SITE INFORMATION AND CORRESPONDENCE

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Messrs. Hall and Musco - 2- Vecember 2002 • The workplan fails to include an additional investigation of the northern area near Wells MW-7, MW-8, and MW-12. In that area,no shallow water table aquifer was identified. The failure to identify a water table aquifer may be a result of the drilling technique employed for well installation. The presence or absence of a water table aquifer must be evaluated in that area as part of this investigation. • The geochemical evaluation described in Sections 3.2.1 and 3.6.1 describes selecting samples for . further analysis. No basis for selection of the samples is provided. Please describe the basis for selection of the wells for further analysis. In addition, if isotope geochemistry will be employed to characterize the age of the groundwater, it is prudent to perform similar tests of the wastewater that is applied. It should be recognized that the chloride in the facility wastewater likely originated in evaporated ocean water and therefore is radioactively"dead"which will influence the interpretation of the groundwater age,making the water appear older than it may actually be. • Section 3.3.2 describes additional monitoring well installations that will be performed. Deeper wells will be installed near Wells MW-1,MW-2, and MW-6 to acquire deeper groundwater data; the workplan states the depths of the wells will be based on the geophysical data evaluation. Section 3.1.1 describes earth resistivity surveys that, "...can be used to identify at least the shallow groundwater and possibly the deeper groundwater zones," and an electromagnetic survey that images conditions to a depth of 18 feet; staff question how the data will be employed to determine conditions in deeper groundwater zones. It is noted that Well MW-6 is not located near Well MW-2 nor is it located in Section 4; the usefulness of the geophysical data for drilling Well MW-6 is questionable. • Section 3.3.2 includes the disclaimer, "...no specific drilling or monitoring well installation parameters can be supplied at this time." The drilling program described in the workplan only commits to drilling one well, a replacement for Well MW-9, such a drilling program does not meet the requirements of WDRs Provision G.2.b and is unlikely to provide enough data to provide an estimate of the groundwater quality that has been described in numerous meetings and promised to the Regional Board at the public hearing on 6 September 2002. Please review Provision G.2.b and describe the additional work that will be completed to comply with the WDRs. • Section 3.3.2 offers to provide the RWQCB with a more precise determination of the scope of work for additional well drilling. It is noted that formal notification is required by Provision G.2.b and the Monitoring and Reporting Program(MRP)which states, "Prior to completion and/or sampling of any groundwater monitoring wells, the Discharger shall submit plans and specifications to the Board for review and approval." • Section 3.3.2 describes drilling the soil borings with a mud rotary drill rig but fails to adequately describe the drilling program. Please provide information on the following issues: o Describe the drill bit size. o Describe how the field personnel will determine groundwater has been encountered. o Describe the drilling fluids and any additives planned for use. o Describe borehole geophysical logs that will be recorded for each boring. o Describe how any excess borehole will be abandoned prior to constructing monitoring wells. V:San_Joaquin_Non15\Staffi0bn=nl j=Film\Mwco\Ha11120202.doc