PAY IT FORWARD – BENEFITS OF THE RICHARD P NELSON FLOODWAY MATERIALIZE IN WARREN, MINNESOTA

The fruits of the late Richard Nelson’s labors were realized in early April, this year when impacts of a major flood in Warren were avoided.   The city’s former Mayor had worked tirelessly at the state and national level to seek approval for the Snake River Watershed Flood Protection Project.  The project was implemented through the USDA Natural Resources Conservation Service’s Watershed Protection and Flood Prevention program and is designed to protect Warren from flood damages.  Although the project is still under construction, damages were reduced considerably.  If the partially completed project components were not in place during this most recent event, flood levels would have been similar to those reached during the spring of 1997.   Floodwaters during 1996 and 1997 resulted in damages of over $12.7 million to the city.  This year, however, because of the fully functioning off channel reservoir upstream and flows in the partially functioning flood diversion around the city, flood levels were at least 3 feet lower than those in 1997.  The flood diversion channel, a component of the project which routes floodwaters of the Snake River around the town, has been named the Richard P. Nelson Floodway in the late Mayor’s honor.   

According to NRCS Hydraulic Engineer Peter Cooper, ”This spring’s snowmelt, combined with about an inch of rainfall, resulted in fairly significant flooding in Marshall County.   It was approximately a 25 year flood event.  Had the project not been in place, the estimated peak discharge through Warren would have been about 3,850 cfs.  Because of the fully functioning reservoir upstream and the partially completed diversion around the city, the flows through town were reduced to about half of that or 1,900 cfs.  The reservoir upstream held back over 5,300 acre feet of runoff which is equivalent to 8.3 feet of water over an entire square mile “ 

Allan Sommer, NRCS Watershed Economist, reported that “Based on economic data collected during the planning phase of the Snake River Project, flood damages that would have occurred absent the project were calculated.  The ability of the structures currently in place to reduce stream velocities and flood levels to the equivalent of a 5 year event resulted in $8.7 million dollars of damage reduction.”  Total project installation costs were $14.9 million.  Based on these estimates, the project benefits from this event covered nearly 58% of all installation costs.   

Engineering and funding for the flood control components at Snake River were provided by the USDA-NRCS under the Public Law 566 Watershed Protection and Flood Prevention Program.  The City of Warren and the Middle River-Snake River Watershed District were responsible for the purchase of right-of-ways, installing road crossings, and all contracting related to construction.  

For more information about the Snake River Project, please contact, John Beckwith, Water Resources Staff Leader at (651)-602-7930.

< Back to Home>