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Feasibility Study <br />Water Treatment Plant <br />City of Lino Lakes, MN <br />WSB Project No. 015822-000 Page 15 <br />5. WATER SUPPLY OPTIONS <br />The primary purpose of this feasibility study was to evaluate alternative water supply options to address <br />the high manganese levels in the City’s drinking water and provide the City with acceptable water quality. <br />These options include drilling new wells, purchasing treated water from another community or water <br />system, and implementing treatment. <br />5.1 Drill New Wells <br />The first option analyzed is to construct and utilize deeper Tunnel City-Wonewoc (CTCW) or Mt. <br />Simon–Hinckley (CMSH) wells instead of the Prairie du Chien-Jordan (OPCJ) wells that are <br />currently being used by the City. For example, the City of Blaine’s Well Nos. 19 and 21 and City <br />of Columbus’ Well No. 3 are developed into the Tunnel City-Wonewoc Aquifer, and the City of <br />Spring Lake Park’s Well No. 5 and City of New Brighton’s Well No. 8 are developed into the Mt. <br />Simon-Hinckley Aquifer. <br />Drilling new Prairie du Chien-Jordan wells at a similar depth as existing wells was not considered <br />feasible because there is no guarantee that the new wells would have lower, acceptable <br />manganese concentrations. <br />The Tunnel City-Wonewoc Aquifer is the next deeper aquifer below the Prairie du Chien-Jordan <br />Aquifer and St. Lawrence Aquitard. Based on the Anoka County Geologic Atlas hydrogeologic <br />cross sections in Appendix C, this aquifer is approximately 250 to 450 feet below ground level <br />depending on the location within the City. Because the static water levels in this aquifer would be <br />lower than in the existing wells, larger well pumps would be required, and the City’s electrical <br />utility costs would increase. The Minnesota Ground Water Association’s Manganese in <br />Minnesota’s Groundwaters report from September 2015 notes that, “higher dissolved manganese <br />concentrations commonly are found in groundwater that has low amounts of oxygen such as <br />deep, isolated aquifers.” Therefore, deeper aquifers are likely to contain equal, if not greater, <br />concentrations of manganese compared to the Prairie du Chien-Jordan Aquifer and would likely <br />still require treatment for manganese. <br />The Mt. Simon-Hinckley Aquifer is the deepest bedrock formation in the Twin Cities and is <br />significantly deeper than the Prairie du Chien-Jordan Aquifer. Based on the Anoka County <br />Geologic Atlas, this aquifer is at least 550 feet below ground level. This aquifer is only shown in <br />the southern portion of Lino Lakes in the Anoka County Geologic Atlas (see cross section H-H’) <br />due to deep wells being located along the same cross section to the west in Blaine and Coon <br />Rapids. New Mt. Simon-Hinckley wells can potentially be drilled, although it is very uncommon for <br />the DNR to approve them. The State of Minnesota currently has a moratorium that restricts the <br />use of this aquifer in the Twin Cities Metropolitan Area. In addition, the Mt. Simon-Hinckley <br />Aquifer is likely to contain high concentrations of natural Radium 226/228 that exceed the EPA <br />MCL of 5.0 pCi/L. Therefore, this source would likely require a treatment process such as <br />greensand filtration, ion exchange, reverse osmosis, or lime softening to treat radium. The DNR <br />does not issue appropriation permits to public water systems to pump groundwater from this <br />protected aquifer when alternative water sources or interconnections with nearby public water <br />systems are available. <br />5.2 Purchase Treated Water <br />The second option analyzed was to purchase treated water on a wholesale basis from St. Paul <br />Regional Water Services (SPRWS). The SPRWS system is supplied by a combination of surface <br />water from the Mississippi River and Northeast Metro lakes and groundwater from ten wells. <br />SPRWS water is treated at the McCarrons Water Treatment Plant.