This aerial photograph shows construction at the Oregon Zoo's Forest Hall, part of the $57 million Elephant Lands habitat.
Elephant Lands, the Oregon Zoo's ambitious effort to build a modern home for the zoo's elephants, is also designed to make a positive impact on the environment.
Part of the efforts to make the new area sustainable includes making the most of the roof on the main building.
"We have a fairly large roof area and it's being used for a number of things," said Jim Mitchell, zoo bond construction manager for the Oregon Zoo.
The roof area covers Forest Hall, the indoor section of the elephant habitat as well as the Elephant Barn, which is a behind-the-scenes area where elephants can be checked out by veterinarians.
About 2,600 square feet of the 32,000-square-foot roof will be used for plants.
"The green area of the roof absorbs rainfall, reduces carbon emissions from the building and enhances wildlife," Mitchell said. "The roof is about 30 feet up, so it will be interesting to see what type of insects or birds we get. We have a time-lapse camera up there."
The green roof section is composed of two-foot-square plastic trays filled with soil and linked together by an irrigation system. Because of the weight of the soil on the roof, the planted section cannot be too large.
The building's roof has many other environmentally-friendly features, including a storm water storage and management system, light colored roof tiles to keep the building cooler, solar heated water and solar photovoltaic panels.
According to Mitchell, using the solar hot water panels to heat water before it goes through the hot water heater reduces energy costs significantly.
Emily Dawson, the architect of record for the zoo's elephant project, said designing a zoo is like nothing she's ever done before.
"It's been a really exciting and awesome project to work on," she said.
For Dawson, the most important aspect of the Elephant Lands roof is the storm water management.
"We get such a high volume of storm water. To capture it and not saturate the soils and not send it to the sewer is really important. We have a huge storm water detention basin under the elephant habitat," Dawson said. "The green roof is part of it. The soil on the roof is going to be saturated with storm water. A lot of strategies come together with the ultimate goal of reducing storm water runoff."
Dawson said that areas of the roof not being used for the garden or storm water storage are covered with thermal plastic roofing tiles in a light color.
"The tiles reduce the temperature of the roof which reduces the need for cooling," Dawson said.
The project is aiming to be certified LEED silver or higher. LEED, or Leadership in Energy and Design, is a green building certification program run by the U.S. Green Building Council.
The zoo's $57 million, six-acre Elephant Lands exhibit, including the 12,065-square-foot indoor habitat, is set to be fully open later this year.