It all began in 1884 with the arrival in Seattle of the visionary engineer, Reginald Heber Thomson. Thomson had noticed that Lake Union and Lake Washington were getting horribly polluted because residents were dropping raw sewage directly into their waters. As City Engineer, he began studies for a plan to move the sewage of out city lakes.
In the fall of 1904, Thomson hired Fred Dehley and directed him to study the currents that touched the waterfront anywhere between two miles south of Alki Point to three miles north of Shilshoe Bay. Next, Dehley was to place floats near the shore and keep records of the hour and place at which each floated out to sea.
From these studies, Dehley located a short stretch of beach in Fort Lawton where there was always an outflow to the north whether the tide was incoming or outgoing. This was the place for which Thomson was searching.
The City began a complicated process in getting permission for the location of Thomson’s proposed sewer line.
Congressman Humphrey secured an Act of Congress, dated the 10th of April, 1909, authorizing the right of way to run the sewer line through Fort Lawton and the Lake Washington Ship Canal. The City of Seattle passed Ordinance No. 20991 recognizing and accepting the Act of Congress. Finally, Thomson’s plan could be realized.
Based on Dehley’s studies, West Point’s north beach in the northwest corner of Fort Lawton was the site selected for the outflow of Seattle’s sewage. Previous dumping into Lake Union and Lake Washington was abandoned, and in 1911 the new sewer line outfall discharged at the depth of 45 feet below high tide in Puget Sound.
In 1918, the large, 12-foot diameter North Trunk Sewer was completed. It ran under Fort Lawton through a tunnel and again discharged its burden into Puget Sound at West Point. But even fast moving currents did not prevent untreated sewage from being deposited onto the beach.
[[In-content Ad]]