Spring 2026
What's Happening Now?
The consultant engineering and design team, Jacobs Engineering, has finalized the 60% Construction Drawings and is working toward 90% documentation and permitting approval. Geotechnical investigations, arborist tree assessments, wetlands reconnaissance, and existing drainage structure video inspections have been completed to help inform the design. The project team continues to coordinate with Seattle Public Utilities (SPU), the Seattle Department of Transportation (SDOT), King County, Washington State Department of Ecology (Ecology), Arboretum partners, and others to help ensure the project’s success.
Project Description
Arboretum Creek within the Washington Park Arboretum faces a lack of dry weather (summertime) flow that is important for stream health, specifically water quality and for aquatic and avian habitat. Friends of Arboretum Creek (FOAC) has identified several nearby springs, Alley and Alder Springs, as potential sources to supplement summer base flows. These springs were historically part of the Arboretum Creek watershed prior to the construction of Lake Washington Boulevard circa 1905.
FOAC and Seattle Parks and Recreation (SPR) are working together to reconnect Alley and Alder Springs to restore the natural hydrology of the Arboretum Creek watershed. In addition to the benefits to stream health and habitat, the project will be designed to capture and treat stormwater runoff that currently causes localized flooding both in the residential neighborhoods and proximate to the Japanese Garden entrance along Lake Washington Boulevard.
Community Participation
Project Document
The project’s 30% project design drawings and a 60% design sketch can be viewed on the Friends of Aboretum Creek website
