4.3 SR 03-20-2023 - Laserfiche WebLink

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The quality of stormwater runoff fi^om the project post consti^uction will be typical of an urban land use with impervious surfaces and lawn/landscaping generally ge�rerating higher conce�rtrations of total suspended solids and total phosph�orus. Stormwater runoff is proposed to be conveyed into permanent constructec� stormwater treatment infi^astructure (e.g. infiltration basins, filtration basins, holding ponds, vegetated swales, etc.) across the site for treatment prior to discharge. Temporary erosion and sediment co�rtrol best manageme�rt practices (BMPs) will initially be installed (per the project's SWPPP), maintained/repaired, and amended through�out the construction phases as required to remain compliant with the applicant's NPDES Construction Stormwater Permit. BMPs may include (but are not limited to) silt fence, bio-rolls/filter logs, rock construction entrances, mulch/hydro mulch, and permanent native seeding or turf seeding in appropriate areas. iii. Water appropriation - Describe if the project proposes to appropriate surface or groundwater (including dewatering). Describe the source, quantity, duration, use and purpose of the water use and if a DNR water appropriation permit is required. Describe any well abandonment. If connecting to an existing municipal water supply, identify the wells to be used as a water source and any effects on, or required expansion of, municipal water infrastructure. Discuss environmental effects from water appropriation, including an assessment of the water resources a�ailable for appropriation. Identify any measures to a�oid, minimize, or mitigate environmental effects from the water appropriation. No appropriations of surface waters are proposed as part of the Project. Water will be sourced fi^om th�e City of Elk River's existing public water supply system (PWS #1710004). The City's PWS is currently sourced fi^om eight groundwater wells (MDH #s 255153, 221176, 481794, 537682, 580320, 664852, 694499, and 757624). Construction of new watermains will be required to service the project but no expansions to the City's PWS are anticipated to be required. Short-term temporary construction dewatering of surface or ground waters may be required at the time of construction (depending on current field conditions) to facilitate construction activities (e.g., utility installation, etc.). If dewatering is anticipated to exceed 10, 000 gallons per day or 1, 000, 000 gallons per year, the contractor will be required to obtain a Water Appropriations Permit fi^om the Department of Natural Resources (N�NR) Division of Waters prior to initiati�rg such activities. Measures to avoid, minimize, or mitigate th�e environmental effects fi^om construction related to dewatering are unknown at this time, a�d therefore will be determined when developing the dewatering plan as required by a Stormwater Pollution Prevention Plan amendment of the NPDES Construction Stormwater Permit. Page ll