Federal officials want suggestions for small-scale cleanup projects in the lower Coeur d’Alene River Basin, which is contaminated by toxic metals from more than a century of hard-rock mining in the upper reaches of the watershed.
The Environmental Protection Agency will pick some pilot projects to do next year that could shape how large-scale cleanup happens one day in the lower basin, which stretches from Enaville down to Harrison on Lake Coeur d’Alene and includes the picturesque Chain Lakes.
“It’s time to start taking a small bite out of the very big chunk that is out there,” said Ed Moreen, remedial project manager in the EPA’s Coeur d’Alene field office.
Lead from mining activity before 1968 is the most prevalent of the heavy metals that get flushed downstream and accumulate in the river bed and stream banks, with concentrations spiking near the mouth of the river. High spring runoffs and floods wash the waste down the basin and spread small lead particles throughout lakes, wetlands, pastures and fields.
The EPA estimates 390 tons of lead washes from the Coeur d’Alene River into Lake Coeur d’Alene each year, on average. While some of that comes out of the north and south forks of the river in the upper basin, about 85 percent of it is due to river bed erosion in the lower basin, officials say.
An estimated 176 tons of lead washed into Lake Coeur d’Alene on Jan. 18, 2011, after heavy rains and melting snow triggered flooding. It was the highest volume of lead recorded in a 24-hour period since major flooding in February 1996, the U.S. Geological Survey said.
The average concentration of lead in the lower basin riverbed is about six times the level that warrants removal to protect human health, according to the EPA.
Contaminated sediments also pose hazards for wildlife throughout the Chain Lakes and the marshes between Cataldo and Harrison. Each year migrating tundra swans that feed in the wetlands die from lead poisoning, and other bird species succumb as well.
The EPA is coordinating cleanup and restoration of the federal Superfund site that encompasses the 1,500-square-mile Coeur d’Alene Basin.
The aim of the lower basin pilot projects is to start small and evaluate how well they work, Moreen said, as opposed to a major cleanup effort like dredging the river.
“We recognize that’s a very challenging cleanup technology in a very complex system,” he said. “So we’re not suggesting that this is the time or place to do that, but we’re suggesting much smaller-scale projects that we can work on to address exposure to wildlife or people, particularly thinking about lead.”
The EPA has $4.5 million to tackle the pilot projects beginning in summer 2014. The types of work the agency will consider include:
• Replacing contaminated beaches and banks.
• Limiting floodwater from entering lakes and wetlands.
• Controlling migration of contaminated sediment along river beds.
• Keeping waterfowl away from the most contaminated area.
The EPA mailed notices of the pilot projects and two public forums this Wednesday to more than 1,700 addresses in the lower basin.
“The lower basin has been an area that’s been of some concern for the people who live in that area,” said Jerry Boyd, chairman of the Citizens Coordinating Committee of the Basin Environmental Improvement Project Commission. “So this is an opportunity for them to participate and provide some input.”