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4.6. SR 11-13-2000 . City of ~ Elk Item 4.6. MEMORANDUM TO: MAYOR AND CITY COUNCIL STEPHEN ROHLF, BUILDING & ZONING ADMINISTRATOR DATE: NOVEMBER 13, 2000 :;-~ FROM: SUBJECT: TEST RESULTS FROM MONITORING WELLS AT OLD CITY DUMP SITE Every year since 1989, the City of Elk River has tested three monitoring well at the old city dump site and four adjacent residential wells that are down gradient (down stream) for signs of contamination from this operation. Two of the residences that are normally tested were removed this year for the construction of Tyler Street. . The old city dump, which is now part of Hillside Park just south of County Road # 12, was a municipal burn and bury facility that closed in 1972. Routinely, contaminates at levels below the limits requiring any actions be taken have been found in the test wells and at one ofthe residences that was razed this year. It is not conclusive that the contaminates found at the residence were associated with the old dump, but the city installed a dinking water filtration system anyway. The city continues to test these wells looking for a definite trend in the levels of these contaminates. In the case of a significant upward trend, staff would recommend an increased testing program and would start considering options for remedial action. Although the levels of contaminates in the test wells have been decreasing each year and this year's testing appears to show a significant decrease, staff is requesting that the city continue this testing. City services being provided to lands down gradient of the old dump will not eliminate the need for all private wells in this area, therefore, caution is warranted. Attached to this memo is the summary letter from the city's consultant, Liesch Associates, Inc., who conducts the testing. The actual test results are available, if the Council wants to see them. Staff recommends that the city test the three wells at the old dump and the remaining two residential wells again in 2001. . 13065 Orono Parkway. P.O. Box 490. Elk River, MN 55330. TDD & Phone (763) 441-7420. Fax (763) 441-7425 - - - - ~ iS~~ I"-r \ I '\)\J \ . Llii3J:H LIESCH ASSOCIATES, INC. 13400 15TH AVENUE NORTH MINNEAPOLIS, MN 55441 763/559-1423 FAX: 763/559-2202 October 13,2000 Mr. Stephen Rohlf Building and Zoning Administration City of Elk River 13065 Orono Parkway Elk River, MN 55330 RE: September 2000 Groundwater Monitoring Results Old City Dump, Elk River, Minnesota Dear Mr. Rohlf: Enclosed are the laboratory results for the groundwater samples collected from the monitoring wells at the old City dump (MW-1, MW-2 and MW-3) and the Vandenberg and Hipsag residential wells that surround the dump (Figure 1). The sampling was completed on September 20,2000. The . Kirkeide and Brown residences no longer exist, thus were not sampled. A general overview of the September 20th data (Table 1) indicates that there was only one VOC detection for this sampling event. This detection was at MW-2 which identified 1,1,2,2- tetrachloroethylene at 1.6 parts per billion. No VOC's were detected in wells MW-1, MW-3 or the Vandenberg and Hipsag residential wells. Consistent with past data, groundwater flow direction was calculated to be southwesterly in direction towards the Mississippi River (Figure 2). Review of past water level data indicates that the water table at the site has steadily dropped 5 to 8 feet over the past 5 or 6 years. In summary, VOC concentrations at the monitoring wells are the lowest identified at the site since sampling initiated in 1989. 1,1,2,2-tetrachloroethylene in MW-2 was the only VOC detected this round of sampling. This concentration is below the Minnesota Department of Health (MDH) Health Risk Limit (HRL) for drinking water, and this compound has been only intermittently detected over the years at low levels. No VOC's have been detected in the Vandenberg and Hipsag wells to date. As in the past, we will provide the results of the private well testing to each individual residence upon your review of data. It is recommended annual monitoring continue at the site. Please call should you have any questions. .