IV. Reclaiming Nature: Flattening Hills and Digging Waterways in Seattle

Bringing order to Seattle’s urban environment demanded more than planning. It required building a new city by changing its physical surroundings to fit civic needs. Engineers and workers moved mountains, straightened rivers, leveled hillsides, dug sewers, paved roads and carved canals as part of making Seattle. These changes to the physical features of Seattle’s landscapes reflected a belief in improving nature to make it more suitable for urban industries and growth. As Clarence Bagley wrote in his 1916 History of Seattle, “No great city on the American continent has overcome so many natural obstacles encountered in its growth.” Seattle, Bagley concluded, was literally “one vast reclamation project.”

From 1890 to 1940, a series of public works projects, the heart of Bagley’s “vast reclamation project,” forever changed the face of Seattle and its environs. These projects began after the 1889 fire that destroyed much of Seattle’s downtown retail district. After the blaze, City Engineer R. H. Thomson initiated an ambitious plan to reinvigorate the city. He convinced the municipal government to level hills, fill tidelands, straighten the Duwamish River, and purchase the Cedar River watershed. Most of these projects were completed between 1890 and 1930, when Seattle matched Bagley’s description of a city under near-constant construction.

One important project was the construction of the Lake Washington Ship Canal. Seattle residents had long dreamed of creating a fresh-water, inland port for shipbuilding and maritime commerce. By the 1890s, two opposing plans for canals vied for public approval. The southern route, touted by former Washington territorial governor Eugene Semple, would have connected Puget Sound to Lake Washington by a canal dug along present-day Dearborn Street in south Seattle. But the northern route through Ballard, Lake Union and the Montlake neighborhood won city and state approval. Led by General Hiram M. Chittenden of the United States Army Corps of Engineers, workers assembled the Ballard Locks, the second largest locks ever built by Americans after the Panama Canal at that time, then carved out the Montlake Cut, opening Lake Union to Lake Washington. When the canal was opened to traffic in 1916, it lowered the lake level almost 12 feet, eliminating lake’s historic outlet at its southern end through the Black and Duwamish Rivers.

Residents on the southern end of Seattle also lobbied to reclaim the Duwamish River, a flood-prone river that was the city’s largest natural waterway. Following a series of destructive floods in November 1906, an investigative board convened the following year to survey the disaster. Chaired by General Chittenden, the board proposed remaking the Duwamish with dams and dikes, dredging and straightening, in concert with the proposed Lake Washington Ship Canal. Local residents agreed with Chittenden’s report and in 1909 created Commercial Waterway District No. 1 to cut the river’s oxbows and meanders, shortening the river’s length by nearly ten miles. The loss of the connection between the Duwamish and Lake Washington stranded hundreds of salmon in the receding Black River. Duwamish Indian Joseph Moses remembered how “people came from miles around, laughing and hollering and stuffing fish into gunny sacks.” Along with other diversions, the subtraction these tributaries reduced the flow of the Duwamish by nearly two-thirds, thereby assisting further construction on the river’s fast-disappearing delta and the southern reaches of Seattle’s growing waterfront.

The indefatigable Thomson and his allies labored on another front to secure reliable, publicly owned water and electrical power for Seattle. Throughout the 1880s and 1890s, city officials and private interests battled over who would control municipal water utilities. After several rounds of political fights, Thomson convinced Seattle voters to acquire the Cedar River watershed in the Cascade Mountains in 1899. City workers completed the first Cedar River pipeline in 1901. After World War II, Seattle would also claim the nearby Tolt River watershed as an additional water source. 

Electrical power was another concern for the growing city. Municipal reformers worried that a private, Boston-based company, Puget Sound Traction, Light & Power Company (known as Puget Power), would have a monopoly on the city’s electrical utilities. An early generating plant, built at Snoqualmie Falls in 1895, quickly proved inadequate, so voters approved the construction of a new plant at Cedar Falls in 1902. In 1910, City Light became an independent city agency and its most-famous superintendent, John D. Ross, appointed in 1911, launched his fight for public power. By 1918, Ross secured federal rights to build hydroelectric plants on the Skagit River, in the North Cascades, east of Bellingham. Workers completed Gorge Dam, the first of three dams to be built on the Skagit, in 1924, with the second facility, Diablo Dam, finished in 1936. Thanks to Ross’s efforts, Seattle residents enjoyed some of the lowest electrical rates in the nation at the time, cheap power for the public good.

Building utilities was only part of what was a massive renovation of Seattle’s physical environment. The scale of these projects, as illustrated by the famed hill regrades, was sometimes immense. A series of glacial ridges and hills originally divided city neighborhoods from the downtown waterfront, making horse and rail travel difficult. In nearly sixty separate projects, workers removed many of these features, moving over 50 million cubic yards of earth in the process. Work began in the 1890s with pickax and horses and concluded in the 1920s with hydraulic cannons and conveyor belts, powered by water and electricity from the city’s Cedar River. Engineers used this material to reclaim tidelands for piers and railway lines, or to add to Harbor Island, the manmade isle that replaced the sandbars at the mouth of the Duwamish River. 

While regrading looks wasteful and ugly to us today, Seattleites at the time saw it as an instrument for improving nature, not destroying it. Charles Evans Fowler, an engineer writing in 1926, said that the regrades improved “much of the primeval forest” within the city “for the pleasure of future generations.” “This system is certainly a wonderful creation of man,” he concluded, “and is the result of allowing full play to the imagination and creative energy of the engineer.” Other observers pointed to how regrading would boost the city’s economy. V. V. Tarbill noted that after the Second Avenue regrade in 1906, street front lots sold for $2,000 per front foot at the corner of Pike Street. One block to the north, where Second Avenue ran into Denny Hill, similar frontages were worth less than $300 per front foot. Two years later, City Engineer Thomson estimated that regrading boosted business real estate values 400 percent and residential real estate 1000 percent throughout downtown Seattle. Beauty lay in both how regarding removed ugly and dangerous hills, making the reclaimed land more valuable.

But the regrades also had negative effects. Letters to city officials complained about blocked streets, broken water and sewage mains, shattered windows, collapsed foundations, triggered landslides, buried debris, muddy streets, unwanted noise, unhealthful dust, destroyed sidewalks and disrupted traffic. Residents who originally had supported the regrades implored contractors to finish early, fearing further erosion of their realty and sanity. In turn, the Engineering Department threatened contractors with lawsuits, citations, and nonpayment. Some litigious residents took matters to court over forty separate cases made their way to the state Supreme Court, which forced the city to pay more damages or change its plans to protect property owners. Since regrading operations often proceeded ahead of judicial decisions, engineers and their contractors removed earth and destroyed buildings before court proceedings concluded. This tactic further complicated legal remedies. Under city guidelines, individual owners arranged for the regrading of their own property upon approval of a given city project. Without an owner’s consent, however, city workers could only remove earth to the edge of private lots, but no farther. Those who refused to cooperate found their lots turned into towers of dirt, popularly known as “spite mounds,” that loomed as high as fifty feet above the flattened land below. 

Spite mounds came to symbolize what regrading had cost many Seattleites. In a 1975 interview, Sandy Moss recalled how in 1907 the Dearborn Street Regrade destroyed her family’s home along with other houses occupied by fellow African-American residents. After being evicted by city engineers, their house tumbled down the regrade face “three blocks down below…and about two hundred feet lower.” “It was just a bunch of matchwood down there…it was all broke up, like you would step on an apple box and crush it.” The house was destroyed and the damage award never covered the loss.

The first round of regrading came to an end by World War I when the city ran out of funds and energy to complete all of its hill-removal projects. A 1926 New Republic article noted that “mastering the natural environment” at the expense of the “defenseless taxpayer” left Seattle “nearly insolvent.” One regrading project remained unfinished, however: the famed Denny Hill regrade, which left half of the hill towering nearly 100 feet above the new “Regrade District” north of downtown when work stopped in 1911. After real estate owners lobbied the city to complete the job, workers began the second Denny Hill Regrade in 1928, moving earth into Elliott Bay with steam shovels and webs of conveyor belts. This second round of regrading elicited further protests, but it was the onset of the Great Depression in 1929 that eventually made further regrading financially impractical. When the shovels finally stopped in 1931, Denny Hill had disappeared and Seattle’s regrading mania came to an end.


The documents for this section focus on three projects designed to reclaim and improve nature in pre-World War II Seattle: the regrading of Seattle’s hills, the straightening of the Duwamish River, and the construction of the Lake Washington Ship Canal. Consider the following questions when analyzing these documents:

39. Duwamish River. "Delta of Duwamish: A Bit of Unexplored Country at Seattle’s Doors," Seattle Telegraph, 12 August 1894.

40. Flood Problems. Hiram M. Chittenden, ed. The Duwamish-Puyallup Flood Problem (Seattle: Lowman and Hanford S. and P. Co., 1907), p. 10-11, 21-22.

41. Duwamish Valley. "Changing the Topography of the Duwamish Valley," Duwamish Valley News, 27 November 1914, 1.

42. "The Straightening." The Duwamish Diary (Seattle: Cleveland High School, 1948), 65-72.

43. Duwamish River and Seattle Industry. Lars Langloe, Report on the Development of Industrial Sites in the Duwamish-Green River Valley (Seattle: City Planning Commission, 1946), 1-5, 16-17.

44. Seattle Regrade. Louis P. Zimmerman, "The Seattle Regrade, With Particular Reference to the Jackson St. Section," Engineering News 60:20 (12 November 1908): 509-11.

45. Seattle Roads. R. H. Thomson, Annual Report, City Engineer’s Office (1908): 18-19. Seattle Municipal Government, Engineering Department, Administration, Annual Reports, Seattle Municipal Archives (at Puget Sound Regional Archives, Washington State Archives), Control No. 2600-01, Box 1.

46. Denny Hill Regrade. O. A. Piper, "Regrading in the Seattle North District," [c. 1910], Local Improvement District 4818. Seattle Municipal Government, Engineering Department, Local Improvement District Files, Seattle Municipal Archives, Office of the City Clerk, Control No. 2600-00, Microform, Letters, Folder 1.

47. Interview with Ester Mumford. Sandy Moss, Interview with Esther Mumford, 22, 25 April 1975, Acc. BL-KNG 75-2em, Washington State Oral/Aural History Program Records, 1974-1977, Washington State Archives.

48. Letter Protesting Second Denny Hill Regrade. George F. Cotterill to Board of Park Commissioners and City Council of Seattle, 17 May 1928.  Seattle Municipal Government, Don Sherwood Parks History Collection, Parks History Files Seattle Municipal Archives, Office of the City Clerk, Control No. 5801-01, Box 24, Folder 8.

49.Seattle Regrades. Arthur H. Dimock, "Preparing the Groundwork for a City: The Regrading of Seattle, Washington," Transactions of the American Society of Civil Engineers Paper No. 1669 (1926): 718-19, 722-23.

50. Seattle Regrades. V. V. Tarbill, "Mountain-moving in Seattle," Harvard Business Review (July 1930): 482-89.

51. "Handling Earth by Belts." W. F. Way, "Handling Earth by Belts," Engineering News-Record 105:21 (27 November 1930): 838-40.

52. Slow Progress of Regrades. Uptown Seattle Association to W. D. Barkhuff, City Engineer, 6 August 1929 and W. D. Barkhuff to George Nelson and Co., 7 October 1929, Local Improvement District 4818. Seattle Municipal Government, Engineering Department, Local Improvement District Files, Seattle Municipal Archives, Office of the City Clerk, Control No. 2600-00, Microform, Letters, Folder 1.

53. A Harbort without a Hinterland. Read Bain, "Seattle: A Harbor without a Hinterland," The New Republic (19 December 1928): 131-34.

54. Ship Canal. Hiram M. Chittenden, "Canal and Waterway," The Argus (16 December 1911): 24.

55. Scenic Beauty of Lake Washington. Hiram M. Chittenden, "Sentiment versus Utility in the Treatment of National Scenery," Pacific Monthly (January 1910), 37-38.

56. Remembrances of Lake Washington and Lake Union. Eldon E. Phillips, "Just Looking Back," [c. 1960s?], W. S. Phillips Papers, University of Washington Libraries, Box 1, Folder 5.

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Center for the Study of the Pacific Northwest