Portal Park

Portal Park

Nicki Bloom + Allison Ong

This design acknowledges the site’s thick history—as a Duwamish village called Little Prairies, a gathering place for several tribes after eviction from other parts of Seattle, a burial ground, and a viaduct—and restores historic function rather than historic form. Water management infrastructure is layered with gathering circles, viewing decks, long views of Mt. Rainier and the Puget Sound, lush planted hillsides, and much-needed open space to immerse visitors in place. A hardscaped plaza allows for formal educational and social programming while the majority of Belltown’s largest future open space is left loose, dedicated to immersive experiences of plants, views, people, and water.

The main program areas of the site include a constructed wetland fed by stormwater collected in the Battery Street tunnel, a bridge from Post Alley into the site, a salal prairie area for intimate bench nooks and plant gathering, a central council ring with a view of Mt. Rainier, a south-facing lawn, and a flexible outdoor plaza adjacent to a glass program house for indoor rainy weather programming.

A series of terraced biofiltration cells treat the lightly filtered stormwater from the tunnel as it descends toward the Puget Sound. As the water is cleaned, it is piped over to a cistern beneath the hill council ring and stored to be used for plant irrigation on site or potentially linked to the greywater system of the adjacent condominium building.
Excess water is expressed in a final round stepwell shape that people can see before it drains back into the sewer, having been slowed and cleaned en route.

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