1A, Safe Routes to School Project

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Safe Routes to School Project/DNR Project Update - 06/09/09 Surface Profiles software, available from the U.S. Army Corps of Engineers. The same software was used in the hydraulic modeling completed as part of the FEMA Flood Insurance Study, and that existing model was available through the Minnesota DNR. Although the floodway is defined to be 45-50 feet wide, the actual channel is approximately 8 ft wide and 3 ft deep. To minimize disturbance of flow within the channel, an 8' x 4' culvert was modeled constructed a foot below the channel to minimize any fill needed at the channel crossing. It was assumed that the existing ground elevations outside the channel, but still within the floodway, would be maintained in the proposed condition. Installing smaller culverts would not have adequate capacity for the design storm events. The modeling results showed a 0.07 ft (0.84 inch) rise in the floodway elevation from the existing condition from the proposed culvert crossing. Additional model iterations were completed to verify that different culvert size or shape options would not have less impact to the water surface elevation. Despite only a 0.07 ft (0.84 inch) rise in the water surface with the installation of an 8' x 4' culvert, it still exceeds the requirement of showing absolutely no rise in the floodway elevation. As a follow-up to the model results, Kimley-Horn met with both the Minnesota DNR and the RCWD to discuss results and explore any other options available. Suzanne Jiwani, a hydrologist with the Minnesota DNR indicated during our meeting that there may be a possibility to waive the need for a CLOMR, and just submit an official Letter of Map Revision (LOMR) after the project was complete. She though this may be possible due to the minimal change in water surface elevation for the proj ect and the project would only affect the City and Ramsey County property (no structure impacts), both of whom are involved in the project already. Suzanne's inquiry to FEMA was met with the response that a CLOMR would be necessary, however given the small impact and no structure impacts, that the typical six-month review process usually needed to obtain a CLOMR could be expedited. The RCWD indicated, based on legal review, that they could not approve a permit if submitted with a project causing a rise in the floodway of 0.07 feet, without a variance request. They indicated that the City would have a good case to demonstrate hardship for a variance request. Also, that the modeling needed to go through the CLOMR/LOMR process to register the change in floodway elevation of the Valentine Lake Discharge Channel, could be used for RCWD variance review. Will Ramsey County Parks and Recreation participate in cost sharing regarding the culvert? Response: Ramsey County does not have additional capitol improvement funds available at this time to assist in the cost of constructing the creek crossing. However, the County is still committed to contributing $15,000 toward construction of this project crosswalk signal. Ramsey County Public Works has agreed to stripe the crosswalks, an estimated contribution of $1,800. Staff also explored the following options for this project: 3