ILWACO, Wash. — The never-ending struggle to keep south Pacific County’s maritime link to the Columbia River is again underway.
Dredging to deepen the Ilwaco Channel commenced in August. The dredging is part of $1.2 million received in federal funding for channel maintenance announced last spring.
The crucial sediment removal is necessary for keeping the local waterway navigable and retaining access to the Port of Ilwaco for commercial and recreational vessels.
Channel condition surveys revealed spots shallower than 5 feet, which will be deepened to the required 18-foot depth, according to Darrell Jamieson, project manager for J.E. McAmis, a marine contractor tasked with doing the heavy digging.
Initial sediment removal started around the jaws of the channel, but has gradually moved further inside the channel in recent weeks.
Using a bucket scoop, the dredge is capable of removing 10 yards of sediment at a time — about 27,000 pounds, or about nine Toyota Priuses. “It’s sand all the way up by Fort Canby then it gradually turns to fine sediment,” Jamieson said during a boat tour of the dredge work in August.
Each scoop is unloaded into a “dump scout,” a barge capable of carrying about 1,200 yards of sediment to the spoil drop site.
Changing tides, currents and boat traffic complicate channel dredging.
“It’s really sneaky and snaky,” Jamieson said. “It will take the barge everywhere, so we have an assist boat that trails behind it and we leave on slack tides.”
During the Renaissance, Leonardo da Vinci designed the draga cavafango, or mud dredge, a simple apparatus that would be a primitive starting point for the technologically advanced dredges of today.
“Today we have GPS and dredge software that shows where the bucket is, the channel — everything,” Jamieson said. “Before, you just dug off of range markers.