Pollutants, milfoil growing problems for lake

The basin isn't clean yet, and neither is Lake Coeur d'Alene.

While discussions continue on the newest plan to clean mining waste in the upper Coeur d'Alene Basin, Lake Coeur d'Alene is still the recipient of sediment contaminated by the same century of mining tailings, pointed out speakers at Wednesday night's Community Conservation put on by the Kootenai Environmental Alliance.

"If we don't achieve our goals (for lake management), the EPA (Environmental Protection Agency) will step back in," said Rebecca Stevens, lake management restoration coordinator for the Coeur d'Alene Tribe.

The state and tribal presentations at the Coeur d'Alene Public Library focused on the status of lake contamination and efforts to address it with the Coeur d'Alene Lake Management Plan.

Besides the mining waste lying on the lake bed, more sediment contaminated with metals flows in each year from the Coeur d'Alene River, Stevens said.

An aerial shot of the lake taken in May showed an expansive plume of such contaminated sediment spreading across the lake.

The Idaho Department of Environmental Quality, which is implementing the LMP with the tribe, is monitoring how such plumes mix into the lake, said spokesperson Glen Rothrock.

"It (contaminated sediment) might shoot straight to the Spokane River, or it might fan out," Rothrock said. "In some areas we know that, and in some areas we don't."

Other lake monitoring has been conducted since the plan began implementation last July, he added, and a new staff member was hired to lead the science team.

It's crucial to understand how big of a problem contamination is in the lake, Rothrock said.

Past water monitoring has revealed that levels of phosphorous and algae increased between 1991 and 2006, especially in 2003, he said.

"Our job is to see if that trend is flattening out," Rothrock said.

Current lead levels in the lake are around 1,500 parts per million, he said, reaching up to 7,700 parts per million in some areas.

"We think in the past, before mining was happening, that number was in the area of 30 (parts per million)," he said.

The state is also studying the movement of Eurasian Watermilfoil, most dense around the southern portion of the lake and a threat to the oxygen cap that contains metals on the lake bed.

"I think surely it (the milfoil) will migrate north. There's no reason why it shouldn't," Rothrock said.

Besides monitoring, the state and tribe are also working to determine the demand for public education on water quality in Lake Coeur d'Alene.

The two entities are launching an ad campaign encouraging locals to fill out an online survey, available at www.cdalakesurvery.com.

"We're just asking, 'What do you know?'" Stevens said.

The state and tribe will be meeting with local government entities and community groups next year to discuss better management practices for water quality, but the general public can do plenty on its own right now, Stevens said.

She advised lakeshore residents to respect the 25-foot buffer zone for shoreline construction, as well as apply fertilizers responsibly and maintain septic systems.

"This is a lake community issue," she said.

Rothrock emphasized that restricting nutrient input into the lake is key to maintaining the oxygen cap at the bottom of the lake.

"You lose your oxygen, and all bets are off," he said.