ARCHIVED REPORTS_2013_1 - Laserfiche WebLink

Home Browse Search

4.5 LEACHATE MONITORING The laboratory results for leachate monitoring well MW-2 are summarized in Table 3 and time-series concentration plots are presented in Appendix D. As shown on Table 3, no VOCs were detected in leachate monitoring well MW-2 during the monitoring period. 4.6 SURFACE WATER MONITORING Field and laboratory results for surface water monitoring stations (SW-1, SW-2, and SW-3) for the current monitoring period are summarized in Table 4 and time-series concentration plots are presented in Appendix D. Stations SW-1 and SW-2 are located upstream of the landfill within the Walker and French Camp Sloughs(respectively) and are used as background sampling points. Station SW-3 is located downstream of the landfill at the confluence of the two sloughs. For the surface water monitoring stations at the French Camp Landfill, CLs are used for the WQPS. Since CLs are not provided in the WDRs,the CLs shown in Table 4 were calculated using historical data from background surface water monitoring stations SW-1 and SW-2. These calculations were performed by Herst& Associates using Sanitas®(a state-approved statistical software program) and are presented in Appendix D. As shown in Table 4, no CLs were exceeded and no VOCs were detected in the samples collected from the surface water stations during the monitoring period. A comparison of upgradient(SW-1 and SW-2)to downgradient(SW-3) surface water samples indicates generally similar inorganic constituent concentrations, suggesting that the landfill is not impacting surface water quality. Only the field turbidity at surface water station SW-1 exhibits a statistically significant increasing trend (Appendix D). However, the increasing trend at upgradient surface water station SW-1 is not indicative of an impact from the landfill. Stream gauging was performed on September 11 and November 17, 2012, at monitoring points SG-1 and SG-2 and the data is summarized in Table 5. As shown in Figures 1 and 2, monitoring point SG-1 is located upgradient in the Walker Slough and monitoring point SG-2 is located upgradient in the French Camp Slough. 5.0 SOIL-PORE GAS MONITORING In accordance with WDR Order No. R5-2007-0046, soil-pore gas probes are monitored semiannually using a field screening protocol, and soil-pore gas samples are only collected if field screening indicates methane concentrations greater than 2.5 percent. During the monitoring period, field screening of soil-pore gas probes was conducted on September 10, 2012. As shown on Table 6, methane was not detected in any of the soil- pore gas probes, and as a result, no samples were collected. c:\zoiz-0027\FC2SAlz.aoc 5 Geo-Logic Associates