the film

Corps of Engineers Gets Earful
about Sediment Problems

by Eric Barker
Lewiston Tribune, February 16, 2007

People told officials from the U.S. Army Corps of Engineers to concentrate on long-term solutions to deal with the accumulation of sediment in Lower Granite Reservoir.

In the same breath, they said drastic short-term measures like raising the levees at Lewiston and Clarkston should be avoided.

About 60 people showed up at the Quality Inn in Clarkston Thursday night to hear corps officials outline their plan to study sediment management alternatives. The officials also collected public comments on their plan that could include a wide range of alternatives from raising levees to cooperating with upstream land managers and private land owners to reduce erosion.

"We want to identify as many different ways as we can to manage sediment in addition to dredging," said Carl Christianson, project leader for the corps at Walla Walla.

About 3 million cubic yards of sediment are deposited in the reservoir each year. One million cubic yards is enough to cover a square mile with sediment 1 foot deep. Over the years that accumulation of sediment has reduced the capacity of the river to handle high flows.

The levee system around Lewiston and Clarkston was designed to have 5 feet of freeboard -- the space between the water level at the highest flows and the top of the levee. Sediment build-up has reduced the freeboard to about 1.5 feet to 2 feet.

Jerry Klemm, a retired mill worker from Lewiston, said raising levees would only lead to more sediment accumulation in the reservoir. "It shouldn't even be on the table," he said.

John Barker, a river guide and hunting outfitter from Lewiston, asked why the corps couldn't lower reservoir levels in times of high flows to reduce the risk of flooding.

Christianson said that technique can and is used. But he said the dams on the Lower Snake River don't store a lot of water and offer only limited flood protection. He also said sediment accumulation has reduced that capacity.

Lewiston Mayor Jeff Nessett said calling levee raising unpopular is "an understatement" and asked the corps to involve local governments in the study process and identification of promising alternatives.

A previous corps study determined raising the Lewiston levee by 3 feet would reduce flood risks. That study identified the levee from the Southway boat ramp downstream to the confluence of the Snake and Clearwater rivers and upstream on the Clearwater to the West Levee Pond near the railroad bridge as candidates for a 3 foot rise.

Steve Fink, of the corps, said a 3-foot rise in that section could be done without having to widen the base of the levee or altering the footing of the Interstate Bridge.

Others, like Dick Wittman, a farmer from Culdesac, praised the corps long-term approach, but said there are a host of proven measures, like direct seed farming, tree plantings and modern logging practices, that could be implemented now to reduce sediment build up.

"I challenge you to take the money you are going to spend studying and use it to implement (the measures)," he said.

Christianson said the corps doesn't have the authority to spend money on measures that could reduce sediment. The study undertaken by the corps could result in special legislation giving the corps more authority to fund erosion control measures, he said.

The urgency of the problem might also help other land management agencies and private landowners obtain funding to reduce erosion and the amount of sediment that reaches the river system, Christianson added.

Several people asked questions or made comments aimed at pointing out that sediment problems might disappear if the lower Snake River dams were breached. Jim Bradford of Lewiston asked if the study would include an economic analysis. He said if the costs of managing sediment are closely scrutinized, the agency might find it would be cheaper to breach the dams. "You have to recognize you have a waterway that is a giant subsidy," he said.

Sam Mace, of Spokane and the Save Our Wild Salmon Coalition, said money spent to manage sediment could be used to upgrade railroad facilities that would replace river navigation. She said that would help threatened runs of salmon and steelhead that are harmed by the dams, and reduce the risk of flooding.

Dustin Aherin, a river guide and construction worker from Lewiston, asked how serious the threat of flooding is for downtown Lewiston with the dam and levee system in place.

"It's a concern," Fink said. "It's not a huge concern."

He said the levee system was designed to withstand flows of 420,000 cubic feet or a 500-year flood event.

Port of Lewiston Manager David Doeringsfeld countered the questions and comments aimed at breaching by asking the corps to make clear one of the purposes of the study is to make sure barge navigation between the mouth of the Snake River and Lewiston is retained.

"I think that needs to be stated in the (study's) purpose," he said.

Eric Barker
Corps of Engineers Gets Earful about Sediment Problems
Lewiston Tribune, February 16, 2007

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