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DISCO PROPERTY,STOCKTON.CALIFORNIA hydrocarbons,then additional boreholes will be drilled further downgradient until the grab groundwater results indicate the vicinity of the plume fringe. • Upon determining the approximate location of the downgradient plume fringe,PHS will be consulted and a shallow monitoring well will be installed that is screened across the water table. Based on the extent of the downgradient plume, one additional shallow monitoring well may be proposed if downgradient lateral coverage is not sufficiently provided by one well. • One deep well will be installed in the vicinity of the downgradient shallow well. This well will be screened at a similar depth interval as MW-11D. • Wells installed during this phase of work will be developed using the standard protocol used for previously installed wells at the property.. Subtask 3 Laboratory Analysis Grab groundwater samples from Activity II will be submitted to a state certified laboratory. The samples will be analyzed for TPH as gasoline,BTEX,and MTBE. The grab groundwater samples will be analyzed in a 24-hour turnaround time period. Subtask 4 Reporting The report for this phase of work will be combined with Activity III. The report contents are described under Activity III. Activity III - Installation of Upgradient Monitoring Well Based on the findings of Activity I and existing upgradient well data,the value and necessity of conducting Activity III will be revisited. If necessary, the purpose of Activity III will be to install an upgradient well in the vicinity of the known release that intersects the current water table;the existing upgradient wells do not intersect the current water table. If it is determined that Activity III is necessary, then this activity will be conducted at the same time as Activity II using similar protocols. Subtask 1 Prefield There appears to be no need to perform any conventional prefield because the permits will have already been acquired during Activity I,the health and safety plan will have been written, and the utilities will have been cleared. Subtask 2 Field Activities If necessary,the field activities will include drilling and installing a monitoring well that is screened across the present-day static water elevation.The location of the well will be determined after consultation with PHS. The well will be drilled and installed using the same methods described in Activity I. The borehole will be continuously cored to 65 feet bgs. Soil samples will be screened in the field and samples will be submitted to a state 6