SAN FRANCISCO, CA — The California Academy of Sciences is poised to publicly unveil its award-winning new facility next month — a move that its leaders hope will literally and figuratively open the doors to new green quarters.

Occupying all but an acre of the academy's former footprint in San Francisco's Golden Gate Park, the $488 million project to reconstruct and reinvent the facility has produced a showcase of green architecture and exhibits that strive to reflect a "sustainability message"  in every facet, the academy's leadership team says.

The 410,000-square-foot structure designed by Pritzker Prize-winning architect Renzo Piano features museum, research and work space on three levels that include multilevel exhibits within that framework. The building is crowned by a 2.5-acre living roof. The rolling landscape of colorful native plants and wildflowers sits 35 feet above the ground and mirrors the nearby slopes of San Francisco's Twin Peaks and Mount Davidson.

Beneath the roof, a single building houses the academy components that once stretched across 12 structures. The key elements are the new iterations of the Morrison Planetarium, Kimball Natural History Museum and Steinhart Aquarium. Also included are eight scientific research departments, an indoor rainforest and a coral reef exhibit with some 4,000 fish in a 212,000-gallon tank that the academy says is the deepest living display of its kind.

"Our goal is to create a new facility that will not only hold powerful exhibits but serve as one itself, inspiring visitors to conserve natural resources and help sustain the diversity of life on Earth," Academy Executive Director Gregory Farrington said in a statement earlier this year as the construction project neared completion.

While the new facility will provide learning journeys for its visitors, it is already providing paths for study and further research for the staff, said Frank Almeda, who as the academy's senior curator of botany has a leading role the living roof project.

"The sustainability message really can reverberate in many different ways," Almeda said, noting that the interactions of birds, other wildlife and the surrounding environment with the green roof make the acreage a living lab.   

"This roof is unique among living roofs," Almeda said during a preview of the facility this week.

The living roof, designed by Piano and created in consultation with Rana Creek Living Architecture, is planted with nine native California species. Once established, the plants are not expected to require artificial irrigation.

The roof is also expected to absorb as much as 3.6 million gallons of rainwater a year, keep interior temperatures about 10 degrees cooler than a standard roof, help maintain a surface temperature about 40 degrees cooler than a traditional roof and reduce low-frequency noise by 40 decibels. The living roof, crafted at a cost of $17 per square foot, will be home to about 1.7 million plants and have a total plant and soil weight of 2.6 million pounds.

The academy's living roof is significant not only in its relationship to its surrounding environment, but also in terms of the development and use of green roofs in the United States, said Mark T. Simmons, a restoration ecologist at the Lady Bird Johnson Wildflower Center at the University of Texas in Austin and the lead investigator for a living roofs study that was published earlier this summer.

"It's pretty big," said Simmons. "The ecosystem service of living roofs and their advantages in cities can be significant."

The advantages change in magnitude, he said, based on the location of the roof within an urban area and the material used to create the green space.  

In describing the attributes of the academy's living roof, Almeda said special care had been taken since the project began almost four years ago to review and select plants, focusing on native species. Almeda also tipped his hat to the research by Simmons and his colleagues, whose study demonstrated, among other things, that use of native plants improves the ability of green roofs to withstand their environment and absorb stormwater, decreasing the runoff to the ecosystem.

Although the living roofs trace their roots to ancient times, their general use in the contemporary world is relatively new. In Europe, particularly in Germany, the modern green roof industry took hold in the 1960s, Almeda said.  Like Simmons, Almeda noted, "the industry in the United States is in its infancy."

In addition to the living elements, the academy's roof includes several other energy efficient features. The mounds on the roof are dotted with circular skylights fitted with heat sensors, and the skylights open to further cool the building when a certain temperature is reached. The planted area is surrounded by 60,000 photovoltaic cells that are to supply 5 to 10 percent of the academy's energy needs and prevent the release of more than 405,000 pounds of greenhouse gas emissions annually.

The building as a whole incorporates a number of other green elements including environmentally sensitive building materials and eco-friendly use of glass and wood; heat recovery, humidity and other energy management systems; widespread use of natural light and automated lighting systems and windows; and water conservation measures for humans and the animal life in the structure.  For its efforts, the academy seeks a platinum designation — the highest possible — under the U.S. Green Building Council's Leadership in Energy and Environmental Design rating system.

The academy and its new home also pay homage to the institution's 155-year legacy and aspects that have struck chords with generations of visitors. Returning elements include two limestone walls of the 1934 African Hall, the Foucault Pendulum with its undulating 235-pound brass weight, the soaring entrance columns of the Steinhart Aquarium and the whimsical sea horse railing and ceramic tiles lining the alligator habitat known as the Swamp.

Construction of the new facility began in September 2005, the same month the academy project was named the North American winner of the silver Holcim Award for Sustainable Construction. The project also has received the U.S. Environmental Protection Agency's regional 2006 Environmental Award.

The new California Academy of Sciences opens to the public on September 27, 2008.