Agenda - Council - 05/26/2015 - Laserfiche WebLink

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Updated Surface Water Management Plan (SWMP) City of Ramsey, Minnesota In areas adjacent to designated flood plains as mapped on a Flood Insurance Rate Map, the Regulatory Flood Protection Elevation (RFE) applies. The RFE is defined as the mapped 100-year flood elevation plus 1 foot. However, the LRRWMO requires that the low floor elevation of structures be 2 feet above the calculated flood elevation. Therefore, all structures, including accessory structures, must be elevated on fill so that the lowest floor including basement floor is lft above the Regulatory Flood Protection Elevation or 2 foot above the mapped 100-year flood elevation. The finished fill elevation for structures shall be no lower than the Regulatory Flood Protection Elevation and the fill shall extend at such elevation at least fifteen (15) feet beyond the outside limits of the structure erected thereon. The following drawing better defines the Regulatory Flood elevations.' The following exhibit applies only when fill is reauired to bring a structure at least two (2) feet above the 100-year flood level. Not to Scale Flood Frei a Floodwa Top of _Hoot-� -� 100-Year at RFPE* 00 Hood Level • No Fill Allowed *RITE — Regulatory Flood Protection Elevation * 100-Yr Flood Level includes the flood stage increase (of up to foot) due to filling in flood hinge Minimum Standards for Structures in 100-year floodplain The numerous natural depressions found throughout Ramsey have been incorporated into the SWMP as ponding areas. The effective use of ponding areas enables the installation of outflow sewers with reduced capacities since the design storm duration is effectively increased over the total time required to fill and empty the ponding reservoirs. Storm sewers represent a sizable investment for the community and this investment can be more 6 Taken from the Minnesota DNR website: http://www. dnr. state.mn.us/waters/watermgmt_section/floodplain/rfpe.html Section IV March 20, 2015 Page 32