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r� <br /> �f ESA 225 Bush Street www.esassoc.com <br /> Suite 1700 <br /> San Francisco,CA 94104 <br /> 415.896.5900 phone <br /> 415.896.0332 fax <br /> 2005 JUN 3 I AM i 1 53 <br /> S.A.N jo �IN COUNTY <br /> June 29, 2005 HEALTH DEPARTMENT <br /> Ms. Margaret Lagorio, Supervising REHS <br /> San Joaquin County . <br /> Public Health Services <br /> Environmental Health Division <br /> 304 East Weber Avenue,Third Floor <br /> Stockton, California 95202 <br /> Subject: Completion of Groundwater Monitoring Well Destruction <br /> Request for Issuance of-No Further Action Required (NFAR) Letter <br /> University of the Pacific (UOP)Former Underground Storage Tank Site <br /> 1081 W. Mendocino Avenue, Stockton, California <br /> Assessor's Parcel Number: 113-140-02 <br /> County of San Joaquin Site Code: R0732 <br /> Dear Margaret: <br /> i <br /> On behalf of the University of the Pacific (UOP),Environmental Science Associates(ESA)has prepared this <br /> letter to document the destruction of the four groundwater monitoring wells at 1081 W. Mendocino Avenue <br /> in Stockton,California. The wells were originally installed as part of an MTBE groundwater investigation <br /> for a former underground.storage tank(UST). In accordance with your letter dated October 18, 2004, we <br /> understand that well destruction is the final step towards receiving a No-Further Action Required(NFAR) <br /> letter for this case. ESA proposed the monitoring well destruction activities in its work plan titled, Work <br /> Plan to Destroy Four Groundwater Monitoring Wells,dated March 9, 2005. The San Joaquin County <br /> Environmental Health Division(SJCEHD) approved this work plan in a letter dated March 16, 2005. <br /> On May 16, 2005,Pete Hudson of ESA supervised Gregg Drilling and Testing, Inc. in the field activities <br /> associated with the monitoring well destruction. Prior to drilling, the well covers,well boxes, and concrete <br /> collar/surface seals from each well were removed. The monitoring wells (MW-1, MW-2,'MW-3, and MW- <br /> 4) were then over-drilled with a track-mounted drilling rig equipped with&inch(outside diameter) augers to <br /> the depth of the well boring(approximately 30-feet). Althoughmuchof the PVC well material was <br /> pulverized during drilling,the over drill removed the monitoring:well casing, sanitary seal (including <br /> bentonite),pre-pack filter medium, and well screen from each boring. After augers were-removed from each <br /> boring, the holes were then backfilled with Portland cement grout to approximately 5-to 8-inches from the <br /> surface(parking lot locations) and 1-foot from the surface at MW-1 (located in the landscaping). SJCEHD <br /> field inspector Victoria McCartney, REHS, observed the majority of well-destruction and all well grouting <br /> activities. Finish repair of the parking lot locations involved concrete in the upper 5-to 8-inches to the <br /> existing parking lot surface (see attached,photos). Topsoil was placed in the upper one-foot of the backfilled <br /> boring in MW-1. Barricades were placed at each former welt location to protect the area while concrete set <br /> up. <br /> i <br /> I <br />