ARCHIVED REPORTS XR0007793 - Laserfiche WebLink

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The San Joaquin Valley is filled with a thick sequence of marine and continental sedimentary rocks ranging in age from the Jurassic to Recent The thickest accumulations underlie the western portion of the valley The Sierra Nevada Range is the primary provenance for this ' sequence of sedimentary rocks 2.2 HYDROLOGY 2 2.1 Groundwater Groundwater in the vicinity of the Site occurs at a depth of approximately 47 feet BGS, based on information compiled in 1994 by Condor Earth Technology Inc (Condor) 2.2.2 Surface Water ' The northern boundary of the Site is the southern border of the Mormon Slough which drains into the San Joaquin River approximately one mile to the west-northwest of the Site ' 3.0 SITE ASSESSMENT WORKPLAN The following workplan will be implemented in potentially two phases Phase I will consist ' of installing monitoring well MW-4 in a downgradient position relative to the presumed source of groundwater impact MW-4 is to be located on the subject Site approximately 60 feet east-northeast of existing monitoring well MW-3 and approximately 80 feet away from the presumes source, TKI-90 Phase II is intended to consist of installation of three groundwater monitoring wells, MW-5, 6 and 7, along the top of the southern embankment of the Mormon Slough also in a presumed downgradient direction from the probable source of ' groundwater impact, TKI-90 The three well locations being considered along the Mormon Slough embankment are a compromise between lack of available on-Site downgradient assessment locations and the ' need to assess the length and breadth of the known groundwater impact as near to the probable source as possible The three locations chosen along the Mormon Slough embankment represent an attempt to constrain the downgradient extents along the only ' corridor available for such assessment to be reasonably accomplished Site access permission is anticipated to be problematical for proposed wells MW-5, 6 and 7 due to the complications inherent in obtaining permission from potentially multiple governmental agencies in control of the Mormon Slough ' In the event that groundwater impact is not detected at location MW-4, attempts to permit wells along the Mormon Slough embankment may not be necessary Therefore, installation ' of wells MW-5, 6 and 7 will not proceed any earlier than when results of groundwater analyses from MW-4 are available ' Figure 2 details the intended locations of these four proposed well locations Report preparation of the results of the two possible phases of assessment may also occur in Iwo phases At present rt is anticipated that a single report of all assessment activities contemplated in this workplan will be accomplished after all four anticipated wells are installed This could change if impact to groundwater is not detected in MW-4, or if time to obtain permission to install wells along the Mormon Slough becomes prohibitive In either of these cases, RFA would produce an interim report detailing the results of soils and 366-002 5-