Duwamish meanders: A river ran through it

For millennia, the Duwamish River sustained a diverse ecosystem of fertile floodplain forests, marshes and tideflats in what is now South Seattle. The geologic record shows that the Duwamish valley was created by glaciers, then repeatedly transformed by catastrophic volcanic mudflows, earthquakes and floods.

This 1922 photo shows the Duwamish River transforming into the Duwamish Waterway.
The Smith Tower is in the distant upper right and a young Harbor Island can be seen at the end of the channel.
File photo / The Seattle Times.

Arguably the greatest transformation the river experienced in recent history was wrought by human engineering. In the early 20th century, a series of major civil engineering projects diverted the comingled flows of three rivers out of the valley, lowered Lake Washington nine feet, shortened the river by four miles, dredged the river into a navigable waterway, filled in the old meanders, and built Harbor Island—the largest manmade island in the world at the time—by washing hillsides into the tide flats. This was largely undertaken for flood control efforts, navigation and commercial interests.

While the pace and scale of the industrialization of the Duwamish valley rivals that of any major city, it also came at a cost. To Coast Salish people, the expansive tidal mud flats and the wetlands adjoining the meandering river were a valuable resource. The channels, islands and shorelines were all populated with names that recorded sacred landscapes, uses, historical memories and meanings.

The engineered changes to Seattle’s shoreline disrupted ecosystems, eliminated traditional food sources (including a productive salmon fishery) and completely reconfigured Coast Salish people's relationship with this place. The land became Seattle’s industrial and commercial heartland and an engine of economic growth for the city. The factories built on top of the old meanders sustained a vibrant economy through two world wars, helping grow Seattle and the Pacific Northwest into what it is today.

The transformed valley continues to provide thousands of jobs. Major efforts are also underway to clean up the river to make the river safe for fish and people alike. The Duwamish Tribe, which plied these waters for millennia, once again have a longhouse along its banks.

Seattle's ghost shorelines

By Peter Lape, Amir Sheikh, and Don Fels

Someday soon, Seattle’s downtown waterfront will look very different than it does today. The City of Seattle is replacing our crumbling seawall, and perhaps Bertha will resume digging the tunnel to replace the rickety, looming and loud Alaska Way Viaduct, scheduled to be torn down in 2016.

These changes create the potential to reconnect to the Elliot Bay shoreline, a main reason the city was established here in the first place. Planning continues for a re-imagined waterfront, and architects, designers, planners and politicians are starting to share their ideas with Seattlites.

An architectural rendering shows what a Pioneer Square beach at the foot of Washington Street could look like.
Photo: Courtesy of James Corner Field Operations and City of Seattle, Adapted from The Seattle Times’ September 12, 2014 article titled “Seattle’s new waterfront: What it might look like and why.”