The Michigan Department of Natural Resources has closed the boating access site at Black River Lake in Gogebic County indefinitely, and the public is advised to avoid the area and the soft soils that have been newly exposed, due to draining of water from the impoundment.

Since June 28, the DNR has been receiving reports of extremely low water levels within Black River Lake. This impoundment, approximately 10 miles southeast of Ironwood, was maintained by a water control structure on the lake’s north side. During an on-site investigation, DNR Fisheries Division staff determined that the water control structure experienced a partial failure, with one of the lower stoplogs breaking, causing the impoundment to slowly drain.

“Upon inspecting the dam, it appeared the lower stoplog(s) failed, and that was the cause of the drainage. Upon further investigation of the downstream area below the dam, sediment was not observed to have washed into the floodplain or caused erosion of the streambanks, indicating that this was not a quick flooding event,” said Jennifer Johnson, DNR fisheries biologist. “During the site visit, I spoke with locals who described the impoundment as being 10-15 feet low over the course of three weeks. It is likely that the stoplog(s) completely failed around June 24 or 25, which coincided with a heavy rainstorm.”

The Black River Lake Dam, managed by the DNR, is located in a remote area of Gogebic County and is considered a “low hazard” dam, meaning a failure poses low risk to public safety, property and the environment. Structurally, the remaining portions of the dam do not show any signs of instability. The dam was last inspected in August 2022 and rated in fair condition.

To reduce the likelihood of the impoundment refilling inadvertently due to stoplog slippage or an obstruction, the DNR removed the remaining stoplogs. Because water has been removed from the impoundment, the DNR closed the boating access site indefinitely.

Communication between DNR and the Michigan Department of Environment, Great Lakes, and Energy – whose Dam Safety Unit also has been alerted – will continue to assess next steps and the future management of this area.