Laserfiche WebLink
Emcon ' <br /> S7� <br /> 1433 North Market Boulevard•Sacramento,CA 95834-1943•(916)9273300•Fax(916)926-3341 <br /> March 5, 1998 <br /> Project 20C42-001.026 <br /> Ms. Gail Wiggett <br /> California Regional Water Quality Control Board <br /> Central Valley Region <br /> 3443 Routier Road, Suite A <br /> Sacramento, California 95827-3098 <br /> Re: Water Production Well Abandonment, Tesoro Distribution Terminal, Stockton, <br /> California <br /> Dear Ms.Wiggett: <br /> The water production well 17A1 at the Tesoro distribution terminal located at 3003 Navy <br /> Drive in Stockton, California, was abandoned on February 6, 1998. The intent of this letter <br /> is to address the issues raised during abandonment activities presented in a March 3, 1998, <br /> letter prepared by Ron Rowe of the San Joaquin County Public Health Services <br /> Environmental Health Division(PHS/EHD). <br /> METHODS <br /> EMCON contracted Water Development Corporation, a licensed California drilling <br /> contractor to perform well abandonment activities. A video log of the well conducted on <br /> September 3, 1997, shows the well casing was in poor condition with numerous corrosion <br /> holes present and that the current depth of the well was approximately 55 feet below <br /> ground surface (bgs). <br /> During the well abandonment, the tremie pipe was placed through the center of the well <br /> casing to a depth of approximately 55 feet. A firm bottom was encountered at a depth of <br /> 55 feet. The tremie pipe encountered an obstruction at this depth, consistent with the <br /> obstruction depth identified in the video log. Four cubic yards (810 gallons) of neat cement <br /> grout were pumped through the tremie pipe starting at 2:35 P.M. The calculated grout <br /> volume to fill the borehole was 323 gallons, which is 480 gallons less than the 810 gallons <br /> pumped into the borehole, suggesting the borehole diameter was larger than 8 inches, <br /> and/or voids were present. Placement of this batch of grout ended at 3:00 P.M. At this <br /> time, the grout level was measured. A firm grout tag indicated the grout level was 10 feet <br /> bgs and the tremie pipe was pulled up to confirm The grout level on the tremie showed <br /> that the grout was present at 5 feet bgs (consistent with Section 4.7.4 of the PHS/EHD <br /> SALIN:\PJC,DC4Z,OC420012.6DE-994ba s:1 <br />