American Construction Co. finishes job in Lewiston-Clarkston ahead of schedule
By ERIC BARKER of the Tribune
Dredging of the navigation channel and port berthing areas on the lower Snake and Clearwater rivers was completed Thursday, a few days ahead of schedule.
Contractor American Construction Co. of Tacoma and a subcontractor removed an estimated 400,000 cubic yards of sand and silt from the confluence of the two rivers while restoring the navigation channel to a minimum depth of 14 feet.
Dredging in the lower Clearwater River near the Port of Lewiston was completed by Monday, and the companies began to demobilize their equipment while also putting finishing touches on juvenile salmon and steelhead habitat that was created from the dredge spoils in Knoxway Canyon.
The project was taken on as a first step in the U.S. Army Corps of Engineers’ $16 million long-term plan to manage sediment near Lewiston and Clarkston at the upper reaches of slackwater created by the four lower Snake River dams.
When the flows of the two rivers slow, sediment drops out of the water column. Over time, it accumulates on the river bottom. Prior to dredging, the navigation channel was judged to be as shallow as 7 feet in some places. That led to occasional grounding of barges, required grain barges to be only partially filled before departing downriver and made it difficult for the largest tour boats to call on the Port of Clarkston’s cruise ship dock.
“Navigation on the lower Snake River is now safer,” said Lt. Col. Timothy Vail, commander of the corps’ Walla Walla District. “We considered potential alternatives, determined dredging was the only effective short-term tool for addressing problem sediment that had accumulated to the point of interfering with navigation and successfully completed maintenance dredging during the designated winter work window.”
Managers at the ports of Lewiston and Clarkston hailed the work and commended the contractor for finishing on a tight deadline.
“We are very pleased with the contractor’s performance,” said Lewiston Port Manager David Doeringsfeld. “The dredging will eliminate safety concerns associated with groundings and eliminate the light loading of grain barges.”
Port of Clarkston Manager Wanda Keefer said the work will make it easier for tour boats to use its cruise ship dock. In the recent past, some of the largest boats have had to dock at the port’s crane dock, an industrial setting that Keefer said was less than ideal.
“It was just the wrong kind of atmosphere for people to get an idea of what your community is like,” she said.
Dredging was well-received by cruise boat operators, according to Keefer.
“The general feeling from the cruise boat (industry) is they are going to be able to provide far better service to their guests,” she said.
The contract called for American Construction Co. to remove the sediment between Dec. 15 and March 1 at a cost of $6.7 million. But another company that unsuccessfully bid on the contract filed an administrative appeal. Clearing up the dispute caused dredging to be delayed by about one month.
To make up for lost time, the corps asked the contractor to accelerate the work. To do that, the company brought in a second dredge and also hired a third dredge operated by a subcontractor. The corps and contractor are still negotiating how much the accelerated effort will increase the cost of the work.
Corps spokesman Bruce Henrickson said the final cost isn’t likely to be known until next month.
Environmental groups seeking to breach the lower Snake River dams filed a lawsuit prior to the start of dredging challenging the corps’ decision to remove sediment from the river. The case is unresolved but a federal judge refused to issue an injunction that would have further delayed the work.
Barker may be contacted at [email protected] or at (208) 848-2273. Follow him on Twitter @ezebarker.[/vc_column_text][/vc_column][/vc_row]