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Brendan Kenny
<br /> Central Valley Regional Water Quality Control Board
<br /> July 15, 2026
<br /> • On May 25, 2026, the flow meters at EW-1, EW-2, EW-3R, and EW-4 were removed to be sent for annual
<br /> calibration. There are currently no flow meters at EW-1, EW-2, EW-3R, and EW-4 while the manufacturer
<br /> repairs the flow meter. It is expected to be replaced during third quarter 2026.
<br /> Total VOCs (up to 5.00 micrograms per liter of total VOCs)were detected in the six system influent samples
<br /> collected. No VOCs were detected above the practical quantitation limit in any of the system effluent samples
<br /> collected at the point of compliance, satisfying the discharge requirements of the Order.
<br /> Per the WDRs in the Order, the effluent sample concentration limit for VOCs at the GWTS was not detected
<br /> above the practical quantitation limit. Given the results from all effluent samples collected, the GWTS was
<br /> compliant with the WDRs during the reporting period. Details regarding influent and effluent sampling, field
<br /> sheets, and copies of the laboratory reports are provided under separate cover in the Second Quarter 2026
<br /> Groundwater Treatment System Monitoring Report and will be submitted by July 31, 2026.
<br /> Residential Treatment Systems
<br /> During the reporting period, Forward continued to provide operation, monitoring, and maintenance for 14
<br /> residential GWTSs on Austin and Newcastle Roads. The treatment systems are composed of inline sediment
<br /> filters and dual GAC vessels that remove VOCs from the water prior to the water entering the residences. Regular
<br /> system sampling and maintenance on the treatment systems are performed by Del-Tech.
<br /> The effluent(post-treatment)sample concentration limit for VOCs at each residential GWTS is non-detect. The
<br /> effluent results represent the water that flows into the tap at each address. All residential GWTSs were in
<br /> compliance with this effluent limit during the reporting period. A separate summary report for the residential
<br /> GWTSs is prepared quarterly and the results for the reporting period will be submitted by August 1, 2026.
<br /> Landfill Gas Collection and Control System
<br /> During the reporting period, the landfill GCCS at the Site was monitored by a network of landfill gas extraction
<br /> wells. The landfill gas collected from these wells is routed and split between two onsite flares (FL-100 and FL-
<br /> 150) and the onsite landfill gas-to-energy plant operated by Ameresco. Flares FL-100 and FL-150 were previously
<br /> reported as Flare A-2 and Flare A-3, respectively. The landfill gas extraction wells are monitored bi-weekly and
<br /> landfill gas probes are monitored quarterly by SCS Engineers (SCS) of Modesto, California and reported by
<br /> Geosyntec Consultants (Geosyntec)of Oakland, California. The SCS quarterly probe monitoring results and bi-
<br /> weekly extraction well monitoring results are included in Tables 1 and 2, respectively, of Geosyntec's Second
<br /> Quarter 2026 Corrective Action Program Update, which is included as Attachment 2.
<br /> The CAO requires annual VOC analysis by United States Environmental Protection Agency (USEPA) Method TO-
<br /> 15 for any probe with methane concentrations exceeding 1 percent by volume and/or VOC concentrations
<br /> exceeding 10 ppbv (parts per billion by volume). On June 11, 2026, six gas probes (GP-1 AD, GP-1 AM, GP-1 AS,
<br /> GP-2AS, GP-1 OD, and GP-10M) had exceedances of methane greater than one percent by volume. In addition,
<br /> nine probes had VOC concentrations above 10 ppbv with concentrations ranging from 300 ppbv in gas probe GP-
<br /> 2AD to 12,800 ppbv in gas probe GP-3AS (Attachment 2, Table 1). On June 26, 2026, four gas probes (GP-1AD,
<br /> GP-1AS, GP-2AS, and GP-2AM) had exceedances of methane greater than one percent by volume. In addition,
<br /> 21 probes had VOC concentrations above 10 ppbv with concentrations ranging from 100 ppbv in gas probes GP-
<br /> 11 M and GP-12S to 385,000 ppbv in gas probe GP-6AM (Attachment 2, Table 1). As a result, 25 probes (GP-
<br /> 1AD, GP-1AM, GP-1AS, GP-2AD, GP-2AM, GP-2AS, GP-3AD, GP-3AM, GP-3AS, GP-4AD, GP-4AS, GP-SAD,
<br /> GP-5AM, GP-SAS, GP-6AM, GP-6AS, GP-1 OD, GP-1 OM, GP-10S, GP-11 D, GP-11 M, GP-11 S, GP-12D, GP-
<br /> 12M, and GP-12S)will require annual sampling and analysis of VOCs using USEPA Method TO-15 in
<br /> accordance with the CAO. The next annual sampling event will be performed no later than fourth quarter 2026.
<br /> www.arcadis.com 3/4
<br /> Forward Landfill 2Q26 CAP Update_07.15.2026
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