DNR looks to remove Grindstone River's dam

August 25, 2017



A plan is in the early stages to remove the dam on the Grindstone River in Hinckley.


The dam has been in place since 1931, when the DNR built it to “create the reservoir to supply water” for the fish-rearing ponds across the highway. As the reservoir’s game fish population, Area Fisheries Supervisor Leslie George shared, is “less than impressive and the dam is in poor condition,” the DNR sees an opportunity to open passage to “gamefish currently blocked by the dam” and “gain access to habitats located upstream.”


While the DNR hopes to remove the dam, George explained that the project is better described as a “river restoration” project. “Dams block the way rivers flow and transport sediment,” George said. “A healthy river is a free-flowing river.”


Removing the dam and transforming the area into a free-flowing river rather than a reservoir is seen “as a positive for the watershed.” Currently, “that dam is blocking fish passage,” George said, and removing it could potentially open passage for lake sturgeon and other varieties of gamefish to get to “habitat located upstream,” and “the mussel community will also likely benefit from the dam’s removal.”


Improving the fish population and overall ecosystem in that area is the main impetus behind the project, but it’s not the only thing driving the DNR.


George shared that the project has been “internally discussed” for the last few years. It came up in 2013, during George’s predecessor’s tenure. A citizen made inquiries about removing the dam, and “as the condition of the dam continued to be of concern, work began to explore the feasibility of a project occurring.” 


That concern is linked to two recorded drownings that have happened at the dam. “It’s a DNR structure, and it’s a liability.” Last October, the dam scored poorly during an inspection. When considered in that light, the project amounts to a public safety issue as well.


Though removing the dam has been on the DNR’s radar for a few years, funding for the project has been secured through recent legislation, a move that has pushed the project to the next step. About $500,000 has been secured from the Dam Safety Program and $100,000 will come from Clean Water Legacy. It is George’s understanding that the $600,000 should cover the costs of removal. “It’s still very preliminary at this point. We’re still working on gathering a little more data and design concepts.”


As an example, George talked about the State Historic Preservation Office (SHPO), which “will be consulted and do a review” of the dam and its surrounding area. “They’ll determine historical significance and anything that might have to be avoided.” As for the lumber mill in that area, George sees “no reason why that would need to be disturbed.”


Other assessments will be made as well. “We also have hydrologists on the project team … who will look at flooding impacts, … and also the impacts on groundwater and the wells in the area.” It’s not a project that can be done overnight, but involves engineers, hydrologists, stream restoration experts — “It’s a department-wide effort.”


Largely, though, the area will remain the same. George explained, “Our intent is to still have a fishing area down there…. The reservoir and dam area are encompassed by the Hinckley Aquatic Management area; it is public land. That’s not going to change.” The biggest change will simply be moving from a reservoir to a free-flowing river. “It won’t change anything about the public being able to use the land.”


In anticipation for the project, George and the DNR have slotted a public meeting regarding the project for 7 p.m. on Tuesday, September 26 at the Hinckley Community Center. There, the team heading up the project will be available for people to ask questions and hear about the DNR’s plans. George hopes there will be some concept drawings for the DNR to present and will also share examples of other dam modification projects that have happened across the state.

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