The U.S. Fish and Wildlife Service has floated a proposal to save two undeveloped islands in the Ohio River Islands National Wildlife Refuge that are sinking and shrinking.
The innovative islands restoration project would use clean river bottom material dredged by the Army Corps of Engineers over the next five years to fill in behind rock dikes built to stabilize Georgetown and Phyllis islands. The islands, in Beaver County, are part of the 22-island refuge that stretches over almost 400 miles of the Ohio River from just east of the Pennsylvania-Ohio border almost to Cincinnati.
The islands near Midland have been severely eroded over the past 60 years by a combination of factors, including river channelization, navigation dam construction, commercial sand and gravel dredging, and heavy storm and flood flows.
"Georgetown will be done first because it needs more protection, faster," said Patricia Morrison, a Wildlife Service biologist at the refuge. "The rock dike features there will be built within the next year or two, and the Corps Pittsburgh District will use the area behind the dike to place clean material, sand and gravel, dredged from around its locks and dams that is now trucked to landfills."
Georgetown Island, 38 river miles from Pittsburgh's Point, has been whittled from 17.4 acres in 1952 to 4.9 acres in 2004, the last year measurements were made. It lost more than 5 acres between 1952 and 1962, a decade during which the New Cumberland Locks and Dam were built, resulting in raised pool levels around the island.
"Georgetown has a very shallow underwater shelf just 3 to 4 feet deep, extending from the head of the island that was once above water and can be restored," Ms. Morrison said.
A commercial dredging operation operating outside its permitted area a decade ago scooped sand and gravel from the river bottom just 80 feet from the island -- much closer than the dredging permit allowed -- also contributed to Georgetown's erosion, she said.
Phyllis Island, 35.5 miles from Pittsburgh, has eroded from 25.8 acres in 1952 to 20.1 acres, losing most of its mass from the head of the island and along the length of the channel side.
Ms. Morrison said the Corps of Engineers office in Huntington, W.Va., which has successfully completed several island and river bank restoration projects in the West Virginia and Ohio sections of the river, is designing the linear and crescent-shaped rock dikes that will be used to stabilize and expand the two islands in Pennsylvania. She said the Corps is still working on the new project drawings and hasn't yet established how much acreage can be restored to either island.
"There will be additional acreage added to what is there now, but I can't say if the restoration will be to 2004 acreage or 1990 acreage or something else," Ms. Morrison said. "These islands are public lands and part of the national refuge system. We have an obligation to protect them in perpetuity."
Sara Siekierski, assistant manager of the refuge, said the pace of the project will be determined by the size of the Pittsburgh-area Corps' dredging budget.
"We've been trying to do this islands restoration for quite a while, but bringing in fill material is very expensive," she said, "It's possible now because the Pittsburgh District is helping by putting its navigation dredging material in place."
Such a project is necessary because the Ohio, pooled and channeled to accommodate economically important commercial barge traffic, no longer functions like a natural river system.
"What we're doing with this project is trying to stabilize some of the processes that caused this island erosion," Ms. Siekierski said. "If we don't do this the islands will continue to shrink because they are not able to rebuild themselves."
Sean Weston, the project engineer for the Corps of Engineers Pittsburgh District, said it will cost about $250,000 to install the rock dikes around Georgetown Island, but the Corps will save between $500,000 and $600,000 in dredge material disposal costs by using it to fill the area behind the dikes. Normally, disposal of dredge material in landfills costs $45 a ton or $96 a cubic yard.
The dikes to expand the area of Phyllis Island, which is bigger, will cost the Corps approximately $400,000, but dredge material disposal savings could total as much as $700,000 over five years.
"We'll use that savings to do more navigation dredging in the rivers so we'll get more bang for the buck with the same amount of money," Mr. Weston said.
The Fish & Wildlife Service is accepting comments on the islands restoration project until Jan. 14. For more information or to comment, please contact the FWS office at 1-304-375-2923 or email firstname.lastname@example.org. The agency will develop and make available detailed plans and an environmental assessment in the near future.mobilehome - region - environment
Don Hopey: email@example.com or 412-263-1983.