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This Century's Top Ten Construction Projects


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

Denny Regrade: Hosing Seattle into shape

Dates:1903-1911; 1929
Amazing Fact: 16 million cubic yards of dirt was removed, mostly by large blasts of water.

During the 1880s Seattle was racing toward new status as a major metropolis. City leaders and engineers were determined to create a prosperous town even if that meant changing the landscape to do it.

Perhaps the city's most famous physical transformation is the Denny Regrade.

Regrade remnant
With its foundation hosed out from under it, a lone house is sandwiched between the remains of Denny Hill.
Today, the only reminders of Denny Hill are old newspaper clippings showing twin mounds of earth which once stymied development north of the central business district.

In 1881, city engineer R.H. Thomson began crafting a new landscape for the area. But it was not until 1898, after building new sewer and water systems for the city, that he was able to turn his attention toward leveling streets, beginning with Denny Hill at First Avenue.

To garner support from property owners, Thomson hired an assistant to walk door-to-door to explain the project, and its benefits, chiefly that the value of leveled property would increase tenfold.

He was right. As Denny Hill melted away, land values soared along Second Avenue. Property owners relished the idea of regrading, and asked for more despite having to foot the bill themselves.

Beginning in 1903 and again in 1910, Denny Hill, which once covered 62 city blocks, was whittled away by continuous blasts of water. Twenty million gallons of water a day were pumped from Lake Union to the top of the hill with force enough to move 2,500-pound boulders.

Cleaning up
Crews aim hoses toward Denny Hill as they work to wash Denny Hill -- which once convered 62 city blocks -- into the bay.
Clay and rocks were sluiced into channels, then routed into the bay via a timber trestle flume between Bell and Battery streets. Some of the earth was hauled away in horse drawn wagons, and on small railways built for the task.

About half of the 16 million cubic yards of dirt removed stayed on site for fill; the rest was dumped in the tideflats between Jackson and Spokane streets, forming Harbor Island.

The deepest cut was made near Fourth Avenue and Blanchard Street, where the hill was reduced by 112 feet.

The bulk of the regrade was complete by 1911, although the hill wasn't quite level. Work resumed in 1929 to finish the project. By that time, giant steam shovels replaced hoses, scooping and dumping soil onto conveyor belts which moved to follow the digging.

Thomson believed his project would create a bustling business district north of Pine Street, but his mission was never fully realized. The Denny Regrade, also known as Belltown, today is home to quirky shops, hip restaurants and apartments rather than towering office buildings.

In fact, some argue the regrade may have thwarted development, or at least reduced real estate prices by robbing the potential for expansive city views, like those of houses perched on Queen Anne Hill.


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