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-A hether the site should or should not be considered for case closure. The following sections summarise: the information collected by Wright to support the request for case: closure and possible No Further Action Required, (NFAR) designation, Each item is summarized in the following sectious and uses the RWQCB NFAR outline to present the information. Selected figures and maps to illustrate the discussion were abstracted from the original reports and are provided in.Appendix A,. 2.0 Site Closure Summary for KFAR Documentation 2,1Site H!Aory and Cur mt its CwWitios Sura many The property is located at 3900 Holly Drive ion. Tracy, California, near the northwest comer of Holly Drive and Larch Road. The WWTP property is north of Interstate 205 and is the wastewater treatment facility for the City of Tracy. Commercial development and some residential development is. located south of WWTP site (see Appendix A, Fiures 1,2,3.and 4), Site Geologj-and Mdrogeolegy Summga A total of nine GeoProbe exploratory borings and one groutrdwater monitoring well were driItedlinstalled at the locations shown on Figurers and Logs/Details in Appendix A. The project site is located on the north side of the City of Tracy. Holocene alluvial fan and fluvial deposits eroded and dissected by streams draining from the nearby Coast Range Hills to the northwest underlie the area. Surficial soils in the region are mapped as Capay-Stomas Zacharias, a moderately well drained and moderately fine textured soil wih;h gravel forming on alluvial fans,interfan,basins and stream terraces. Capey soils are mapped as moderately slow permeability, The: development of the site for use as the WWTP plant, including excavation for large impoundment areas, has greatly altered or removed the very shallow native soils.. The deeper underlying alluvial sediment may ,generally consist of weakly consolidated and irregularly interbedded sand, silt and clay de.Pos ts. These subsurface strata.mrty, show vanable late rat and vertical continuity and i extent(Page, 1986;Bertold,et al„ X1991). In general,shallow groundwater occurs in the upper to to 20 feet below the surface in the Tracy region. Large groundwater aquifer$ underlie the Tracy region at depth, providing agricultural and municipal drinking water for the area. Regional groundwater flow in the deep aquifer is estimated as northerly. With the exception sof nearby City of Tracy industrial waste ponds, the .nearest large surface bodies of water are the Sugar taut just north of the WWTP and.the Paine Slough, located about one mile north northeast of the site. Groundwater data from the C142M 2008 Annual Monitoring Report for the WWTP showed a northwesterly flow ditection for the shallow groundwater aquifer at the plant site vicinity, One large impoundment occurs just north of the projectsite, however its 48b5,/CSRlRept Page 4 or 17