(Reuters) – Floodwaters that breached two privately owned dams in Michigan began to recede on Thursday after displacing thousands of people and spreading to a Dow Chemical plant and a nearby hazardous waste cleanup site.

Governor Gretchen Whitmer said U.S. President Donald Trump had pledged federal support in the aftermath of the floods. Days of heavy rain caused the Tittabawassee River to overflow its banks and breach two dams, the Edenville and Sanford, in central Michigan earlier in the week.

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“This is unlike everything we’ve seen before. The damage is truly devastating,” Whitmer told a news conference.

Around 11,000 people in Midland County were evacuated as flood waters lapped around heavy buildings and submerged parts of roads and bridges. No deaths have been reported.

National Weather Service meteorologist Ian Lee said flood waters had begun to recede but would likely last into the weekend.

The Federal Energy Regulatory Commission is sending teams to both dams to assist authorities in an investigation. The agency in 2018 revoked the hydropower-generating license for the Edenville structure, accusing its operators of deficiencies.

A representative of Boyce Hydro LLC, which owns both dams, could not immediately be reached for comment.

Chemical giant Dow Chemical, which is headquartered in Midland and operates a 1,900-acre (770-hectare) facility, said in a statement on Thursday that it was working with state and federal agencies to assess damage, including inspections at the hazardous waste site.