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 I I -9 - groundwater beneath the site is believed to flow to the southeast and dis- charges into the Mississippi and Rum Rivers. The site is about one and a half miles from the Mississippi and slightly over a mile from the Rum. The county's report indicates that well logs for the area tend to show that static groundwater levels in the bedrock are about the same as static levels in the surficial aquifer. Data is incomplete for a conclusive finding but indi- cates little potential for vertical seepage from the surficial aquifer through the till to the underlying bedrock. MPCA's review of the site noted that the sandy soil "allows very rapid perco- lation to the water table and provides little if any leachate attenuation."* Also, those soils do not satisfy Council cr~iteria for soil type suitable 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 protec- tion for shallow water wells located between the site and discharge zone, the county has proposed that additional safeguards be provided at the Ramsey site. Figure 6 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 location, design and operation, waste facilities shall minimize potential public health risks and groundwater contamination. The Ramsey site by location provides no inherent protection of the surficial and upper drift aquifers. The lower aquifers, however, appear to be protected by the overlying till, the St. Lawrence formation and the low potential for ver- tical groundwater movement. 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 City of Ramsey is in the early stages of developing a plan for a public water supply. If implemented, the long-term risk to potable water supplies in the surroundin§ areas would also be less. The southwestern portion of the site includes a marshy area formerly designated as a Type III protected wetland. This marshy area is connected hydrogeologi- cally and by'two culverts to a protected wetland south of the site. Council criteria specify that in order to protect environmentally sensitive areas, land- fills should not be located on or near wetlands. In further studies on this site, the county should evaluate means of protecting or buffering this area. * MPCA, ~epo~tjoo ~h~ .Director's Proposed Recommendation$~ 1981, p. 18.