8.2. SR 11-07-2016 - Laserfiche WebLink

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handled internally through infiltration and evaporation and is and not discharged off- site. Potential impacts to the water quality of stormwater runoff are mitigated through the implementation of a Site specific stormwater pollution prevention plan (SWPPP). The plan provides for stormwater best management practices (BMPs) and phasing of mining operations. Perimeter controls will consist of silt fence, diversion swales and or berms placed around the downslope edge of any area that has the potential to drain off-site during stripping operations. Perimeter controls will remain in place until mining has redirected drainage internally. Infiltration areas and temporary sedimentation basins will be used as needed on the floor of the mine to manage stormwater on the mine floor. The locations of these stormwater management features move as mining progresses through the Site. Establishment of vegetation through seeding and mulching will be conducted as soon as reclaimed areas have been final graded. Erosion control matting, sediment logs and other erosion and sediment control practices will be used as needed throughout the mining operations. Other BMP's for the Site will include good housekeeping, employee training on proper handling of Site materials, on-going maintenance of all Site equipment, containing all stormwater on-site, routine Site inspections, seeding and stabilization of perimeter berms, no discharge of storm water runoff from the Site (all storm water runoff generated within the active mining area will be managed internally), routine street and entrance sweeping to prevent sediment from leaving the Site, rock construction entrances if needed to prevent tracking offsite, and on-going reclamation of the Site once the sand and gravel resource in the perimeter areas has been recovered. Both mining operations will operate under NPDES general permits for non-metallic mineral mining and Site specific stormwater pollution prevention plans (SWPPP) will be prepared for each site. 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 available for appropriation. Identify any measures to avoid, minimize, or mitigate environmental effects from the water appropriation. Sand and gravel washing is proposed at both mining facilities and a DNR water appropriations permit will be required for both Sites. Aggregate washing occurs seasonally during nonfreezing weather conditions (generally April — November). The washplant discharge, which contains a high concentration of suspended solids is treated through a series of sedimentation ponds. Treated water is recycled back through the washplant for reuse. The quantity of washwater depends upon the percentage of fine Environmental Assessment Worksheet Page 16 Elk River Sand and Gravel Mines:Tiller Corporation and Max Steininger, Inc.