North Ottawa Impoundment Project
Completed in 2016, the impoundment controls 75 square miles of the 320 square mile Rabbit River Watershed in Grant and Otter Tail Counties by storing the excess runoff on 1,920 acres of land. The project involved constructing dikes around the perimeter of the impoundment area, building a collection system to bring water into the impoundment, and partitioning the interior to provide a complex of subimpoundments. Waters carried by existing drainage ditches are intercepted by 10 miles of diversion channels, and brought into the impoundment through a diked inlet channel.
We have big plans for the impoundment, but are awaiting state agency approval.
Flood Damage Reduction (Primary objective): Provides 16,000 acre feet of gate-controlled storage which is equivalent to 75% of the estimated 100 year spring runoff. This is expected to reduce peak flows on the Bois de Sioux River at Wahpeton/Breckenridge by about 5%.
Downstream Flow Augmentation:
Release of about 5 cfs flow during the ice free season in most years.
Downstream waters are improved through the reduction of sedimentation, nutrient removal by cropped interior farmlands, and stream augmentation - we will add a constant flow of water into the Rabbit River (especially important during summer and fall months, when there is naturally little to no-flow).
Flooding occurs at two levels - locally within 10 to 15 square miles, and regionally in the Wahpeton/Breckenridge. This project protects both rural and urban property and infrastructure.
- Red River Watershed Management Board
- State of Minnesota
- Bois de Sioux Watershed District