Ice Harbor Dam navigation locks gate hoist machinery replacement project
A crane slowly hoisted the bottom half of an 18-foot-diameter drum to the top of one of the 95-foot-tall towers standing beside the navigation lock at Ice Harbor Dam on Thursday morning.
It was one more step toward returning boat traffic to the Columbia and Snake rivers by a planned date of March 20.
The locks for the eight dams between Portland on the Columbia River and Lewiston on the Snake River were taken out of service Dec. 12 for a 14-week maintenance outage.
The Army Corps of Engineers plans an extended outage at the dams about every five years, with the last one in 2011.
“It is something that they don’t do in other parts of the country,” said Lt. Col. Damon Delarosa, commander for the Corps’ Walla Walla District. “As a result, they are facing some real challenges, particularly on the Mississippi and Missouri rivers.”
The extended outage was planned for the winter months to minimize disruption to shippers and others who use the 359-mile navigation channel.
Forty percent of the nation’s wheat moves on the Snake and Columbia rivers, with goods of all kinds transported annually valued at $3 billion. The most common cargo are agricultural products, petroleum products and steel and other metal items.
At Ice Harbor Dam, the lock gates are raised and lowered an average of 1,381 times a year to allow commercial and recreational vessels to pass.
$25 million Approximate estimate for the non-routine work at all eight dams during the extended outage
While river traffic slows in the winter, it does not stop. Had the Ice Harbor lock been open this winter, it would have been used about 250 times from December through February, based on estimates from recent years’ traffic.
This has turned out to be a tough winter for an extended maintenance outage, particularly for dams along the Columbia River Gorge, where Interstate 84 has had to be closed at times because of ice and snow.
“The situation is very dynamic as the poor weather forecast continues,” said information about The Dalles Dam given to shippers a week ago. “We continue to do everything possible to safely complete our work within the outage window.”
At Ice Harbor Dam on the Snake River, the main issue has been finding more wear than expected on some equipment.
The hubs and shafts of the drums used for winding up the wire rope that lowers and raises the lock gates had gouging. It needed to be machined down to clean metal, with some additional modifications and fabrication of new parts.
Knight Construction of Deer Park, Wash., was awarded the contract to replace the downstream gate hoist machinery at Ice Harbor during the extended outage, a project initially estimated at $4.7 million.
This work will improve the long-term functionality and safety of these locks.
Lt. Col. Damon Delarosa
The company has been working seven days a week, 12 hours a day to try to complete work on time and reopen the river to traffic.
The work may be more expensive, but the Corps is committed to reopening locks on schedule.
Costs were estimated at about $25 million for the nonroutine work at all eight dams as of about 10 days ago. Corps employees will perform additional maintenance during the outage.
“This work will improve the long-term functionality and safety of these locks and further reliability of the Snake and Columbia rivers navigation systems,” benefiting the entire Northwest, Delarosa said.
Ice Harbor Dam’s navigation lock opened to river traffic in 1962 and has been opened and closed more than 96,000 times since.
The downstream lift gate, weighing 720 tons, was replaced in 1995 and the wire ropes were replaced in 2012.
Current work on the downstream hoist machinery includes replacing a 2.5-ton overhead service crane with a 4-ton crane; replacing the shafts for the drums and replacing the electrical and controls equipment.