DETROIT LAKES — The final piece of Becker Soil & Water Conservation District’s $708,262 sediment reduction work in the Upper Buffalo River watershed is on pace to finish this spring.
The most complex of the projects leveraging a $328,160 Clean Water Fund grant from the Minnesota Board of Water and Soil Resources, it involves water that flows from shallow lakes and wetlands across a field and under a driveway to the Buffalo River.
“You’re getting a number of different benefits, but the main thing is you’re controlling the flows and you’re removing that issue of suspended solids — because that’s a huge problem in this area where you’ve got this real rolly topography,” said landowner Bill Steffl.
In Steffl’s Callaway Township field north of Detroit Lakes, the elevation drops 40 feet in a half-mile. That’s typical in this part of the 1,100-square-mile Buffalo River watershed, where forest meets field, and soils tend to be productive but erosive.
The $184,000 project tackled one of the Top 5 sources of sediment identified in a 2015 watershed study.
An 80-year-old drainage channel, built to manage the water levels of Squash Lake for ag production, was eroding at the downstream end. An undersized pipe at the lake’s outlet was in danger of washing out.
A culvert built after a storm flooded the private driveway in 2003 sent water — and the sediment it carried — directly from the field to the river. The resulting gully eroded the bank where it entered the river.
“The biggest problem is the fact that there’s no control on that erosion along this ditch bank, and then going into the river. There’s nothing that really controls that water coming out of the lake,” Steffl said as he showed SWCD staff the progress made before heavy August rains halted work.
Now, a 2,000-foot-long pipe carries most of the lake flows. Re-sloped and seeded, the man-made channel serves as an emergency spillway that can be traversed. A series of small dams and basins slow water and curb field erosion. A new concrete structure at the outlet controls the lake elevation and transports runoff into the outlet pipe.
This spring, work will finish when basins are constructed and filter strips planted near Anderson Lake. More rock will buttress the driveway and Squash Lake outlet.
“The benefit to everybody, in my opinion, is the fact that that water entering the Buffalo River is going to have a reduced sediment load. That’s one reason there’s so many different agencies involved in this, is because everybody’s gaining something,” Steffl said.
The Callaway Township project draws from a second BWSR Clean Water Fund grant, a Minnesota Pollution Control Agency EPA grant, and assistance from the USDA’s Natural Resources Conservation Service.
“We provided most of the technical expertise,” said Ed Musielewicz, NRCS’ Detroit Lakes-based district conservationist. “We did most of the engineering, the design. We worked with the Buffalo-Red River Watershed District on wetland issues. We worked with the DNR on protected waters.”
The project will keep an estimated 229 tons of sediment — the equivalent of more than 17 dump truck loads — out of the Buffalo River each year.
Segments of the Buffalo River are impaired for sediment, exceeding Total Maximum Daily Load (TMDL) thresholds set by the MPCA.
“Ideally, all of these efforts will get us a fair ways toward the sediment-reduction goals for those TMDL-listed reaches,” said Becker SWCD Administrator Peter Mead.
The entire Upper Buffalo River sediment reduction project — three grade-stabilizations, 28 basins, one grassed waterway and about 25 acres of filter strips — will cut sediment-loading by an estimated 44%, exceeding its goal of 41%.
Projects within larger watersheds such as the Buffalo River carry the additional challenges of coordinating with several landowners and securing funding.
“That’s where Clean Water Legacy dollars have been the saving grace to make these things actually happen. We can pay up to 90% to get something done. A known problem for 20 years is suddenly able to be addressed,” Mead said.
· $101,740 from Becker SWCD includes two Clean Water Fund grants from BWSR: $44,380 from a 2017 Upper Buffalo River Sediment Reduction projects and practices grant, $57,360 from a 2018 Top-Down Buffalo River Watershed accelerated improvement grant
· $57,360 from Buffalo-Red River Watershed District’s Environmental Protection Agency sediment reduction project grant
· $18,400 from the landowner’s 10% match
· $6,500 in NRCS assistance
Annual sediment reduction estimates: 168 tons from channel erosion and headcutting; 61 tons from overland erosion