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affected by the contaminant plume or potentially affected in the future, imposes deed restrictions on future residential development adjacent to the site downgradient, requires a signed Interagency Management Agreement to control future groundwater use at the site, and requires DDRW-Tracy to provide bottled water to two families. As with Alternative 1, the groundwater plume would be monitored using 30 wells. This alternative would also be implemented for 30 years. The estimated costs are shown below: Monitoring Costs $1,734,300 Bottled Water Costs $13,800 Capital Costs 0 Annual O&M Costs 0 Present Worth Cost for 30 years $1,748,100 Alternative 3 is groundwater extraction at 1000 gpm with treatment by air stripping and vapor-phase carbon and injection into the aquifer, and is designed to capture and remediate the entire OU #1 on-site and off-site contaminant plume. This alternative would use the current IRM air stripping system plus one additional similar air stripping system to handle up to 1000 gpm of extracted groundwater. Groundwater would be extracted using a total of 41 extraction wells, treated by the two air strippers, and injected back into the upper and middle horizons of the aquifer using a total of 34 injection wells. This alternative includes monitoring of the groundwater and would be implemented for 45 years. The estimated costs for the EPA-mandated 30-year period are: Monitoring Costs $1,734,300 Capital Costs $3,324,400 Annual O&M Costs $285,200 5-year Performance Evaluation $69,600 (performed at end of years 5, 10, 15, 20, 25, and 30) Present Worth Costs for 30 years $9,512,500 Alternative 4 is groundwater extraction at 1000 gpm with treatment by air stripping and vapor-phase carbon with in situ biological treatment and injection into the aquifer. This is a novel approach to treat the extracted groundwater by air stripping, as in Alternative 3, then Q:-N9WO43.1(90380CN I 11 M1007922139