Bending the Grid

When developers approached SOM in 2005 to refine preliminary development plans for Treasure Island, the 400-acre former Navy base located two miles across the Bay from downtown San Francisco, SOM team leader Craig Hartman recognized the opportunity to demonstrate advanced principles of design sustainability within these plans. He and his team set out to create a new kind of pedestrian-friendly, transit-based neighborhood, which balanced dense, environmentally-aware, mixed-use development with an unprecedented percentage of open space.

The effort’s overarching theme was to mobilize sustainability practices in order to take advantage of the powerful appeal of island life, breathtaking downtown views, and a physical and emotional connection to San Francisco.

According to Hartman, the ultimate goal of the year-long effort “was to exceed the expectations of San Francisco Bay residents, who are among the most environmentally aware citizens in the world.”

Initial planning reached back to embrace Treasure Island’s storied history. In the mid-1930s, the island was dredged from San Francisco Bay; debris from the region’s cataclysmic 1906 earthquake was used as fill. Originally planned as the terminus for the legendary China Clipper seaplane service, the island was chosen in 1939 as the site for the Golden Gate International Exposition. The two-year World’s Fair celebrated the completion of the Golden Gate and Bay Bridges, as well as the culmination of thirty years of growth that had transformed the Bay Area from a quake-ravaged disaster area into a leading international center of industry, education, and technology. The International Exposition closed in 1941, and from the Pearl Harbor attack until the mid-‘90s, Treasure Island served as an important naval facility and Navy housing site.

With a large percentage of the island’s former military housing already in civilian use, planners faced the additional imperative of staging development so that current residents could seamlessly segue into the island’s renewed life. Another pressing issue was toxic contamination resulting from Treasure Island’s six-decade use as a naval base.

SOM planners began by addressing the toxicity problem, the inherent disadvantages of the island’s often-harsh west winds and persistent fog, and the dangerous ramps on and off the Bay Bridge that limited the island’s capacity to handle auto traffic.

Submitted in early 2006, the Treasure Island Plan proposes remaking the island into a fine-grained, walkable, transit-rich San Francisco neighborhood, as well as a recognized global model for sustainable urban life and design.

The plan envisions one commercial district and four residential neighborhoods, which would enable 10-to 12-thousand residents to live in the style and density of other well-known, mixed-use San Francisco districts, such as North Beach and The Marina. Housing is designed at a density as high as 100-units per acre—enough to support ferry service while allowing the majority of the island’s acreage to be dedicated to a variety of open spaces. The plan designates these to include wetlands capable of filtering the island’s gray water, bike and hiking paths, and a large demonstration site for organic gardening.

The plan’s transportation component focuses on pedestrian and bicycle uses connecting to frequent, fast ferry service into San Francisco. To encourage residents to use water transportation, SOM situated ferry slips and a central terminal 500 feet inside the island’s western edge. By insetting the terminal, Islanders living in the four mid- and low-rise residential neighborhoods would have a maximum eight-minute walk to the ferry, followed by a 13-minute boat ride downtown.

The ferry terminal itself was relocated from the eastern flank of Treasure Island to its western, San Francisco-facing side—an alteration critical to the practical and symbolic connection of the island to downtown San Francisco. Using new technology, a unique, aerodynamically-vented glass canopy was proposed to shelter the ferry terminal and plaza from the elements. The canopy would shield pedestrians from wind and rain. During hot days, the canopy would channel air through an urban space designed to become a popular landmark of a new, yet instantly identifiable, San Francisco neighborhood.

A similar correlation with San Francisco’s unique urban style would be achieved by mandating housing of various densities and types. These would range from two-story walkups to a 40-story high-rise apartment building, and also include different housing options—apartment rentals, condominiums, houses—and price points. Thirty percent of the new housing would be designated as below market rate.

The plan’s architecture drew inspiration from the 1939 Golden Gate Exposition’s renowned ‘streamline moderne’ design themes. The new ferry terminal was capped by a slender 40-story tower referencing the Exposition’s most famous landmark—the 400-foot “Tower of the Sun” campanile. A series of smaller but similarly narrow towers, designed with sustainability in mind, would provide a recognizable urban skyline without blocking precious sunlight from reaching streets, parks, and pedestrian and bike pathways.

Along with proposing other advanced elements to make the island as self-sustaining as possible in terms of water, waste, and sewage, the SOM team also recognized the importance of addressing the island’s constant winds and fog. SOM Consulting Partner John Kriken came up with a simple, novel scheme to largely mitigate the island’s difficult weather by proposing that the developmental grid be tilted to the north and west. The grid shift would work in concert with stands of trees, berms, and buildings located on neighborhood peripheries to effectively block out winds. According to Kriken, bending the grid would allow “maximum southern solar exposure throughout the neighborhoods, achieving personal comfort as well as maximizing light.” The latter was key to the installation of photovoltaic “light-shelf” arrays in new island structures that would work in conjunction with advanced wind turbines to provide renewable power for the new community.

Currently, the Treasure Island Plan is undergoing detailed feasibility studies designed to lead to the beginning of the public approvals process. A jurisdictional disagreement between San Francisco and the State of California has left the exact usage of open space still undecided.

Richard Rapaport