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ATC Associates Inc. <br /> V 1117 Lone Palm Avenue,Suite 201 <br /> Modesto,California 95351 <br /> 209-579-2221 <br /> fax:209-579-2225 <br /> A S S O C-1`>AT E;S fly C'= <br /> A site plan illustrating the locations of the groundwater monitoring wells and soil borings is <br /> provided as Figure 2. <br /> GROUNDWATER ZONES <br /> As discussed in the previous workplan submitted to the SJCEHD on July.17, 2008, three water <br /> bearing zones were identified during the advancement of CPT-1 and CPT-2 at the site in 2004. <br /> These zones have been described by ATC as the shallow A water bearing zone present between 5 �-- <br /> and 25 feet bgs; the intermediate B water zone present between 35 and 45 feet bgs,a d the <br /> deeper C water bearing zone present between 65 and 75 feet bgs.These water bearing zones <br /> were characterized using CPT methods as silt, sand, and/or gravelly sand units from the CPT <br /> logs. Clay and/or silty clay, based on the CPT soil profiles or visual observations, separated each <br /> of these water bearing zones. However, this does not imply that there are three distinct and <br /> ubiquitous water zones (A, B, and C)beneath the site. It could be concluded,that one or more of <br /> these identified zones pinches out laterally, or that two or more units may in fact be hydraulically <br /> connected. <br /> SCOPE OF WORK <br /> Planning and Permitting <br /> Prior to commencement of drilling activities, ATC personnel will conduct a site walk and mark <br /> the ground surface for Underground Services Alert (USA). USA will be contacted at least 48 <br /> hours prior to any field work to allow time for utility companies to identify any underground <br /> lines, pipes, or utilities that may be affected by subsurface investigation activities. The locations <br /> of the proposed boring locations will be further evaluated with respect to utilities identified by <br /> USA and a private utility locating service, if warranted. Following approval of the Workplan, <br /> ATC will obtain boring permits from the SJCEHD. _Off-site.access.authorization-will_be_sought <br /> for the proposed..groundwater-monitoring well-located off--site to the vest. Additionally, ATC' <br /> will request an encroachment permit from the City of Tracy prior to conducting the off-site <br /> drilling activities. <br /> Drillinjj Activities <br /> This task includes mobilization to the site, advancing four vertical soil borings,_collecting soil <br /> samples, and completing the borings as-groundwater.monitoringwells: Threelof the,proposed, <br /> wells-are planned to.be located on-site'The fourth well is planned to be-located off-site to-the , <br /> west,,-.across Holly Drive. ATC will notify the SJCEHD ai least-48 hours prior to the � <br /> commencement of field activities. <br /> Drilling will be conducted by a State-licensed (C57) drilling company. A geologist will be <br /> present to log soil samples,collected.from.the borings. Descriptions of soil types-encountered and <br /> sample collection intervals will'be recorded on-boring logs. Soil samples will be collected and <br /> SAEnvironmenta1\25847\37 Tracy\Reports\wkp-addendum 2009.6c 4 — <br />