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Groundwater Well Installation Work Plan Sharpe Army Depot Lathrop, California The wells will also be protected by three or more bollards of concrete-filled, 4-inch-diameter steel pipe cast surrounding the installed well. Monitoring Wells For onsite monitoring wells (MW549C and MW550C), a 6-inch diameter locking steel casing set into a concrete pad (2 to 4 ft square pad)will be installed around each well casing the top of the steel casing will be set approximately 3 ft above the ground surface. The stickup (steel casing) diameter will be 6 inches. The concrete pad will be sloped from the edge of the steel casing to the edge of the pad and smoothed with a trowel to facilitate the flow of surface water away from the well.The well will also be protected by three or more bollards of concrete-filled, 4-inch-diameter steel pipe cast surrounding the installed well. For offsite monitoring wells (MW551B/C and MW552C), the completions will be flush mounted to an elevation similar to that of the surrounding street. A traffic-rated 16-inch diameter steel casing and lid completion will be installed. The concrete apron will be sloped from the edge of the steel casing to the edge of the pad and smoothed with a trowel to facilitate the flow of surface water away from the well. 3.2.5 Conveyance Piping Installation and Electrical Hook-up Preliminary conveyance piping line routes are shown on Figures 13 and 14. Final conveyance line locations will be determined after negotiations with UPRR. Extraction wells EWC6 and EWC7 will be connected to the existing contaminated-water conveyance piping that runs to the South Balloon GWTP (Figure 13). Electrical and communications conduits will be installed to allow connection of the new wells to the existing electrical power supply and allow for connection to the GWTP control systems. EWC6 is located approximately 800 ft southwest of the existing well EWC5, as shown in Figure 13. EWC7 is located about 200 ft northwest of the existing well EWC5, as shown in Figure 13. Extraction wells EWC8 and EWC9 will also be connected to the existing contaminated-water conveyance piping that runs to the South Balloon GWTP (Figure 13). Electrical and communications conduits will be installed to allow connection of the new wells to the existing electrical power supply and allow for connection to the GWTP control systems. EWC8 is located offsite approximately 100 ft northeast of MW543C on the east side of the UPRR tracks, and EWC9 is located offsite approximately 675 ft north of MW540C on the west side of the UPRR tracks. Conveyance piping to connect EWC8 to the South Balloon GWTP will require directional drilling beneath the UPRR tracks. Extraction well EWCC7 will be connected to the existing contaminated-water conveyance piping that runs to the Central Area GWTP (Figure 14). Electrical and communications conduits will be installed to allow connection of the new well to the existing electrical power supply and allow for connection to the GWTP control systems. EWCC7 is located approximately 550 ft southwest of the existing well MW514C and approximately 275 ft east of existing wells MW525C and EWC6, as shown in Figure 14. Trenching will be required to install the new conveyance piping and electrical and communications conduits, and the displaced soil will be managed as discussed in Section 3.3, "Waste Management." The new wells and trenching will not be located in areas of contaminated soils. Ahtna Environmental,Inc. 16