ARCHIVED REPORTS_2011 REVISED FEASABILITY STUDY

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amec— • The well spacing for the injection and extraction wells is based on existing hydrogeologic information for the site and is assumed to be 300 feet (i.e. every three hundred feet there would be either an injection well or an extraction well; the distance between two extraction wells would be 600 feet; the distance between two injection wells would be 600 feet). This configuration amounts to 40 extraction wells and 40 injection wells. Two wells are proposed for each location with one in the upper aquifer zone and one in the intermediate aquifer zone. The total linear feet of drilling for this well configuration is estimated to be 18,800 feet. The total well installation costs are estimated to be $1.5 million. • The capital costs for the treatment system are based on the cost for the Stockton system (approximately $1.0 million). • For estimating purposes it is assumed that all extracted groundwater will be treated in one centralized compound. All conveyance piping to the treatment compound will be located in a common trench. All extraction wells will tie into a common conveyance pipe. Similarly, all injection wells will also tie into a common conveyance pipe. Based on the design flow rate, we estimate that conveyance pipe will need to be 12-inches in diameter. The costs for trenching and pipe installation are estimated to be $1.5 million. • Construction management costs are estimated to be 6% of capital costs or$251,000. • O&M costs include groundwater treatment, electricity costs, maintenance, and performance monitoring. These costs are based on the actual treatment costs for the Stockton Avenue treatment system ($4,000/million gallons) and scaled up to the larger 2,000 gpm extraction rate. Total annual O&M costs are estimated to be $4.4 million per year for a 30 year net present value (7% discount rate) of$53.7 million. 3.5 ENERGY REQUIREMENTS The injection pumps (50 gpm centrifugal, 100' head) and extraction pump (4" submersible, 33 - 55 gpm) are both 3 horsepower (hp) pumps. In addition to the injection and extraction well pump power requirements, the treatment compound air stripper (- 20,000 cubic feet per minute) and centrifugal pump (2,000 gpm centrifugal) would have power requirements of around 30 hp and 75 hp respectively. The annual power requirement to run the extraction pumps, treatment system compound, and injection pumps is estimated at 2,255 mega-watt hours (MWh). Using a carbon dioxide (CO2) electricity equivalent factor of 878.71 pounds of CO2/MWh, for California, as reported in the California Climate Action Registry, General Reporting Protocol, Version 3, April 2008, annual CO2 emissions would amount to approximately 991 tons per year. AMEC Geomatrix, Inc. \\oad-fs1\doc_safe\9000s\9837.006\4000 REGULATORYTS Assessment_Apx B_012711\Attachment B.3\Attach B-3.docx 1334