Details about our Ditches
The Bois de Sioux Watershed District serves as a ditch authority for drainage systems in Grant, Wilkin, and Traverse Counties.
Bois de Sioux & Mustinka Watersheds: 2019 Aggressive Water Quality Improvement Project
Landowners and agricultural producers are working voluntarily to reduce sediment in the Bois de Sioux and Mustinka Watersheds in West Central Minnesota. Over the past decade, projects on farmland and throughout small drainage areas have helped to reduce erosion, reduce flooding, and improve water quality. One such project, led locally by landowners in the Wilkin County Ditches #9 & #10 districts, modernizes an outdated drainage system. Drainage systems are vital infrastructure because they protect our public roads, highways, bridges, towns, family farms, and even the land itself – removing excess water is important for soil health. Furthermore, existing public drainage systems under the authority of the Bois de Sioux Watershed District are being evaluated for updates that include strategic culvert sizing, floodplain restoration, side-inlet culverts and other erosion and flood mitigation features. This project incorporates all of these features, resulting in cleaner water and reduced flooding. No substantial work has been done to Wilkin County Ditches #9 & #10 since 1910. As stated in the Detailed Survey Report prepared by Moore Engineering, the current systems suffer from:
• Uncontrolled flows into the drainage system that cause excessive erosion and sediment transport
• Improper culvert sizing that causes unnecessary flooding and downstream impacts
• Excessive spoil bank heights that force floodwaters over a major highway, posing safety hazard
• High velocity areas that promote channel erosion
The proposed project is estimated to cost landowners approximately $2.0 million. “When designed correctly, these projects control water flow and improve water quality” says Bois de Sioux Watershed District Engineer Chad Engels.
Engels believes there is a serious public misconception that agricultural drains cause floods. Engels continues, “The design goal for public drainage system improvements is more complex. The idea is to provide the capacity needed to convey the smaller more frequent summer rainfall events in a manner that results in minimal crop loss. However, larger flows, like those resulting from spring snow melts or heavy summer rain storms, are actually controlled by the project if designed correctly. The secret to the design is to size channels and culverts just large enough to pass the smaller flows. When flows exceed the design flow, excess water is pushed out of the channel and is directed into floodplain storage in adjacent fields. Culvert are used to meter the flow. The most benefit is seen when existing oversized bridges are replaced with smaller culverts.”
In response to the anticipated water quality benefits that this project will provide, the Board of Soil and Water Resources provided a $60,000 Clean Water Multi-Purposes Management Grant in coordination with the Wilkin County Soil and Water Conservation District. Construction bids will be reviewed in April. Bois de Sioux Board Managers hope to award a contract for construction this summer.
Hearings and meetings will soon resume regarding a repair and redetermination of Judicial Ditch #11. Construction could begin as early as 2020 if the project approvals are made.
Traverse County's First Ditch Retrofit: Project eases flood damage as it improves water quality within the Bois de Sioux Watershed District, setting the stage for similar work