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Planning the Canal

Before canal construction, the Shilshole Bay inlet from Puget Sound was not connected to Lake Washington, and Lake Union, fed by natural springs, drained west into the lower, shallow saltwater of Salmon Bay. The region's shorelands were home and food source to the native Duwamish people.


Above: Plat map establishing Salmon Bay Road, 1880. The road is indicated by the red line connecting Union Lake (now Lake Union) to Puget Sound. Salmon Bay is located where the word “Shilshole” begins on this map. Road Book Volume 4, Series 320, King County Commissioners’ Road Books, King County Archives.

The idea of a canal joining the lakes and the Sound emerged among non-native settlers soon after the establishment of the Washington Territory in 1853. The United States government also began contemplating a canal in the 1860s, evaluating the possibility of Lake Washington as a site for a naval base and shipyard.

Seattle business and civic leaders promoted the idea of a waterway that would allow goods such as timber and coal to be easily transported west to connect with mills and shipping. Boosters also saw potential for industrial development along the waterway and increased property values.

First Cuts - 1881-1907

In 1881, mill-owner David T. Denny and other Seattle investors established the Washington Improvement Company, which in 1884-85 employed Chinese laborers to construct a 16-foot channel with two locks to move vessels between Lake Union and Lake Washington. The company also built log canals parallel to the channel and between Lake Union and Salmon Bay.

A ship canal: approved and then rejected

In 1891, the United States Army Corps of Engineers studied several possible routes across Seattle and King County for a ship-worthy canal connecting Lake Washington to Puget Sound. The north canal option, through Salmon Bay, was recommended, to continue to the Sound either south to Smith Cove and Elliott Bay, or west to Shilshole Bay. But federal support for a canal was withdrawn the following year.


Anderson Map Company's 1909 Official Map of Greater Seattle. The ship canal (labeled the "Government Canal") by this time was partially dredged, but Salmon Bay, Lake Washington and Lake Union were only connected by smaller canals and remained at different elevations. Semple's East and West Duwamish Waterways can be seen at the south end of Elliott Bay. Map ID 1282, Seattle Municipal Archives.

A south canal?

Meanwhile, Eugene Semple, former governor of the Washington Territory, proposed to build a canal that would cut through Seattle's southern Rainier Valley and Beacon Hill neighborhoods and connect to excavated waterways at the mouth of the Duwamish River. Earth from the dig would be used to fill tidelands south of downtown.

Shilshole Bay route confirmed

In 1894, the U.S. government conducted a new survey for the north canal. They selected the route west from Salmon Bay through Shilshole Bay for the last stretch, after the Great Northern Railway objected to the route south to Smith Cove, which was the location of its railroad terminal.

With the canal route decided, King County began obtaining the right-of-way to be deeded to the United States government. Payments to property owners included damages for the planned rising of the water level along the canal. The Corps began excavating channels between Salmon Bay to the Sound and to Lake Union in 1901, as Semple began work on his southern canal.

Competing canals

In 1902, when north canal advocates sought additional funding from the United States government, Semple made his own request to fund his south canal. In response to the competing requests, a federal board of engineers evaluated the merits of both the north and south options. The board found that the south canal was impractical. But it also determined that the north canal’s promised benefits did not justify federal investment, and again federal support was withdrawn. Letter to County Commissioners regarding bonding James Moore

Above: letter from King County Prosecuting Attorney Kenneth Mackintosh advising the King County Commissioners on a citizen-approved bond to serve as insurance against damages and to pay James Mooore for the construction of the Lake Washington canal, 1906. King County Archives.

The City of Seattle forced Semple to halt the destructive hydraulic process he was using to cut through Beacon Hill in 1904. Semple continued development of the Duwamish waterways and filling tidelands, but the south canal was abandoned.

A new effort

Frustrated Seattle residents looked to a proposal by local developer James Moore to build a canal with a wooden lock at the head of Salmon Bay. In response to a citizen petition, in 1906 King County held a bond election to fund Moore’s project. It passed 5 to 1, and the United States granted Moore the right to undertake the work.

Hiram M. Chittenden

Major Hiram M. Chittenden became the Army Corps of Engineers’ District Engineer in Seattle in 1906. He convinced Moore’s supporters that the wooden lock would be inadequate, and Moore was directed by Congress to work only on dredging west from Salmon Bay. In 1907, after the state Supreme Court found the bond measure funding Moore’s project to be unconstitutional, Moore transferred his right to construct the canal to the newly formed Lake Washington Ship Canal Association.

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