ARCHIVED REPORTS_2013_1 - Laserfiche WebLink

Home Browse Search

1.0 Surface Water Monitoring During the third quarter 2012 monitoring event, surface water sampling was performed at the French Camp Landfill by Del-Tech Geotechnical Support Services, Inc. (Del-Tech). Surface water samples were collected from monitoring points SW-1, SW-2, and SW-3. Upstream surface water monitoring points SW-1 in Walker Slough and SW-2 in French Camp Slough are sampled to provide background monitoring data. Surface water monitoring point SW-3 is downstream at the confluence of the sloughs. The Waste Discharge Requirements (WDRs) stipulate semi-annual sampling of the surface water monitoring points for field parameters (pH, specific conductance, temperature, and turbidity) and monitoring parameters (bicarbonate alkalinity, calcium, carbonate alkalinity, chloride, magnesium, nitrate,potassium, sodium, sulfate, total dissolved solids [TDS], and volatile organic compounds [VOCs]). The field-results provided by Del-Tech and the laboratory results provided by BC Laboratories, Inc. (BC Labs) for the third quarter 2012 surface water monitoring event are summarized on Table 2.1. The historical surface water data are presented in Appendix A. Time series concentration plots of historical surface water data are presented in Appendix B. The concentration limits presented on Table 2.1 were calculated from upstream data collected through the third quarter 2012 monitoring event. The statistical analysis calculations for surface water monitoring points are presented in Appendix B. Information on the development of the concentration limits can be found in the Fourth QuarterlAnnual 1999 Monitoring Report, French Camp Landfill prepared by CH2M HILL in January 2000. A copy of the statistical analysis methodology is presented in Appendix C. There were no constituents that exceeded their concentration limits at SW-3 during the third quarter 2012 monitoring event. There were no VOCs detected at surface water monitoring points during the third quarter 2012 monitoring event. Historical data from the surface water monitoring points were evaluated for temporal trend using Mann-Kendall / Sen's Slope trend analysis. Graphs and summary tables of the Mann-Kendall/ Sen's Slope analyses are presented in Appendix B. Only carbonate alkalinity at SW-1 and SW-3 and field turbidity at SW-1 exhibited significant increasing statistical trends according to the Mann-Kendall / Sen's Slope evaluation. Given that carbonate alkalinity exhibits a significant increasing statistical trend at upstream monitoring point SW-1, the increasing trend for carbonate alkalinity at downstream point SW-3 is likely due to ongoing changes in the natural surface water geochemistry at the site. Chloride at SW-2, nitrate at SW-1 and SW-3, sulfate at SW-1, and TDS at SW-1 exhibited significant decreasing statistical trends according to the Mann-Kendall / Sen's Slope evaluation. Soil cover has been placed over the waste material to prevent ponding of stormwater and to protect surface water. In addition, a perimeter ditch directs stormwater to a basin in the southeast comer of the site. A smaller ditch collects stormwater from the grinding area in the northeast comer of the site. Inspection and maintenance procedures for these stormwater control structures are provided in the site's Stormwater Pollution Prevention Plan. The facility reported that these control structures effectively directed stormwater from the waste material during the third quarter 2012. 2.0 Groundwater Monitoring Program During the third quarter 2012 monitoring event, groundwater monitoring was performed at the French Camp Landfill by Del-Tech. Groundwater samples were collected from one background