Agenda - Council - 12/12/2017 - Laserfiche WebLink

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1. Water Supply Infrastructure Needs It is anticipated that the existing Ramsey water supply system will need to be expanded to meet future water demands. If the City continues to plan on utilizing groundwater sources, new wells will be required to meet water demand during the design period. Minnesota Department of Natural Resources staff has indicated that future well construction will need to be coordinated with the overall water use of the area. Surface water sources, such as the Mississippi River, will need to be evaluated. 2. Water Treatment Infrastructure Needs All current water sources for the City of Ramsey exceed recommended levels for iron and manganese. The average iron concentration from the City's eight wells is four times greater than the recommended concentration of 0.3 mg/L. The average manganese concentration is three times greater than the recommended concentration of 0.05 mg/L. As the city's population continues to grow, it is anticipated that there will be increasing demand for improved water quality regarding iron and manganese levels. The current treatment utilizing polyphosphates for sequestering of iron and manganese does mitigate some of the impact of these contaminants on customers; however, sequestering does not remove iron and manganese, and over time, a certain amount of iron and manganese deposits in the distribution system, thus adding to maintenance costs of the system. Due to significant increases in the water supply demands, and the unknown quantity of groundwater that can be pumped from the Ironton -Galesville formation, surface water sources will need to be considered to meet the City's water needs. A water treatment facility would be required to treat surface water sources. Due to the number of wells which would be required to meet the future system supply needs, the current system of multiple chemical feed points may result in water quality inconsistency across the system. Also, multiple feed points will represent a substantial security risk to the system. City of Ramsey, Minnesota — R13.104504 Page 3 Comprehensive Water System Study Prepared by Bolton & Menk, Inc.