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WORK PLAN FOR GROUNDWATER MONITORING WELL INSTALLATION This work plan is for the installation of a groundwater monitoring well at the Austin Road Landfill, San Joaquin County, California. Preparation of this work plan was authorized by the City of Stockton by purchase order number 070956, dated June 15, 1995. This work plan was prepared by the Environmental Services Division of The Twining Laboratories, Inc. (Twining) in Fresno, California. wllm� KH fi 1 1 �i�� 1 i► i i On June 28, 1995, The Twining Laboratories, Inc. (Twining) installed monitoring well MW - 14 to a depth of 92 feet below site grade (BSG) using a hollow -stem auger drilling rig. Groundwater was encountered during drilling activities at a depth of 77 feet BSG. This depth was confirmed by withdrawing the augers to above the top of the saturated zone and allowing the water in the borehole to stabilize for the period of 20 minutes. At the end of this period of time, the standing water level was checked and again found to be 77 feet BSG. The depth of the boring was then adjusted from an initial depth of 100 feet to a depth of 92 feet BSG. The shallower depth was chosen to allow for the use of a 20 -foot long screened section. The screen was placed 15 feet into groundwater. Five feet of screen was positioned above the static water level to allow for potential groundwater fluctuations (i.e., a rise in the groundwater elevation). On June 29, 1995, the newly installed monitoring well was initially developed. Prior to development, the depth to groundwater was measured at 77.18 feet BSG. Additional development was performed on the well the following day (June 30, 1995). The depth to the standing water level was 77.30 feet BSG at this time. A dedicated bladder pump was installed in the well on August 15, 1995. The depth to groundwater was measured at 83.15 feet BSG prior to pump installation. Based on this depth to groundwater, the water level had declined 5.85 feet since the well was installed. On October 6, 1995, Twining was notified by Mr. John Fukumoto of the City of Stockton that the depth to water in Well MW -14 was 85 feet and that the dedicated bladder pump