2004-04-22_AgendaPacket - Laserfiche WebLink

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West Vadnais Outlet Project Proposal Project Sponsor: Ramsey County Public Works There are three main reasons for the proposed West Vadnais outlet project. These are to: - Prevent flooding of Rice Street and protect road base material from prolonged saturation, which decreases the road's stability and accelerates deterioration of the travel surface and shoulders. - Prevent flooding of the St. Paul Regional Water Services pumping station at Vadnais Lake. - Restore the historic drainage flow path, which was eliminated by construction. of I-694. MnDOT's `Unweave the Weave' project on I-694 provides a unique opportunity to address these problems as part of a much larger project, while minimizing the project's cost and impact to citizens. From the County's perspective, the project is necessary to protect the traffic flow and physical structure of a vital arterial roadway within our road system. During conditions of high. water levels in nearby lakes and wetlands in recent years, the vertical elevation of West Vadnais Lake approached within 0.5 feet of the Rice St. travel lanes. Road base material within 2.5 vertical feet. of the road surface has been saturated with water for prolonged periods, reducing the road's strength and promoting erosion of road shoulder material. The portion of Rice St. most affected is near the north end of West Vadnais Lake, immediately south of the overhead railroad bridge. Rice St. cannot be elevated to provide additional freeboard from West Vadnais Lake due to height restrictions of the railroad bridge. Because West Vadnais Lake is located within the Vadnais Lake Area Water Management Organization, Ramsey County requested this organization to convene a meeting of involved parties to discuss technical and administrative issues related to the potential project. The initial meeting was held in July 2003 with a total of four interagency meetings to date. Agency staff participating in the interagency meetings and receiving periodic project updates are listed in Attachment 1 (below). St. Paul Regional Water Services has participated in these meetings and has identified flooding of their Vadnais Lake Pumping Station due to high water level in West Vadnais Lake as an important operational concern. Ramsey County and St. Paul Regional Water Services have committed to paying preliminary engineering design costs for the proposed West Vadnais outlet project. An elevation of 881.9 (1988 datum) is proposed for the West Vadnais outlet, which would provide approximately 2.5 feet of protection relative to the Rice St. surface elevation. The DNR conducted an Ordinary High Water (OHW) survey of West Vadnais Lake in 2003 and concluded that the proposed control elevation 881.9 is reasonably consistent with the observed OHW of 882..7 (1988 datum). 3/19/2004