DNR to prepare environmental impact statement on Grindstone Dam

May 27, 2021


The Minnesota Department of Natural Resources will prepare an environmental impact statement (EIS) for the proposed Grindstone Dam removal project located in Hinckley, Minnesota. The EIS will evaluate the potential environmental effects of the project as well as  several alternatives.

The DNR proposes to remove the dam on the Grindstone River in Hinckley and restore connectivity to the river channel. This would result in the permanent removal of the 26.6-acre Grindstone Reservoir, which is a public water basin. The removal is proposed because the dam is in poor condition,  presents a safety hazard and  is a barrier to fish and other aquatic wildlife. The dam also does not allow for natural sediment transport, natural stream features or habitat diversity.

The DNR distributed a scoping environmental assessment worksheet and draft scoping decision document in October. The DNR held a public meeting regarding the draft scoping decision in November and accepted public comments.

The DNR carefully considered all comments received and issued a final scoping decision document (FSDD) in December. The FSDD identifies project alternatives and issues that will be addressed in the EIS and presents a tentative schedule for EIS completion.

The EIS will address potential environmental effects related to wetlands; hydrology; sediment and contaminants; fish, wildlife and ecologically sensitive resources; geology; groundwater; cumulative potential effects; physical impacts on water resources and riparian rights; and mitigation. A more detailed description of each of these topics can be found in the FSDD, which is available on the DNR website.

The EIS will evaluate the project as proposed, which would involve removing the Grindstone Dam, regrading the channel in the area of the removed dam, and allowing the river to reform naturally.  Project alternatives that will be assessed include leaving the current dam in place and other engineering approaches that would remove the dam but involve other measures post-removal.

EIS schedule
The tentative EIS schedule has been updated to reflect the current scope of the EIS and the anticipated timelines necessary to complete the EIS and associated studies. The schedule now anticipates the draft EIS publication in December 2021, final EIS publication in March 2022 and determination of EIS adequacy in May 2022.