Taken from May 1997 Engineering Study

District dredges up home for endangered bird

By Tim Dugan

Mobile District

There's an island in Mobile Bay that was not put there by nature. It's a dredged material disposal site called Gaillard Island. It has become an environmental showcase, home to thousands of birds, particularly brown pelicans, a once-endangered species with no recorded nesting in Alabama dating back to 1900.

During planning for the Theodore Ship Channel, a heated debate ensued over depositing dredged material in Mobile Bay and creating a disposal island. It was controversial from environmental and engineering aspects. Many engineers thought an island of dredged material would not hold together in open water. Environmentalists and fishermen were concerned about the impact to the bay.

But after many years and studies, construction began in 1979. Initial dredging was completed in 1981 using 31 million cubic yards of material, and the island now shows the beneficial use of dredged material, according to Susan Rees of the Coastal Environmental Section.

Although the island is still an active disposal area, it is one of the most significant coastal nesting areas of brown pelicans and other birds between Texas and Florida.

Soon after the island rose above water, shorebirds began using its favorable habitat and isolation. In June 1983, four brown pelican nests were discovered. By 1985, there were 119 brown pelican nests, and 16,000 other seabird nests. From that, the pelican population has grown to more than 5,000 nesting pairs. The island has gained national attention as a positive compromise between industrial growth and environmental protection.

Gaillard Island is a 1,300 acre triangle about three miles east of Theodore Industrial Complex and 11 miles south of Mobile, Ala. Each side is about one mile long. It's named for Dr. Wilson M. Gaillard, a Mobile dentist, environmentalist, and supporter of industrial growth.

During the study period, a model of the channel and island was built at the Waterways Experiment Station (WES) in Vicksburg, Miss. The model reproduced the bay's hydrography and topography, tides, currents, and salinity. Ten disposal site configurations were tested and results showed that building the Theodore Channel without the island would raise salinity levels. With the island, there was little change in either salinity or water currents.

"We looked at the plan that least impacted the bay," said Jim Baxter, former assistant chief of Operations Division. "We came up with this triangular design. The biggest challenge was gaining acceptance that the island could be built. It was a new technique and there were a lot of skeptics who felt the material was not suitable.

"We also had environmental concerns about the island," Baxter said. "We felt it could have a lot of benefits, but little did we know that we'd bring the brown pelican back. It's gained a lot of recognition. I've taken visitors from as far away as Australia to look at it. They want to observe how we built it and look at the island's development."

"Although the project was our second planned beneficial use of coastal dredged material, many staff members didn't believe an island was possible due to the poor foundation conditions and the characteristics of the dredged material," said Hugh McClellan, chief of Environment and Resources Branch.

Project critics, including some engineers, said the material would wash away or create a muddy mess in the bay. Environmentalists and fishing groups opposed most plans. The district looked at many designs in light of environmental considerations.

"There were a lot of Doubting Thomases that we couldn't pull it off," said Ted Love, formerly of Engineering Division. "I remember we did a test section. We dredged about a quarter of a million cubic yards where the channel would be." They pumped until a desk-sized mound broke the surface, but in days it washed away.

"That test caused some concern," Love said. "It reinforced those guys who said it never could be done."

But the test encouraged others. Harvey Blakeney, now retired from Soil Design, and some of his geotechnical people thought it could be done, with the proper design.

Designers studied other dredge disposal projects, but found this one unique. "Ours presented more challenges because of that soft foundation," said Wayne Odom, former chief of Hydrology and Hydraulics Branch. The contractor excavated the land-cut portion of the turning basin, put the material on barges and transported it to the site. This harder material helped form a solid foundation.

"We worked on it even after construction with stabilizing slopes and slope protection, rip-rap, and groins," said Odom.

Birds and wetlands have been successful on the island. In fact, in the early stages birds were a problem.

"When we started building the island we ran into concerns about what to do about so many birds nesting in the area while we were trying to complete construction," said Paul Bradley, Operations Division Navigation Section chief. "We had to develop a management plan to make it compatible for both bird nesting and our construction."

With WES assistance, the district also developed a marsh establishment plan that included state-of-the-art techniques. "We developed techniques that are now used nationwide," Bradley said. These included floating tire breakwaters to protect from wave action so root systems could get established. The marsh was needed to help stabilize the island and as an environmentally beneficial feature of the island.

"The thing was touted as an environmental disaster by environmentalists and it turned out to be an environmental boon," Bradley said. "It's really a success."

The Alabama State Docks is responsible for the island now, but the Corps has the mission to maintain the ship channel and dispose of dredged material there.

"Our mission is management of dredged material on the island and compliance with the bird management plan," Rees said. "We can't negatively impact the birds in any way."

The Corps manages disposal to protect nesting birds. Five pipeline corridors on the island's southern end are used to deposit dredged material during nesting season. Outside that, any area on the island can be accessed.

Dredged material is poured into the diked area and settles sloping toward the weir box in the north corner. While the material settles, the weir box allows clean water to drain into the bay.

The island is remote, which minimizes visits by people and predators. "The island is successful because a lot of people can't get to it easily," Rees said. "The bird population has greatly benefited from this situation."

The island has become a haven for more than 22 species of birds, including gulls, terns, herons, egrets, and black skimmers. "This island is the only breeding ground for the brown pelican in Alabama," said Paul Warren, assistant chief of the Physical Support Branch. "In fact, it had a lot to do with taking the brown pelican off the endangered species list."

State officials have helped protect and monitor the island's nesting birds since 1985. Since then, more than 4,600 pelicans have fledged from the island.

"It shows that the environmental and industrial communities can work together and have development as well as protect the environment," Rees said.

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