUAL) TRAVEL TIME(MIN.) = 2.09 Tc(MIN.) = 8.35 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 81 >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<< 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.3500 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 2.38 SUBAREA RUNOFF(CFS) = 2.94 TOTAL AREA(ACRES) = 2.5 TOTAL RUNOFF(CFS) = 3.10 TC(MIN.) = 8.35 FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< USER-SPECIFIED RUNOFF COEFFICIENT =.4000 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = 10.00

25 URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.35 TOTAL AREA(ACRES) = 0.22 TOTAL RUNOFF(CFS) = 0.35 FLOW PROCESS FROM NODE TO NODE IS CODE = 51 >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<< >>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<< ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = CHANNEL LENGTH THRU SUBAREA(FEET) = CHANNEL SLOPE = CHANNEL BASE(FEET) = "Z" FACTOR = MANNING'S FACTOR = MAXIMUM DEPTH(FEET) = YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.3500 TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.63 TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 3.19 AVERAGE FLOW DEPTH(FEET) = 0.05 TRAVEL TIME(MIN.) = 4.22 Tc(MIN.) = SUBAREA AREA(ACRES) = 2.21 SUBAREA RUNOFF(CFS) = 2.47 AREA-AVERAGE RUNOFF COEFFICIENT = TOTAL AREA(ACRES) = 2.4 PEAK FLOW RATE(CFS) = 2.75 END OF SUBAREA CHANNEL FLOW HYDRAULICS: DEPTH(FEET) = 0.07 FLOW VELOCITY(FEET/SEC.) = 3.79 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 3.19 TOTAL STREAM AREA(ACRES) = 2.43 PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.75 FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< USER-SPECIFIED RUNOFF COEFFICIENT =.3500 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = 6.30 URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.14 TOTAL AREA(ACRES) = 0.11 TOTAL RUNOFF(CFS) = 0.14 FLOW PROCESS FROM NODE TO NODE IS CODE = 53 >>>>>COMPUTE NATURAL MOUNTAIN CHANNEL FLOW<<<<< >>>>>TRAVELTIME THRU SUBAREA<<<<< ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = CHANNEL LENGTH THRU SUBAREA(FEET) = CHANNEL SLOPE = NOTE: CHANNEL FLOW OF 1. CFS WAS ASSUMED IN VELOCITY ESTIMATION CHANNEL FLOW THRU SUBAREA(CFS) = 0.14 FLOW VELOCITY(FEET/SEC) = 1.66 (PER LACFCD/RCFC&WCD HYDROLOGY MANUAL) TRAVEL TIME(MIN.) = 7.57 Tc(MIN.) = LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 81 >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<< 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = 2.712

26 USER-SPECIFIED RUNOFF COEFFICIENT =.4500 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 3.35 SUBAREA RUNOFF(CFS) = 4.09 TOTAL AREA(ACRES) = 3.5 TOTAL RUNOFF(CFS) = 4.19 TC(MIN.) = FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< >>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 2.71 TOTAL STREAM AREA(ACRES) = 3.46 PEAK FLOW RATE(CFS) AT CONFLUENCE = 4.19 ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY NUMBER (CFS) (MIN.) (INCH/HOUR) COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 6.53 Tc(MIN.) = TOTAL AREA(ACRES) = 5.9 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 31 >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<< >>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = FLOW LENGTH(FEET) = MANNING'S N = ESTIMATED PIPE DIAMETER(INCH) INCREASED TO DEPTH OF FLOW IN 18.0 INCH PIPE IS 6.8 INCHES PIPE-FLOW VELOCITY(FEET/SEC.) = ESTIMATED PIPE DIAMETER(INCH) = NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 6.53 PIPE TRAVEL TIME(MIN.) = 0.30 Tc(MIN.) = LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 2.69 TOTAL STREAM AREA(ACRES) = 5.89 PEAK FLOW RATE(CFS) AT CONFLUENCE = 6.53 FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< USER-SPECIFIED RUNOFF COEFFICIENT =.3500 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = 10.00

27 URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.36 TOTAL AREA(ACRES) = 0.26 TOTAL RUNOFF(CFS) = 0.36 FLOW PROCESS FROM NODE TO NODE IS CODE = 52 >>>>>COMPUTE NATURAL VALLEY CHANNEL FLOW<<<<< >>>>>TRAVELTIME THRU SUBAREA<<<<< ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = CHANNEL LENGTH THRU SUBAREA(FEET) = CHANNEL SLOPE = NOTE: CHANNEL FLOW OF 1. CFS WAS ASSUMED IN VELOCITY ESTIMATION CHANNEL FLOW THRU SUBAREA(CFS) = 0.36 FLOW VELOCITY(FEET/SEC) = 4.57 (PER LACFCD/RCFC&WCD HYDROLOGY MANUAL) TRAVEL TIME(MIN.) = 3.75 Tc(MIN.) = LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 81 >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<< 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.4000 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 9.97 SUBAREA RUNOFF(CFS) = TOTAL AREA(ACRES) = 10.2 TOTAL RUNOFF(CFS) = TC(MIN.) = FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< >>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 3.20 TOTAL STREAM AREA(ACRES) = PEAK FLOW RATE(CFS) AT CONFLUENCE = ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY NUMBER (CFS) (MIN.) (INCH/HOUR) COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = Tc(MIN.) = TOTAL AREA(ACRES) = 16.1 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 52 >>>>>COMPUTE NATURAL VALLEY CHANNEL FLOW<<<<< >>>>>TRAVELTIME THRU SUBAREA<<<<< ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = CHANNEL LENGTH THRU SUBAREA(FEET) = CHANNEL SLOPE = CHANNEL FLOW THRU SUBAREA(CFS) = FLOW VELOCITY(FEET/SEC) = 6.19 (PER LACFCD/RCFC&WCD HYDROLOGY MANUAL) TRAVEL TIME(MIN.) = 1.80 Tc(MIN.) = LONGEST FLOWPATH FROM NODE TO NODE = FEET.

28 FLOW PROCESS FROM NODE TO NODE IS CODE = 81 >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<< 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.4000 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 4.29 SUBAREA RUNOFF(CFS) = 5.18 TOTAL AREA(ACRES) = 20.4 TOTAL RUNOFF(CFS) = TC(MIN.) = FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 3.02 TOTAL STREAM AREA(ACRES) = PEAK FLOW RATE(CFS) AT CONFLUENCE = FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< USER-SPECIFIED RUNOFF COEFFICIENT =.4000 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.34 TOTAL AREA(ACRES) = 0.21 TOTAL RUNOFF(CFS) = 0.34 FLOW PROCESS FROM NODE TO NODE IS CODE = 53 >>>>>COMPUTE NATURAL MOUNTAIN CHANNEL FLOW<<<<< >>>>>TRAVELTIME THRU SUBAREA<<<<< ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = CHANNEL LENGTH THRU SUBAREA(FEET) = CHANNEL SLOPE = NOTE: CHANNEL FLOW OF 1. CFS WAS ASSUMED IN VELOCITY ESTIMATION CHANNEL FLOW THRU SUBAREA(CFS) = 0.34 FLOW VELOCITY(FEET/SEC) = 2.06 (PER LACFCD/RCFC&WCD HYDROLOGY MANUAL) TRAVEL TIME(MIN.) = 3.78 Tc(MIN.) = 9.63 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 81 >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<< 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.3500 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 3.72 SUBAREA RUNOFF(CFS) = 4.26 TOTAL AREA(ACRES) = 3.9 TOTAL RUNOFF(CFS) = 4.54 TC(MIN.) = 9.63 FLOW PROCESS FROM NODE TO NODE IS CODE = 52 >>>>>COMPUTE NATURAL VALLEY CHANNEL FLOW<<<<< >>>>>TRAVELTIME THRU SUBAREA<<<<< ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = CHANNEL LENGTH THRU SUBAREA(FEET) = CHANNEL SLOPE = CHANNEL FLOW THRU SUBAREA(CFS) = 4.54 FLOW VELOCITY(FEET/SEC) = 5.04 (PER LACFCD/RCFC&WCD HYDROLOGY MANUAL)

29 TRAVEL TIME(MIN.) = 2.56 Tc(MIN.) = LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 81 >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<< 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.4500 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 4.51 SUBAREA RUNOFF(CFS) = 6.05 TOTAL AREA(ACRES) = 8.4 TOTAL RUNOFF(CFS) = TC(MIN.) = FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< >>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 2.98 TOTAL STREAM AREA(ACRES) = 8.44 PEAK FLOW RATE(CFS) AT CONFLUENCE = ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY NUMBER (CFS) (MIN.) (INCH/HOUR) COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = Tc(MIN.) = TOTAL AREA(ACRES) = 28.9 LONGEST FLOWPATH FROM NODE TO NODE = FEET FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< USER-SPECIFIED RUNOFF COEFFICIENT =.4900 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = 1.70 URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = (Reference: Table 3-1B of Hydrology Manual) THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.65 TOTAL AREA(ACRES) = 0.36 TOTAL RUNOFF(CFS) = 0.65 FLOW PROCESS FROM NODE TO NODE IS CODE = 61 >>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<

30 >>>>>(STANDARD CURB SECTION USED)<<<<< UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = STREET LENGTH(FEET) = CURB HEIGHT(INCHES) = 6.0 STREET HALFWIDTH(FEET) = DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 5.00 INSIDE STREET CROSSFALL(DECIMAL) = OUTSIDE STREET CROSSFALL(DECIMAL) = SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 2 STREET PARKWAY CROSSFALL(DECIMAL) = Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = Manning's FRICTION FACTOR for Back-of-Walk Flow Section = **TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 6.28 STREETFLOW MODEL RESULTS USING ESTIMATED FLOW: STREET FLOW DEPTH(FEET) = 0.31 HALFSTREET FLOOD WIDTH(FEET) = 9.41 AVERAGE FLOW VELOCITY(FEET/SEC.) = 3.13 PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.98 STREET FLOW TRAVEL TIME(MIN.) = 3.71 Tc(MIN.) = YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.4600 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 7.90 SUBAREA RUNOFF(CFS) = TOTAL AREA(ACRES) = 8.3 PEAK FLOW RATE(CFS) = END OF SUBAREA STREET FLOW HYDRAULICS: DEPTH(FEET) = 0.36 HALFSTREET FLOOD WIDTH(FEET) = FLOW VELOCITY(FEET/SEC.) = 3.93 DEPTH*VELOCITY(FT*FT/SEC.) = 1.43 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 81 >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<< 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.4000 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 2.71 SUBAREA RUNOFF(CFS) = 3.33 TOTAL AREA(ACRES) = 11.0 TOTAL RUNOFF(CFS) = TC(MIN.) = FLOW PROCESS FROM NODE TO NODE IS CODE = 31 >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<< >>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = FLOW LENGTH(FEET) = MANNING'S N = ESTIMATED PIPE DIAMETER(INCH) INCREASED TO DEPTH OF FLOW IN 18.0 INCH PIPE IS 9.9 INCHES PIPE-FLOW VELOCITY(FEET/SEC.) = ESTIMATED PIPE DIAMETER(INCH) = NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = PIPE TRAVEL TIME(MIN.) = 0.34 Tc(MIN.) = LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 3.04 TOTAL STREAM AREA(ACRES) = PEAK FLOW RATE(CFS) AT CONFLUENCE = FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<

31 USER-SPECIFIED RUNOFF COEFFICIENT =.4600 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = 1.70 URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = (Reference: Table 3-1B of Hydrology Manual) THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.77 TOTAL AREA(ACRES) = 0.46 TOTAL RUNOFF(CFS) = 0.77 FLOW PROCESS FROM NODE TO NODE IS CODE = 61 >>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<< >>>>>(STANDARD CURB SECTION USED)<<<<< UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = STREET LENGTH(FEET) = CURB HEIGHT(INCHES) = 6.0 STREET HALFWIDTH(FEET) = DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 7.00 INSIDE STREET CROSSFALL(DECIMAL) = OUTSIDE STREET CROSSFALL(DECIMAL) = SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 2 STREET PARKWAY CROSSFALL(DECIMAL) = Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = Manning's FRICTION FACTOR for Back-of-Walk Flow Section = **TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 3.71 STREETFLOW MODEL RESULTS USING ESTIMATED FLOW: STREET FLOW DEPTH(FEET) = 0.27 HALFSTREET FLOOD WIDTH(FEET) = 7.26 AVERAGE FLOW VELOCITY(FEET/SEC.) = 2.87 PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.78 STREET FLOW TRAVEL TIME(MIN.) = 2.60 Tc(MIN.) = YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.4600 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 4.06 SUBAREA RUNOFF(CFS) = 5.88 TOTAL AREA(ACRES) = 4.5 PEAK FLOW RATE(CFS) = 6.55 END OF SUBAREA STREET FLOW HYDRAULICS: DEPTH(FEET) = 0.32 HALFSTREET FLOOD WIDTH(FEET) = 9.45 FLOW VELOCITY(FEET/SEC.) = 3.24 DEPTH*VELOCITY(FT*FT/SEC.) = 1.02 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 31 >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<< >>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = FLOW LENGTH(FEET) = MANNING'S N = DEPTH OF FLOW IN 18.0 INCH PIPE IS 11.3 INCHES PIPE-FLOW VELOCITY(FEET/SEC.) = 5.60 ESTIMATED PIPE DIAMETER(INCH) = NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 6.55 PIPE TRAVEL TIME(MIN.) = 0.36 Tc(MIN.) = LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< >>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 3.11

32 TOTAL STREAM AREA(ACRES) = 4.52 PEAK FLOW RATE(CFS) AT CONFLUENCE = 6.55 ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY NUMBER (CFS) (MIN.) (INCH/HOUR) COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = Tc(MIN.) = TOTAL AREA(ACRES) = 15.5 LONGEST FLOWPATH FROM NODE TO NODE = FEET. END OF STUDY SUMMARY: TOTAL AREA(ACRES) = 15.5 TC(MIN.) = PEAK FLOW RATE(CFS) = END OF RATIONAL METHOD ANALYSIS

33 LEGEND: HYDROLOGY NODE WATERSHED AREA WATERSHED BOUNDARY SUB-WATERSHED BOUNDARY FLOW DIRECTION PREPARED BY: EXHIBIT 1 2 DEVELOPED EXISTING CONDITION CONDITION HYDROLOGY MAP MAP AMANDA ESTATES OF CITY OF ESCONDIDO, CALIFORNIA

34 PROPOSED CONDITION

35 RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT 2003,1985,1981 HYDROLOGY MANUAL (c) Copyright Advanced Engineering Software (aes) Ver Release Date: 07/01/2010 License ID 1239 Analysis prepared by: Hunsaker & Associates San Diego, Inc Waples Street San Diego, CA ************************** DESCRIPTION OF STUDY ************************** * Amanda Lane * * PROPOSED CONDITION, 50 year return interval * * W.O , DLN 1166 * ************************************************************************** FILE NAME: R:\1166\HYD\CALCS\AES\50PR.DAT TIME/DATE OF STUDY: 10:52 02/11/2015 USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION: USER SPECIFIED STORM EVENT(YEAR) = SPECIFIED MINIMUM PIPE SIZE(INCH) = SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.90 RAINFALL-INTENSITY ADJUSTMENT FACTOR = *USER SPECIFIED: NUMBER OF [TIME,INTENSITY] DATA PAIRS = 9 1) 5.000; ) ; ) ; ) ; ) ; ) ; ) ; ) ; ) ; SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD NOTE: ONLY PEAK CONFLUENCE VALUES CONSIDERED *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n) === ===== ========= ================= ====== ===== ====== ===== ======= /0.018/ 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.* FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< USER-SPECIFIED RUNOFF COEFFICIENT =.3500 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.21 TOTAL AREA(ACRES) = 0.15 TOTAL RUNOFF(CFS) = 0.21 FLOW PROCESS FROM NODE TO NODE IS CODE = 53 >>>>>COMPUTE NATURAL MOUNTAIN CHANNEL FLOW<<<<< >>>>>TRAVELTIME THRU SUBAREA<<<<<

36 ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = CHANNEL LENGTH THRU SUBAREA(FEET) = CHANNEL SLOPE = NOTE: CHANNEL FLOW OF 1. CFS WAS ASSUMED IN VELOCITY ESTIMATION CHANNEL FLOW THRU SUBAREA(CFS) = 0.21 FLOW VELOCITY(FEET/SEC) = 2.30 (PER LACFCD/RCFC&WCD HYDROLOGY MANUAL) TRAVEL TIME(MIN.) = 2.76 Tc(MIN.) = 9.02 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 81 >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<< 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.3500 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 1.28 SUBAREA RUNOFF(CFS) = 1.52 TOTAL AREA(ACRES) = 1.4 TOTAL RUNOFF(CFS) = 1.70 TC(MIN.) = 9.02 FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< USER-SPECIFIED RUNOFF COEFFICIENT =.3500 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = WARNING: THE MAXIMUM OVERLAND FLOW SLOPE, 10.%, IS USED IN Tc CALCULATION! 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.25 TOTAL AREA(ACRES) = 0.18 TOTAL RUNOFF(CFS) = 0.25 FLOW PROCESS FROM NODE TO NODE IS CODE = 53 >>>>>COMPUTE NATURAL MOUNTAIN CHANNEL FLOW<<<<< >>>>>TRAVELTIME THRU SUBAREA<<<<< ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) = CHANNEL LENGTH THRU SUBAREA(FEET) = CHANNEL SLOPE = NOTE: CHANNEL FLOW OF 1. CFS WAS ASSUMED IN VELOCITY ESTIMATION CHANNEL FLOW THRU SUBAREA(CFS) = 0.25 FLOW VELOCITY(FEET/SEC) = 0.75 (PER LACFCD/RCFC&WCD HYDROLOGY MANUAL) TRAVEL TIME(MIN.) = 4.99 Tc(MIN.) = LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 81 >>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<< 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.3500 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 1.14 SUBAREA RUNOFF(CFS) = 1.23 TOTAL AREA(ACRES) = 1.3 TOTAL RUNOFF(CFS) = 1.42 TC(MIN.) = FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<

37 USER-SPECIFIED RUNOFF COEFFICIENT =.5500 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = 0.70 URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = (Reference: Table 3-1B of Hydrology Manual) THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.55 TOTAL AREA(ACRES) = 0.28 TOTAL RUNOFF(CFS) = 0.55 FLOW PROCESS FROM NODE TO NODE IS CODE = 61 >>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<< >>>>>(STANDARD CURB SECTION USED)<<<<< UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = STREET LENGTH(FEET) = CURB HEIGHT(INCHES) = 6.0 STREET HALFWIDTH(FEET) = DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00 INSIDE STREET CROSSFALL(DECIMAL) = OUTSIDE STREET CROSSFALL(DECIMAL) = SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1 STREET PARKWAY CROSSFALL(DECIMAL) = Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = Manning's FRICTION FACTOR for Back-of-Walk Flow Section = **TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 2.18 STREETFLOW MODEL RESULTS USING ESTIMATED FLOW: STREET FLOW DEPTH(FEET) = 0.23 HALFSTREET FLOOD WIDTH(FEET) = 5.38 AVERAGE FLOW VELOCITY(FEET/SEC.) = 5.35 PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 1.25 STREET FLOW TRAVEL TIME(MIN.) = 1.87 Tc(MIN.) = YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.5500 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 1.87 SUBAREA RUNOFF(CFS) = 3.28 TOTAL AREA(ACRES) = 2.2 PEAK FLOW RATE(CFS) = 3.77 END OF SUBAREA STREET FLOW HYDRAULICS: DEPTH(FEET) = 0.27 HALFSTREET FLOOD WIDTH(FEET) = 7.16 FLOW VELOCITY(FEET/SEC.) = 5.97 DEPTH*VELOCITY(FT*FT/SEC.) = 1.61 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 3.18 TOTAL STREAM AREA(ACRES) = 2.15 PEAK FLOW RATE(CFS) AT CONFLUENCE = 3.77 FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< USER-SPECIFIED RUNOFF COEFFICIENT =.5500 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = 0.70 URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.45

38 TOTAL AREA(ACRES) = 0.23 TOTAL RUNOFF(CFS) = 0.45 FLOW PROCESS FROM NODE TO NODE IS CODE = 61 >>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<< >>>>>(STANDARD CURB SECTION USED)<<<<< UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = STREET LENGTH(FEET) = CURB HEIGHT(INCHES) = 6.0 STREET HALFWIDTH(FEET) = DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00 INSIDE STREET CROSSFALL(DECIMAL) = OUTSIDE STREET CROSSFALL(DECIMAL) = SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1 STREET PARKWAY CROSSFALL(DECIMAL) = Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = Manning's FRICTION FACTOR for Back-of-Walk Flow Section = **TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.28 STREETFLOW MODEL RESULTS USING ESTIMATED FLOW: STREET FLOW DEPTH(FEET) = 0.24 HALFSTREET FLOOD WIDTH(FEET) = 5.69 AVERAGE FLOW VELOCITY(FEET/SEC.) = 2.90 PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.70 STREET FLOW TRAVEL TIME(MIN.) = 2.54 Tc(MIN.) = YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.5500 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 0.97 SUBAREA RUNOFF(CFS) = 1.66 TOTAL AREA(ACRES) = 1.2 PEAK FLOW RATE(CFS) = 2.06 END OF SUBAREA STREET FLOW HYDRAULICS: DEPTH(FEET) = 0.27 HALFSTREET FLOOD WIDTH(FEET) = 7.26 FLOW VELOCITY(FEET/SEC.) = 3.19 DEPTH*VELOCITY(FT*FT/SEC.) = 0.87 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< >>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 3.12 TOTAL STREAM AREA(ACRES) = 1.20 PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.06 ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY NUMBER (CFS) (MIN.) (INCH/HOUR) COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 5.74 Tc(MIN.) = TOTAL AREA(ACRES) = 3.4 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 31 >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<< >>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ELEVATION DATA: UPSTREAM(FEET) = DOWNSTREAM(FEET) =

39 FLOW LENGTH(FEET) = MANNING'S N = ESTIMATED PIPE DIAMETER(INCH) INCREASED TO DEPTH OF FLOW IN 18.0 INCH PIPE IS 9.1 INCHES PIPE-FLOW VELOCITY(FEET/SEC.) = 6.44 ESTIMATED PIPE DIAMETER(INCH) = NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 5.74 PIPE TRAVEL TIME(MIN.) = 0.20 Tc(MIN.) = LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 3.10 TOTAL STREAM AREA(ACRES) = 3.35 PEAK FLOW RATE(CFS) AT CONFLUENCE = 5.74 FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< USER-SPECIFIED RUNOFF COEFFICIENT =.5500 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = 0.70 URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = (Reference: Table 3-1B of Hydrology Manual) THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.45 TOTAL AREA(ACRES) = 0.23 TOTAL RUNOFF(CFS) = 0.45 FLOW PROCESS FROM NODE TO NODE IS CODE = 61 >>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<< >>>>>(STANDARD CURB SECTION USED)<<<<< UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = STREET LENGTH(FEET) = CURB HEIGHT(INCHES) = 6.0 STREET HALFWIDTH(FEET) = DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00 INSIDE STREET CROSSFALL(DECIMAL) = OUTSIDE STREET CROSSFALL(DECIMAL) = SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1 STREET PARKWAY CROSSFALL(DECIMAL) = Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = Manning's FRICTION FACTOR for Back-of-Walk Flow Section = **TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.67 STREETFLOW MODEL RESULTS USING ESTIMATED FLOW: STREET FLOW DEPTH(FEET) = 0.22 HALFSTREET FLOOD WIDTH(FEET) = 4.78 AVERAGE FLOW VELOCITY(FEET/SEC.) = 4.83 PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 1.07 STREET FLOW TRAVEL TIME(MIN.) = 2.38 Tc(MIN.) = YEAR RAINFALL INTENSITY(INCH/HOUR) = USER-SPECIFIED RUNOFF COEFFICIENT =.5500 AREA-AVERAGE RUNOFF COEFFICIENT = SUBAREA AREA(ACRES) = 1.42 SUBAREA RUNOFF(CFS) = 2.45 TOTAL AREA(ACRES) = 1.6 PEAK FLOW RATE(CFS) = 2.84 END OF SUBAREA STREET FLOW HYDRAULICS: DEPTH(FEET) = 0.26 HALFSTREET FLOOD WIDTH(FEET) = 6.45 FLOW VELOCITY(FEET/SEC.) = 5.32 DEPTH*VELOCITY(FT*FT/SEC.) = 1.36 LONGEST FLOWPATH FROM NODE TO NODE = FEET.

40 FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< >>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 3.13 TOTAL STREAM AREA(ACRES) = 1.65 PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.84 ** CONFLUENCE DATA ** STREAM RUNOFF Tc INTENSITY AREA NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE) RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO CONFLUENCE FORMULA USED FOR 2 STREAMS. ** PEAK FLOW RATE TABLE ** STREAM RUNOFF Tc INTENSITY NUMBER (CFS) (MIN.) (INCH/HOUR) COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS: PEAK FLOW RATE(CFS) = 8.56 Tc(MIN.) = TOTAL AREA(ACRES) = 5.0 LONGEST FLOWPATH FROM NODE TO NODE = FEET. FLOW PROCESS FROM NODE TO NODE IS CODE = 1 >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<< TOTAL NUMBER OF STREAMS = 2 CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE: TIME OF CONCENTRATION(MIN.) = RAINFALL INTENSITY(INCH/HR) = 3.10 TOTAL STREAM AREA(ACRES) = 5.00 PEAK FLOW RATE(CFS) AT CONFLUENCE = 8.56 FLOW PROCESS FROM NODE TO NODE IS CODE = 21 >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<< USER-SPECIFIED RUNOFF COEFFICIENT =.5500 INITIAL SUBAREA FLOW-LENGTH(FEET) = UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = ELEVATION DIFFERENCE(FEET) = 0.70 URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN THE MAXIMUM OVERLAND FLOW LENGTH = (Reference: Table 3-1B of Hydrology Manual) THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION! 50 YEAR RAINFALL INTENSITY(INCH/HOUR) = SUBAREA RUNOFF(CFS) = 0.53 TOTAL AREA(ACRES) = 0.27 TOTAL RUNOFF(CFS) = 0.53 FLOW PROCESS FROM NODE TO NODE IS CODE = 61 >>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<< >>>>>(STANDARD CURB SECTION USED)<<<<< UPSTREAM ELEVATION(FEET) = DOWNSTREAM ELEVATION(FEET) = STREET LENGTH(FEET) = CURB HEIGHT(INCHES) = 6.0 STREET HALFWIDTH(FEET) = DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00 INSIDE STREET CROSSFALL(DECIMAL) = OUTSIDE STREET CROSSFALL(DECIMAL) = SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1