Agenda - Environmental Policy Board - 03/02/2015

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Updated Storm Water Management Plan (SWMP) City of Ramsey, Minnesota 5. Final high water levels governing building elevations adjacent to ponding areas and floodplains should be established as development occurs or when drainage facilities are constructed. 6. Overflow routes should be established and maintained, where feasible, to provide relief during extreme storm conditions, which exceed design conditions. 7. An emergency overflow should be constructed for Lake Itasca to relieve the extreme fluctuation in lake levels of this isolated lake. 8. A storm water maintenance program should be enforced, where feasible, to ensure the successful operation of the drainage system. 9. The erosion and sedimentation control criteria for new developments should be enforced, where feasible. 10. An education program for City residents, staff, and development community should be implemented, where feasible. 11. Amendments to the plan should be adopted and implemented as warranted by future standards or regulations, where feasible. 12. That the plan should be updated in the year 2015 or earlier if needed and feasible. The existing storm sewer system of the City of Ramsey is not adequate to handle the continued development around the presently developed area. If development continues, the existing system will need major improvement and enlargements to effectively serve the community without excessive flooding. The proposed infiltration and oversized ponding development scenario together with strategically located regional ponds presents one method of accommodating the present growth of Ramsey. However, this report and the proposed scenario is not necessarily the only method of accomplishing the goal of comprehensive storm water management. Given this, it is imperative that this plan and the SSA model of the City is continually updated on a regular basis and compared to the baseline runoff of the existing conditions model to ensure that any adjustments in area developments continue to be coordinated. In addition, the proposed storm water development charges should be updated annually to ensure that the associated City costs are fully financed. In this manner, the plan can maintain its usefulness as a current document. Finally, the EPA has initiated the NPDES Phase II requirements whereby cities with populations in excess of 10,000 people are required to apply for a Phase II permit. Some additional cities that are actually under 10,000 in population are also included. The City of Ramsey is a mandatory small MS4 community. One of the requirements of the NPDES permitting process is the existence of a storm water management plan. As stated earlier, this report is predominantly based on information obtained from available topographic data, field verification of the watershed areas, "ground truthing" of modeled flood prone areas, and discussions with City staff relative to the historical flooding areas. Since the modeled existing system closely matches that described by observation, we feel that this plan has significant benefit as a planning and design tool. However, the quality and accuracy of this report could be further validated with more detailed survey data in the growth areas around the City. We request that City staff and interested parties carefully review the accompanying Section X February 20, 2015March 6, 2015 Page 70