SR0084138 - Laserfiche WebLink

Home Browse Search

Second Semi-Annual 2021 Groundwater Monitoring, Batch Extraction Results Report & Supplemental Site Investigation Waterloo Food and Fuel 3032 East Waterloo Road, Stockton, California Page 5 MODIFICATIONS FROM STANDARD MONITORING PROGRAM On August 4, 2021, the Central Valley Regional Valley Water Quality Control Board (CVRWQCB) issued a letter responding to a review of the Apex First Semi-Annual 2021 Groundwater Monitoring Report for the Site dated June 15, 2021 (1Q21 GMR) and a review of the Apex Underground Storage Tank System Leak Investigation Report of Findings (UST Report), dated June 14, 2021. In summary, the CVRWCB provided the following six (6) comments: Please sample all Site monitoring wells deemed functional in the 1Q21 GMR, as well as remedial wells EW-1 through EW-3 during the 3rd quarter 2021 and submit a groundwater monitoring report by 1 November 2021. In this report, and all subsequent GMRs, please include Site free product data, including measured depth to product and product thickness, in the current and historical groundwater data tables. Additionally, as part of the GMR, please include photos of well EW-1 and the nearby UST fill port, both with and without vault lids, and inside of the EW-1 well casing. Central Valley Water board staff does not concur with Apex's theory of an accidental diesel release into EW-1; however, staff concurs with groundwater remediation to reduce petroleum concentrations in wells that exceed the State Water Resources Control Board's Low Threat UST Case Closure Policy (LTCP). Following the 3' quarter 2021 sampling event, please complete three batch extraction events consisting of 300 gallons removed from each of wells EW-1 through EW-3 during 3' and 4th quarters 2021 and 1St quarter 2022. Please monitor the batch extractions as proposed. Please sample site monitoring wells and remedial wells EW-1 through EW-3 during Pt quarter 2022, following the 3rd batch extraction event, and submit a GMR by 1 April 2022. In this report, please include conclusions and recommendations related to current groundwater conditions, free product, the efficacy of the batch extractions, and the need for additional remedial action. Please include all free product measurement data collected during the batch extractions in the historical groundwater data tables. In the January 2019 directive letter, Central Valley Water Boards staff concurred with a scope of work that included on-Site soil sampling and on- and off-site soil gas sampling. The soil gas sampling was intended to assess the potential vapor intrusion risk to off-Site properties. However, as conditions have changed in the past three years, after review of current Site conditions Staff no longer believe that the soil gas sampling scope of work is warranted. By 3 November 2021, please complete only the soil sampling scope of work as discussed and concurred with in the January 2019 directive letter and submit a Site Assessment Report. In this report, please provide discussion and comparison of the collected data to criteria established in the LTCP. This report, Second Semi-Annual 2021 Groundwater Monitoring, Batch Extraction, & Supplemental Investigation Results Report (SAMR 3Q21), modified the typical SAMR scope to include activities that address comment 1, the first of three batch extraction events in comment 2 (see Batch Extraction section below), and comment 4 (Supplemental Site Investigation section below). The remaining comments will be addressed in subsequent sampling events. Photos of EW-1 and the nearby UST fill port are included in Appendix E.