Summer 2009
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Kitia Chambers

Workers place ground pumice – nesting material for Caspian terns – on a floating island during construction.

Combine the enthusiasm of an environmental engineer and the challenging setting of a remote lake, add a few tons of recycled plastic and migrating Caspian terns and – voilá! – a floating island to help save threatened and endangered salmon.

Kitia Chambers, an environmental engineer with Portland District's Design Branch, worked with Corps biologists and a recycling contractor to launch the first of several floating rookeries.

Chambers is part of a team creating nesting habitat for Caspian terns to draw them away from islands in the Columbia River estuary, where annually they feast on more than 4 million juvenile salmon listed as threatened under the Endangered Species Act.

The estuary islands formed over many years of material the Corps dredged from the Columbia River. The barren, sandy terrain, ideal for nesting, attracts terns to the estuary. The abundant supply of fish helped create the world's largest tern colony. The colony markedly reduces juvenile salmon populations making their way to the Pacific Ocean.

The Corps sought alternative nesting locations for the birds. One was Dutchy Lake, in the remote Summer Lake Wildlife Area in south-central Oregon. "Terns historically nested in the area and we were confident we could lure them back, if only an island could be built," explained Chambers.

In three other locations, the Corps constructed nesting islands during dry season, when the lakes were empty. However, water filled Dutchy lake year 'round.

"Building the same type of island was cost– prohibitive and environmentally disruptive. Then the concept of a barge-like island came to mind."

Chambers searched the Internet on the subject and found a company already building floating islands.

The company had already installed island habitat around the country. "Adding to the attraction was their use of recycled plastics and an environmentally sensitive design," Chambers said. "I just had to dig into this alternative."

A crew of 13 assembled modular, 22,000-square-foot main island on a ramp by the lake. Each module measured approximately 5 feet by 14 feet and used 200 pounds of polypropylene (from recycled carpet) and 125 pounds of polyester (from recycled drinking bottles). These materials would otherwise occupy acres of landfill space.

The five-week window between the waterfowl hunting and bird migration seasons meant crews had to move fast once all the pieces arrived at the site.

Crews slid assembled portions far enough into the lake to get them floating but with one side exposed to connect onto the next group of modules. Boats pulled the completed island to the middle of the water.

"Since the island was not built up from the lake bottom or require the construction of a causeway to bring the equipment to the site, we did not disrupt aquatic life in the lake and we can position the island anywhere we desire," explained Chambers. "I made a commitment that my career would help make the world a better place. I think this is a fantastic project where we made a difference."

This new habitat is within the bird's historic range and once colonies are settled, they will enjoy a more varied diet from more abundant and sustainable sources. Last summer, 428 pairs of nesting terns moved onto a new artificial island in nearby Crump Lake.

The Corps is now designing a 30,000-square-foot floating island for Sheepy Lake in Northern California, part of the plan to build eight more islands. The Corps might consider more floating islands based on environmental and cost considerations, Chambers said.

Biologists spotted Caspian terns near Dutchy Lake this spring.

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