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Leachate was sampled(collection point L-1, L-3, and L-4) in the first semester of 2012 (Table 6). The next Leachate sampling event is scheduled for the second semester of 2012 and will be included in the second semester 2012 report. Twenty Six different VOCs were reported in the first semester 2012 leachate sample. The highest VOC concentrations reported were the Xylenes, MtBE, TBA,Acetone,the benzene compounds, and Toluene. Results are consistent with past leachate monitoring events. Presence of VOCs in the leachate do not indicate groundwater contamination,but rather indicate the success of the liners at North County Landfill in preventing groundwater contamination. Secondary Sump Monitoring The liquid level in the secondary sumps of Module 3 and 4 are monitored quarterly. No liquid was found in either secondary sump since monitoring began in July 2010. This lack of liquid indicates that the primary liner is not leaking. Module 1 is not provided with a secondary sump. GROUNDWATER DIRECTION AND FLOW RATE The groundwater elevations indicate that groundwater flow is to the east during first and second quarter of 2012 (Figures 3 and 4). These are unusual groundwater flow conditions, as flow is historically in a westerly direction. It appears that starting in 2009 the regional flow pattern has shifted to the south- southeasterly and sometimes to the easterly direction. This change in flow direction may be due to changes in groundwater pumping. The average calculated groundwater velocity is 15.30 ft/yr in the first quarter and 13.47 ft/yr in the second quarter(Appendix G). STANDARD OBSERVATIONS Site inspections were performed weekly this semester(Included as PDF on CD). An electronic signature on the form certifies that all observations were performed and are accurate. RUN-OFF/RUN-ON FACILITIES The NCRC&SL utilizes several facilities to control run-on and run-off. A perimeter berm around the waste management unit prevents any run-on to the unit. This perimeter berm, along with a series of ditches, also controls all surface run-off during storm events, and directs surface run-off from the landfill to a retention basin on the east side of the site (Figure 3). The primary path for water entering the site is from a tributary of South Paddy Creek east of the site. Water entering from this source is diverted into the wetlands on the north end of the site and around the unit (Figure 3). North County RC&SL Public Works/Solid Waste 15'Semester 2012 Groundwater Monitoring 9 County of San Joaquin—July 26,2012