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New Brighton/St. Anthony Basic Water Management Project – Phase 1 Rice Creek Watershed District 5555-221 Revised Final 1 June 10, 2014 EXECUTIVE SUMMARY Ramsey County Ditches 2, 3 and 5 (RCD 2, 3, and 5) are public drainage systems managed by the Rice Creek Watershed District (RCWD) that drain stormwater runoff from land primarily within the Cities of New Brighton, St. Anthony, and Roseville. The public drainage systems convey stormwater runoff from urban catchments, downstream to Pike Lake and Long Lake which are both regional flooding and water quality concerns of the RCWD. An extreme rainfall event on July 16, 2011 greatly heightened the awareness of flooding and flood risk along the RCD 2, 3 and 5 public drainage systems. The consequences of this rainfall event have prompted the Cities to evaluate the adequacy of their existing stormwater conveyance and management facilities resulting in the submission of a petition to the RCWD to develop a comprehensive plan to address flood risks in the watershed. The defined project goals are primarily to reduce flood risks at localized areas in the RCD 2, 3 and 5 watershed while considering project impacts at a regional scale, and seeking water quality improvements and opportunities to incorporate ecological and public amenity elements into a comprehensive plan. The comprehensive plan approach provides the benefit of efficient analysis for localized issues (versus individual analysis) and more flexibility to implement projects yielding a greater net benefit towards regional issues. The purpose of Phase 1 is to identify potential projects for further technical evaluation that are feasible, practicable, affordable, constructible, can reasonably be expected to obtain local approval and be permitted by state and federal agencies. This Phase 1 report presents detailed information on: x Project goals and objectives; x Identification of flood prone areas; x Design criteria and standards to be used in future detailed analysis; x Descriptions of project types under consideration; x A review of the watershed in regards to runoff volumes, timing and storage; x Identification of projects for further evaluation; x A review of permitting needs; and x A review of public drainage system law in MS103E and their implications regarding construction of potential projects. Several conclusions were drawn during the Watershed Analysis in Phase 1 that are worth mentioning and may provide direction moving forward: x The projects proposed will not resolve the regional flooding issue at Long Lake and precautions should be taken to avoid worsening regional flooding issues as a result of flood risk reduction projects. x Conveyance improvements are a reasonable alternative to improve localized flooding issues. Their adverse downstream impacts resulting from increased peak flow rates and loss of detention 74