Idaho


Emaciated delta returning to roots

THURSDAY, MARCH 12, 2009

With human help, eroded land becoming rich habitat again

Once, the Pack River Delta pulsed with life.

The boggy land bred swarms of mosquitoes, which attracted silent bats and garrulous songbirds. Tall grasses concealed shrews and voles, protecting them from hunting foxes and owls. Geese and ducks nested in sheltered spots on the delta, while enterprising beavers built dams there, slowing the river’s current so that sediment dropped out of the water before it reached Lake Pend Oreille.

Today, only a remnant of that rich ecosystem remains. After Albeni Falls Dam was built in the 1950s, hundreds of acres of delta were lost to erosion.

“It’s almost ghostly,” Katherine Cousins, an Idaho Fish and Game mitigation biologist, said as she trekked across the delta last week.

Much of the residual delta is made of sterile mud flats, which sucked and pulled at Cousins’ hip waders as she walked. But armed with $800,000 in grants, Cousins and others are working to restore the landscape.

By next spring, the delta should green up with willows, cattails and sedges. Breakwaters and log structures will protect the 24 acres of new plantings and slow the silt-laden waters, so the delta can start rebuilding itself into a braided river channel.

“The delta wants to be a delta,” Cousins said. “It has a really important role in the ecosystem, and we’re working to restore its function.”

The federal government contributed $500,000 of grant money to the project, which is on property owned by the U.S. Army Corps of Engineers. Other funding came from Avista Corp., Ducks Unlimited and Idaho Fish and Game, which each put in $100,000.

The work done on the Pack River Delta could guide other restoration work on Lake Pend Oreille, which lost more than 15,000 acres of wetlands and deep-water marshes to Albeni Falls Dam.

When it’s running at capacity, the dam produces enough electricity for 15,000 homes, according to the Corps of Engineers. But the kilowatts come at a cost to wildlife. Operation of the dam raises and lowers the lake about 11 feet a year – creating a high summer pool that is good for boaters but chews away at the Pack River Delta and other shoreline habitat.

“It’s altered the hydrology and crippled the delta,” Cousins said.

Photos from the 1930s show the Pack River Delta extending twice as far into Lake Pend Oreille. The restoration work will protect the delta’s 640 remaining acres and – if all goes according to plan – create conditions for recovering some of the lost territory.

“We’re using the river system itself to rebuild the delta,” said Frank Reckendorf, an Oregon consultant who worked on the project with Ducks Unlimited engineer Brian Heck.

Each year, the Pack River deposits 200,000 tons of sediment into the lake. Reckendorf incorporated 250 logs into screenlike structures that will slow the water and snag debris floating down the river. Both actions will help deposit sediment in the delta, spurring the growth of trees, shrubs and grasses.

“Then we might attract a real engineer – a beaver. They can do 10 times the work that we can,” Cousins said.

“I like working with beavers,” Reckendorf said. Through their stick-and-mud dams, the beavers will carry on the restoration work and make the project self-sustaining, he said.

As the delta greens up, the fertile zone will attract other wildlife, including muskrats. “They’re like the gardeners. They keep the wetland plants under control,” Cousins said. Open areas of cropped grasses become a magnet for waterfowl, while the presence of muskrat lures hawks and other predators.

“Muskrats are a pretty tasty morsel. They’re almost all fat,” Cousins said. “They’re part of this orchestra of animals that make up life on the delta. When one or two fall out, it’s not the same.”

Over the next two weeks, crews will finish installing the breakwaters and the log screens. Cousins is recruiting volunteers to help with April planting efforts. So many willow shoots will be planted in the delta that they would stretch for eight miles if they were lined up end to end. A final planting of coniferous trees will take place this summer.

Cousins already has her eye on another delta project. Farther to the east, the Clark Fork River Delta is losing 50 acres of ground a year. Lake Pend Oreille is starting to lap at old-growth cottonwood trees on the delta, which have high habitat values. “You can almost feel its pain,” Cousins said.

At eight times the size of the Pack River Delta, the Clark Fork is a much more complicated project. Two dams on the Clark Fork River trap sediment upstream, which means there’s less silt available for the delta to rebuild itself.

But the Clark Fork Delta is a spot worth saving, said Chip Corsi, Fish and Game’s regional manager in Coeur d’Alene.

“It’s such a unique place,” he said. “You’re at a confluence of a river and a lake. You can poke around in a canoe, and feel like you’re going back in time.”

The deltas are a practical lesson in unintended consequences, Cousins said.

“When you mess something up,” she said, “it takes all of this effort to get it back.”

Contact Becky Kramer at (208) 765-7122 or beckyk@spokesman.com.


Click here to comment on this story »