Filling the Flats

On July 29, 1895, thousands of Seattleites came out for what one paper crowned “the greatest enterprise yet inaugurated in this city.” They stood on a barge, watched from docks, and looked on from boats. (Fortunately, wrote one reporter, that nasty “old Sol” was hidden behind the clouds and no one would get too hot.) All were in the protean landscape of the Duwamish River’s tideflats, which for half of the day was underwater and for the other half was an expanse of mud. They had come to see an unusual boat.

Anaconda Drawing
Anaconda Drawing

The Anaconda was 110 feet long and 32 feet wide with a spewing smoke stack and strange stern, which was attached to a long pole anchored into the tidal mud. The bow was also odd with a hoist that held a movable cutting head. The two part structure consisted of a seven-blade spinning cutter inside a 13-blade rotating cutter. Extending out of the hollow cutter was a suction pipe connected to a huge centrifugal pump. Built to suck up muck, the Anaconda could discharge 10,000 cubic yards of material every 24 hours.

Eugene Semple, who had organized the event, owned the Anaconda. His plan was to use it and a sister dredger, the Python, to pump sediment from one part of the tideflats to another, in the process making new land for the city of Seattle. The main source of sediment would could from the Anaconda and Python excavating what are now the East and West Waterways on either side of Harbor Island. That sediment and material from the Jackson Street and Dearborn Street regrades, as well as from Semple’s failed attempt at a South Canal, would eventually lead to making around 2200 acres of new land.

Close up of the Cutter Head
Close up of the Cutter Head

On that great day, Semple stood in the upper deck of the Anaconda’s engine room with his daughter Zoe. A reporter noted that Miss Semple made “a very pretty picture as she stood clad in a pure white costume…with a waist made of white dimity … and [a] skirt of white ducking.” (If any reader can educate me on what this means, I would appreciate it.) At 11:29 A.M., Miss Semple stepped up onto a wooden block, reached toward a small lever with her hand, and pushed it.

The Anaconda began to shudder as cogs turned and set in motion the blades of the cutting tool sunk into the mud 25 feet below the surface of Elliott Bay. Mud and water began shooting through a stationary pipe suspended above the tideflats. The 2,700-foot-long pipe curved northeast on triangle-shaped trestles to an area that is now just west of Safeco Field. At the time it was adjacent to the southern most wharves and piers in Seattle, where most of the crowd watched the event.

The pipe expelled the mud onto tideflats recently protected by a brush bulkhead. The structure consisted of two or more pile rows ten feet apart with six feet between piles. At the base directly on tidal mud was a mattress of young firs laid between the rows and built to one foot above low tide. Resting atop the mattress were 24-foot-long bundles of brushes, called fascines. Sand had also been pumped over the fascines to strengthen the support wall; the excess water escaped through the branches. With every three feet rise in elevation, a horizontal tree would be laid perpendicular to the bulkhead with its bare trunk over the fascine and its branched end extending into the area destined for fill. Additional strength came from anchoring the mattress and fascine to the tree trunks. More fascines and more tie-backs would be added until the fill reached two feet above high tide line.

The Python
The Python

By June 1897, the Anaconda and Python had excavated three thousand feet of the East Waterway to a depth of thirty-five feet below low water, which created 75 acres of made land. Seven years later, after various legal and financial setbacks, the total had risen to more than 333 acres. By 1917, about 92 percent of the tideflats had been filled.

From: Determinants of City Form, City of Seattle, 1971
Tideflats Filling Dates, from: Determinants of City Form, City of Seattle, 1971

The last area of filling was west of Harbor Island, along the edge of West Seattle. It had remained somewhat wild through the 1940s, with a stream cutting across a sandy lowland but after World War II, industries, including a plant for creosoting wood pilings, a ship building facility, and later a banana warehouse, began to make the area more suitable for their needs.

Material for for this story comes out of research I have done for my new book on Seattle – Too High and Too Steep: Reshaping Seattle’s Topography.

If you so desire, you can like my geologywriter Facebook page.

South Canal Seattle Photo

Of all the crazy schemes that didn’t come to fruition in Seattle, the South Canal through Beacon Hill is one of my favorites. Unfortunately, I know of only one photograph of it and it’s not very good, but I have decided to look at it anyway. (Just wish I knew how to make provide one of those magnifying things so it can be looked at more closely.) As I noted in a previous post, little of the South Canal was built. Here is that story.

Semple's Folly on Beacon Hill
Semple’s Folly on Beacon Hill – View looks north toward S. Hanford St. Note hydraulic cannon on right side and tideflasts to the far left. S. Columbia Way cuts through middle of this scene in modern times.

The hill-cutting phase of the project had begun in February 1901, when Eugene Semple acquired rights to surplus water from the city’s new water source, the Cedar River. Built as a response to the lack of water to put out the Great Fire of 1889, the new system brought water from the Cedar River to reservoirs atop the city’s hills. Semple’s plan was to take advantage of the elevated reservoir on Beacon Hill by tapping into it via wood stave pipes. Water from Beacon Hill would drop nearly 300 feet down to the base of the hill. As the water plunged down slope, it would enter narrower and narrower high pressure steel pipes, which would increase the water pressure to the point that the water shot out with enough force to dislodge soil, rocks, and boulders.

On November 14, Semple’s crews began their attack on the western edge of Beacon Hill, directly east of the Bayview Brewery at 10th Ave S and Hanford Street. Everyday the crews blasted the hill with 14 million gallons of water, which created about 2,000 cubic yards of fill that flowed in flumes out into the Duwamish River’s tideflats. The first area filled was just north of the brewery, where the Washington Iron Works and Frye-Bruhn Meat Packing Company would be able to replace their old pile-supported buildings with new structures built on the new land.

By late 1904, the hydraulic giant had blasted away enough of Beacon Hill to create 52 acres of solid land along the hill’s western edge. But not everyone was happy. Philip and Maria French filed a petition with the city council seeking an award of $6,000 for damages to their home. The couple lived atop Beacon Hill, at 14th Avenue South and Hanford Street. Originally built more than 700 feet from the edge of the hill, the house and surrounding property were now just 30 feet north of a 100-foot-high sheer cliff created by Semple’s hydraulic cannon. Amazingly, the French’s lost their case.

Map of area covered by photograph.
Map of area covered by photograph.

Wielding a bit of hyperbole, the Seattle Times reported that “without authority and unknown to the public,” Semple’s crews had washed away seven streets of Beacon Hill, creating the “great hole” adjacent to the French’s property. The resulting damage suits against the city, added the Times, were piling “up so high that the corporation counsel is unable to see over them.” In contrast, real estate agents didn’t understand the Times’ concerns. Henry Dearborn noted that that “it is certainly good business ethics” to sluice down less valuable lands, such as Beacon Hill, in order to create more valuable land below.

With all of the bad publicity, Semple’s plan was doomed. By the end of 1904, the city council had voted to stop Semple’s use of Cedar River water. Eventually weeds started to grow in the chasm that was to be the South Canal and the project became another example of Seattle’s failed attempts at creating a new transportation corridor.

The chasm still survives. Have you ever wondered why the Columbia Way off ramps from I-90 go up to Beacon Hill where they do? It’s because the I-5 engineers took advantage of Semple’s folly, which provided a nice access point up to Beacon Hill.

Material for for this story comes out of research I have done for my new book on Seattle – Too High and Too Steep: Reshaping Seattle’s Topography.

If you so desire, you can like my geologywriter Facebook page.