|Tsunami silt buster! Port dredge project up and running|
|Written by Scott Graves, Pilot staff writer|
|September 14, 2012 09:34 pm|
Brian Lofgren keeps an eye on 6,000 feet of pipe carrying silt out to sea Friday. The Pilot/Scott Graves
The dredge and 6,000 feet of pipe being used to suck tsunami silt from the Port of Brookings Harbor boat basins and dump it nearly a mile out to sea on Friday are catching more than silt.
Ropes. Nets. TVs. Furniture. Carpet. Mufflers. Grocery carts. You name it.
And Friday was only the first day of a dredging project that, because of the amount of underwater debris clogging the intake, will now take six weeks to finish instead of the initial three.
“Anything that broke up and sank during the tsunami; we’re finding it,” said Brian Lofgren, owner of the Vancouver, Wash.-based Underwater Earth Movers Inc.
The Port of Brookings Harbor contracted with the company to help dredge the boat basin of silt and debris, much of which was deposited by a tsunami spawned by the Japanese earthquake in March 2012.
The dredging method, which will pump about 28,000 cubic yards of silt from the boat basin, is regularly used in some port cities, but the debris is usually placed in trucks and deposited on dry land. Transporting the silt and debris by pipe to an offshore depository is something new for the Oregon Coast, which has attracted attention for state and national media as well as journalists from a Japanese newspaper, who visited the port on Thursday.
Getting the project up and running hasn’t been easy. With the swells and strong currents just off Sporthaven Beach, building and floating the pipe 6,000 feet from land to the deposit site has been tricky, Lofgren said.
“With the swells making the pipe go up and down, like a seesaw, it’s difficult to bolt together two pieces,” he said. “We had one section that took more than an hour to finish.”
During a test run of the system on Thursday, a section of the pipe just offshore split, but a work crew was quick to patch it, he said. By Friday afternoon, the system was running smoothly, aside from the random TV or grocery cart clogging the intake.
The process begins in the port basin, where a dredge barge equipped with a large, high pressure pump sucks silt and debris from the bottom. The material is sent through a flexible, plastic pipe that travels from the stern of the dredge underwater through the basin and up to the surface, where it runs along the south bank of the Chetco River to Sporthaven Beach, at the south jetty. There, another “booster” pump sends the silt through the pipe heading out to sea. The pumps are calibrated to move a water-silt mixture 12 feet per second.
The pipe in the ocean is lashed to empty sections of pipe that act as pontoons and keep it afloat until it reaches the final destination.
All of the 12-inch-diameter pipe in the ocean is marked every 100 feet with anchored buoys topped with flashing amber lights to warn vessels as they pass through the area.
On shore, fencing and warning signs have been erected along the length of the pipeline to keep people from getting near the highly-pressurize pipe, Lofgren said.
A iron grid flap prevents large debris, such as rocks and grocery carts, from entering the intake valve. When the grid is clogged, workers on the dredge barge simply raise the flap out of the water and remove the debris. The junk is then placed in dumpsters to be hauled away, Fitzgerald.
Initially, the project was expected to take about three weeks to finish, he said. With the amount of large debris clogging the intake valve, it will now take about six weeks, he said.
The project is the last of the repairs required after the tsunami destroyed significant portions of the harbor.
The 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. Port Director Ted Fitzgerald said that doing the work all at one time will save money, as well.
“Things are working out great so far,” he said.
He said it was too early to tell if the delay was going to cost more money.
Meanwhile, beachgoers reported finding a 5-foot-tall orange buoy with a flashing light on top of it at the far south end of the Sporthaven Beach, thinking it might be tsunami debris from Japan.
Instead it is a buoy that came loose from the ocean-based part of the pipe on Thursday, Lofgren said.
For more information, contact the Port of Brookings Harbor at 541-469-2218.