Paradise Under Construction
By Ben Ikenson
AUGUST 28, 2000: Mere mortals may not be able to move mountains, but, by using material dredged from the Houston Ship Channel as it undergoes expansion, biologists and engineers in Texas are creating a six-acre, 12-foot-high island in the sea. The island is being built in the Gulf of Mexico's largest estuary, and biologists hope it will soon be a nesting habitat for hundreds of colonial waterbirds.
At once associated with both warm gulf breezes and imposing offshore oil rigs, the Texas coast is a paradox of coexisting natural resources and industrial enterprises. At the fringes of its fractured coastline are innumerable bayous and fingers of marsh inlets. A mile off the coast, hordes of shrimp trawlers scour the bottom of the ocean. This duality of nature and industry seems somehow to merge with the creation of Bird Island.
Bird Island is thought to be the first island designed and built using dredged material specifically as a nesting site for colonial waterbirds such as black skimmers, roseate spoonbills, reddish egrets, gull-billed terns and endangered brown pelicans. Located just a mile and a half off the north shoreline of the Bolivar Peninsula in lower Galveston Bay, the island is expected to be completed in August.
Already, large numbers of terns, gulls and pelicans are using the island to rest, a sign that nesting success may be on the way, said U.S. Fish and Wildlife Service biologist Phil Glass. Glass, who is credited with coming up with the idea for the project in 1995, pointed to Bird Island as a good example of cooperation among many federal agencies as well as industry.
"The construction of Bird Island shows that industry and the environment do not always have to be at odds," said Glass. Perhaps cooperation between the two interests can even bring about mutual success.
In the instance of Bird Island, success demanded a concerted effort by a number of natural resources agencies, private conservation organizations and others who worked on the project.
First, dredged earth was pumped from the bottom and sides of the existing Houston Ship Channel as far as five miles. Where the material was deposited, a network of aquatic bulldozers, backhoes, and other machinery was used to orchestrate the formation of the land mass. On the wind and wave-prevailing southeast side, a sand beach was pumped in behind an offshore breakwater to form a sheltered lagoon. Fifteen thousand tons of granite were then used to form a ring of stones around the perimeter shoreline and the lagoon.
Finally, since different birds prefer different habitats for nesting, biologists will plant various grasses and tree seedlings beginning this fall. Biologists plan to provide mulch and water in the form of slow-release watering packets to allow the plants to survive in the nutrient-poor dredged material.
Eventually, this island of sludge may become a manmade paradise for the waterbirds of Galveston Bay for several reasons, Glass said. It is far enough offshore to discourage predation by racoons or coyotes, yet it is near enough to future sources of dredged material to allow periodic refurbishment if necessary. Also, the island is located near large areas of marsh-feeding habitat but is sufficiently distant from existing waterbird colonies. And along with the Texas Audubon Society, biologists from an interagency group of state, local and federal agencies, will carefully manage and monitor Bird Island.
The interagency group, which includes the U.S. Fish and Wildlife Service, is also responsible for planning environmentally-beneficial uses for some 180 million cubic yards of dredged material expected to be produced by the channel expansion project over its projected fifty-year life span. Bird Island is just one of several environmental features resulting from Houston Channel enlargement, which began in 1998.
Other features--such as the creation of a 1,000-acre marsh on Bolivar Peninsula--will add more than 4,000 acres of salt marsh to the Galveston Bay ecosystem, making these collective efforts one of the largest marsh-creation enterprises in North America, Glass said.
"In areas like the Texas Gulf Coast, loss of important habitat, such as tidal salt marsh, continues because of manmade processes like ship channel dredging and water and mineral extraction started over a hundred years ago," he said. "While pure preservation is best for many wild areas, several places on the upper Texas Coast have been so altered for so long they require some engineering effort to restore."
This is especially true around Galveston Bay, where erosion and subsidence (the sinking of land resulting from removal of underground water, oil, and gas) have dramatically altered both the ecology and the geography of the area.
On the Gulf Coast, tidal salt marshes are critical not only to birds but to the entire bay ecosystem. These salt marshes produce marine species such as red drum, southern flounder, and white and brown shrimp, which sustain the seafood and recreational fishing industries. Tidal marshes also remove pollutants and buffer nutrient levels in bay and coastal waters. Colonial waterbirds historically flourished here, and their periodic population fluctuations are good indicators as to the overall health of the bay ecosystem.
"It is crucial we pay attention to these indicators," said Glass, "and it is crucial that we use our engineering knowledge to correct the situation where needed. The environmental features coming from the Houston Ship Channel project will be a good demonstration of taking this knowledge and putting it into action."
Prior to this "knowledge in action," earlier plans had been approved which would have resulted in the dumping of 180 million cubic yards of mud directly into the bay. Fortunately, a coalition of government agencies and environmental groups successfully opposed the original channel enlargement plan. Not only would the action have been wasteful of material that could be used in rebuilding marshes, it would have covered large sections of productive bay bottom, including valuable oyster reef.
The plan developed by the interagency group, which now includes the Houston Port Authority, uses material once thought of as waste in addressing and, hopefully, resolving environmental problems once thought of as near-hopeless.
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