For the first time in nearly 100 years, Otter Tail County is considering building a new ditch.
And that proposed ditch is causing consternation in neighboring Douglas County.
Otter Tail County says a ditch is needed to lower the level of Nelson Lake near Parkers Prairie, which has no natural outlet and which frequently washes over County Road 6. The county has poured gravel to raise the road level, but water continues to spill over it when lake levels are high.
"Currently the lake level is up to the shoulder of (County Road) 6, and presents a traffic safety hazard," says a preliminary engineering report on the ditch. "Landowners and road authorities have experienced prolonged flooding of agricultural lands, public roads and building sites around Nelson Lake for several years."
The $960,000 ditch would allow water to drain into Fish Lake, which drains into Dittberner's Creek, which empties into Lake Miltona, a popular recreational lake in northern Douglas County. Miltona then drains into Lake Ida, which is where nearly $1 million of state and local money have been allocated to keep phosphorus from reaching its relatively pristine waters.
In a letter to Otter Tail County, the Douglas County Lakes Association (DCLA) voiced concerns that the proposed ditch would carry pollution from Otter Tail County to Douglas County.
"The Douglas County Soil and Water District just received a grant to remediate the phosphorus entering out of a wetland via Ditch 23 into Lake Ida," wrote DCLA President Steve Henry and DCLA Secretary Gene Rose to Otter Tail County Drainage Inspector Kevin Fellbaum. "The Ditch 23 grant addresses the leaching of phosphorus from a wetland that became saturated with phosphorus from upstream sources, which is exactly what could happen with the drainage of Nelson Lake into this Fish Lake to Dittberners Creek watershed."
They quoted the DNR's assessment of Nelson Lake as, "Not always suitable for swimming and wading due to low clarity or excessive algae caused by the presence of nutrients such as phosphorus in the water."
And they cited concerns that if water starts running too quickly through Dittberner's Creek, it could harm the fish spawning population there.
Otter Tail County has scheduled a preliminary public hearing for the proposed ditch at 7 p.m. Wednesday, May 5, at the Prairie Regional Event Center in Parkers Prairie. Following the hearing, county commissioners will decide whether to proceed with the project. If given a green light, the county will pursue permits and there will be more public hearings and a final engineering report. Construction would not take place before 2022, Fellbaum said.
Minnesota has been draining its wetlands to provide for farm land and roads since it became a state in 1858, according to the Minnesota Pollution Control Agency. Otter Tail County's ditches were built in the early part of the 1900s, with the last one completed in 1923, Fellbaum said.
Nelson Lake and Fish Lakes are both listed as impaired by nutrients such as phosphorus on the Minnesota Impaired Waters List, while neither Ida nor Miltona are listed as impaired for nutrients.
Fellbaum said the county's testing showed a greater load of phosphorus in Fish Lake than Nelson Lake. Since Fish Lake already drains through Dittberner's Creek into Lake Miltona, he said Nelson Lake might help dilute the phosphorus concentration. But ultimately, it's up to lake quality experts, he said.
He said the ditch would come with a plug, much like a bathtub, so that the county could monitor water quality and volume and plug it when necessary.
Several state and federal agencies would need to agree to the project, including the Minnesota Department of Natural Resources, the Minnesota Pollution Control Agency, the Minnesota State Historic Preservation Office and the U.S. Army Corps of Engineers.
“We think it’s awfully dumb for DNR or MPCA to allow a project like that when we are spending $1 million trying to ameliorate what happened on Lake Ida,“ Rose said during a recent DCLA meeting.