Duwamish River

The Duwamish River runs north for about 11 miles (18 km) through the cities of Tukwila and Seattle in the US state of Washington before emptying into Elliott Bay on the Puget Sound. Historically, the river formed from the confluence of the White and Black rivers in what is now Renton, but human modifications in the early 20th century led it to become the lower portion of the Green River. During the Last Glacial Period, the Duwamish Valley was carved out by glacial meltwater from the advancing Cordilleran ice sheet, forming what was initially an inlet of Puget Sound, which was later filled by the eruption of Mount Rainier and the Osceola Mudflow around 5,600 years ago. Lushootseed-speaking Coast Salish peoples, including the eponymous Duwamish people, occupied the region for thousands of years prior to colonization. Euro-American settlement began in the 1850s, and many Duwamish were forced to leave the region after the 1855 Treaty of Point Elliott. Industrial development in the growing city of Seattle led to various efforts to reclaim land in the river's broad mudflats, culminating in the construction of Harbor Island and the channelization of the river into the Duwamish Waterway during the early 20th century. During this period, the White River was diverted away from the Duwamish, and the construction of the Lake Washington Ship Canal cut off the river from the Lake Washington watershed, greatly lessening its flow. The area around the Duwamish Waterway was extensively industrialized during the 20th century, supporting industries such as ship and airplane manufacture. Extensive shoreline modifications such as bulkheads, piers, wharves and sheet pile retaining walls were installed across the river, resulting in limited natural habitat. The Duwamish has been subject to restoration and cleanup efforts since the late 20th century, and was declared a federal Superfund site...