CORRESPONDENCE_2018-2023 - Laserfiche WebLink

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3) The alleged failure to restore beneficial uses of aquifer in the timeframe required by the CAO: 1 July 2023. To summarize the NOV, it is alleged that Forward failed to submit a Revised Engineering Feasibility Study that includes a proposal for a remedial action capable of stopping further migration of VOC- impacted groundwater beyond the Landfill's point of compliance (POC), as well as restoring the beneficial uses of the aquifer by July 1, 2023. However, Forward has already demonstrated to the RWQCB that the improvements to the groundwater extraction and treatment system at the Forward landfill have provided complete capture of VOCs at the Landfill's POC, meeting one of the Remedial Action Objectives (RAOs)stipulated in the CAO. Since February 2009, the groundwater extraction and treatment system designed to capture groundwater from the shallow and intermediate zones along the Landfill's POC has been improved with well rehabilitation efforts, the installation of additional groundwater recovery wells, and the construction of an artificial recharge basin. These improvements provided complete capture of VOCs at the POC, meeting one of the remedial action objectives (RAO) stipulated in the CAO (see enclosed figure and summary table). Combined with previous landfill enhancements, these improvements also resulted in downgradient water quality improvements by the creation of a clean groundwater waterfront migrating downgradient of the POC. Since the installation of the POC performance monitoring wells (AMW- 40S/M, AMW-41 S/M, AMW-42S/M, and AMW 43S/M), VOCs were not detected at concentrations above 0.5 pg/L in the following quarters: 1Q 2023, 4Q 2002, 3Q 2022, 2Q 2022, 1Q 2022, 4Q 2021, 3Q 2021, 1Q 2021, and 4Q 2020. Concentrations above detection levels were only observed in 2Q 2021 (AMW-41 M with 0.59 pg/L PCE) and 3Q 2020 (AMW-41 M with 0.53 pg/L TCE). This indicates that the clean waterfront has been migrating at least since the installation of the compliance points and likely before this point, when EW-5 was brought online at the end of 2019. As of March 2023, concentrations of PCE in groundwater potentially contributed by the Landfill (prior to establishment of the clean waterfront)within the shallow and intermediate zones slightly exceed the drinking water maximum contaminant level (MCL) of 5 micrograms per liter (pg/L). The plume that extends to the northeast of the separate offsite VOC source(s) on the CDCR property includes compliance wells with PCE concentrations that marginally exceed the MCL of 5 pg/L; however, access restrictions to the CDCR property from 2017 to 2021 had limited potential investigation of this offsite source and remedial action for these areas and subsequently delayed restoring the beneficial use of groundwater. Finally,the CAO does not require the restoring of all beneficial uses(however that term may be defined) in groundwater north of the landfill by July 1,2023.The 2017 CAO required Forward to submit combined reports by December 1, 2019, containing "a proposal for a remedial action capable of stopping further migration of VOC impacted groundwater beyond the point of compliance. as well as restoring the beneficial uses of groundwater in all zones affected by the release for the entire plume by 1 July 2023." (CAO, § 5(c)(iii)). Forward provided such a report to the RWQCB based on the information available to it at the time. In 2019, Forward did not have access to the prison property or know about the separate source of TCE contamination at 7833 Newcastle Road. Forward respectfully submits that the off-site contamination caused by these separate sources are not the result of"the release"from the landfill as described in the CAO. Forward has advised the RWQCB that further investigation of the CDCR property is required to fully understand the nature and extent of the contamination at the CDCR property (which, so far, the RWQCB has declined to authorize)and that remedial action other than extraction wells now appears to be the most appropriate means to deal with the off-site contamination at the prison facilities. 4