Laserfiche WebLink
i <br /> San Joaquin County DIRECTOR <br /> PQ u N Donna Heran,RENS <br /> Environmental Health Department ASSISTANT DIRECTOR <br /> 600 East Main Street Laurie Cotulla,RENS <br /> Stockton, California 95202-3029 <br /> PROGRAM COORDINATORS <br /> s Carl Borgman,REHS <br /> Website:www.s ov.or /ehd Mike Huggins, RENS,RDI <br /> 4�!�0 l9 g Margaret Lagorio,REHS <br /> Phone: (209)468-3420 Robert McCiellon, REHS <br /> Fax: (209) 464-0138 Jeff Carruesco; REHS,RDI <br /> December 3,`2008 Kasey Foley,REHS <br /> Mr. Sergio Morescalchi <br /> Atlantic Richfield Company <br /> Post Office Box 1257 <br /> San Ramon, California 94583 <br /> Subject: ARCO Service Station No. 2186 <br /> 3212 North California Street <br /> Stockton, California 94570 <br /> The San Joaquin County Environmental Health Department (EHD) has reviewed Work <br /> Plan for Vapor Probe Destruction, Well Destruction, and Well Installation dated October <br /> 14, 2008, prepared by Stantec Consulting Corporation (Stantec) on your behalf for the <br /> above-referenced site. The work plan includes destroying soil vapor probes VP-1, VP-2, <br /> and VP-3, and groundwater monitoring wells MW-1 and MW-3,, and installing two <br /> monitoring wells (MW-IR and MW-3R) screened across the first groundwater bearing <br /> zone, and one monitoring well (MW-1D) screened across a deep groundwater bearing <br /> zone. The work plan was submitted in response to the EMD directive by letter dated <br /> August 22, 2008. <br /> Stantec proposes to destroy soil vapor probes VP-I through VP-3 by pressure grouting <br /> the borings from total depth of six feet below surface grade (bsg) to ground surface using <br /> neat cement. Instead, the EHD believes the three vapor probes should be over drilled to <br /> total depth and grouted using a tremie pipe. The EHD concluded this because the casing <br /> diameter for each soil vapor probe is only one-quarter inch in diameter and does not have <br /> a large enough opening for the grout to penetrate to a depth of six feet, even under <br /> pressure. <br /> Stantec proposes to destroy monitoring wells MW-1 and MW-3 by removing the well <br /> contents by over drilling the boreholes to total depth, then backfilling the boreholes to <br /> three feet bsg with neat cement using a tremie-pipe system, .forming a mushroom grout <br /> cap/surface seal. The EHD approves the proposed method for the destruction of MW-1 <br /> and MW-3. <br /> Stantec proposes to advance shallow wells MW-1R and MW-3R to approximately fifty- <br /> five feet bsg using eight-inch diameter hollow-stem augers while collecting soil samples <br /> at five-foot intervals for lithological evaluation. Soil samples will be screened in the field <br /> I <br /> I <br />