Rushford dike might get bumped up
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Rushford Dike Report: www.mvp.usace.army.mil/disaster_response/default.asp?pageid=1326
By John Weiss
RUSHFORD — Rushford’s dike along Rush Creek might be raised to better protect it against future floods, depending on results of a survey being done now.
The Minnesota Department of Natural Resources is a few weeks away from completing a hydrologic study of the Rush Creek Watershed based on new data from the Corps of Engineers, said Suzanne Jawani, DNR floodplain mapping engineer. That will determine the extent of a flood that theoretically will happen once a century; the dike was built about 40 years ago to that standard.
The August flood, however, was much more than a 100-year event on Rush Creek. The corps estimated the 100-year flood would mean about 18,100 cubic feet of water would flow down the creek; in August, the creek had about 38,000 cubic feet roaring down it.
New calculations are needed because the bed of the creek itself may have changed in the past 40 years, Jawani said. Also, the corps looks at changes in weather patterns and the August flood, which followed record rainfall for the state, will change that data, she said.
If there are changes to the 100-year floodplain, or the city wants a bigger dike, Rushford and the corps can meet to determine if it makes sense to raise the dike, said Roland Hamborg, the corps’ project manager. A major question is whether benefits of a bigger dike outweigh costs, he said.
Until that is known, the present dike is planned to be brought to its configuration before the flood. Some work on the $3 million repair project has already been done, such as taking out debris and replacing pumps destroyed by floodwaters, he said.
If the environmental assessment on it is approved, final work will begin in May and should be done by fall.
The corps, which built the dike about 40 years ago, said the work won’t "significantly affect the quality of the human environment." Benefits are to public safety and health, community cohesion and less flooding.
The dike was damaged when up to 17 inches of rain fell in its watershed. The creek went over the dike and caused huge damage to the town. The dike left debris at bridges, a new channel in the upstream end, sediment in the storm drainage pipes, displaced riprap and destruction of pumps in the pumping stations.
The project will include getting rid of debris, fixing the channels, removing sediment and replacing electrical systems.