Laden freighters are finding the Columbia River route to the docks of the Port of Portland blocked by tons of debris poured into the water-way by the volcanic eruptions of Mr. St. Helens. But ships bound for the Port's huge dry dock No. 4 will reach their destination with little difficulty.
A spokesman for the port said the 95-foot-long BT Alaska, a tanker, returned to the river shortly after June 1. Another tanker, the 883-foot-long ARCO Juneau, was to come into dry dock about mid-June.
"These ships come in and go out empty, so they don't have the water depth problem facing a loaded freighter," he said.
The river's normal 40-foot-deep channel was but by more than half when the mass of debris reached the Columbia from tributary rivers flowing out of the Mt. St. Helens area. Dredging is not expected to restore the 40-foot depth before October. Seven dredges have been brought here to do the job.
The latest eruption of Mt. St. Helens, the night of June 12, has posed no new problems for the port. Although the eruption was severe, there was no new flooding or mud flow into the Columbia out of its tributary rivers.
There is some criticism of the probable $219 million cost of clearing the Columbia and its tributary Cowlitz river, out of which the Mt. St. Helens debris spewed into the Columbia.
Port of Portland officials, however, say cost is secondary to the goal of getting river traffic back to normal as soon as possible. There are 21,000 harbor-related jobs in Portland and Vancouver, Wash., directly affected by the slowdown in freighter movements.
The speed and effectiveness with which work was begun in clearing the river were the result of almost 90 years of cooperation between port officials and the US Army Corps of Engineers in providing and maintaining the ship channel since 1891 when the port was established.
The massive 982-foot dry dock, largest on the West coast and one of the three largest in the world, was delivered by its Japanese builder in September 1978. It has been a moneymaker for the port since the end of the first seven months.
A major factor in the dry dock's quick success is the port's shipyard ballast water-treatment plant, a facility unique among US shipyards.
Only here, among all US shipyards, can a tanker put in for dry-dock repairs without first going to an oil-refinery dock to have its ballast pumped out. Moving first to an oil-refinery dock and then to dry dock increases the cost of repair and maintenance.
According to estimates of the US Army Corps of Engineers, dredges will have to remove some 22 billion cubic yards of debris before the river channel is once again clear and of proper depth and width.
While the dredging is going on ships move to and from the port docks at specified times when the Coast Guard authorizes such movement. According to the Columbia River Pilots Association, passage of the ships is being made "successfully and with no problems."