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3-1 0 3.0 SITE CHARACTERISTICS 3.1 Topography The terrain at the landfill and surrounding vicinity consists of a relatively featureless plain. Both the North Branch and South Branch of the South Fork of Littlejohn's Creek traverse the site, generally flowing from the east to the west; however the North Branch has been relocated north of the landfill footprint. Original ground surface elevations range from 30 to 40 feet above mean seal level (amsl) (see Figure 3). Currently developed portions of the site reach a maximum elevation of approximately 150 feet amsl in the Austin Road Unit, and approximately 194 feet amsl in the Forward Landfill as shown on the Site Plan (see Drawing 2). The site is currently permitted to reach a maximum fill elevation of 210 feet amsl as shown on the Existing Permitted Final Grading Plan (see Drawing 3). 3.2 Climate The climate of the region is typical of the California Central Valley. Winters are generally cold and wet with fog, while summers are hot and dry. Climatological data was gathered from representative weather stations near the site. Representative climatologic stations were selected based on their proximity to the site and reliable period of records for the station (30 years or more). 3.2.1 Temperature Summer high temperatures often exceed 100 degrees Fahrenheit (°F), averaging from the low 9O's in the northern part of the valley to the high 9O's in the south. The daily summer temperature variation can be as high as 30° F. Winters are for the most part mild and humid. Average high temperatures during the winter are in the 5O's, while the average daily low temperature is approximately 45° F. 3.2.2 Precipitation Precipitation at the project site is typical of the Central Valley region. Rainfall is seasonal, with approximately 90 percent of the rainfall occurring between November and April. Snowfall is unusual at the site. Figure 4 presents an isohyetal precipitation map for San Joaquin County showing lines of equal precipitation on a countywide basis (San Joaquin County Department of Public Works, 1991). The isohyetal precipitation map divides the whole of San Joaquin County into three rainfall intensity zones. The project site is located in Zone 2 of the three rainfall zones, as shown on Figure 4. Mean annual precipitation for Zone 2 on the San Joaquin County isohyetal precipitation map is approximately 13.5 inches. 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