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3-2 Specific precipitation intensities are based on precipitation data from the Stockton weather station number BOO -8560, located approximately 8 miles northwest of the site at latitude 38000', longitude 1210316', and an elevation of 12 feet National Geodetic Vertical Datum (NGVD) (California Department of Water Resources, 1981). This precipitation was selected due to its long and reliable period of record and its proximity to the project site. The precipitation depth -duration -frequency data for the site from the Stockton WBAP Station Number BOO -8560 (except where noted) are: ♦ 100 -year, 24-hour storm intensity of 3.58 inches* ♦ 1,000 -year, 24-hour storm intensity of 4.92 inches* ♦ 100 -year annual precipitation of 25.42 inches ♦ Annual mean precipitation of 14.27 inches *Source: Non -Water Corrective Action Plan for Forward Landfill, Geologic Associates, November 2011. 3.2.3 Evaporation The estimated annual evaporation for the site is 78.43 inches based on Pan A evaporation data recorded between 1919 and 1968 at Oakdale Woodward Dam (Station No. BOO 630500, latitude 37051'28", longitude 120052'42", Elevation 215 feet amsl), located approximately 13 miles southeast of the site (California Department of Water Resources, 1979). A minimum mean monthly evaporation of 1.14 inches has been calculated for December and January, and a maximum mean monthly evaporation of 14.69 inches has been calculated for July. 3.2.4 Wind During summer periods, winds usually originate from the north end of the San Joaquin Valley and flow in a south -southeasterly direction through the valley and Tehachapi pass, and then into the neighboring Southeastern Desert Air Basin. During winter months, winds occasionally originate from the south end of the valley and flow in a north -northwesterly direction. During winter months, the valley experiences light, variable winds, less than 10 miles per hour (mph). Low wind speeds, combined with low inversion layers in the winter, create a climate conductive to high concentrations of certain air pollutants. The California Air Resources Board (1984) analyzed wind data for the Stockton WB Airport for the period from 1964 to 1980. The prevailing wind for the Stockton station blows from the west-northwest (45.3 percent of the time) and the north (15.9 percent of the time). Calms occur 6.9 percent of the time. A wind rose (Figure 5) developed from the Stockton WB Airport data provides wind direction information. The mean annual wind speed is 8.2 miles per hour. Forward Landfill SWT Engineering Joint Technical Document - April 2014 z:\projects\allied waste\forward\five year permit rvw 2013\itd-5 yr pr 2013\text\sec 3_final.doc