Port will use unique system to remove tsunami silt

By Jane Stebbins, Pilot staff writer August 28, 2012 08:09 pm

 

The last bit of long overdue and much-needed dredging in the boat basin at the Port of Brookings Harbor will begin next week after workers finish laying a mile of pipe atop the water from the harbor to an EPA-approved disposal site in the ocean southwest of Brookings.

It’s a first for ports along the West Coast.

 

While other cities, notably Crescent City, dredges its port using this method, it dumps all its spoils on dry land. Other ports are too far from EPA disposal sites and must use barges to haul debris away.

Using FEMA tsunami repair funds, the port will lay a mile of 12-inch diameter pipeline and pump 28,000 cubic yards of silt from the channel. The pumps are calibrated to move a water-silt mixture about 12 feet per second. Floats will keep the pipeline on top of the water for the 28 days of expected work.

Jack Akin, the Jacksonville engineer who designed the project, said a mile of pipe “is easily doable.”

This part – the last of tsunami-related repair work – will involve using a small dredge to remove silt swept in on the March 2011 event. Its removal will give boaters an additional 2 feet of clearance by which to leave or enter the port.

“The tsunami compromised some of the usability of the port,” Port Director Ted Fitzgerald said. “It’s a relatively small amount of dredging, but that’s the amount approved by FEMA.”

Anchoring pipelines to the sea floor is not an option, he said.

“We could anchor it on the sea floor at about 90 feet, but then we’d be stuck with an incredibly heavy ballast when we’re done,” Fitzgerald said. “There’s just not another way to do it. We came up with a plan that worked.”

Beacons will warn marine traffic of the pipe’s placement. Installation of the pipe will take place after the Slam’n Salmon Derby, scheduled for this weekend.

Those involved are giving the project an additional 17 days in anticipation of delays that could be caused by the type of material that is dredged from the channel.

The timing couldn’t have been better, either, Fitzgerald said.

The U.S. Army Corps of Engineers is expected to complete its two-part dredging work in the channel this week to make room for the last part of the work. The first involved sucking sand from the channel and into a barge, then depositing it off Sportshaven Beach; the second involved collecting larger cobblestones and taking it to the dump site.

That, said port manager Ted Fitzgerald, was merely annual maintenance conducted by the Army Corps of Engineers.

This work is funded by a $673,000 Oregon State Marine Board grant from FEMA; the port secured an additional $94,500 in marine board grant monies to dredge the end of the harbor where passing boats can moor as they go port-hopping. Fitzgerald said that doing the work all at one time will save money, as well. 

The Army Corps has jurisdiction over all coastal channels, but boat basins are the responsibility of each port, Fitzgerald said. And the boat basins here haven’t been dredged in almost five decades.

“This is the last part of the tsunami repair,’ Fitzgerald said. “When we’re done with this, we’re done. We’ll be very happy.”