Agenda - Planning Commission - 05/03/2018

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Updated Surface Water Management Plan (SWMP) City of Ramsey, Minnesota • Temporary Wetland Protections During Construction — Areas within 16.5 feet of a wetland boundary must be protected from land grading and other disturbance during the construction process. The area shall be demarcated with properly installed heavy duty silt fence. • Native Plant Seeding in Common Spaces at the Conclusion of Construction — Within common spaces, areas adjacent to wetlands that are disturbed through the construction process and ponding areas (stormwater management areas) should be seeded with a BWSR native seed mix that matches site conditions. • Wetland Protections after Construction — Following construction, site stabilization, and vegetation establishment certain activities shall be prohibited within 16.5 feet of the wetland edge. Activities prohibited include: o Structures, excluding fences. Fences are not allowed inside the wetland boundary. o Paving, except projects with a public purpose such as public trails. o Retaining walls. o Filling, dumping or yard waste disposal. o Fertilization o Septic Systems. • Relationship to Drainage and Utility Easement - Drainage and utility easements must encompass the area within 16.5 feet from the wetland edge. The process outlined in the LRRWMO Third Generation Plan shall be followed when a development is proposed adjacent to wetlands. E. Storm Water Modeling 1. Runoff Storm water runoff is defined as that portion of precipitation, which flows over the ground surface during, and for a short time after, a storm. The quantity of runoff is dependent on the intensity of the storm, the length of storm, the amount of rainfall, the type of ground cover, and the slope of the ground surface. The intensity of a storm is described by the amount of rainfall that occurs during a specific time interval. A specific rainfall amount occurring during a given time interval will statistically recur, on the average, at a certain frequency (usually measured in years). This is called a return frequency. A return frequency designates the average time span during which a single storm of a specific magnitude is likely to occur. For example, a 100-year rainfall event in Ramsey is that 24-hour rainfall amount (7.1 inches) that recurs, on the average, once in 100 years. The degree of protection afforded by storm sewer facilities is determined by selecting a return frequency to be used for design based on good economic sense and current engineering practices. See section E.3 for further discussion. Section IV October 21, 2015 Page 35