Project of the Year
The Minnesota Association of Floodplain Managers annually recognizes a great project which has helped, or will help, reduce flood risk in Minnesota. The projects can be related to the design and construction of a flood risk reduction feature or non-construction related to a policy or program implemented to address flood risk. The projects can be in the public or private sector.
Previous Award Winners:
2022 - Pine River Dam Removal and Rock Riffle Installation Project; City of Pine River, Bolton & Menk, MN DNR
Halstad Flood Control Project; City of Halstad, Wild Rice Watershed District, Houston Engineering
2021 - Long Term Flood Mitigation - Golden Valley; City of Golden Valley, Bassett Creek Watershed District, Barr Engineering
2022 - Pine River Dam Removal and Rock Riffle Installation
The Pine River dam was built in 1910. The dam was 200 feet long and 13 feet high. It included an earthen embankment and a gated spillway. It created a reservoir within Pine River including the 500-acre Norway Lake. Electricity was generated at the dam until 1946. Trunk Highway 84 was built on the dam embankment. The highway included a concrete bridge to span the spillways of the dam. The dam was classified as high-hazard and was also a significant fish barrier. The primary goal of the Pine River project was to remove the high hazard dam and replace it with a rock rapids to improve public safety, reduce flood risk, and reestablish aquatic organism connectivity.
In 2022, the dam was removed and replaced with a rock-arch rapids by the City of Pine River. Replacing the high hazard dam with a rock riffle enhanced fish passage, biological connectivity, habitat, safety, aesthetics, fishing, and recreational access to the river. The riffle pools and channels enhanced recreational opportunities for wading, fishing, paddling and other water-based fun. This work restored fish passage and connectivity between the Whitefish Chain of Lakes and reconnected 134 lakes (11,338 acres) and 80 miles of river and stream corridors benefitting fish, mussels and many game and non-game animal species. Water levels up and downstream from the rock arch rapids will be similar to levels that would have resulted from operation of the gated spillways of the dam — however the hazard and flood risk due to potential breaching of the dam during a flood is greatly reduced.
In 2013 and 2014, the city, MnDOT, and MN DNR Dam Safety and Fisheries staff worked collaboratively to develop dam and roadway concepts for city consideration. The city explored alternatives to reduce the hazard including: dam repair, dam rehabilitation with more capacity, dam replacement with more capacity, dam replacement with rock riffle, and dam removal. The city sought a concept that would maintain the reservoir, preserve and increase recreational functions, and have lower capital and long-term maintenance costs.
Benefits to the community and to the environment:
The City of Pine River lead this project with assistance and support from the Minnesota Department of Natural Resources (Ecological and Water Resources, Dam Safety, Fish and Wildlife); Minnesota Department of Transportation; Cass County and the Lessard Sams Outdoor Heritage Council. The project received support from the community. Public use and community support has been high following the completion of construction although some have voiced concerns about the increased noise level of the water flowing through the riffle.
The Norway Lake dam was a fish barrier for 112 years (1910-2022) and created a significant fragmentation of aquatic habitat. Removal of the dam and replacement with a rock-arch rapids has restored fish passage and connectivity between the Whitefish Chain of Lakes and the 149 square mile watershed above the dam. This reconnected watershed includes 134 lakes with surface areas totaling 11,338 acres and 80 miles of rivers and streams. Twenty-seven lakes exceed 100 acres, with the larges-Pine Mountain Lake-having 1,622 acres. The removal of the dam and the reconnection of these high quality, diverse habitats and stream corridors benefits fish, mussels and many game and non-game animal species.
Blandings Turtle (threatened) have been found in the area around the City of Pine River and any turtles moving along the river will now be able to move through the rock riffle instead of crossing the dam and road as required before the project.
The Corps of Engineers declared the dam to be high hazard in 1978, due to potential for breaching. The dam was renovated in 1983 with new slide gates and riprap for overtopping protection. In 2014, DNR Dam Safety staff analyzed hydraulics and concurred with the high hazard classification since 45 structures were at risk in a 500-year flood with dam failure. Although the city does not currently participate in the national flood insurance program, the high-hazard dam classification has been removed, and the new rock riffle is now classed as a low-hazard.
In 2018, the City of Pine River applied for and received funding through the Lessard-Sams Outdoor Heritage Council ($2.2 Million), sponsored by the Clean Water Land & Legacy Amendment, and the DNR Dam Safety Program ($200 Thousand), for the removal of the Pine River Dam and the replacement with rock riffle. Construction was completed in 2022 with a total project cost of $2.5 Million.
2021 - Long Term Flood Mitigation - Golden Valley
The City of Golden Valley has been successfully implementing projects identified in a long-term flood mitigation plan for an area of the city that has had chronic flooding issues. This success is due to the planning, partnerships, phasing and varied funding sources that have been secured to implement the plan. Completion of the first phase of the flood mitigation projects (constructed as two separate projects) that ultimately work together, will result in the reduction of flooding on Medicine Lake Road during intense events, reducing damages to surrounding structures as well as allowing for safe passage of emergency vehicles during these rain events. Although primarily flood mitigation projects, the projects also provided a variety of benefits to the watershed, city, and surrounding neighborhood including water quality improvement, increased habitat diversity, addressing known sanitary sewer issues, and improving public open space and recreation.