Dredging causing islands to shrink

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Georgetown and Phyllis islands, two of 22 protected islands in the Ohio River Islands National Wildlife Refuge, are shrinking, and commercial sand and gravel dredging is at least partly responsible.

Georgetown, 38 river miles from the Pittsburgh's Point, was once a 17-acre evocation of the river's undeveloped, pre-colonial past but was whittled to 12 acres in 1982 and down to 4.9 acres in 2004. Phyllis Island, 35.5 river miles from Pittsburgh in Beaver County, has lost 3 acres, including a Native American historical site, and now measures 20 acres.

According to Dean Rhine, manager of the refuge islands, the sand and gravel dredging that has legally occurred up river from Georgetown Island has redirected the main river channel toward the island, accelerating its shrinkage. And dredging legally done beside both islands has cut into their base and is undermining their stability.

"After the dredging, the islands have experienced significantly more erosion," Mr. Rhine said.

Dan Giovannitti, a spokesman for the river aggregates industry, said dredging around the islands hasn't affected them, and cited other factors -- high water, river traffic wave action and creation of the navigational pool -- as reasons for their erosion.

But Mr. Rhine said the islands are made up of glacial sand and gravel, the very material that commercial dredgers are taking out of the rivers. Because the rivers' locks and dams have turned the rivers into long pools, new glacial material is not washing down and being deposited as it once was. The pools have also submerged big parts of the islands that were once above the waterline.

"The reason the dredgers want to be around the islands, is they're actually mining the base of the islands," Mr. Rhine said. "And once that material is gone the sediments aren't there to rebuild them. That will hurt recreational users."

The U.S. Fish and Wildlife Service, which manages the island wildlife refuge, asked the U.S. Corps of Engineers to increase the buffer around the islands to 2,000 feet., the same distance imposed on commercial dredging by the Corps' Huntington District,.

But the new permits issued by the Corps' Pittsburgh District office increase the no-dredge area to 1,500 feet.

The Service also sent letters to the state Department of Environmental Protection and the Corps of Engineers, complaining that the commercial dredger, Tri-State River Products, had dredged closer to the islands than its permits allowed in 2005 and 2002.

The Corps has absolved Tri-State River Products of those charges, and Tri-State has "unequivocally and emphatically" denied them.

The state DEP also took no action against Tri-State based on those complaints. But Helen Humphreys, a DEP spokeswoman, said the department has imposed bigger up-river buffers around the islands, "as a result of the concerns raised by the Fish and Wildlife Service."


Don Hopey can be reached at dhopey@post-gazette.com or 412-263-1983.


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