ILWACO: Port managers in Ilwaco and Chinook say they are lucky to have landed a commitment from the US Army Corps of Engineers to dredge federally managed channels crucial to both ports’ continued survival for the second year in a row, but that doesn’t mean all of their problems are solved.
Despite the dredging the Corps completed last year, the Port of Ilwaco’s Baker Bay is already filling back up and will likely need work well into the future. Meanwhile, a dredge disposal site at the far end of the marina is nearing capacity and port commissioners will have to come up with a new way to dispose of or disperse the material dredged from the river and the marina.
At a meeting with congressional representatives and employees with the Corps April 2, port staff and commissioners listened to an informal presentation by Vladimir Shepsis, a coastal engineer with Coast and Harbor Engineering.
After examining a variety of possible solutions, Shepsis said that, from an engineering point of view, the port’s best option would likely be to use a flow lane dispersal system where dredged material is dumped in naturally occurring depressions or holes on the river bottom. The strong flow of water that already scoops out these holes scatters the excess sediment.
Shepsis said the sediment comes from the Columbia River and should, preferably, go back into that ecosystem.
He said he had some trouble finding good, deep holes in places he’d otherwise except to see them near the port, but he and other staff did locate two eventually: one near the marina and one near the Cape Disappointment Coast Guard station.
Such a system has been successfully implemented at the Port of Willapa Harbor in north Pacific County. “But,” said Port Manager Rebecca Chaffee, “and there’s always a but…”
She said they did have some trouble working out how to manage a floating pipeline that feeds the material towards the underwater dispersal site.That port also decided to place the system in an area somewhat shallower than Shepsis would normally prefer.
It was worth the risk, Chaffee said April 2. “We probably would have lost Bay Center (marina) and Tokeland (marina) if we didn’t have flow lane disposal.”The process was just more complicated than they thought it would be, she told the people gathered in the Port of Ilwaco’s conference room.
The Port of Ilwaco’s current disposal site, a strip of land east of the marina, is filling up and the port has not successfully found a way to move the material elsewhere. Under permits from the state Department of Ecology, the port can use dredge spoils for “beneficial use,” using the material on its own lands or possibly giving it to other entities. The material coming out of the marina is considered “clean.”
However, efforts to use or get rid of the material have not been successful.
But taking care of the sediment is one of the port’s major concerns. Not much more than a decade ago, Baker Bay did not need the constant attention it seems to require now. Many things could be influencing the build up of sentiment and much of the sediment could technically be coming from across the river.But, as Shepsis said, “You can’t say to Oregon, ‘Take your sediment back.’”
From an engineering perspective, the flow lane disposal would likely work for Ilwaco, Shepsis said. It doesn’t mean it is the best solution, he added, since he is not aware of what other issues surrounding those areas — habitat concerns, politics might make such a use less feasible if not impossible. That is information he will look to the Ilwaco Port Commission to provide.Port Manager Guy Glenn Jr., said he and the commission will likely discuss these things at a port meeting this month.
