1A, Safe Routes to School Project

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Safe Routes to School Project/DNR Project Update - 06/09/09 time employees for 9 full working days (about 2 weeks). Constructing the retaining walls for the County Road E-2 project would take 3 full time employees and 2 seasonal employees about 4 weeks. In addition, we would need to, rent special equipment to complete the work. Please review the attached memo from Greg Hoag regarding the impact these types of projects would have on our day to day City tasks. The Council had a number of questions regarding the crossing of the Valentine Lake Discharge channel located in the Ramsey County Open Space. Including; Are there ways to reduce the costs of the culvert? Could we install smaller pipes, or fill within the floodplain? Staff has requested that Beth Kunkel, Kimley- Horn, attend the W orksession to address any further questions the Council may have. Response: The proposed crossing of the Valentine Lake Discharge Channel is in an area where the floodplain and floodway boundaries are defined to be the same line. The floodplain and floodway for the entire discharge channel is identified in the 1981 Flood Insurance Study (FEMA). The Rice Creek Watershed District (RCWD) rules contain the following provision for floodplain alteration. "If a 1 DO-year floodway has been defined according to FEMA procedures andfloodplain encroachment is subject to a DNR-approvedfloodplain ordinance, fill in the floodway is prohibited but fill within the flood fringe is permitted. "[Rule E, Item 3aJ To strictly meet the rule listed above, the only option to provide a pathway crossing of the floodway would be the construction of a pedestrian bridge that spanned the entire width of the floodway. This pedestrian bridge would need to be approximately 50' long by 14' wide. A typical prefabricated steel bridge of this size would cost approximately $150,000. Technically, this rule eliminates the option of providing a culvert crossing at the channel, as any culvert crossing would require some amount of fill to be placed within the defined floodway. In addition to the cost, staff did not feel a bridge structure was compatible with the natural feel of this open space. Kimley-Horn conducted a meeting with the RCWD and its consultant, Houston Engineering. The RCWD indicated that the intention of the rule is to eliminate any rise in the surface water elevation of the floodplain. The RCWD indicated that if the City can show a proposed crossing option that did not raise the water surface elevation, the RCWD would be able to permit the project in accordance with their rules. Conversely, if the culvert would result in some rise, the City could request a variance to the rule demonstrating hardship caused by a bridge. Similarly, FEMA regulations require demonstration of how much rise a culvert would have on the floodway and floodplain. The process for providing this information is via a request for a Conditional Letter of Map Revision (CLOMR) for any improvements in a floodplain. If the City can show and verify that the project will cause absolutely no rise (0.00 Feet) in the floodplain elevation, then the Minnesota Department of Natural Resources can approve the project without a CLOMR and no involvement from FEMA. The most cost-effective option for this project to cross the Valentine Lake Discharge Channel is the construction of a culvert. To analyze the impacts a culvert would have on the channel's floodway water surface elevation, Kimley-Horn used the HEC-2 Water 2