Group Tests Berms For Erosion Control Project Aimed At Keeping Tainted Soil From Cda River

A scaleddown experiment aimed at controlling Coeur d’Alene River erosion will begin in January.

The Silver Valley Natural Resource Trustees have obtained the necessary permits from the U.S. Army Corps of Engineers and the state of Idaho to proceed, trustee coordinator Marti Calabretta said Wednesday.

The Coeur d’Alene Basin Commission is sponsoring the project, which will place 6,400 cubic yards of rock riprap in berms just off the shoreline of the river downstream of Cataldo.

The work is being funded by the state and the mining industry. Its purpose is to reduce erosion of metals-contaminated soils, which is caused by boat wakes and spring runoff. The lead and other toxic metals resulted from historic mining practices.

The work will be done over two winters when the water level is low, Calabretta said. The berms will be placed near 750 feet of bank on opposite sides of the river, covering a total of 1,500 feet.

The trustees had initially targeted a five-mile stretch of river between Cataldo and Rose Lake for berm construction. They hoped to complete work on some 6,000 feet of shoreline this winter. That distance was reduced after concerns about the experiment were raised by federal wildlife and environmental officials and the Coeur d’Alene Tribe.

The work is in keeping with the 1996 Lake Coeur d’Alene Management Plan, which called for ways to reduce sediment that enters the lake, Calabretta said.

Also this winter, the trustees will construct three rock barbs in the South Fork of the Coeur d’Alene River upstream of Elizabeth Park. Calabretta described the work as an emergency effort to reduce erosion of mine tailings and contaminated soils along the Union Pacific railroad embankment.