On November 19, 1911, massive floods on the Cedar River destroy the water pipelines that power Seattle's hydroelectric plant at Cedar Falls and the separate pipelines that carry the city's water supply from the Cedar River to in-city reservoirs, leaving Seattle without electricity and dangerously short of water. As rushed repairs are made, the Department of Lighting arranges to buy power from the competing Seattle Electric Company and from Tacoma. The Water Department activates the old pumping station on Lake Washington and street-sprinkling wagons deliver water to residents. The need to rely on unsanitary lake water prompts the first use of chlorination to purify Seattle water, which helps to avoid an outbreak of disease.
The Cedar was one of many Western Washington rivers that flooded in late November 1911, following heavy rains and several days of warm Chinook winds that melted snow in the Cascade Mountains. Railroad bridges and interurban tracks were washed out, disrupting transportation across the state. But the flood damage on the Cedar River was particularly devastating, because Seattle depended on the Cedar for its water and its power.
Wave of Destruction
Cedar River water had filled Seattle reservoirs since 1901, when the first pipeline was completed from an intake on the river at Landsburg to the city. Use of water from the largely uninhabited Cedar River watershed, in place of water pumped from Lake Washington, on which the city previously depended but into which considerable sewage flowed, significantly reduced the incidence of typhoid fever and other disease in Seattle. A second, larger pipeline from the river was added in 1909. Both wood-stave supply pipes were carried across the river on a wooden trestle bridge just below the Landsburg headworks.
By 1905, the Cedar River was also powering Seattle, as a hydroelectric plant at Cedar Falls, 12 miles upriver from the water intake at Landsburg, generated electricity for the city. A dam consisting of a timber crib built atop a concrete base was constructed at the mouth of Cedar Lake (now Chester Morse Lake) three miles above Cedar Falls, and the water that powered the generating turbines flowed through two wood-stave pipes from the dam to the power plant.
By the morning of November 19, 1911, heavy rains and melting snow had raised the level of Cedar Lake well above the height of the dam -- nine feet of water was pouring over the top of the dam. At around 8:00 that morning, the top five feet of the dam's timber crib was washed away, allowing a tide of floodwater to sweep down the Cedar River. Soon water rushing over, and around the sides of, the dam destroyed the two pipes carrying water to the power plant, cutting off Seattle's electric supply. At almost the same time, the rising water downstream washed out 150 feet of the 250-foot-long bridge carrying the water supply pipelines over the river near Landsburg, destroying both pipes.
The causes of the flood and pipeline washout were complex, and hotly debated at the time. Modern scholars point out that logging in the foothills above Cedar Lake denuded slopes and thereby greatly increased run-off into the lake during rains. Most histories also tend to align with R. H. Thomson (1856-1949) in identifying the Milwaukee, Chicago, and St. Paul Railroad (commonly known as the Milwaukee Road) as the immediate cause of the Landsburg pipeline washout. Thomson, whose many accomplishments in two decades as Seattle's City Engineer (he'd stepped down a few months before the 1911 flood to become the first chief engineer of the newly-formed Port of Seattle) included constructing the Cedar River water and power systems, suggested that dredging by the Milwaukee Road, when it built a rail line through the Cedar River watershed in 1907, shifted the river's course too close to the bridge carrying the pipelines. However, The Seattle Times -- long a vociferous critic of the city engineer and a frequent champion of railroad interests -- insisted that the Milwaukee Road dredging had nothing to do with the pipeline break and that Thomson alone was responsible for the water famine: he had both pipelines cross the Cedar on a single trestle at "the most treacherous point" and failed to provide for any backup water supply, rejecting plans to use Swan Lake (now Lake Youngs), located between Maple Valley and Renton along the pipeline route into the city, as an impounding reservoir and backup supply (Seattle Times, November 26, 1911, p. 1).
Running Out of Water
Whatever the causes, by 3:00 p.m. on November 19, water mains in much of Seattle were empty. People flocked to city reservoirs, trying to obtain water in pails, milk bottles, and other containers that they dipped into the reservoirs with ropes. To ease the situation, Mayor George W. Dilling (1869-1951) ordered 24 600-gallon water wagons and two water tanks on streetcars to distribute water in affected neighborhoods. Residents collected it at street corners in pitchers and buckets.
With the reservoirs holding only a two-day supply, and even temporary pipeline repairs predicted to take as much as a week, the pump station at Lake Washington, long since abandoned, was brought back into service. Emergency pumping was also utilized at Union Bay and Swan Lake.
Even so, water remained scarce. Schools closed for lack of steam heat, as did the county courthouse. Hospitals were forced to rely on water held in storage tanks. Outside toilets were constructed because sewers could not function without a flow of water. The fire danger in the city was high because little water was available to fight any outbreak (fortunately no significant fire occurred).
The biggest concern was the possibility of disease caused by drinking contaminated lake water. Residents were repeatedly advised to boil, filter, or chemically purify all water. The city's health department was particularly conscious of the risk from drinking Lake Washington water because major typhoid epidemics, which sickened hundreds and killed dozens, had followed use of water from the lake during shortages in 1907 and 1909. This time, the health department provided the public with detailed instructions on how to chlorinate water using a solution made from chloride of lime, a substance that the department assumed to be "in use by all housewives" (Seattle Times, November 26, 1911, p. 4). This advice marked the first concerted effort to use chlorination to protect Seattle's water. In addition, the water department pumped the potentially contaminated lake water only into the distribution mains, not the reservoirs, and flushed out all those mains once the Cedar River supply was restored. With these precautions in place, no disease outbreak occurred.
Repairs and Improvements
It took nearly a week before electricity and water from the Cedar River again reached Seattle. The Seattle Times reported that power from the Cedar Falls plant became available again at 2:00 in the morning on Saturday, November 25. With only one of its two pipelines back in service, the plant could only produce one fourth of the needed electricity, so the Department of Lighting continued buying power from private companies until the plant was fully operational. Cedar River water began flowing into city reservoirs again on Saturday evening, but it was several more days before the system was fully flushed and residents were told they could stop chlorinating or otherwise treating the water.
After the pipeline was repaired, steps were taken to prevent a similar disaster in the future. The pipeline right of way was shifted south, eliminating two river crossings, and new policy was written abolishing bridges as pipeline carriers whenever possible. The 1911 break, along with smaller breaks over the next few years, also led to plans to construct a third pipeline from the Cedar River at Landsburg and to convert Swan Lake into a storage reservoir and impounding basin (in a sense reverting to the plan that The Seattle Times criticized R. H. Thomson for omitting). Pipeline Number Three was constructed of 60-inch steel pipe, in contrast to the wood-stave construction that had been used for much of the length of the first two pipelines. The new pipeline delivered its first water in 1923, and the impounding reservoir, renamed Lake Youngs following the 1923 death of longtime water department superintendent L. B. Youngs (1860-1923), was in use by 1927.
Well before the new reservoir and pipeline were constructed, the water department had moved to regular chlorination of the water supply. Chlorinating equipment was installed at the Landsburg headworks around 1914 or 1915. Little record exists of this equipment, constructed by the Electro Bleaching Gas Company of New York and among the first of its type. In 1918, a new chlorine apparatus was installed at Landsburg. Consisting of two chlorine tanks tapped to the pipelines, it chlorinated 22.5 million gallons of water in Pipeline Number One and 40 million gallons of water in Pipeline Number Two each day. Chlorine was introduced manually by turning valves. Various improvements and upgrades to the chlorine equipment at Landsburg were made over the next decade. In 1927, the chlorination equipment was moved to the new control works at Molasses Creek near Lake Youngs, and automatic chlorinators were placed in service there by 1929.