2017.04.17 CC Packet - Laserfiche WebLink

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Adelaide Landing Residential Development EAW, Hugo January 31, 2017 Volume Control Volume control will be provided via stormwater reuse for irrigation of the residential lots, the adjacent road boulevards and the playfield, a total irrigated area of 62.4 acres. Irrigation pumps will draw water from deep water Ponds 15, 16 & 17, the ponds with the largest dead storage. The Stormwater Reuse Calculator developed by Ramsey Washington Metro Watershed District was used to estimate the volume reduction on an annual basis. As determined using the Reuse Calculator, an average year generates 84.4 ac-ft. of runoff from the developed area. Typical irrigation occurs for 16 weeks from mid -May to mid -September. Irrigation at an average of one inch per week over the proposed irrigation area yields a volume of 84.1 ac-ft., which is greater than 90% of the annual runoff volume. This is consistent with MIDS volume reduction guidance. Volume reduction numbers are currently unavailable for a per -storm basis. Stormwater and Erosion Control BMPs Because the project will involve disturbance of more than one acre of land, application for coverage under the National Pollutant Discharge Elimination System/State Disposal System (NPDES/SDS) General Permit will be submitted to the MPCA prior to initiating earthwork on the site. This permit is required for discharge of stormwater during construction activity and requires that Best Management Practices (BMPs) be used to control erosion, and that erosion controls be inspected after each rainfall exceeding 0.5 inches in 24 hours. Erosion control practices that will be implemented on the site include: 1. Construction of temporary sediment basins in the locations proposed for stormwater ponding, and development of these basins for permanent use following construction. 2. Silt fence and other erosion control features installed prior to initiation of earthwork and maintained until viable turf or ground cover is established on exposed areas. 3. Periodic street cleaning and installation of a rock construction entrance to reduce tracking of dirt onto public streets. 4. Stabilization of exposed soils within 7 days. 5. Energy dissipation, such as riprap, installed at storm sewer outfalls. 6. Use of cover crops, native seed mixes, sod, and landscaping to stabilize exposed surface soils after final grading. Erosion control plans must be reviewed and accepted by the City of Hugo and the RCWD prior to project construction. Because the above BMPs will be implemented during and after construction, potential adverse effects from construction -related sediment and erosion on water quality will be minimized. 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. 20