Agenda - Council - 11/13/1984 - Laserfiche WebLink

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Mr. Harold P. Cahill, Jr. P.E. Page lnree You also offer in your letter the till unit which underlies the area as a second layer of protection for area wells, lnis till unit does contain clay; however, contains significant amount of sand and gravel layers, some of which it also are supplying water to area wells. An independent study of the hydrogeology of the area around the landfill found that one-third of the well logs examined showed wells finished in gravel or sand deposits in this glacial till at depths ranging from 60 to 130 feet (Evaluation of Water Resources Monitortng~ Sanitary Landfills of Anoka County, report to the Anok~ COdnty Board of Commissioners by ~arr Engineering, january, 1981). This correlates with the MPCA staff experience with this till unit in other areas of the county, where it also exhibits a heterogeneous nature and supplies water to wells, lhe MPCA staff feel that more ~etaileU studies on the hydrogeologic properties of this till unit are necessary to define the degree of protection which it affords area water wells around the landfill. With regard to the Anoka city wells, you cite in your the fact that letter upward gradient are expected in the ~rift in the area of the wells because of their proximity to the Mississippi aha Rum Rivers. MPCA staff accept this as a reasonable assumption; however, in our view, this does not eliminate possible impacts Uue to infiltration at points more distant from the wells. Also, as mentioned previously, the ranking system does not allow for consideration of flow patterns in development of the score. In sunwnary, MPCA staff feel that the Hazard Ranking System has been correctly applied to the scoring of the Anoka Municipal Landfill, following the criteria as outlined in Minnesota State statutes. We are therefore not recommending that the score be changed. We are very appreciative of Waste Management, Incorporatea's past cooperation in the investigation of ground water impacts from this landfill, and we look forward to working with you in the future on the ~evelopment of a Remedial Investigation and Feasibility Study plan. The MPCA staff will be in contact with you in the near future to discuss additional investigation needed at the landfill. If you have any further questions, do not hesitate to contact either Daniel Comeau at 612/296-7274 or Michael Wiltfang at 612/296-728D of my staff. Chief, Regulatory Compliance Section Solid and Hazardous Waste Division REM/MW:pak cc: lhe Honorable Robert C. Burmah, Anoka County Co~issioner, Anoka Mr. Lloyd Sc~nelle, City Administrator, Amoka Mr. Robert Hutchison, Anoka County Comprehensive Health Department, Anoka Mr. lerry Miller, Waste Management of Mit, Inc., Anoka Ms. Lynne Bly, Metropolitan Council, St. Paul