Seattle: the most extensive terrain alteration in city building history

Between 1897 and 1930, builders of the city of Seattle took tremendous efforts to modify the hilly topography where the city extended. The dramatic alterations of the landscape involved the use of powerful water cannons to wash away bulky chunks of mounds and entire hills.

The early city planners believed that regrading the terrains and leveling all elevations would boost business in the city. That trade and commerce will significantly improve once the city opens up.

Thousands of engineers and workers used all the available technology of the day to move mountains, slice hills in half, redirect rivers, dig new sewers, and adjust road and railway infrastructure.

A fire that reduced to rubble most of Seattle’s downtown area in 1889 prompted the first regrade projects. The landscape manipulation was proposed as a bold plan to resuscitate the city. City Engineer R. H. Thomson oversaw the construction efforts. As the municipal government approved the proposed plans, most of the following four decades meant near-constant construction in and around Seattle. Probably nothing like that had ever happened to a city before.

One of the most remarkable efforts entailed the Denny Regrade, which was carried in two phases. This project aimed at opening up the area adjacent to the waterfront and increasing the land values. In the first phase, half of the hill was clear cut with water pumped from Lake Union. Records suggest that 20,000,000 US gallons (75,708 m3) of water a day were repurposed from the lake as jets of water targetted the hill. Unsurprisingly, the sight of a hill sliced up at first turned away investors who feared their real estate would eventually diminish with the continuing leveling.

For a while, the building scapes of Seattle looked really crooked. Sights almost surreal. Little remains of the city from its 19th-century buildings; however, Seattle has grown into the largest city in both the state of Washington and the Pacific Northwest region of North America nowadays. The photos enclosed in this article reveal the scale of effort it took to build the modern city of Seattle.