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3.5 MONITORING WELL INSTALLATION REPORT As required in the July 7, 2011, Order from the RWQCB, a groundwater monitoring well installation report was submitted by December 15, 2011. A second groundwater monitoring well installation report will be submitted to the RWQCB within four weeks after the permanent wells are constructed. The report will describe the field work, including drilling, sampling, logging, well construction, well survey, and well development methodologies, final rationale for monitoring well siting, total depths, and screened intervals, and a summary of geologic and hydrogeologic findings. The report will include copies of the final well permit documents, drafted geologic logs of each borehole, drafted well construction logs, and well development data. Proposed additional well locations will be identified, if VOCs are found in any well. ® 3.6 EVALUATION MONITORING PROGRAM REPORT The EMP report will be prepared to summarize all field work, results of laboratory analyses, and data analysis and interpretations culminating in an assessment of the nature and extent of the release from the CHSL. The EMP report will also address any new understanding of the groundwater flow system in the shallow, perched aquifer. Existing and new analytical data will be reviewed to characterize the nature of groundwater release in the perched, shallow aquifer at the CHSL. GLA will evaluate historical groundwater chemistry data for samples from wells MW -5 and MW -8 to assess trends in VOC concentrations as they pertain to seasonal influences (precipitation events preceding microbial degradation of wastes and subsequent increases in VOCs), breakdown of primary VOCs and formation of daughter products, and responses to existing corrective actions. Groundwater chemistry data from existing monitoring wells and the new EMP wells will be used to construct isoconcentration contours of principal VOCs and the total VOC load to illustrate the distribution of VOCs in the perched aquifer and to estimate the extent of VOCs. To evaluate groundwater flow conditions, groundwater equipotential surface data will be calculated for all perched, shallow aquifer wells using surveyed top -of -casing elevations and depth to water measurements so that equipotential contours can be developed and groundwater flow directions and gradients can be calculated. Hydraulic conductivity estimations from bail down and recovery tests will be used, along with the hydraulic gradients, to estimate groundwater flow velocities in the perched aquifer. The results will be presented on a groundwater contour map encompassing the existing site and the new monitoring wells. Groundwater flow and chemistry data will be used to construct simple numerical models employing the U.S. EPA's Biochlor and Bioscreen programs to simulate transport of contaminants, and various graphical methods will be used to evaluate the fate of 14 2011-0115 CHSL EMP Workplan Geo -logic Associates Revision 2 — January 11, 2012