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Mr. Ken Gillies <br /> Gillies Trucking <br /> 3931 Newton Road, Stockton <br /> Page 2 0£3 <br /> testing would be appropriate only in hydrogeologic units that are likely to require <br /> remediation or that are likely to act as contaminant migration pathways. <br /> UEC will engage an experienced downhole logging company to perform a video <br /> survey of the Gullies and Bardot domestic wells to determine the screen interval <br /> depths and check casing integrity. EHD approves this proposal. <br /> The WP presents information that the Gullies domestic well is suspected of being <br /> approximately 100 feet deep and details site conditions that limit the prospect of <br /> obtaining useful information from pumping tests EHD recommended on the two <br /> domestic water wells. EHD agrees that the distances of existing observation <br /> wells limits the potential for a successful pumping test. Therefore, if the video log <br /> confirms the suspected well construction details for the domestic wells, EHD will <br /> consider the occasional occurrences of TPH-d in the Gillies domestic well an <br /> adequate demonstration that the well is a pumping influence that has some <br /> destabilizing effect on the plume of impacted ground water. EHD therefore drops <br /> the recommendation for this test at this time. <br /> EHD has directed destruction of the domestic well onsite for human health <br /> reasons and, as noted above, the well probably destabilizes the plume of <br /> impacted ground water, therefore EHD approves this portion of the work plan. <br /> UEC proposes to advance eight CPT soil borings; no target depth was stated for <br /> the CPT borings. UEC also did not explicitly state that soil behavior data would <br /> be collected from the CPT borings, which can be utilized to expand and refine the <br /> three-dimensional hydrogeological model of the site. Typically, an initial CPT <br /> boring is advanced to obtain the soil behavior data from which permeable zones <br /> of interest are identified; then a second boring is advance adjacent to the initial <br /> boring to obtain hydropunch ground water and/or soil samples from intervals of <br /> interest. UEC proposes no further investigation or characterization of the <br /> Modesto Channel at this time. EHD considers the full characterization of the <br /> Modesto Channel to be of great importance as it has been identified as the major <br /> receptor of the bulk of adsorbed and dissolved contaminants, and is therefore a <br /> potential migration pathway of significance. <br /> With these points in mind, EHD recommends moving proposed CPT boring #8 <br /> approximately 25 feet closer to GT-6 and CPT boring #4 approximately 25 feet <br /> southeast of GT-2 to confirm the projected Modesto channel model shown in <br /> Figure 7 of Problem Assessment Report, dated 31 October 1996, and First <br /> Quarter Report dated 01 June 1999. If the channel sediments are present as <br /> modeled, but are not saturated, it may be prudent to collect soil samples from the <br /> base of the channel deposits. In addition, EHD suggests combining proposed <br /> CPT borings #1 and #2 and place the boring at an advantageous point outside <br /> the modeled channel and between the former UST pit and the Bardot well. The <br />