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• Draft Supplemental Environmental Impact Report Page IV.G-13 • Forward Inc. Landfill 2018 Expansion Project • nowhere to feasibly relocate MW-18, this well was proposed to be decommissioned without replacement. It appears that sufficient groundwater information can be obtained from surrounding wells to negate the need for a MW-18 replacement well. A workplan to • decommission and replace MW-17 and 19 and to abandon MW-18 was provided to the RWQCB . and approved by them. It is proposed that the replacement wells be installed before the • decommissioning of existing wells to provide some overlap in the data. • The well MW-17 is the only one of the three wells to be decommissioned that has a history of • VOC hydrochemistry. In Q1-2018 the Well MW-17 showed trace levels of carbon tetrachloride, • chloroform, and trichlorfluromethane above the limits, albeit at trace concentrations. • As discussed previously, there are two groundwater monitoring programs for the Forward • Landfill, one for the Forward Unit and the other for the Austin Road Unit. The Forward • Landfill, initiated in 1973, has had a groundwater-monitoring program since 1977. In accordance with WDR Order R5-2005-0049, there are 37 monitoring wells (including well pairs), • 19 associated with the Forward Unit, and 18 associated with the Austin Road Unit. Additional wells have been added to the monitoring program since the WDR Order was issued,however • the WDR Order has not yet been modified to reflect these changes. The additional wells are (or • will be in the case of the newly installed wells) sampled and reported in quarterly monitoring reports. Both landfill units also have water supply wells. The monitoring and supply well locations are depicted on Figure IV.G-1. The existing monitoring system meets the requirements • of the landfill's Detection Monitoring Plan(DMP) for groundwater monitoring, and the CAP for • groundwater impact. • Austin Road Unit • The main area of groundwater impact is downgradient of the landfill units in the Northern • California Youth Center (NCYC). This facility historically had its own groundwater production • wells which served to pull the Landfill related plume downgradient towards it until it stopped • production and municipal water was piped into the facility in 2011. The RWQCB has required • Forward to evaluate the offsite plume vertical sampling at the Forward Landfill well AMW-37. In September 2017 was completed by GLA in compliance with the Cleanup and Abatement • Order(CAO) No. R5-2017-0703, Requirement 4.A. This was done based on the approval of April 28, 2017 West Side Monitoring Well Installation Workplan,Forward Landfill, San Joaquin • County issued by the RWQCB. The vertical profile well was drilled to a total depth of 500 bgs • and discreet groundwater samples were collected at first water(71 feet) and within observed water-bearing sands depths of 90, 100, 168, and 380 feet bgs. No volatile organic compounds • were detected in the groundwater below 71 feet bgs. • Groundwater quality is summarized in the quarterly and annual monitoring reports. Reports • are submitted to the RWQCB and DTSC and can be viewed on the California Geotracker system • (http://geotracker.swrcb.ca.gov/). The groundwater-monitoring system is designed to detect • the presence of contaminants in groundwater by analyzing groundwater chemistry at • point-of-compliance wells. Chlorinated halocarbons, also referred to as volatile organic compounds, are typically the chemicals of concern that are detected at landfills. Numerous • studies and groundwater monitoring events have been completed. • • • •