12/03/2003 Env Bd Packet - Laserfiche WebLink

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The proposed development site is characterized by gently rolling topography, but contains some areas of slopes approaching 12 %. The construction of local roads, utilities, and development may require extensive grading and landscape manipulation at specific locations within the site. Erosion will present a hazard in slope areas if soils are exposed and left bare during construction activities. Construction of the project will disturb more than 1 acre of land and therefore will require a National Pollutant Discharge Elimination System (NPDES) permit. A likely requirement of the NPDES permit and a requirement of the Rice Creek Watershed District is that a storm water runoff and erosion control plan be prepared for the site. The proposed plan will include the collection and treatment of runoff through grass swales, temporary sediment basins, storm water detention ponds, silt fencing, and vegetative filter/buffer strips (utilizing existing vegetation or manufactured materials). These control and treatment techniques will be utilized throughout the site and will be appropriately located to protect wetlands located along the eastem side of the site. Furthermore, City policies and standards for controlling erosion and sedimentation will be required. These standards are consistent with the MPCA Best Management Practices for. Protecting Water Quality in Urban Areas, the BWSR Minnesota Construction Site Erosion and Sediment Control Planning Handbook, and the EPA Nationwide Urban Runoff Program (NURP). Vegetative filter strips will be used around the eastern and southern boundary of the site to help control erosion. As stated in the Lino Lakes Handbook for Environmental Planning and Conservation Development, filter/buffer strips provide an important function in minimizing erosion, reducing direct runoff of storm water into vulnerable ecological resources, and help sustain wildlife populations through suitable habitat. The City and the developer will coordinate efforts with the Rice Creek Watershed District, MPCA, and the City's Environmental Board to ensure erosion concerns are addressed. 17. Water quality: surface water runoff a. Compare the quantity and quality of site runoff before and after the project. Describe permanent controls to manage or treat runoff. Describe any storm water pollution prevention plans. After additional impervious surface area is created by the construction of buildings and pavements, the rate and volume of surface water runoff will increase during storm events. Therefore, a surface water management plan for the development is being proposed that will retain storm water runoff on -site for the purpose of improving water quality and incorporate infiltration to reduce surface discharge and promote recharge of the groundwater. To comply with City and Rice Creek Watershed District requirements, the surface water management plan has incorporated rate control, which will ensure that there is a 0% post - development increase in runoff rates from the site. The development proposes to construct a drainage system within all the street improvements and parking areas to convey runoff to proposed ponding areas and infiltration cells (green space or underground storage chambers). Subsurface chamber technology takes advantage of the soil's inherent filtration and renovation capabilities to store and treat storm water runoff while providing the flexibility to plan for additional buildings and green space. To maximize pollutant removal efficiencies, the water quality control structures will be designed and constructed according to NURP, the City of Lino Lakes, and Rice Creek Watershed District standards. Appendix B contains Legacy at Woods Edge Development EAW DRAFT 16 Lino Lakes, MN