Posted on February 27, 2023
The contractor working to clear sediment in the Snake and Clearwater rivers near Lewiston and Clarkston is on pace to finish the work by the end of this month.
As of Thursday, American Construction Co. of Tacoma and a subcontractor had removed 89 percent of the estimated 400,000 cubic yards of sediment clogging the navigation channel and port berthing areas in the two rivers.
“We are on track with dredging. We plan to complete dredging at the confluence of the Snake and Clearwater rivers by Feb. 28,” said Bruce Henrickson, a spokesman with the U.S. Army Corps of Engineers at Walla Walla. “Our goal all along was to complete dredging during the annual in-water work window when (threatened and endangered salmon and steelhead) are least present in the river.”
That goal was put in jeopardy when the start of dredging was delayed because of a contract dispute. American Construction Co. was set to begin the work Dec. 15. But another contractor who unsuccessfully bid on the work filed an administrative appeal that required a review by the corps.
Dredging finally began Jan. 12. To make up for lost time, the corps asked the contractor to increase the pace of the work. To do that, American Construction Co. deployed a second dredge to the area and also hired a third dredge operated by a subcontractor.
The accelerated pace required renegotiation of the $6.7 million contract. Henrickson said the final details are pending.
“Increased dredging costs due to accelerating the contractor’s efforts have not yet been determined,” Henrickson said.
Shortly after the dredging is complete, navigation on the Snake River will shut down for about four weeks as the corps performs annual maintenance on gates and locks at Lower Granite, Little Goose, Lower Monumental and Ice Harbor dams. The locks are scheduled to close March 7 and reopen April 4.
The locks are closed for about two weeks every year for routine maintenance. The closure will be extended by an additional two weeks this year because the work plan includes nonroutine repairs as well as some machinery replacement.
Locks on the Columbia River will be closed for the normal two-week period from March 7 to March 21.