Laserfiche WebLink
9 <br />4.2.3 Precipitation <br />The facility receives an average of 17.6 inches of precipitation per year (Western Regional <br />Climate Center Lodi Station, data from 1948 to 2007). Monthly precipitation varies from 0.03 <br />inches in September to 3.4 inches in January. Spatial variation of total annual rainfall is shown <br />on the isohyetal map (Plate 9) <br />4.2.4 Design Storm <br />The drainage facilities of the NCRC&SL are designed to withstand a 100 -year 24-hour <br />precipitation event, with a total 3.65 inches of precipitation (California Department of Water <br />Resources, Oakdale Woodward Dam). The requirements for the design storm for the landfill are <br />identified in the waste discharge requirements (Appendix A). <br />4.2.4.1 Evaporation <br />The mean annual pan evaporation at the NCRC&SL is 64.92 inches (Western Regional Climate <br />Center Lodi Station, data from 1948 through 2005). The mean monthly evaporation varied <br />between 0.06 inches in December and 10.60 inches in July. These values can be adjusted by <br />multiplying by 0.7 or 0.8 to more closely estimate the evaporation from large bodies of water such <br />as ponds and lakes. <br />4.2.5 Runoff Volume and Pattern <br />The primary path for water entering the landfill property is from a tributary of South Paddy Creek <br />east of the site. Water entering from this source is diverted into the mitigation area on the <br />northern portion of the site (Plate 3). <br />The NCRC&SL utilizes several facilities to control run-on and runoff. A perimeter berm around <br />portions of the waste management unit intercepts run-on to the landfill. This perimeter berm, <br />berms on the landfill, and a series of ditches, controls surface runoff during storm events, and <br />directs surface runoff to an interim sedimentation basin on the east side of the site. <br />0 <br />North County RC&SL Page 15 of 69 Public Works/Solid Waste <br />Joint Technical Document County of San Joaquin — February 10, 2010 <br />