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REPORT-WELL DESTRUCTION AT MW-9E AND INSTALLATION OF REPLACEMENT WELL MW-11 CITY OF MANTECA WASTEWATER ' QUALITY CONTROL FACILITY San Joaquin County,California 1.0 INTRODUCTION ' Condor Earth Technologies, Inc. (Condor) supervised the destruction of monitor well MW-9E and the installation of a new replacement monitor well MW-11 at the City of Manteca's (the City) Wastewater Quality Control Facility (Facility). The Facility is located approximately l mile west-southwest of the ' town of Manteca (Figure 0. Well MW-11 is located on the north side near the west end of the road between Fields 11-N and 11-S. ' The monitor well was installed as required by the California Regional Water Quality Control Board (CRWQCB) Waste Discharge Requirements (WDRs) Order No. R5-2004-0028 and in accordance with the Groundwater Well Destruction and Replacement Well Installation Work Plan for the City of Manteca ' Wastewater Quality Control Facility(Work Plan); dated December 8, 2006 and prepared by Condor. The Work Plan was approved by James D. Marshall of the CRWQCB via email to Warren Shannon at the city of Manteca on January 5,2007. ' 2.0 SITE BACKGROUND INFORMATION The City owns and operates a wastewater treatment facility that receives wastewater from the city of ' Manteca and from a portion of the city of Lathrop. Treated effluent from the facility is either discharged to the San Joaquin River or applied at agronomic rates to land adjacent to the wastewater treatment plant. The land application area is approximately 172 acres, and 6 monitor wells located within, up gradient, ' and downgradient of the land application area have been installed to monitor groundwater quality. The layout of the Facility and the land application facility is shown on Figure 2. ' Rainfall at the site occurs primarily in the months between November and March. Annual precipitation is reported to be approximately 11 inches. Pan evaporation measured by the State of California (California Department of Resources Bulletin 73-79, November 1979) at Manteca indicates mean evaporation to be ' 69.3 inches from a Class A Evaporation Pan. Using a 0.79 pan correction factor on the pan measurement, annual evaporation is calculated to be 54.7 inches per year. ' 3.0 GEOLOGY AND GROUNDWATER The Facility is located in California's Great Central Valley physiographic province. The valley is filled with Tertiary and Quaternary clastic sediments to depths of greater than 20,000 feet. The Facility is directly underlain by alluvial sediments mapped as the Quaternary Modesto Formation (California Division of Mines and Geology Regional.Geologic Map of the San Francisco-San Jose Quadrangle — Map No 5A published in 1991). The ground surface at the project site ranges from 20 to 25 feet above t mean sea level and is generally flat with a slight slope towards the west. The San Joaquin River is a gaining stream and is located approximately 10,000 feet to the west of the Facility. The river flows generally from the south to the north. 1 L� CONDOR