Leola Ditch Denitrification
The Leola Marsh made up much of our 14 Mile Watershed before ditching occurred in the early 1900s in an attempt to farm the land. Most failed and the land reverted to the state, much of it still owned by the DNR along Hwy D upstream. A tour last fall with friends from WI Wetlands, WI Wildlife, Little Plover Partnership, and some of our 14 Mile members and advisors resulted in a test project to determine if bringing water levels back up into the organic soil layer will result in denitrification of the water that flows into our lakes. This very promising, multi-year trial will begin this spring.
In November of 2020 Tracy Hames with the Wisconsin Wetland Association, Steve Gaffield with EOR Inc., Erin Grossman Wildlife Biologist and property manager with the DNR, John Endrizzi, Don Ystad, Scott Provost and Taylor Hasz met at Owen’s Rock to walk the DNR property to discuss management opportunities.
For the first part of the walk, Erin Grossman discussed what her management goals were for the property. She wanted to plug some of the ditches while at the same time ensure the rest of the property would not become too wet for cattle to graze. The participents discussed a couple of different ideas that could be implemented on the DNR land. One idea was to put two plugs on one of the ditch laterals to attempt to raise the groundwater level so it contacts the rich organic soils. This can cause denitrification of groundwater due to the denitrifying bacteria living in these organic soils.
Denitrifying bacteria convert nitrates into harmless nitrogen gas which can remove nitrogen from our groundwater and surface water before reaching the Tri-Lakes. These two plugs would have water control structure(s) on both ends to allow for water movement into other ditches. This would also allow the property manager to manage water levels as needed to ensure flooding does not occur.
There are multiple goals with this project: managing water levels for grazing, providing habitat for prairie chickens; potential demonstration site for similar applications on other properties, and to decrease the nitrogen load into the Tri-Lakes.
See more information on Watershed-based hydrologic restoration in Wisconsin