2016.04.18 CC Packet - Laserfiche WebLink

Home

Columbus was taken from the City's existing comprehensive plan rather than predicted by population projections and existing per capita use. 9.0 It is assumed that the future ratio of peak day water use to average day water use will reflect the previous historical five year average for each of the cities. The average peaking factor of the joint utility was computed by taking a population -weighted average of the six cities' individual peaking factors. This is likely conservative as a larger population base of a Joint Utility should result in a lower peaking factor. 10.0 The required fire flow for the City of Lino Lakes is 4,500 gpm for four hours. As this is the highest known fire flow requirement for any of the six cities, 4,500 gpm for four hours was also assumed to be the requirement of the combined utility. Lino Lake's fire flow is relatively large in comparison to what would be normally expected for cities of similar size; in the absence of city - specific data for the remaining five cities, fire flow requirements were assumed to be 3,500 gpm for three hours for the cities of Centerville, Circle Pines, Columbus, Hugo and Lexington. 11.0 For the purposes of this preliminary analysis it is assumed that pressure zones are compatible for connecting water systems, sharing elevated storage and pumping stations. Further detailed analysis would be needed to determine the compatibility of the various systems with regards to pressure zones and operating pressures. 12.0 Cost estimates in this study are preliminary, high-level estimates intended only for comparison purposes within this study. A more detailed review of the costs to install and maintain various system components is needed to increase the accuracy of the predicted costs of the future systems and reduce uncertainty. 13.0 All future development within the cities will utilize groundwater for water supply. Surface water options were not considered in this study. 14.0 New groundwater wells would have a nominal capacity of 1,000 gpm. Note that some locations within the study area may reliably supply greater amounts and this could be considered in a future study to better analyze the benefits of a joint supply system. 15.0 We did not assume any regional water treatment plants as part of this study. It is assumed that water quality issues would be handled by chemical addition or small treatment plants at the well. If all cities plan to treat for iron and manganese then large regional treatment plants will almost always prove to be more cost effective than small distributed local plants. This is actually a potential benefit of a Joint Utility as many communities tend to move towards treated water as they mature. Doing so in a Joint Utility setting would add even more benefit by reducing the number of plants needed to meet the quality needs. 16.0 Infrastructure repair and replacement costs were estimated as a percent of total capital costs. The following assumptions were made regarding annual maintenance costs: 1 % per year for watermain replacement, 2% per year for storage and wells maintenance and replacement, 3% per year for SCADA system replacement and repair. 17.0 Specific projections of future joint utility operational costs are not accounted for in this study. It was assumed that operational costs such as power and labor would be the same for the given total future water use, regardless of the specific system ownership or configuration. 18.0 Staffing is discussed at a high level in Section 8.0; however, staffing would be largely dependent on how the joint utility is formed. Thus, staffing costs for Options 1-3 are not directly compared. 19.0 For the creation of comparative future water costs it was assumed that the developers would pay for 100% of new watermain costs, and all other capital costs would be funded 80% through development and water availability charges, and 20% by rate payers. Joint water Utility Feasibility Study 12