SITE INFORMATION AND CORRESPONDENCE_1987-1992

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SLUE'OF CALIFORNIA GEORGE DEUKM EJIAN.Governor CALIFDRNIA REGIONAL WATER QUALITY CONTROL BOARD CENTRAL VALLEY REGION 3443 ROUTIER ROAD +S SACRAMENTO,CA 95827-3098 L'N�V ��11� ((ul 16 October 1987 " I 1 5987 ENVjhu-Mb ]AL HEALTH Mr. Wilbur H. Smith FERMIT/SERVICES Lincoln Properties Limited 628 Lincoln Center Stockton, CA 95207 GROUND WATER INVESTIGATION WORKPLAN, LINCOLN VILLAGE CENTER, STOCKTON, SAN JOAQUIN COUNTY We have reviewed the workplan you have submitted dated 30 September 1987 . We generally agree with the proposal. However, we have concerns regarding the proposed location of monitoring wells, the proposed timing of source identification, and the plan to sample domestic wells. The number of proposed monitoring well locations is not sufficient. Additional wells are needed near Lincoln Village well number one to confirm existing contamination and determine the vertical extent of that contamination. A cluster of wells completed in different intervals should be considered in this initial phase. The existing proposed well locations will give the necessary information to determine the ground water gradient. They will do little, however, to define the extent of ground water contamination. The workplan you submitted offers no proposal to confirm the source of PCE and TCE contamination at this site. This is one of the tasks clearly identified in our request of 18 August 1987 . There is a Iarge body of information, gathered primarily by the San Joaquin Department of Public Works, which should be used to focus the investigation, and develop a proposal for exact source identification. The present phase of work should also include a plan to locate all supply wells within a mile of the site and sample water supply wells downgradient of the site. This will have to be done before the workplan for the next phase of this investigation is developed. Wording in the proposal you have submitted indicates that your consultant feels a second phase of this investigation may not be required based on the results of the Phase I investigation. There is nothing proposed in the workplan which could result in the completion of the investigation after Phase I . The omission of source identification from this phase of the workplan is unacceptable, since it may result in unnecessary delays in defining the extent of ground water contamination at this site.