Eagle Canyon

New Exhibit at Oregon Zoo Incorporates Artistic Flair

The new Eagle Canyon exhibit combines old fashioned construction methods with detailed artistry.

by Sheila Bacon

If it weren't for the rebar and heavy equipment, the Oregon Zoo's Eagle Canyon exhibit currently under construction might be mistaken for an artists' oasis instead of a jobsite.

The 16,195-sq.-ft. exhibit at the Portland, Ore., zoo features a number of carefully crafted fallen logs, painstakingly painted faux boulders and artificial salmon that look striking real.

The sculptures are part of an exhibit that recreates the habitat of bald eagles and endangered salmon in a wooded ravine. While the backbones of the exhibit involve its share of construction-related activity, it's the artistic detail that sets this project apart from the typical jobsite.

Artificial trees are crafted out of steel pipe covered with fiberglass and epoxy, while latex stamps are created to apply dozens of different bark patterns and knotholes. Faux boulders are created similarly, then painted to resemble the real thing.

A cast of a taxidermist's model of a salmon was used to create a polyurethane likeness that will be mounted to an armature in an interactive man-made stream - an invitation for visitors to experience salmon habitat hands-on.

Recreating Nature

The Oregon Zoo's exhibits staff is responsible for the design and construction of much of the zoo's exhibits, including Eagle Canyon. The staff serves as the general contractor, subbing out much of the trades work. Photo by Michael Durham/Oregon Zoo

Eagle Canyon is part of the zoo's $37 million Great Northwest exhibit, which includes Cascade Crest (opened in 1998) and Steller Cove (opened in 2000). This $2.4 million exhibit will take visitors along a wooded path and over a series of small footbridges spanning waterfalls and tributaries.

A covered bridge provides a view of Tanner Creek and leads visitors to an enclosure featuring bald eagles. A path continues past the salmon sculptures and into a lava tube tunnel, where a 3-in.-thick acrylic window offers a view into a pool of salmon. This enclosed structure connects to the zoo's existing Cascade Building.

Crews are using a number of construction materials new to the zoo, said Brent Shelby, the zoo's exhibits designer. Pervious concrete is being poured for the exhibit's walkways. The extremely porous concrete, used extensively in areas of the country where flash floods are common, will allow rainwater to flow through the concrete and be absorbed into the ground below.

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"It's a good way to mitigate the rain we get," and it eliminates the need to install an extensive and potentially expensive drainage system beneath the Cascade Building, Shelby added.

The zoo is also using an additive - Glacier Northwest's Everdure Caltite - to the concrete in the salmon-viewing tunnel, which makes the concrete waterproof without the use of a water-blocking membrane. The absence of a membrane allows designers to retain the color and texture of the concrete, which is important so the exhibit will look as natural as possible, Shelby said.

The additive has also been used at the new Exhibition Hall in Seattle and the basement of the new Seattle Waterfront Marriott Hotel.

Shelby said heavy snow in the Pacific Northwest in early January pushed the schedule back three weeks and even encased a bundle of rebar to be used on the job in ice, but once things thawed out, work resumed. The jobsite, which is located in a deep ravine, has been tricky to access, but a small road was built specifically for heavy equipment, and zoo crews have worked carefully with contractors to ensure a smooth working environment.

Keeping it Close to Home

This cross-section of the Oregon Zoo's Eagle Canyon exhibit shows the salmon viewing area at left and the eagle viewing area at right. Image courtesy of the Oregon Zoo

For the past five years, the zoo has served as its own project manager and general contractor on the major construction projects on its campus. While most structural work such as framing, concrete, electrical and mechanical is subbed out, the design and construction of the exhibit are performed by the in-house exhibits staff of three full-time employees. Their work includes the artificial streams, rocks and trees; landscaping; and informational materials.

By keeping many aspects of design and construction so close to home, the exhibits can be built more efficiently, Shelby said. Time and money aren't spent seeking out contractors qualified to work in a specialized environment, and dialog between the exhibits staff and the rest of the zoo employees is unhampered by contracts and a chain of command.

"We get feedback from the horticulture crew, zookeepers and maintenance staff," Shelby added. "We collaborate instead of dealing with mounds of paperwork, weeks of delays and more money for changes in design."

In fact, input from the zoo's maintenance staff helped zoo designers and builders tweak a drain in the Eagle Canyon's salmon pool. A maintenance worker's sketch outlined a reconfigured drain that would alleviate the problem of leaves clogging up the intake. A simple conversation instead of costly and time consuming change orders solved the problem.

"(In-house,) we can handle things more economically and effectively," Shelby said.

Eagle Canyon will open to visitors on Memorial Day. A smaller zoo exhibit - Trillium Creek Family Farm - will open in the summer and feature a barn, farmhouse and unique species of farm animals.

Condor Creek Conservation Facility