May 12, 2011

Landscape is locally rooted at foundation’s campus

Nichol

The landscape of the Bill & Melinda Gates Foundation campus is designed as a locally rooted environment for global work and dialogue.

The natural history of the site — as a large wet meadow and a dark-watered bog — are interpreted into an urban format in Gustafson Guthrie Nichol’s Local Ground landscape concept. The Local Ground is one facet of a larger, integrated design concept for the campus that resulted from an exceptionally close collaboration between NBBJ architects and GGN.

The Local Ground’s meadow plants, blueberries, boardwalks, dark water and textured paving are formatted into a series of flexible spaces that range from small meeting nooks to an open central square that appears to be suspended over a planted reflection pool.

The NBBJ/GGN design team felt that the unique work of the foundation would be best reflected in a campus that is both exceptionally grounded and open to the world: local roots and global vision.

GGN applied the role of “local roots” to the landscape, as Local Ground. The orthogonal geometry of the landscape is derived from the streets and buildings of the surrounding neighborhoods of Uptown and South Lake Union. This grounded geometry contrasts with the architecture’s sweeping “global vision” forms above.

NBBJ strengthened the urban definition of the landscape below by creating a podium layer in the buildings that is anchored in the landscape geometry and provides linear street edges along Fifth Avenue and Mercer Street.

To enhance the sense of groundedness in a campus “ground” that is almost entirely on structure, GGN created a sense of thick, dark earth underfoot with natural textures of salvaged and domestically sourced paving stones.

Custom formliners were used on the faces of dark concrete retaining walls along sidewalks and at water edges to abstractly imply cuts through a single, dense slab of earth.

To create the flexible mixing ground and gathering space of the Central Heart (the paved square in the center of the campus), a contrastingly thin, light-toned “blanket” of paving appears to float over the large reflection pool, as if it was added on top of the campus. This paving is patterned on a traditional textile strip-weave layout.

Soaking up rainwater

With green roofs, a million-gallon cistern, and rainwater-fed pools, the campus is designed to be a rainwater “sponge” — to honor the site’s natural history as a wet meadow and sedge bog and to minimize the amount of water that leaves the site in stormwater or sewer drains.

All rooftops and ground surfaces either absorb rainwater or capture it for re-use in the campus.

Campus buildings include over half an acre of green roofs that add to the benefits of the neighboring 1.4-acre green roof on the Seattle Center garage and Gates Foundation Visitor Center. These green roofs are designed for optimal water absorption, based on on-site mockups and data from the Seattle Green Roof Evaluation project. They are modeled to absorb 90 percent of the water that falls on them.

The building atrium and central courtyard’s stone paving appear to float over a large, rainwater-fed reflection pool. The pool, with a dark bottom of locally sourced, crushed basalt, is planted with native reeds and cattails to enhance its habitat value and to bring additional seasonal texture to the space.

Nearly all of the rainwater from non-pollutant-generating hard surfaces in the campus is collected into the cistern below the courtyard. The cistern is used to feed the reflection pool and serve as the source for campus irrigation and toilet-flushing. It is expected to conserve up to 2 million gallons of rainwater annually.

Edge forest

The campus’ planted areas are designed to eventually become almost entirely shaded by 43 native big leaf maples and 46 vine maples. This tree canopy will create an edge-forest surrounding the central courtyard and pool. Throughout the paved central courtyard and its entry walk, 36 drought-tolerant Raywood ash trees are planted to continue the tree canopy over the pavement with a contrasting, fine texture.

The site’s history as a lush meadow and deep bog influenced both the aesthetic and habitat type of the plantings. Large mats of blueberries can be found in the campus along the pool’s edge and public sidewalks on its perimeter.

Meadow-like drifts of thick grasses also characterize the sunnier areas of the site. In the shadier areas, thick drifts of native and non-native ferns, evergreen huckleberries and forest groundcovers are planted.

Edible plants include 1,715 blueberry plants, 250 native evergreen huckleberries, 117 native thimbleberries, and over 10,000 native camas bulbs.

Narrow-leafed cattail and native bulrush are planted in the water in large masses. The ratio between open and planted water was guided by bird-habitat criteria and was laid out to optimize views of both texture and of reflections of light, architecture and landscape.

Other Stories:

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• Campus was no ordinary construction project
  
• Engineering makes campus efficient and quiet
  
• More than meets the eye — below ground