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Scarce map illustrating the earliest US Government Surveys for what would become the Lake Washington Ship Canal.

The map accompanied Thomas William Symons report on a proposed canal to connect Lake Washington and Lake Union with Puget Sound.

Relief and bathymetry shown by contours. Includes:

  • Inset of Seattle metropolitan area
  • "Profile of canal from Smith's Cove to Salmon Bay"
  • "Profile of canal between Shilshole Bay and Lake Washington." "Feb 1891." 

The Lake Washington Ship Canal

Thomas Mercer first proposed a canal from Lake Washington at a July 4 picnic in 1854. His bold vision of the future took place when Seattle was only three years old, so young that the lake where he stood had yet to be formally named by the new pioneers. Mercer suggested calling it Lake Union, because of the possibility “of this little body of water sometime providing a connecting link uniting the larger lake and Puget Sound.” He went on to recommend that the “larger lake” be called Lake Washington, replacing other monikers such as Lake Geneva and Duwamish Lake.

Several years would pass before work began on Mercer’s vision. Harvey L. Pike was the first to attack the problem, in the 1860s. His tools of choice: pick, shovel, and wheel barrow. His short-lived efforts created a ditch at roughly the location of the SR-520.

In 1871, the United States government began its first investigations into the possibility of a canal, which would enable naval vessels to dock in Lake Washington’s less damaging fresh water, instead of in the salt water of Puget Sound. Brig. Gen. Barton Alexander recommended either the “Mercer farm” route, which started at the south end of Lake Union and connected with Elliott Bay near Battery Street, or a canal following the Seattle Coal Company’s Tramway, which ran roughly from Lake Union up Westlake Avenue to Pike Street and then down to Elliott Bay. These routes would have required cutting through a high point of 119 feet, as well as the construction of two or three locks to enable boats to pass from Lake Union to Elliott Bay.

Despite the government’s inclination toward a route connecting Lake Union and Elliott Bay, local promoters thought that the best canal route ran from Lake Washington via Portage Bay to Lake Union and through Salmon Bay to Shilshole Bay. Although they may have incorporated the Navy’s desires in their plans, the locals primary concerns, however, were coal and real estate. Seattle’s main export in the late 1870s and early 1880s was coal quarried east of the city in Renton and Newcastle. A canal connecting Lake Washington to Lake Union to Puget Sound would allow coal producers to transport their black gold without having to rely on the railroads.

Recognition of the importance of controlling the water route led such stalwarts as Judge Thomas Burke and David Denny to form the Lake Washington Improvement Company (LWIC) in 1883. Denny and Burke, as well as other LWIC board members, also happened to own land on Lake Union. With $50,000 in capitalization, the LWIC proposed to cut two canals to connect the lakes. They were completed in 1885 by Chinese contractor Wa Chong.

In spite of this initial success, canal backers realized that they would need significant outside money to build a canal large enough to allow naval vessels and coal carrying barges to travel between Puget Sound and Lake Washington. The best source was the U.S. government and in 1889, when Washington territory became a state, one of the first acts of the state legislative body was to petition Congress for a canal feasibility study.

Congress complied and in 1892 published a report analyzing five potential routes for a “ship canal to connect Lake Union, Samamish (sic), and Washington with Puget Sound.” The Duwamish/Black River route was rejected, as well as Gen. Alexander’s preferred Mercer farm and Tramway locations. The favored routes were Shilshole to Salmon to Union to Washington and Smith’s Cove (in Elliott Bay) across what is now known as Interbay to Salmon to the lakes. The report favored the Smith’s Cove route because of its entrance in Seattle’s harbor and its lower exposure to bombardment by an enemy fleet.

While Congress and local powerbrokers like Burke, Denny, and recently-elected Governor John McGraw were supporting a canal north of downtown, former Territorial Governor Eugene Semple arrived in Seattle. Semple, who became the leading promoter of a south canal connecting Elliott Bay to Lake Washington, had moved to the Northwest in 1863.

After a career as a newspaper editor, lawyer, and sawmill owner, he was appointed the Territorial Governor of Washington in 1887. Semple moved to Seattle in 1889 following his single, two-year term as governor. Despite having lost the state’s first popular election for governor, Semple’s rival Elisha Ferry appointed him to be a member of the State Harbor Line Commission in 1890.

In his Commission capacity, Semple became enamored with the money making potential of filling in the Duwamish tidal flats. Along with dredging land at the mouth of the Duwamish, additional fill material would come from cutting a canal through Beacon Hill connecting with Lake Washington at roughly modern day Mt. Baker Park.

After filing plans for his canal, Semple acquired backing from the Mississippi Valley Trust Company, which had connections with his wealthy nephews. With this support and public backing following the 4,000-strong, Seattle armory meeting, Semple started to dig. By late 1896, his firm, the Seattle and Lake Washington Waterways Company (SLWWC), had dredged 2,000 feet up the Duwamish from Elliott Bay, creating what is known as the East Waterway. It also filled 70 acres of tideland.

Lake Union shoreline landowners, such as Burke, Denny, and Dennis Gilman (who helped start the railroad now memorialized by the Burke-Gilman Trail), teamed up with the Chamber of Commerce to protest Semple’s actions. To combat Semple, they sent Erastus Brainerd (Seattle’s leading Klondike gold rush promoter) to Washington, D.C. to lobby Congress for the north route.

Work, meanwhile, continued on the south canal. Semple did not meet his goal of completing the canal by 1900, but gravity fed water had started to sluice a gap into Beacon Hill in 1901. Water cannons, using roughly 14 million gallons of surplus water a day obtained from the new Cedar River water system, cut into the west side of the hill (14th and Hanford) and washed material into the tidal flats. By 1904, more than 300 acres had been reclaimed. In addition, the East and West waterways had been dredged, which created Harbor Island.

Although the northern canal promoters lost their battle in Congress, they were finding Seattle more hospitable to their allegations against Semple. After public sentiment turned against him and his project, Semple resigned from the Seattle and Lake Washington Waterway Company and within a few months work stopped on the south canal. Semple’s foes appeared to have won their push for a northern ship canal, but not without a Congressional scare.

Up through 1903, Congress and the state had generally supported a north canal. Appropriations in 1894 and 1896 had authorized $175,000 for dredging of Shilshole. In 1900, King County secured the right of way for the present canal route from private landholders for $250,000 and deeded it to the United States. On January 6, 1903, though, a new government commission report stated: “The construction of a canal, with necessary locks and dams, connecting Puget Sound with Lakes Union and Washington…is feasible [but] not advisable at the present time.”

In stepped entrepreneur and engineer James Moore, who had developed Capitol Hill. In 1906, he offered to complete the canal, which he would turn over to the U.S. government in three years, if King County and Seattle ponied up $500,000. The canal would be 60 feet wide, 25 feet deep and have single wooden lock 600 feet long by 75 feet wide.

Moore’s single lock was unusual; most other plans had envisioned a lock between Salmon Bay and Lake Union and another connecting the two lakes. Two locks meant Lake Washington would not have to be lowered. Lowering the lake, however, would eliminate flooding of the Black River and reduce the acreage of swampy land south of the city and around the lake.

While Moore’s plan was circulating and gaining public support, a man arrived in Seattle who would quickly and permanently leave his mark on the canal. Hiram M. Chittenden had spent most of his career with the Corps of Engineers and had surveyed in Yellowstone and Yosemite, when he was assigned to Seattle in 1906. His biographer described Chittenden as “a dedicated, highly intelligent, inhumanely industrious man, [who] fixed immediately upon the Lake Washington canal as the most important project in his district.”

As district engineer for the Corps, Chittenden quickly realized that if he did not act, then Moore might build an inadequate canal; therefore, Chittenden worked to alter Moore’s plan. He suggested two smaller locks, side by side, one for large vessels and the other for Seattle’s mosquito fleet and smaller craft. He also favored masonry locks to be built at the Narrows, at the western end of Salmon Bay. These new requirements forced Moore out of the picture.

Chittenden eventually rallied the US Congress to obtain passage of the Rivers and Harbors Act of June 25, 1910, which authorized $2,275,000 for U.S. government construction of the locks. King County would be responsible for improving the waterways.

Lock construction began in September 1911. The first concrete was poured in February 1913 and the first boat passed through three years later, during a rare snowstorm. The gates closed on July 12, 1916 and thirteen days later Salmon Bay had risen to its present level of 21 feet above mean sea level. In late August, the dam separating Lake Washington and Lake Union was breached and water drained for four months, until the water levels equilibrated.

Seattle’s local papers heralded the grand opening of the Lake Washington Ship Canal on July 4, 1917. A carnival and fireworks attracted 50,000 celebrants. Unfortunately, Hiram Chittenden could not attend the ceremonies; bad health restricted him to a wheelchair and he died only three months later. Eugene Semple was not in attendance either. He had died in 1908 after failed attempts on further waterway-related projects on the Yukon River and in Astoria, Oregon. Work on his tideland filling project had continued, though, and by 1917 more than 2,400 acres had been reclaimed, which became home for Seattle’s industrial base, as well as the Port of Seattle.  

Condition Description
Minor toning along folds