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Soil Suitability Nitrate Loading Study <br /> Manteca Unified School District <br /> 14600 Austin Rd.,Manteca,California <br /> Page 4 <br /> 1.4.2 Existing and/or Potential Groundwater Contamination Issues in the General Location <br /> The presence of nitrates is common in shallow groundwater aquifers in the San Joaquin County region. <br /> Nitrate in groundwater occurs as a result of the application of fertilizers, livestock waste, and untreated <br /> septic tank waste.The Site is surrounded by agricultural farmlands and rural housing,and activities related <br /> to agricultural practices and the use of existing septic systems should be considered potential contamination <br /> sources. <br /> 1.4.3 Location,Type and Construction of Well and Well Sample(s) <br /> One water supply well is located on-site that is used for domestic use and irrigation purposes. No well <br /> construction details are readily available for the well, identified as 3901163-001 (Global ID W0603901163) <br /> A copy of a permit to install a 10"cased well in 1981 is included in Appendix E. <br /> 1.4.4 Constituents Being Tested for in the Water Sample <br /> Copies of readily available testing results pertaining to the wells(DWR's GAMA database)are included in <br /> Appendix E. <br /> 1.4.5 Sample Collection and Handling Methodology <br /> The groundwater samples collected from the wells were collected pursuant to state and federal requirements <br /> as required for a public water system. <br /> 1.4.6 Chain of Custody Documentation <br /> No chain of custody documentation is provided in the Consumer Confidence Report(Appendix E). <br /> 1.5 SOIL PROFILE INFORMATION <br /> The Site is located in the northern San Joaquin Valley in the Great Valley Geomorphic Province of <br /> California. Based upon published geologic maps, near-surface geology underlying the Site consists of <br /> Quaternary dune sand underlain at some depth by the Modesto Formation. The geologic distribution of <br /> near-surface deposits in the vicinity of the Site is shown in Figure 6 (Appendix A). The subsurface soils <br /> encountered at the New Haven Elementary School Site consist of unconsolidated dune sand to <br /> approximately 15 to 17.5 feet bgs, underlain by silts and clays to approximately 50 feet bgs, the maximum <br /> depth explored. Shallow groundwater was encountered at a depth of approximately 45 feet bgs just below <br /> a thin layer of silty sand. <br /> 1.5.1 Site Map Showing Location of the Soil Profile Pit on the Parcel <br /> See Figure 2(Appendix A). <br /> 1.5.2 Description of Soil Profile Pit Including Depth and Dimensions <br /> See Table 3, below. <br /> Table 3 <br /> Descri tion of Soil Profile/Test Holes <br /> Test Hole Diameter in Depth Interyal ft Soil Type Soil Class USCS <br /> 1 4 0-3 Sil Sand SM <br /> 1.5.3 Soil Lithology <br /> Condor classified shallow soil as a poorly graded silty sand(SM)pursuant to the Unified Soil Classification <br /> System (USCS). Shallow soil in the proposed project area was classified by the U.S. Department of <br /> %4? CONDOR <br />