Minutes - Council - 05/09/2006 - Laserfiche WebLink

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This would allow the floodway to spill over the road as it currently does, but in a location further to the west that would allow the violating property to be outside the revised floodway. Alternative 4 Install Twin Box Culverts- Cost $120,000 to $160,000 The existing 72 inch culvert would be replaced with two 60 foot long 10 x 7 box culverts that would allow the floodway to be revised so that the entire 100 year flood would be carried through the culvert and would no longer overtop Ermine Boulevard. In addition, this alternative may require the acquisition of easements if the installation of the twin culverts cannot be confined within the Ordinary High Water (OHW) of Trott Brook. Alternative $ Combination of Culvert Replacement & Ermine Street Regrading- Cost $90,000 to $100,000 This alternative is a combination of Alternative 3 & 4. It calls for the replacement of the existing 72 inch culvert with a single 12 x 7 foot box culvert and a less extensive need to regmde Ermine Boulevard. However, this alternative would not provide enough culvert capacity to prevent the overtopping of Ermine Boulevard during the 100 year flood event. Public Works Director Olson advised two other elements should be considered in recommending the preferred alternative. Alternatives 4 & 5 would both replace the existing 72 inch concrete culvert, which has open joints that are permitting soil loss from the base of the road and shoulder areas. A second consideration is that altemative 4 would remove the 100 year flood from overtopping Ermine Boulevard while alternative 5 would not eliminate this condition. Both of these options merit a decision based on financial considerations. Although Alternative 3 is the least costly presented it does not address the cost, which will eventually need to be incurred in replacing the existing culvert. Alternative 1 & 2 are the most costly and fail to rectify either of these auxiliary issues. Mr. Olson advised staff recommends that either alternative 4 or 5 be recommended for implementation. Staff should be directed to prepare plans and specifications for the selected alternative. Funding for this project would be from the Storm Water Utility. Mr. Olson advised the Committee recommended to City Council that Alternative 4 be implemented and that staff should be directed to prepare plans and specifications for the selected alternative. Funding for this project would be from the Storm Water Utility. Councilmember Elvig noted there was discussion about whether it would be possible to build trails or amenities of some sort when this work is being done; however, it did not seem that would be possible. To quote a former Councilmember, this is exactly what the stormwater utility fund was developed for. Motion by Councilmember Elvig, seconded by Councilmember Olson, to ratify the recommendation of the Public Works Committee in Case No. 6 and to authorize that Alternative 4 be implemented and to direct staff to prepare plans and specifications for the selected alternative. Funding for this project should come from the Storm Water Utility. Further discussion: Councilmember Elvig asked if it is common to design areas with overflow water over the top of roads. Public Works Director Olson replied the City does not do this, but there is sometimes a result of a combination of things. Trott Brook was in place before Ermine Boulevard, and at that time the City either did not have funds to put box culverts in or felt it was City Council / May 9, 2006 Page 28 of 30