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Water produced during the development process will be temporarily contained in 55 -gallon drums. Groundwater will be discharged to the ground surface is laboratory data indicate that concentrations of VOCs are below Maximum Contaminant Levels (MCLs). If VOC concentrations are higher than MCLS, the purged groundwater will be disposed of at the ground surface near the monitoring well in a manner that does not cause erosion or affect the well. 3.4.5 Aquifer Testing Following development and sampling, bail -down and recovery tests will be performed in the new wells to help identify. aquifer properties for later use in predicting the fate of groundwater impacts. Bail -down tests will be performed by bailing the wells dry, and then monitoring recovery of the water levels (similar to a "slug out" test). The data from the bail -down tests will allow calculation of hydraulic conductivity. 3.4.6 Groundwater Sampling and Analysis Groundwater samples will be collected from each new monitoring well and analyzed for the routine monitoring parameters. Groundwater samples will be collected by GLA's field geologist following the procedures outlined in the Practical Guide for Ground Water Sampling (Barcelona, et al., 1985) and RCRA Ground water Monitoring Technical Enforcement Guidance Document (U.S. EPA, 1986). Wells will be sampled using new, disposable polyethylene bailers. Prior to sampling the wells, the depth to groundwater will be measured to the nearest 0.01 foot from an established well datum (e.g., top of casing) using a decontaminated electronic water level sounder. The depth to water will then be used to calculate the water surface elevations in the wells by subtracting the depth -to -water from the estimated top -of -casing elevation. To evaluate groundwater flow directions and hydraulic gradients beneath the site, groundwater depths will be measured in all shallow, perched monitoring wells on the same day. Well purging will be accomplished by bailing with a new, disposable bailer attached to Teflon® rope. Periodically, samples of purged water will be collected and monitored for stabilization indicator parameters (pH, temperature, electric conductivity, and turbidity). The well will be sampled after a minimum of three well casing volumes have been purged, and the indicator parameters have stabilized to within 10 percent of the preceding three measurements and show no discernible upward or downward trend. As described elsewhere, water that is purged from each well will be temporarily contained and stored in 55 -gallon drums, and then discharged to the ground surface in a manner that does not cause erosion or runoff to other properties. 12 2011-0115 CHSL EMP Workplan Geo -Logic Associates Revision 2 — January 11, 2012