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Updated Surface Water Management Plan (SWMP) <br />City of Ramsey, Minnesota <br />7 2005 <br />The Metropolitan Council has requirements for local governments to include <br />local water management plans as part of their Comprehensive Plans. The <br />Metropolitan Council does not have authority to set policy or administer local <br />storm water regulations. This Surface Water Management Plan Update is <br />designed to address current requirements governing local water management <br />plans. The general boundary of the plan includes all property within the City <br />limits of Ramsey. When accepted by all local, regional, state and federal <br />agencies having jurisdiction, the City of Ramsey will be the sole responsible <br />party for administering this plan. <br />8. 2012 <br />The Lower Rum River Watershed Management Organization adopted their Third <br />Generation Plan. The new plan requires infiltration for new and redeveloped <br />sites, use of the Atlas-14 rainfall distributions and reductions in Total Suspended <br />Solids (TSS) and Total Phosphorus (TP) for runoff discharged from new <br />permitted projects. <br />B. General Content of Required Local Plans <br />This SWMP follows the general report structure listed in Minnesota Rules Chapter <br />8410.0170, the general requirements in Minnesota Statute sections 103B.205 - 103B.255, <br />and the Metropolitan Council's requirements for local water management plans as <br />adopted May 2005 as part of the Metropolitan Council's Water Resources Management <br />Plan. As stated above, the City will update this plan subsequent to the adoption of the <br />Metropolitan Council's 2040 Water Resources Policy Plan. <br />C. Summary of the Goals, Problems, and Potential Solutions <br />The general findings of this Surface Water Management Plan report are summarized as <br />follows: <br />1. Ramsey is located in the Anoka Sand Plain. The area is well known for its <br />highly permeable soil. As such, the runoff from significant rainfalls is generally <br />reduced to the extent that the existing drainage network functions well with no <br />significant flooding outside the Mississippi River, Rum River, Trott Brook, Ford <br />Brook, County Ditch 43 and County Ditch 66 flood plains. <br />Because of the pervious nature of the Anoka Sand Plain, the City will need to <br />review its development ordinances to mitigate the adverse effect that a significant <br />increase in impervious surfacing and mass grading can have on runoff conditions. <br />The addition of significant amounts of impervious surfaces and the reduced <br />permeability associated with the soil compaction in mass grading without a <br />reasonable attempt to restore or duplicate the current infiltration pattern could <br />create very significant increases in runoff volumes and downstream flooding. <br />This is especially true in the Trott Brook, D66, EMISS and WMISS watersheds <br />(see Figure 9), where improvements in uppermost watershed limits must flow a <br />significant distance to the ultimate watershed outlet. The longer flow path <br />associated with each of these watersheds allows greater opportunities for peak <br />flows from conventional detention ponds to coincide. <br />One solution to the problem of coincident peak flows is the use of low impact <br />development techniques. There are a variety of low impact development <br />Section II <br />March 20, 2015 Page 4 <br />