Debris torn from Western North Carolina and East Tennessee by flooding rivers largely dumped into one East Tennessee reservoir, and the cleanup of a hazardous debris field is taking the coordination of local, state and federal agencies.

Three rivers that swelled to deadly levels during Hurricane Helene on Sept. 27 – the French Broad, Nolichucky and Pigeon – start in North Carolina and empty into Douglas Lake. They transformed the waters of the popular recreation and fishing destination to brown muck and left a one-square-mile island of wreckage after the historic floods.

The Tennessee Emergency Management Agency warned residents to stay off the lake until further notice, as the debris could be dangerous or even deadly, though the agency did not provide a specific timeline for the cleanup. Two other state agencies issued a boating safety advisory and a water contact advisory in October.

Lined with vacation homes against a scenic mountain backdrop, Douglas Lake is mostly within Jefferson County, though it also touches Cocke, Hamblen and Sevier counties. In the days after the flooding, Douglas Dam released around 450,000 gallons of water a second and helped the Tennessee Valley Authority prevent $406 million in flood damage, though some downstream communities experienced flooding.

TEMA, which is leading the cleanup effort, hired TVA in early November to lead removal and disposal of the debris, TVA spokesperson Melissa Greene told Knox News. TVA owns and operates Douglas Dam, the hydroelectric facility that impounds the French Broad River to create the lake.

Multiple federal agencies help TEMA clean Douglas Lake

TVA installed a 4,000-foot floating boom across the lake upstream of Dandridge on Oct. 3 to catch debris and protect infrastructure downstream. The utility also added floating buoys and lights to warn boaters.

Photos and videos showed a debris field largely composed of splintered wood, though it appeared to contain household items and parts of buildings as well.

Federal agencies involved in the cleanup include the Federal Emergency Management Agency, the Environmental Protection Agency, the U.S. Army Corps of Engineers and the Occupational Safety and Health Administration, according to TEMA.

TEMA did not specify the exact roles of the federal agencies supporting the effort.

“We are committed to restoring normal conditions and protecting the well-being of the community throughout this process,” TEMA Director Patrick Sheehan said.

After setting up the agency relationships, the next step is removing the debris with equipment both on land and water, according to a TEMA webpage about the cleanup. The agencies will then set up temporary disposal sites, organize the debris and haul it away.

Daniel Dassow is a growth and development reporter focused on technology and energy. Phone 423-637-0878. Email daniel.dassow@knoxnews.com.

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