Dalen Coulee Water Management Study

Background

The 7-mile long Dalen Coulee has a drainage area of approximately 12-square-miles and is located in Norman and Clay counties, MN. The coulee is located within an area of intense agricultural production and outlets into the Wild Rice River.

Frequent flooding in the area was resulting in repeated crop loss. While frequent flooding led to a substantial economic loss for the agricultural community, conversely natural and wetland areas along the coulee were flourishing. Maturing vegetation along the coulee such as willow trees, box elders, and grasses provided important habitat for wildlife.

Expanding wetland areas along the coulee also provided habitat for wildlife. Landowners along the coulee believed the expansion of wetland areas and the increased frequency and severity of floods had resulted from increased sedimentation and the growth of vegetation within the coulee.

The Wild Rice Watershed District (WRWD) and HEI developed a concept that would reduce flooding while maintaining the ecological integrity of Dalen Coulee.

The Project

The Dalen Coulee project consists of the following improvements:

• A flow reduction structure on County Ditch 6, which reduces runoff into the Dalen Coulee
• A runoff (wetland) detention structure, which creates 80 acres of permanent flood storage
• One and one-half-miles of sinuous channel construction/reconstruction
• Channel clearing and grubbing/structure removal and replacement
• Over 700 acres of land set-aside and flood easement

The construction of this large-scale project created a solution that now decreases crop loss while enhancing one of the few existing natural waterways in the area through wetland and wildlife habitat. The techniques used to reduce crop damage while enhancing the environment can also be applied to similar waterways in the Wild Rice Watershed District.