Agenda - Council - 07/28/2015 - Laserfiche WebLink

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50 • State -designated calcareous fens • Springs • Surface waters where hydrogeologic conditions suggest a connection between groundwater and surface waters such that there is a potential to impact surface water levels and stream flows - these may include: rivers, lakes and wetlands These indicators should not be considered regulatory cut-offs. Rather they are to help provide information about planning expectations, so that there are fewer surprises when permits are requested or plans are made. Where groundwater and surface water are likely to interact, additional monitoring and assessment may be needed to evaluate impacts of increased groundwater pumping or stormwater best management practices. Water quality For several communities, water quality is a more challenging issue that water quantity. A recent study estimated $0.7-12 million in costs (present values over a 20 year horizon) to address the increased risk of nitrate contamination of private wells (Keeler and Polasky, 2014). Public water suppliers are responsible for providing water that meets Safe Drinking Water Act and other state requirements. The Minnesota Department of Health is the responsible agency for all public and private water quality issues. Depending on potential contamination sources, whether the system uses wells or surface water, depth to wells, geology and past test results, the Minnesota Department of Health may test a public water supply for up to 118 different contaminants. Surface water and groundwater supplies are susceptible both to chronic and acute contamination from natural and human -produced sources. Spills in the Mississippi River may affect the Minneapolis Water Works and Saint Paul Regional Water Services systems; large industrial contamination plumes have affected many groundwater users, and nitrate contamination is a considerable issue in some parts of the metropolitan area such as Dakota County. Chronic contamination in both surface water and groundwater can have long-term public health and economic consequences. While chronic contamination of municipal supplies can often be treated once it is discovered, treatment costs may cause significant price increases for consumers and may, in severe cases, limit use of the water source. All costs associated with treating known contaminants in a public water supply are borne by that system. Private well owners also face considerable costs when groundwater supplies are contaminated. The following points are important to consider when evaluating risk of water supply contamination: • Proximity to known areas of groundwater contamination, such as Special Well and Boring Construction Areas • Proximity to designated Wellhead Protection Areas, Drinking Water Supply Management Areas, or Source Water Protection Areas • Proximity to karst features such as sinkholes, which provide direct connections between land surface and underlying aquifers • Estimated vertical travel time from land surface to bedrock aquifers Efforts to protect and manage water supply quality (both groundwater and surface water) should consider, as shown in Figure 23: • Vulnerable source water protection areas - for surface water (dark orange) and groundwater (light orange) • Designated Special Well and Boring Construction Areas (red cross -hatched areas) • Karst features (black dots) WATER SUPPLY MASTER PLAN- Draft June 2015