08-04-25 - City Council Work Session Agenda

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gallons per year are withdrawn. It is anticipated that the temporary dewatering would only occur during utility installation and potential construction of building foundations Estimated Water Supply Existing water infrastructure within the study area includes a 12-inch diameter ductile iron pipe (DIP) watermain along Robinson Drive and Century Trail south of the site and 8-inch DIP watermain on Carl Street (west cul-de-sac). There is a 10-inch DIP water stub for the Robinson Property off of Cardinal Way and two 12-inch diameter DIP watermain stubs at the intersection of Robinson Drive and Century Trail. The City's DNR water appropriation permit currently allows an annual withdrawal volume of 900 million gallons per year (MGY). The City's existing annual demand plus the projected annual demand for the study area will exceed this volume. Therefore, the City's DNR appropriation permit annual withdrawal volume will need to be amended prior to full build out of the study area. Scenario 1 and 2 The projected water demand for the proposed development scenarios is approximately 559,800 gallons per day (GPD) for Scenario 1 and approximately 620,100 GPD for Scenario 2 (see Table 9). Table 9: Project Water Demands Water Demands Scenario 1 Average Daily Scenario 2 Average Daily Flow (GPD) Flow (GPD) •- 1 111 . 1 111 � • :11 1 11 .M.T.-TITIN 1 11 The City's current water production capacity will not be sufficient to serve the entire study area. It is anticipated that only a small percentage of the area could be served by the City's existing system assuming the City's proposed Well No. 7 is constructed in 2026. The City will need to install new wells, Wells No. 8 and 9, to serve the entirety of the study area and satisfy City-wide water demands. The 2040 Comprehensive Water Plan provides additional details on water demand for the city through the projected 2040 planning period. It is feasible to extend the watermain to serve future lots. However, the size and layout of the watermain will have to be determined during preliminary design, and the watermain will need to be looped through the site. At a minimum, the larger 12-inch diameter trunk watermain will need to be looped through the high density residential areas. All proposed units will be required to connect to the City's water system. The City is constructing a water treatment plant for manganese removal which will be placed in service in the fall of 2026 and will provide adequate treatment capacity through Well No. 9. The City's total elevated storage volume is 3.5 million gallons (MG), which is projected to be sufficient for the entire study area. V. Surface Waters 4) Wetlands — Describe any anticipated physical effects or alterations to wetland features, such as draining, filling, permanent inundation, dredging, and vegetative removal. Discuss direct and indirect environmental effects from physical modification of wetlands, including the anticipated effects that any proposed wetland alterations may have to the host watershed, taking into consideration how current Minnesota climate trends and anticipated climate Lino Lakes Main Street - AUAR 50 July 2025 Page 58 of 617