COMPLIANCE INFO_EW-5 INSTALL PERMIT PACKAGE 2/14/25

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Forward, Inc. - 2 - 27 March 2023 1. Proposed groundwater monitoring well AMW-52s shall not have a screen interval greater than 20 feet in length and shall be installed such that the screen interval intersects the water table. 2. All monitoring wells shall be developed such that the measured turbidity is equal to or below 5 NTUs. Following development, the wells should rest for a period time prior to purging and then sampling. If elevated turbidity is an issue, please take the necessary steps to properly engineer and construct the filter pack interval, and the slotted interval. Forward, Inc. should consider using a tremie pipe when placing all material in the well annulus. Adding the use of a surge block during the introduction of filter pack material can improve the performance of the well. Prepacking the well screen is another engineered practice that has been shown to reduce turbidity in wells. If turbidity cannot be achieved after multiple development efforts, then Forward, Inc will need to submit a plan to re-install/reconstruct the monitoring wells. 3. Based on the proposed piezometer construction details in Table 1 of the workplan for PZ-4, PZ-5 and PZ-6, these are to be constructed as observation wells for the aquifer testing. Following the aquifer tests, these wells shall be become a part of the well network and shall be monitored in accordance with the monitoring schedule in the MRP. Prior to long-term sampling these wells should be designated as a monitoring well “MW” to reduce confusion. The first sampling following development shall include all analytes listed on the 5-year sampling event in the MRP. The Geotracker database account for this site shall be set up such that these three observation wells are identified as monitoring wells. 4. Since Forward Inc., has proposed extraction wells EW-2, EW-3 and EW-4 only to be installed in the intermediate aquifer zone with no additional extraction wells with proposed in the shallow zone, it does not seem that these small diameter wells will be able to achieve compliance with the CAO which requires Forward Inc., to optimize the extraction rate to address contamination present in both the shallow and intermediate aquifer zones, as well as create a measurable drawdown in the wells Forward Inc., installed at the edge of the plume. For clarification of the requirements in the CAO, Item 3c states in part, “…The extraction wells shall be located near the center of plume mass and must be able to contain and treat the VOCs, create an inward gradient of the groundwater table, measured from existing monitoring wells within the plume, in all zones affected by the release….” As previously stated in our letter dated 24 March 2022, the Central Valley Water Board staff cannot direct the Discharger on how to comply with the requirements of the CAO. The bulleted list above clearly identifies Central Valley Water Board staff’s concerns. At this time, Forward, Inc may proceed with the well installation, with the understanding additional extraction wells may be necessary to address all zones affected by the release”, and create the required the inward gradient. Considering the amount of time it has taken to install these wells, failure to comply with the conditions of the CAO will initiate further enforcement. Following the completion of the field work, Forward Inc is required by the CAO to submit the following information: “…the Discharger shall submit an Interim Groundwater Plume Remediation System Installation Report that certifies the installation and continuous operation of the additional groundwater extraction wells. Once installed, the extraction wells shall be monitored weekly for flow...”. Again, to clarify the requirements in the Order,the CAO states: “If the Discharger fails