Crews shore up Cannon River at Welch
Erosion along the Cannon River is nothing new.
But with a troublesome bend now threatening County Road 7 across from Welch Village Ski and Snowboard Area, Goodhue County SWCD and Public Works had to take action.
Work crews have been stabilizing the eroding riverbank since Oct. 17 using a stream restoration design from the Minnesota Department of Natural Resources.
The plan calls for two limestone rock walls and bundles of tree roots and other natural materials to reinforce the banks and reduce the river’s velocity at the curve, Kennedy said.
A line of boulders are arranged in a “J hook,” Public Works Director Greg Isakson said. Starting at a 35-degree angle from the bank, the limestone walls stretch about halfway across the water before curving downstream.
They work to channel the current away from the shoreline and “take a lot of the water’s cutting power out,” Isakson said.
The eroding riverbanks and surrounding land will be preserved with tree roots and “soil burritos,” rolls of dirt and natural debris confined in a geotextile material, Isakson said.
Willow trees, known for their large root system, will be planted in the burritos and along the shore to help stabilize the ground for the future, he added.
Once work is completed, the county will seed the area with native grasses as part of an easement agreement with two local landowners to maintain the area as a natural habitat, Kennedy said.
Isakson said the project will serve two major functions, foremost of which is protecting County Road 7.
If left alone, the Cannon River would begin eating into the road within 15 years, Isakson said.
Secondly, the stabilized shoreline will help reduce downstream sediment pollution from washing into the Mississippi River.
Over the past 10 years, Isakson said the county estimates the river moved close to 100 feet and released 50,000 cubic yards of sediment into the water.
Although erosion in the area had been developing for decades, Kennedy said recent storms have exacerbated the problem. As much as 30 feet of nearby shoreline eroded during 2010 storms and flooding.
The cost of the project is around $170,000, Isakson said, the bulk of which was paid by grant money that SWCD secured.
Because the restoration is being done so close to the road, Isakson said he hopes it can be used as a showcase for other landowners along the Cannon River.
“It’s an easy-to-find and easy-to-view example of this kind of project,” he said.
Goodhue County Public Works, SWCD and Sentence to Service are providing labor, with additional assistance from Flueger Construction from Red Wing, Kennedy said.
Most of the work should be completed by the end of the week, he said. “We’re moving pretty fast here.”