Agenda - Council - 03/23/1982 - Laserfiche WebLink

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I I I ! I I I i I I I I I I I I I - 7 - MPCA's review of the site noted that the underlying sandy soil "allows very rapid percolation to the water table and provides little if any leachate atten- uation.''* Also, those soils do not satisfy Council criteria for soil type suit- able for landfills. In recognition of the limiting hydrologic characteristics of the Anoka sandplain, Anoka County's adopted policy is to require both a liner and leachate collection system for new landfills. In order to provide added protection for shallow water wells located between the site and discharge zone, the county has proposed that additional safeguards be provided at the Bunker Hills lite. Figure 4 illustrates the county's proposal--in essence a system of double liners and dual leachate collection systems. The county has studies in progress to evaluate means of further reducing risks associated with the site by shortening the period in which high levels of pol- lutants are generated. The county is studying the effects of waste shredding on leachate production and methane gas generation. The MPCA has certified the site as intrinsically suitable under the condition that the county's development proposal be implemented. The MPCA findings also noted that groundwater can be monitored by routine methods. Council landfill siting criteria specify that there should be no connection between the site and either a surficial or buried drift aquifer. Site review criteria further state that by loc'ation, design and operation, waste facili- ties shall minimize potential public health risks and groundwater contamina- tion. The Bunker Hills site by location provides no inherent protection of the surficial and upper drift aquifers. The lower aquifers, however, may be pro- tected to some degree by the overlying till and the St. Lawrence formation. With respect to design and operation, the county's proposal has been developed to protect the surficial groundwater and to shorten the period when risk of contamination is great. The long-term risk to potable water supplies in the surrounding areas is lessened by the planned extension of public water supply to this area. Council siting criteria specify that slopes should be between two and 12 per- cent in order to provide adequate but not excessive drainage. MPCA's review noted that the site should require no special drainage control measures. Protection of Agriculture and Natural Resources Soils on the site do not exhibit high agricultural potential, and the proposed use would not conflict with Council policies for agricultural protection. Council siting criteria discourage si§nificant alteration of forested areas. Development of the site would require considerable clearing of woods. Such clearing, however, is expected to occur irrespective of the proposed landfill in order to implement park development plans. * MPCA, Report on the Director's Proposed Recommendations~ 1981.