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

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1. Construction of infiltration or water reuse practices on site such as infiltration trenches, rain gardens, tree trenches or water re -use practices. 2. Constructing detention facilities that retain the peak flow and discharge it at a slower rate. 3. Construction of wet ponds that provide adequate time for settling of the Total Suspended Solids and Total Phosphorus and prevent re -suspension with the next storm event. Timeframe: The SWMP was reviewed by the EPB at their March meeting. They were in general agreement with the content of the SWMP. The SWMP was also reviewed by the Public Works Committee at their March meeting. They were in general agreement with the content of the SWMP and passed a motion to recommend City Council approval. The SWMP will be the subject of a Public Hearing before the Planning Commission tonight with particular emphasis on the recommended changes to City Code related to land use. A Public Hearing is required when considering changes to City Code and any potential ordinance amendments resulting from the SWMP will also be subject to the public hearing process. The SWMP will be brought to the City Council at the April28 meeting for review and approval. The plan will then be sent to the LRRWMO and the Metropolitan Council during the first week of May for concurrent reviews. The LRRWMO has sixty (60) days to review and approve the plan, while the Metropolitan Council has forty-five (45) days for review. The document will then be updated as necessary after comments are received and will be brought back to City Council for adoption. This is anticipated to be the first meeting in August. Observations/Alternatives: The City of Ramsey is bordered on the east by the Rum River and on the south by the Mississippi River. The City has many wetlands, lakes and streams within its borders. Managing the discharge of stormwater from developed sites is a critical component of preserving the water quality of the wetlands, lakes, streams and rivers in and adjacent to the City. The Surface Water Management Plan provides a framework for allowing development while maintaining surface water quality. The changes to the document include: • Updating City Code references to the current system • Updating the Stormwater management requirements for new construction o Infiltrate first 1" of runoff from new impervious surfaces o Provide rate control and water quality treatment for the 2, 10 and 100 year return events. o Provide reduction for Total Suspended Solids and Total Phosphorus concentrations in stormwater leaving the site. o Update the reference storms to use the Atlas 14 publication. The LRRWMO adopted use of the Atlas 14 and required the member cities to adopt this standard. • Remove references to wetland buffers for new construction. The City completed a Wetland Management Plan with the 2008 SWMP. The implementation of the Wetland Management Plan was postponed by City Council Action. • Update the Stormwater Models to include developments constructed after 2008 and use Atlas 14 for rainfall events. • Update the tables and figures to include the new model results. The tables and an overall map of the watersheds is attached for reference. The 10 year storm sewer capacity map and 100 year pond capacity map for the D43 watershed have also been attached to the case. The descriptions of the tables and maps is included in the plan. Funding Source: