11-19-2018 Planning Commission Packet

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CMP Part 4C. Water Supply (MDH) was granted authority to implement wellhead protection and rules governing wellhead protection were adopted in March 2007. Grouping of wells eases wellhead protection and potential treatment beyond the existing facilities. Water Treatment The Navarre Water System currently uses sand filtration for iron and manganese removal, ion exchange softening to reduce hardness, and adds fluoride,chlorine, and polyphosphate to the water before entry into the distribution system. At this time, the City does not need to pursue additional water treatment capacity at the Navarre WTP. However, the City should make chemical feed and other improvements at the Navarre WTP as outlined in Section 6 in the Water Supply Plan, 2018. The Highway 12 Water System adds chlorine and fluoride, as well as polyphosphate to inhibit corrosion to water before entry into the distribution system. Water Storage -- • . . •- • li ii, - tower in the Navarre system and a 100,000 gallon elevated water tower in the Highway 12 system. Details of the storage tanks are presented in Table 4C-2. The principal purpose of storage is to provide the ability to equalize pumping rates during periods of variable rate demand. Adequate storage permits a reduction in the size of the pumps required to supply a community because peak demands are diminished by the reserve provided in storage. Storage is typically provided in elevated tanks for communities the size of Orono to provide storage and a pressure source even when the wells are not pumping. The primary reasons for providing storage are as follows: • To equalize pressure in the distribution system. • For emergency requirements (pump failure,power failure). • Fire protection. Storage adequacy can be assessed using the Average Day Criteria or the Maximum Day, Fire Protection and Emergency Storage Criteria. Average Day Criteria Generally, the minimum recommended standard, without fire protection, is equal to the average day demand (Ten State Standards, 1997). By this standard, the Navarre Water System currently has a slight storage deficit since the average day demand is 220,000 gpd and the current storage capacity is 20,000 gallons. As shown in Table 4C-9, the Navarre Water System will have a storage deficit of 100,000 gallons when the population using the system reaches 3,000. 3000 population equates to about 335 new households. 100% build out of the planned development areas in the Navarre area identifies 250 new households. City of Orono Community Management Plan 2020-2040 Part 4C, Page 11