[Originally published on my blog Historical Threads on April 22, 2010. This version has been refined & corrected, where necessary.]
I recently discovered a source detailing the planning and construction of Portland’s west-side harbor wall, written by the city engineer who planned and implemented the project, Olaf Laurgaard. There will be a short section of one chapter in my book that will provide an overview of the construction of Portland’s sewage infrastructure up to the 1930s, and Laurgaard’s source will help me immensely in describing the construction of the west-side harbor wall–which also included an intercepting sewer.
Laurgaard first proposed the project in February 1920 as a way to re-develop this portion of the harbor and protect a large section of downtown that was prone to seasonal flooding. This part of Portland Harbor was a center of waterfront warehousing, commerce, and transportation through the first years of the twentieth century. By the 1910s, however, the area became increasingly run-down, and by 1920 the area from Clay Street on the south to Flanders on the North was marked by abandoned buildings, empty lots, and derelict wharves.
Twenty-eight gravity-fed raw sewage outfalls lined this portion of the waterfront, a number of which were exposed during low-flow periods of the Willamette River. These gravity-fed lines backed-up during seasonal freshets, causing raw sewage to fill the basements of downtown buildings.
Decrepit infrastructure, crumbling buildings, vacant lots, and periodic inundations of sewage appreciably reduced the real estate values within a 425-acre swath of the downtown business district. The Portland City Council requested plans of City Engineer Laurgaard to clean-up this area and resolve the flooding issue. Laurgaard submitted his plans in May 1925, and City Commissioners awarded the J. F. Shea Company the $2,135,000 contract in November 1926. On May 1, 1929, Laurgaard and his team ran an official pump test for the entire interceptor and pump station to check the quality of the contractor’s work.
Below are a selection of images and diagrams from Laurgaard’s 1933 treatise on the Portland Harbor wall project, supplemented by a few images from the City of Portland Auditor’s Office Historic Photos website (as indicated)
 Laurgaard, Olaf. “Treatise on the Design, Test, & Construction of the Front St. Intercepting Sewer and Drainage System in Portland, Oregon, Including Intercepting Sewer, Pumping Plant, & Concrete Bulkhead-Wall on Gravel Filled Timber Cribs,” Oregon State Agricultural College, 1933.
 $2,135,000 is approximately $21,800,000 in 2009; see http://www.measuringworth.com/uscompare/ (using GDP Deflator formula).