Agenda - Parks and Recreation Commission - 04/09/2015

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wells will be periodically sampled to verify that the Tunnel City Group bedrock aquifer is still contaminant free. Methane Gas Area of Concern The Methane Gas Area of Concern (MGAOC) is defined as the area of land surrounding a landfill waste footprint where the presence of certain activities, such as construction of enclosed structures, may be impacted or precluded by subsurface migration of methane gas. Methane gas is an odorless gas produced when municipal solid waste decomposes, and can be explosive in confined spaces such as basements when mixed in air. The MGAOC is used to inform the public about the risks to current and future land owners regarding certain uses they may want to consider. The MGAOC is shown in Appendix E. Soils in the vicinity of the Anoka/Ramsey Landfill are generally coarse sands. Depth to the groundwater table is approximately 20 feet below ground surface. The landfill waste footprint is approximately 65 acres and contains approximately 5,700,000 cubic yards of waste. A low permeability cover system is in place. The closest residences are located greater than 300 feet from the waste footprint The cover system has 43 vertical gas extraction wells connected to an enclosed blower/flare unit. All 16 gas monitoring probes located around the landfill perimeter have had zero percent methane measured in them for more than 5 years, indicating that there likely is no gas migrating off the property. An investigation of the waste quality conducted in 2011 found the waste to be very dry, confirming that the lower gas generation rate being extracted by the flare system was not due to fouled gas wells, but rather a slower degradation rate due to lack of moisture. Based on the large mass of waste present, the highly permeable soils in the area, the potential for an extended shutdown of the gas extraction system due to unforeseen circumstances, the dry waste present, and recognizing the potential for gas to migrate under seasonal low permeable (frozen) conditions, the MGAOC is revised down from the previous estimate to extend 250 feet beyond the waste footprint. It is important to note that these Areas of Concern can change over time. Therefore, updated information will be provided to the City when the existing information becomes obsolete or misleading. CURRENT ZONING FOR THE LMA As listed on the City's Official Zoning Proposed Map updated March 2011, the portion of the LMA containing the waste footprint is zoned Public/Quasi-Public. The intent of this district is to provide for public and private recreational uses, government buildings and facilities, and schools. Two parcels south of the waste footprint, but within the LMA are zoned E-2 Employment District. The intent of this district is to provide for the mix of typically large volumes of bulk commercial goods and services, wholesale or warehouse activities and limited retail activities. Three parcels on the east side of the LMA are zoned R- 2 Multiple Family Districts. The intent of this district is to accommodate duplexes, twinhomes, townhomes, or multifamily units at a maximum density of seven units per acre and a minimum density of three units per acres. Lastly, seven parcels on the west side, within the LMA are zoned 2030 MUSA 3