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2017 Corrective Action Evaluation Report-Austin Road Unit Forward Landfill Forward will begin installing _ more perimeter monitoring probes around the Austin Unit in August 2017 to evaluate the effectiveness of the existing LFG extraction system. 6.0 COMPARISON OF CURRENT TO MODELED GROUNDWATER QUALITY The August 8, 2001 Revised Engineering Feasibility Study for Austin Rood Landfill (hereafter, EFS) presented projected isoconcentration contour maps for select VOCs in groundwater based on computer modeling simulations. The four VOCs that were modeled were PCE, trichloroethene (TCE), cis-1,2-dichloroethene (cis-1,2-DCE), and vinyl chloride. These simulations projected how the concentrations of individual VOCs could potentially change following the initiation of recharge within the artificial basin. The EFS presented projected maps corresponding to each year following the initiation of recharge. In past Annual Corrective Action Evaluation Reports, these projected isoconcentration maps were compared to maps based on contemporary data collected from the same monitoring wells utilized in modeling. However, the EFS simulations projected that none of the modeled VOCs would be detected above 1 µg/L by 2012 after nine years of recharge from the recharge basin. Accordingly, there are no projected isoconcentration maps available for comparison to current results. Consistent with past Annual Corrective Action Evaluation Reports, isoconcentration maps for the four modeled VOCs are presented in Appendix D using the second quarter monitoring results. The maps in Appendix D utilize a contour interval of 10 µg/L and do not include values less than 1 µg/L. Figure D-1 presents PCE results in ARU groundwater monitoring wells from May 2017. The May 2017 results indicate that PCE concentrations exceed 1 µg/L at CAP monitoring wells AMW-1 and AMW-13; detection monitoring wells AMW-6 and AMW-12; domestic supply wells 7898-A and 8106-A; and in EMP/CAP wells AMW-13, AMW-13B, AMW-186, AMW-19, AMW-19BR, AMW-21, AMW-21S, AMW-22, AMW-22S, AMW-24R, AMW-26R, AMW-29, AMW-31, and AMW-31S. The highest concentration of PCE was measured at 23 µg/L in well AMW-22S. Figure D-2 presents TCE results in ARU groundwater monitoring wells from May 2017. The May 2017 results indicate that TCE concentrations exceed 1 µg/L at CAP monitoring wells AMW-1 and AMW-13; domestic supply well 8106-A; and in EMP/CAP wells AMW-21, AMW-22, AMW- 22S, AMW-26R, and AMW-29. The highest concentration of TCE was measured at 20 µg/L in well AMW-22S. Project No 5017.1030 ( 2017 Corrective Action Evaluation Report-Austin Road Unit 5 Forward Landfill