2022 01-18 CC PACKET - Laserfiche WebLink

Home

Table 5 — White Bear Township North System Storage Capacity White Bear Township's Water Supply Plan states that their 2022 ADD and MDD are estimated to be 1.687 MGD and 6.550 MGD respectively and that by 2040 their ADD and MDD are estimated to be 1.814 MGD and 7.042 MGD respectively. According to the DNR's water use data, from 2016 to 2018 the South System accounted for an average of 7.41 % of the demand. Based on this, the North System's 2022 ADD and MDD are estimated to be 1.562 MGD and 6.065 MGD respectively and the 2040 ADD and MDD estimated to be 1.680 MGD and 6.520 MGD respectively. According to the DNR, as of 2018 White Bear Township's Water Appropriations Permit allows them to pump 550 MGY or an average of 1.51 MGD in the North System, which is just shy of the estimated ADD With a firm capacity of 4.39 MGD and an estimated existing MDD of 6.065 and estimated 2040 MDD of 6.520 MGD for the North System, as well as a permit to pump an average of 1.51 MGD for the North System, it appears that White Bear Township's North System may require additional capacity and an increased limit in their Water Appropriations Permit to be able to adequately supply a Gem Lake water system. Further discussions with White Bear Township regarding future plans for the North System are recommended if Gem Lake wishes to proceed with a White Bear Township system interconnection. 3 Water, Modeling To determine how a Gem Lake water system would hydraulically operate using White Bear Lake and White Bear Township's water systems as a source, a hydraulic computer model was developed using WaterGEMS1, a pipe network program developed by Bentley@. 3. m L White Bear Lake Water Svstem sing White Bear Lake's watermain shapefiles, MDD demands, and water tower overflow elevations as the hydraulic grade line (HGL) for the system, a White Bear Lake fed Gem Lake water system was modelled. White Bear Lake's MDD demands were spread evenly throughout their system except for assigning their top ten users' demands to their appropriate locations, and each scenario was analyzed with no water being pumped into the system by the City's water treatment plant and with their water towers full to their overflow elevation. A map of the proposed Gem Lake — White Bear Lake water system can be seen in Appendix E. 3.1.1 Gem Lake — White Bear Lake Pressures Water system pressure is primarily a function of the elevation of the water in the system's elevated storage towers with some degree of pressure loss as water flows through the system. Lower pressures generally occur in areas of higher elevation and higher pressures FEASIBILITY STUDY UPDATE City of Gem Lake, MN Page 6