SITE INFORMATION AND CORRESPONDENCE_1987-1992

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MEMORANDUM DRAFT DATE: March 25, 1992 T0: Dean Gillman San Joaquin County Department of Public Worksw FROM: Fred Kaufman, Program Manager Environmental Health Division RE: Lincoln Village Well Destructions Our office has received a copy of the Draft Engineer' s Estimate and Technical Specifications for Lincoln Village Well Destruction" from Larry Phillips, Project Engineer of Brown and Caldwell, dated March 17, 1992 . We have the following concerns and comments. I called Michael Higgins, Project Engineer, from the Central valley Regional Water Quality Board (CVRWQCB) regarding the referenced project . I felt this was necessary as the CVRWQCB was the responsible state agency involved in the site clean-up of the Lincoln Village property. He indicated to me that their department did not have the expertise or hands on technique to necessarily approve the Brown and Caldwell proposal for the destruction of the four water wells. He felt that your Department and our Division had the background and experiences necessary to review and approve the destructions, given the nature of the project, as long as we considered the issues he raised in his letter to me dated 25 September 1991. However, he did indicate that CVRWQCB would like to receive a copy of the final accepted proposal, and if anything "jumped out, " they would note it. I have reviewed the 25 September letter referred to above and note what CVRWQCB had raised as concerns or recomendations . * Eliminate inter-aquifer migration pathways by puncturing and pressure grouting the outer well casings for the entire depth of the wells . * Minimize excessive escape of grout by increasing grout viscosity in the main transmissive zones or by pressure grouting in stages from the bottom. * The contractor should first abandon the supply well farthest away from the most highly polluted zone. * Make the maximum effort to eliminate the migration pathways by sealing the full length of each well' s annular space and isolate the polluted zones from the deeper aquifers. I have also reviewed a letter sent from Michael Tognolini, Project Engineer for Kennedy/Jenks, Consultants of the property owners, to Michael Higgins dated 28 August 1991 (copy enclosed) . He noted that Kennedy/Jenks believes that it is necessary to puncture the blank casing and pressure grout the well throughout the depths corresponding to the suspected aquitards. He identified a defined aquitard apparently from a depth of 140 to 180 feet and