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TfreadwelEftlb <br /> 12 May 2010 <br /> Project 4843.01 <br /> Ms. Amy Terrell <br /> California Regional Water Quality Control Board <br /> Central Valley Region <br /> 11020 Sun Center Drive, #200 <br /> Rancho Cordova, CA 95670-6114 <br /> Subject: Report of Agricultural Well Destruction <br /> Former Ripon Farm Services Site <br /> 938 Frontage Road <br /> Ripon, California 95366 <br /> Dear Ms. Terrell: <br /> On behalf of Ripon Farm Services,Treadwell & Rollo, Inc. (T&R) has prepared this report to summarize <br /> activities performed to destroy the agricultural water supply well at the former Ripon Farm Services site <br /> at 938 Frontage Road in Ripon, California (Site, Figure 1). The well destruction was performed at the <br /> request of the Regional Water Quality Control Board, Central Valley Region (Water Board letter dated <br /> 28 May 2008). Well destruction activities are summarized below. <br /> Well Condition Assessment <br /> The agricultural water supply well was located along the northeast perimeter of the Site (Figure 2). <br /> The well was constructed of 6-inch-diameter, 1/8-inch thick steel well casing with a reported original total <br /> depth of approximately 100 feet below ground surface (B. Den Ouden, personal communication, <br /> 8 March 2010). Well construction logs were not available to confirm the total depth of the well. On <br /> 18 February 2010, T&R measured the bottom of the well to be 83 feet below ground surface (bgs). <br /> Based upon discussion between T&R, the Water Board, and San Joaquin County Environmental Health <br /> Department(SJCEH), it was deemed necessary to perform air-lifting and removal of collapsed sediment <br /> to identify the original depth of the well. Woodward Drilling, of Rio Vista, California (Woodward, C57 <br /> License No. 710079), used compressed air driven through a 2-inch metal pipe (air lift tool) to force <br /> sediment from the bottom of the well to ground surface, while simultaneously advancing the air-lift tool. <br /> Sediment and groundwater displaced during air-lifting was placed in a drum onsite. <br /> T&R identified the original well depth based upon changes in rate of advancement of the air lift tool. <br /> At approximately 102 feet bgs the rate of tool advancement decreased from approximately 2 feet per <br /> minute to 4 to 6 inches per minute. <br /> T&R discussed the results of air lifting with SJCEH and the Water Board to determine the appropriate <br /> method of destruction. SJCEH and the Water Board agreed that the well should be destroyed by <br /> explosive grouting from 0 to 83 feet bgs. <br /> Well Destruction <br /> T&R obtained a well destruction permit from SJCEH on 29 March 2010 (Permit No. SR0059619, <br /> Attached). On 5 to 7 April 2010, Water Well Technology, Inc. (WWT, C57 License No. 731133) destroyed <br /> the agricultural water well using explosive grouting methods. Ms. Lisa Medina, inspector for SJCEH was <br /> ENVIRONMENTAL AND GEOTECHNICAL CONSULTANTS <br /> 501 14TH STREET,3RD FLOOR OAKLAND CALIFORNIA 94612 T 510 874 4500 F 510 874 4507 www.treadwellrollo.com <br />