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regulated contaminants were sampled as part of the Fourth Unregulated Contaminant Rule (UCMR4) sampling, which included monitoring from 2018 to 2020 for 30 different non - regulated contaminants. 2.2.2 White bear i ownship Water Quality The source of water for White Bear Township is from six wells ranging from 360 to 445 feet deep that draw water from the Prairie Du Chien -Jordan and Jordan aquifers. Prior to being pumped into the water distribution system, the water from all the wells is treated with chemical additions of chlorine for disinfection, fluoride for water fluoridation, and polyphosphate for iron and manganese sequestration which prevents color and taste issues by preventing the precipitation of iron and manganese. One well is treated with filtration for iron and manganese removal. The water does not go through a water softening treatment process and the Township's website states that water hardness is around 18 grains per gallon, which is considered very hard water. As can be seen in their CCR, their water meets all State and Federal regulations. No detected non -regulated contaminants are reported in the 2020 CCR. Because UCMR4 sampling was conducted between 2018 and 2020, White Bear Township's UCMR4 sampling was conducted in 2019 and the results are found in their 2019 CCR. As can be seen in their 2019 CCR in Appendix D, manganese levels were detected in their wells in the range of 116 to 200 parts per billion (ppb). According to MDH, for infants 12 months old or younger who drink tap water or drink formula made with tap water, a safe level of manganese in water is 100 ppb or less. Their well which is filtered to remove iron and manganese is nearest Gem Lake, so it could be expected that most of the water entering Gem Lake's water system would be from that well. although this warrants further evaluation. 2.3 1 Water Availa; ,,;ty With an ultimate ADD of 0.152 MGD and an ultimate MDD of 0.456 MGD, determining whether the White Bear Lake or White Bear Township water systems can supply the projected Gem Lake demand is crucial. In evaluating the ability to supply a Gem Lake water system, we looked at White Bear Lake and White Bear Township's supply capacity, firm capacity, storage capacity, their own system's water demands, and their permitted annual water usage. Firm capacity, defined as the total capacity with the largest well offline, is a more accurate reflection of a water system's capacity as wells are routinely taken offline for maintenance or repair. MDH recommends having a minimum of an average day of water use in storage. 2.3. i White Beer Lake Water Availability White Bear Lake has a total of five wells, with one of those wells designated as emergency use only. i'able 2 — White Bear Lake Supply Capacity Well Capacity Capacity -4 (gpm) (MGD) Well #1 00 1.58 FEASIBILITY STUDY UPDATE City of Gem Lake, MN Page 4