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Re-Revised Groundwater Monitoring Well Construction Workplan August 2023 Once the upper bentonite annular seal has hydrated, a a .,,,,,, lar-seat -neat cement sanitary seal will be placed in the annular space,,in one continuous pour using a tremie pipe, between the top bentonite seal to ground surface. The top of the wells will be secured with lockable plugs, within an above-grade steel locking enclosures and by 2-foot-square concrete pad surrounded by four steel bollards. Each well casing will be properly permanently marked with the well identification number. The site geologist will record groundwater elevations from each well following drilling operations and surveying. Well Development DWR will oversee and document monitoring well development activities. Each monitoring well will be developed initially by the driller using a surge block and pumping to immediately begin to clear up the wells and clean up the borehole wall from the drilling process. The wells will be further developed using the air-lift development method. Accumulated sediments in the well bottom will be removed via bailing. Wells will be subsequently developed using a pump with additional surge block until turbidity in the purge water is sustained below 5 NTU during pumping. Well development efforts will be recorded including volume of water and debris removed, and general parameters including temperature, conductivity,pH, and total volume pumped throughout the development process. Groundwater Quality Sampling Groundwater quality sampling of the monitoring wells will occur after the monitoring wells are constructed and analyzed for general minerals, nitrate, and drinking water metals. The samples will be analyzed by a California ELAP certified laboratory. Samples will be collected after purging the well until field parameters stabilize. Purge water will be placed in the adjacent former BCID canal. Surveying After completion of the monitoring wells, their location and reference point at the top of each well casing will be surveyed by a California licensed Professional Surveyor. Reference point elevations for the top of casings were surveyed to the nearest 0.01 foot relative to the North American Datum, 1983 (NAD83) State Planes Zone II (US Foot) for well location coordinates, and vertical datum North American Vertical Datum, 1988 (NAVD88). GEI Consultants, Inc. 20