The Aurora Bridge Swales, located in Seattle’s Lake Union stormwater basin, are along a salmon migration route where toxic runoff is detrimental to the health of spawning salmon and Orca populations. Image Credit: Weber Thompson

The three phases (Data 1, Watershed, and Phase 3) are found adjacent to Troll Ave., north and south of 34th st., under the Aurora Bridge in the Fremont neighborhood. Image Credit: Weber Thompson

Rendered site plan of all phases. 0.5 acre (21,000sf frontage improvements), 2,400 sf of green infrastructure (10% of site), they clean approximately ¾ acre of bridge surface overhead (35,500sf). Image Credit: Weber Thompson

The bridge structure above, with arching concrete and crisscrossed steel girders, takes on the feeling of a forest canopy as the bridge pillars land within the swales, much like the scale of old-growth cedars once did on this site. Image Credit: Built Work Photography

Phase One uses an adaptation of conventional settling pools that clean the stormwater. The design innovates by creating consecutive swales that step and overflow Corten steel weirs with every two feet of grade change. Image Credit: Built Work Photography

Native shrubs and rushes, along with Vine Maples serve as understory plantings to provide a robust forest floor below the contrived overhead canopy that the bridge structure and columns simulate. Image Credit: Built Work Photography

The Aurora Bridge Swales are a welcoming place to walk, sit, eat and enjoy people-watching. Its plazas and stairs are flanked by terraces of native plants. Image Credit: Built Work Photography

Bronze spillways create a table for bees to drink from during summer months, a benefit for the four hives located on the adjacent commercial building. Image Credit: Built Work Photography

Phase Two includes an area to promote evaporation, where staggered concrete walls reference the geometry of the log booms seen here a century ago, slowing building roof runoff before reaching the swale. Image Credit: Built Work Photography

Phase Three, sited closer to Lake Union, and situated on the very busy Burke-Gilman Trail, has transformed a little-used patch of land into a destination with public art and resting stops to take in the views. Image Credit: Built Work Photography

South of the swales a bridge archway welcomes approximately 3 million bicyclists and pedestrians annually along the Burke-Gilman Trail. A vital opportunity to share the value of green infrastructure in urban areas. The project provides places of respite, to linger, to watch the foliage change through the year. Image Credit: Built Work Photography

Phase Three increased the volume of filtered bridge water to two million gallons, effectively treating the north half of the above bridge deck. Image Credit: Built Work Photography

The use of steel is echoed in all phases, with custom details expressing the water story throughout. Image Credit: Built Work Photography

Laser cutouts of the silhouettes of the five salmon species cue pedestrians to the greater story of how, through smart development and design, we can help restore the aquatic environment. Image Credit: Built Work Photography

Phase three of the swales renovated a formerly scraggly, tract of land covered with grass. Today, it is a beautiful, thoughtfully landscaped oasis, that provides curated places to stop along the trail. Image Credit: Built Work Photography

Testing of the water entering and leaving the swales confirmed measurable filtration of a large range of contaminants. The three phases of the Aurora Bridge Bioswales collectively clean almost 2 million gallons of runoff annually. Image Credit: Built Work Photography