Location: Seattle, WA
The Golden Gardens Drainage and Stairway Renovation project replaced popular yet unsafe and failing stairs with a new ADA-complaint 6 ft. wide concrete stairway in Golden Gardens Park, located along the Puget Sound in Ballard. Developed in the early 20th century, the park has since become a Seattle landmark, known for its historic stairway connecting the beach to an off-leash dog park and neighborhoods.
The previous drainage system under the steep, non-ADA compliant stairway consisted of a stacked-concrete slab channel, which turned into an open concrete channel adjacent to the lower stairs. This drainage system supported storm flows and a steady base flow year around and was leaking due to gaps between the stacked-concrete slabs, allowing groundwater to wash the fine sand out from beneath the existing steps, causing the steps to unevenly settle and crack. This failure of the stairs and drainage infrastructure created serious safety concerns for park visitors who used the stairs.
The improved closed drainage and underdrain system captures and redirects surface and subsurface flows to reduce subgrade settling and re-occurrence of erosion problems which had caused the original failure. The cracks were sealed in the lower open channel, popular with visiting school groups and children.
Stairway prior to improvements: