Honor Award

California Academy of Sciences, San Francisco, CA

SWA Group, Sausalito, CA
client: California Academy of Sciences

Project Statement

The California Academy of Sciences, the "world's greenest museum", has earned LEED-Platinum certification through an ambitious vision for sustainable design. Landscape architecture played a major role in the realization of the design team's concept of "lifting up a piece of the park and putting a building under it", resulting in a sculptural 2.5-acre living roof that provides a unique interpretive experience and helps the project to achieve the highest level of sustainability.

Project Narrative

Project Scope
Located in the heart of San Francisco's Golden Gate Park, the new California Academy of Sciences replaces an outmoded, earthquake-damaged complex of buildings with a remarkable new facility that promotes the Academy goals to "explore, explain and protect the natural world." As demonstrated by early record crowds, the Academy is expected to attract millions of visitors from local, national, and international audiences, thereby reconfirming its historic importance as the oldest scientific institution in the West and setting a bold model for integration of sustainable technology, natural systems, design innovation, and public education.

Under the sculptural form of a 2.5-acre living roof, the 400,000-square foot museum houses the Steinhart Aquarium (the oldest such facility in the U.S.) and Morrison Planetarium as well as 18 million scientific specimens, over 10,000 live animals, space for education and research, and brand new exhibits such as a multi-level, glass-enclosed rainforest dome. As part of the design teams' commitment to sustainability, the new building reduces the former facility's physical footprint and surrounding pavement by approximately 1.5 acres creating space for new gardens that transition to adjacent mature parkland.

Since it opened in September 2008, the "greenest museum in the world" has become the only such facility to have earned LEED Platinum certification. The living roof has proved to be a highlight interpretive attraction that is introducing visitors to a living experiment in native plant restoration in the midst of a major city. In addition to a comprehensive set of technologies relating to building systems-from water recycling in the basement-level aquaria to synchronized ventilation openings in the building curtain walls and roof domes-the key features relating to landscape sustainability include the self-sustaining living roof that captures storm water, improves air quality by creating and scrubbing oxygen, mitigates microclimatic anomalies, and provides habitat values for migratory and local wildlife.

Design Program and Intent
The architect's initial design concept was to lift the natural landscape on top of the three-story building, creating a dramatic living roof. The roof's contours conform to the major exhibit components, research, collections and administration facilities below, and romantically echo the seven major hills of San Francisco. The two largest domes, with their strategically placed skylights, rise above the planetarium and rainforest exhibit. The landscape architect embraced this approach and collaborated closely with the design team to develop innovative design and implementation techniques required for such a unique project.

Because the domed portions of the living roof are as steep as 45 degrees in some places, the team developed full-scale models to test the multi-layered soil-drainage section and anchoring system that form the foundation to receive the plant materials. A grid of intercept channels created by linear rock-filled baskets (gabions) provides both surface flow drainage and midslope support for the 3" layer of planting media and the pre-planted, biodegradable coir (coconut husk) flats. Plants established in the biodegradable flats off-site, to the landscape architect's specifications, were transported to the site in refrigerated trucks on bakery racks; hoisted atop the roof and laid by hand onto the planting media sub layer within the gabion channel grid. The coir flats provided temporary support until the plants become well established on the rooftop. Over time, the flats will disintegrate and become part of the soil system.

The resulting vegetated roof includes nearly one-half million native California plants, all of which require limited or no supplemental irrigation. Of the 25 plant species recommended and tested on the roof of the older museum prior to demolition, the design team selected nine species for the full scale offsite mockup and contract growing:

• Perennials: Beach Strawberry (Fragaria chiloensis), Sea Thrift (Armeria maritima), Self Heal (Prunella vulgaris), and Pacific Stonecrop (Sedum spathifolium)
• Annuals: Coast California poppy (Eschscholzia californica), Miniature lupine Lupinus bicolor), Goldfields (Lasthenia californica), California Plantain (Plantago erecta), and Tidy tips (Layia platyglossa).

All plants were selected to be adaptable to the site and attract local butterflies, birds and insects, some of them endangered. In addition, the small stature of the selected plants helps to maintain a manicured appearance and express the rolling forms of the roof structure.

A 3,500-square foot observation deck and with interpretive signage provides access to the living roof as well as magnificent views to Golden Gate Park and the recently completed deYoung Art Museum. The deck accommodates 200 people and earned innovation LEED credit for using the roof as an exhibit to raise public awareness. Additional native annuals, perennials and grasses species were introduced around the observation deck to realize the tested and recommended palette while increasing the biodiversity of the exhibit.

Sustainability highlights of the six-inch deep living roof include a reduction of storm water runoff by at least 90 percent (up to 2 million gallons of water per year), reduced energy needs for air conditioning, and longer roof life potentially doubling the life of the roof membrane. Additionally, the extended roof plane forms a broad shade canopy over the building's perimeter circulation and outdoor gathering spaces and houses 62,000 photovoltaic cells to supply almost 213,000 kilowatt hours of clean energy per year (about five percent of the new academy's needs), thereby preventing the release of more than 450,000 lbs of greenhouse gas emissions.

In addition to the living roof, the landscape architect designed the new entries and the side gardens created by the new building's more compact footprint. These ground-level areas provide flexible outdoor rooms for cafes, receptions, exhibits, sculpture, and casual outdoor use. Weather-based, high-efficiency irrigation technology helps to reduce water usage in these areas. Planting design ensures that a minimum of 30% of non-roof impervious surfaces will be shaded.

Landscape Architect's Role
The landscape architect provided full landscape architectural services, from design through construction observation, for the living roof and all exterior site areas. They worked closely with the architects and engineering/sustainability consultants, and retained ecology/horticultural consultants to develop the native plant palette and delivery system for the living roof.