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This Century's Top Ten Construction Projects

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This Century's Top Ten Construction Projects
December 9, 1999

Ship canal locks in top spot

Dates: 1911 - 1916
Costs: $2.3 million
Contractor: U.S. Army Corps of Engineers
Amazing Fact: Hiram Chittenden's decision to use concrete, not wood, proved wise: 80 years later the locks still function without any major repair.

Locks under construction
All 200,000 cubic yards of concrete poured at the locks were placed by hand at a cost of $4 per yard.
Like the Indians before them, the first European settlers on Puget Sound found a region rich in natural resources. But in Seattle, they had a problem. If they were to exploit the forests and coal fields east of Lake Sammamish, how would they move the coal and logs to Seattle, where the sawmills and industry were?

The huge old-growth logs were too big and heavy to move overland, and though a railroad eventually was built, the preferred method was to float them by water. Coal, meanwhile, was easily moved by rail except that it had to be transferred 11 times enroute.

So, from the city's earliest era, it was thought that a ship canal from Lake Washington to Puget Sound was essential for the efficient movement of these materials.

After a couple of false starts by private boosters, and the beginnings of a waterway undertaken by the business-led Lake Washington Improvement Co., the U.S. Army Corps of Engineers in 1911 finally began construction of the Lake Washington Ship Canal.

Using a congressional appropriation of $2.3 million, the Corps on Sept. 1 began to create the system of channels and locks conceived by engineer Hiram Chittenden. He proposed double locks at Salmon Bay -- a large one, 825 feet long and 80 feet wide, and a smaller one, 150 feet by 30 feet -- to conserve water at times when the locks were used by smaller vessels.

Ballard Locks
The locks opened to vessel traffic on July 12,1916. Today, they are used primarily by leisure craft, although it is still critical to commercial users on Salmon Bay, Lake Union and Lake Washington. The American Society of Civil Engineers designated the Ballard Locks as a National Historic Civil Engineering Landmark on its 80th birthday, July 4, 1997.
It was also Chittenden who insisted on concrete for the locks, which originally had been envisioned as a wooden structure. The project required an on-site railroad, gantry crane and concrete mixing plant.

According to historical accounts, all 200,000 cubic yards of concrete poured at the locks were placed by hand at a cost of $4 per yard. A crew of 300 worked on the locks site, and were paid $2 per day in gold and silver.

The locks opened to vessel traffic four years later, on July 12, 1916. Immediately following their completion, Lake Washington was lowered nine feet to the level of Lake Union, which eliminated the need for a second set of locks between them.

Formal dedication of the new waterway came on July 4, 1917, some 63 years after it was first proposed by pioneer Thomas Mercer. Today it is used primarily by leisure craft, although it is still important to commercial users on Salmon Bay, Lake Union and Lake Washington.

And, naturally, the locks are named after Hiram Chittenden.

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