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r- <br /> Mr. Wm. J. Hunter <br /> July 2, 1998 <br /> Page 2 <br /> costs of this task if well construction details are unknown. The estimated budget outlined in Exhibit <br /> A does not include costs for the video survey. <br /> Miect 3: SoO4c. Greundmokr Investiation <br /> After discussing the subject site with the regulator, Mr. Ron Rowe of PHS/EHD, Ground Zero is <br /> submitting costs to use a cone penetrometer test (CPT) drill rig to complete the scope of work <br /> outlined in the workplan submitted to PHS/EHD. Mr. Rowe feels that use of a CPT rig would be <br /> the preferred method due to his desire to collect soil samples at changes in lithology rather than at <br /> 5-foot intervals. It should be noted however, that Mr. Rowe is under the impression that a CPT rig <br /> is, by definition, a limited access rig. Discussions with several contractors indicate that this is not i <br /> " necessarily the case. Consequently, the proposed location of Boring A (pump island) may need to <br /> be modified slightly to clear overhead power lines. j <br /> '-Historical regional groundwater information from Department of Water Resources (April 1990) and <br /> San Joaquin County Flood Control and Water Conservation District (Spring 1993 through Spring <br /> 190`lO indicates that the depth to water in the vicinity of the site has ranged from approximately 41 <br /> feet, below ground surface (bgs) in 1967 to approximately 80 feet bgs in 1990 and 1996. <br /> Therefore, Ground Zero estimates the maximum boring depths will be approximately 80 feet, <br /> rather than 120 feet as stated in the workplan. However, the total depth drilled will depend on soil <br /> conditions encountered. <br /> The CPT method will first be used at the two boring locations shown in the workplan to establish <br /> the lithology. After the stratigraphy is determined and the CPT holes are grouted, sample borings <br /> are advanced within 8 feet of the original CPT bore holes for collection of soil and groundwater <br /> I's**. Ground Zero's cost estimate assumes that three (3) soil samples and up to two (2) <br /> egroundwater samples will be collected from each sample boring. Groundwater samples will be <br /> ,collected using a hydropunch at first encountered groundwater and at the total depth of the boring, <br /> 4water is,preseot. Since the number of soil samples depends on the lithology and evidence of <br /> petroleum hydrocarbon contamination, more than 3 samples from each boring may be required by <br /> 4 the County: The sample borings will be grouted after completion. Rinsate water will be stored <br /> A`M ons m-appropriately labe'ed'DOT-approved 55-gallon drums. No soil cuttings will be generated <br /> by thii drillii method. <br /> The soil and groundwater samples will be submitted to a state-certified laboratory and analyzed for <br /> .TPHg, BTEX, and oxygenates using EPA methods 8015m, 8020, and 8260, respectively. <br /> Summary R= <br /> After .the field work portions are completed, a summary report will be completed which will <br /> comply with the PHS/EHD and Regional Water Quality Control Board Tri-Regional Guidelines. <br /> The report will include results from the well retreptor survey, onsite well sampling methods and <br /> results,' soil and groundwater investigation methods and results, conclusions, and recommendations. <br /> propo.alâ–şbimter <br />