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pathway around the proposed cap extension area back to the original drainage path flow line pathway. 2.0 Methodology The National Oceanic and Atmospheric Administration (NOAA 2012) (latitude 37.6675, longitude-121.4573)estimated the 24-hour I00-year storm event at 3.53 inches located near bye the Tracy Airport. The Soil Conservation Services (SCS) Method was utilized to estimate the peak flows for a 24-hour 100-year event. Maturing equation and Kirpich equation was used in conjunction with Auto CAD Civil 31) Hydraflow software to calculated flow characteristics in the proposed ditches. I 1 3.0 Results of Hydrologic Analysis The perimeter and Caltrans V-shaped ditch were sized based on the results from the 24-hour 100-year storm event modeling methodology as described in Section 2.0. The perimeter ditch F depth shall be 1.25 feet with side slopes 3:1 and 2:1 to accommodate a 24-hour 100-year storm event peak flow of 23.34 cubic feet per second (cfs). The Caltrans ditches depth shall be 1 foot 3 with 2:1 side slopes to accommodate a 24-hour 100-year storm event peak flow of 8.42 efs. Appendix C in the sample calculations contains flow depths for the down drain culverts and the access road channel during a 24-hour 100-year storm event. The down drains and access road i channel was sized to meet the peak flow during such an event.- I 4.0 References ATational Oceanic and Atmospheric 4dininistration Hydrometeorlogical Design Studies Center I Precipitation Frequency Data Server,2012,http://hdsc.nws.noaa.gov/hdsc/pfds/ j Hydr.tflow Hydrographs Extension for-AutoCAD Civil 3D 2010 I i Hydr aflow Stor rn Seiver s Extension for AutoCAD Civil 3D 2010 I E SHAW ENV/RONMENTAL,INC. SACon mrcWM-mPrgccls%anJWqumCoun1y1141515-2011-201M*adCorral449-12000 Rev.t,4t19/12 2