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kn KLEINFELDER An employ..'owneAernnpany File No. 20-4099-04.E02 August 31, 2005 Mr. John Fio ' HydroFocus, Inc P.O. Box 477 Dixon, CA 95617-2401 ' Re: Disposition of Destroyed Wells and Piezometers Mossdale Village, Lathrop, California ' Dear Mr. Fio: Kleinfelder completed the abandonment procedures of nine (9) damaged J unserviceable / un-needed monitoring wells and piezometers at the Mossdale Village development site located west of Interstate 5 in Lathrop, California. As described in j Kleinfelder's Letter to HydroFocus, Inc. dated June 8, 2005 the abandonment procedures were conducted in accordance with the Regional Water Quality Control Board (RWQCB) requirements and Kleinfelder's letter describing the abandonment ' procedures dated December 20, 2004, titled "Monitoring Well Abandonment Procedures, Mossdale Area, Lathrop, California" and San Joaquin County Public Health Services Environmental Health Division Well Standards. i i ' However, as stated in the June 8, 2005 correspondence to HydroFocus, eleven former monitoring wells/piezometers could not be located by field reconnaissance (TMW-1, TMW-7, TMW-9, TMW-10, LMW-2, LMW-3, LMW-5, LMW-6, P-3, P-7, and P-8), and ' are assumed destroyed by development and construction activities such as grading and construction. The former well/piezometers were previously only surveyed for top-of- casing elevations and not horizontal coordinates. Hence, locating them with GPS or surveying techniques is not possible. On more than one occasion, Kleinfelder's field reconnaissance efforts included physically canvassing the area where the destroyed wells/piezometers were formerly located (based on historical drawings and distances ' from known landmarks), and digging down with a shovel in an attempt to uncover the remnant well casing. These efforts failed to locate the remnant well casings. As part of these well location efforts, Kleinfelder also performed an extensive aerial photograph ' review to determine approximate well locations of wells located near application areas. Plate 1 shows the locations of all previously installed wells and piezometers at the Mossdale site, including the eight destroyed wells and three destroyed piezometers. ' Most of the destroyed well/piezometer sites (TMW-1, TMW-7, TMW-9, TMW-10, LMW- 2, LMW-3, LMW-6, P-3, P-7 and P-8) are now located in developed areas outside the boundaries of the constructed agricultural disposal fields, whereas one well (LMW-5) is ' located outside the eastern boundary of agricultural disposal field 52a. C20-4099-04.E02/ST05 R 1 057/J DZ:Iv Page 1 of 5 ' ©2005 Kleinfelder, Inc. August 31,2005 KLEINFELDER 2825 East Myrtle Street, Stockton, CA 95205-4794 (209)948-1345 (209)948-0621 fax