Agenda - Environmental Policy Board - 10/15/2018

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ultimate discharge to this reach of the Mississippi River (see Item 17 discussion). The discharge is not expected to impact the existing impairment. • Design and management strategies to minimize the discharge of pollutants from the MS4 to the Maximum Extent Practicable (MEP) with an annual report on implementation. The SWPP must be completed at least 30 days prior to commencing construction and prior to applying for construction permits. Elements 4, 5 and 6 are directly applicable to the stormwater management approach adopted for the RTC site as it develops. The stormwater management appivaLl is spelled -out in Item 17. In addition to the complying with the City's MS4 requirements, essentially any construction activity that is part of this —mmon plan of development" must apply for a construction permit under the NPDES Phase II Construction Permit process. Elements of this program are intended to avoid erosion and construction site pollution. To prevent this, construction at the RTC site should: • Establish fast growing cover crops as soon as possible to disturbed soils to prevent both water and wind erosion. The sand content of the soils on site could lead to wind blown sands could be potentially hazardous, particularly to traffic on Highway 10. • Install temporary sediment basins for any areas of disturbance, installed before discharge leaves the site or enters a surface water body. • Install a permanent stormwater management system that assure stormwater is . discharged in a manner that does not cause nuisance conditions, erosion in receiving channels or on downslope properties, or harmful inundation in wetlands." Maintain peak flow rates from two, twenty, and one hundred year twenty four hour events at existing conditions. • During construction, the maximum area of disturbance shall not exceed the ability to keep up with exposed area limits on slopes. All areas with greater than 3:1 slopes must have vegetative cover by November first. Site inspections will be once every seven days during construction and within 24 hours after a quarter inch event in 24 hours. At that time, any non-functioning BMPs must be repaired. • If stormwater discharge to a wetland has potential for significant adverse impacts to the wetland, the impacts should be addressed with BMPs and permit provisions. Appropriate rules (7050.0186) and any applicable regulations must be followed. All of these elements would be part of the erosion and sediment control plan listed in the mitigation element under Item 16 of the AUAR. The Mississippi River as it passes through Ramsey is an Outstanding Resource Value Water (ORVW). Prior to stormwater discharge to an ORVW, the MPCA must find that there are no prudent or feasible alternatives to the new or expanded discharge. For ORVWs the following BMPs are also required. 8-5