Riverbanks project keeps soil, pollution out of water

Recreational boat traffic on the Coeur d’Alene River once cost Mike Schlepp up to 5 feet a year in lost farmland.

The wake from passing powerboats lashed at his shoreline, dislodging 1,000-pound dirt clods rusty with heavy metals from a century of upstream mining activity in Idaho’s Silver Valley.

“I think any landowner would be somewhat concerned if their property line was moving that much per year,” said Schlepp, who raises hay, cattle and grass seed on 540 acres along the Coeur d’Alene River.

While boat traffic in front of Schlepp’s ranch continues to increase, he’s no longer losing ground thanks to an erosion control program created by the Natural Resource Conservation Service’s Coeur d’Alene office.

Plans are under way to protect seven of the Coeur d’Alene River’s 25 miles of shoreline between Harrison and Cataldo. The work will be completed within three years.

On Schlepp’s land, the treatment involved placing cobblestones along his mile of shoreline and planting willows, cottonwoods and sedges in the rocks. As the cobblestones silted in, the vegetation took off. Instead of eroded mudflats, Schlepp’s property slopes down to the river in a thicket of brush and trees.

In total, the erosion-control project will keep roughly 3,000 truckloads of contaminated soil out of the river each year, said Mark Addy, district conservationist with the conservation service’s Coeur d’Alene office.

“I can safely say that all of the banks along the Coeur d’Alene River up to Cataldo are eroding one-half to 1 foot per year,” he said. “The river is getting wider and shallower.”

Federal and state dollars are paying the $1.2 million cost of the work. Landowners contribute materials and labor.

The erosion-control design builds on two decades of trial and error. Previous efforts to stop the sloughing banks on Schlepp’s property failed. He planted willows under an earlier program, but without the anchoring rock, they washed away.

Some landowners use pure rock to buttress their shorelines, Addy said. It stops the erosion but also removes the streamside vegetation that shades the river and keeps the water cool for fish.

“This is as close to natural as we can get,” Addy said.

Boats and banks

The issue of boat traffic battering the riverbanks is politically prickly. Decades of artificially high summer water levels in Lake Coeur d’Alene has allowed bigger, more powerful craft to navigate the Coeur d’Alene River.

Avista Utilities, which regulates the lake level with its Post Falls dam, is seeking another 50-year dam operating license from the federal government.

The company wants to continue to keep the lake’s summer pool at 2,128 feet. High lake levels are a boon for summer tourism, creating good river conditions for boaters and deeper dock access for property owners along Lake Coeur d’Alene.

“We don’t anticipate that lake levels will change,” said Hugh Imhof, Avista spokesman.

However, the utility will likely pay something toward erosion control as part of the dam relicensing, he said.

Schlepp’s property is near the turnoff channel to Killarney Lake, a popular day trip destination. On hot August afternoons, he said, it isn’t unusual to see two boats a minute cruising by his ranch.

At one time, a stretch of the lower Coeur d’Alene River was designated as a “no wake” zone, but the Kootenai County Sheriff’s Department didn’t have enough marine officers to enforce it, said Sgt. Matt Street.

As a result, the speed limit was reset to 35 mph, with the “no wake” zone in effect within 100 feet of the shoreline.

“We’ve seen (boats) run so close to the shore that they’re churning up mud,” Street said. But because of the demands of patrolling Lake Coeur d’Alene, the sheriff’s boat typically makes just one run up the river every week, he said.

With this year’s heavy snowpack in the mountains, the natural erosion process will chip away at the banks as well.

‘A big splash’

Rose Frutchey and her husband, Frank, farm along the Coeur d’Alene River near Cataldo. Last year, the couple used the Natural Resources Conservation Service design to protect part of their shoreline. Over the next two years, the Frutcheys hope to shore up the entire one-mile stretch.

The Coeur d’Alene River was dredged in the early 1900s, with mine tailings containing lead, zinc, arsenic and cadmium spread over the farm’s fields.

The tailings are easy to spot, Rose Frutchey said. They’re bright red.

Protecting the riverbank will keep the heavy metals sequestered, she said. Frutchey only regrets that the work comes too late for a 12-foot length of dirt currently crumbling away from the shoreline.

“When it goes,” she said, “it’s going to make a big splash.”