My final project for the Geographic Information Systems (GIS) course I took during the Fall 2013 quarter offered me the opportunity to build upon an earlier project and posit a qualitative and somewhat whimsical question: Where could I have lived in Portland in the 1930s and have been far enough from the river not to smell the stench (say, five blocks) yet close enough to walk to it (say, up to 1.25 miles) during the rest of the year when it didn’t stink? The darker green areas in the map to the right generally show where this would have been possible.
Read the rest of this post for more information about how I created this map and to see the full map with accompanying images and text.
To create my earlier map, I used Metro Regional Land Information System (RLIS) data for the shape of the Willamette and Columbia rivers and other bodies of water and the location of the cross-Willamette bridges. This data represents the landscape of about 2010. For my recent project, I wanted to create my own data from earlier sources to represent the landscape more accurately during the period in which the water quality data I used was gathered (September 1934).
To do this, I first downloaded a PDF version of this 1935 industrial map of Portland from the City of Portland Archives website, converted the image to JPEG format, and then brought the JPEG version into ArcMap for georeferencing. Once I completed these steps, I digitized those parts of the 1935 map that I needed to use to create the map I had in mind. These parts included the arterial streets and rail lines, industrial and commercial areas, parks and schools, and waterways such as the Willamette River through Portland, Columbia Slough, sections of the lower Columbia River, and the lakes and streams in the North Portland peninsula. Completing these steps I now had the data necessary to create a map that would be a more accurate representation of the landscape of the 1930s, rather than showing the 1934 water quality data I wanted to show on a landscape that represented the early second decade of the twenty-first century.
I applied the same tools in ArcMap that I used in the earlier map to create the graduated shading representing the changes in Portland Harbor dissolved oxygen levels between the seven sampling stations. However, for this project I added three data points to the sampling stations data set. I took one point (4.8 ppm average) from late August 1929 measured between Willamette Falls and the confluence of the Clackamas River. I took two points from May 1941 at the confluence of the Willamette and Columbia Rivers (11.5 ppm average, “over 12” ppm average). By including these additional data points I was able to generate what I am confident are representative extensions of the 1934 dissolved oxygen data that helps contextualize spatially the data at sampling stations 1 and 7. There are two primary reasons why I’m confident these additional data points would not have been significantly far off from September 1934 data–which wasn’t gathered. The first is that neither industry nor municipal governments had taken any meaningful pollution abatement steps by 1941. Second, the larger storage reservoirs developed as part of the Willamette Valley Project (and that have so significantly influenced Willamette River water quality) had not been built by 1941.
The full map that I created for this project included the image above plus some descriptive text and images for context. As I write in this map, “White people began settling the Willamette Valley in large numbers in the 1840s and 1850s. Just forty years later at least some of them recognized that the Willamette River had become ‘the great sewer of this great Willamette Valley.'”
 H. S. Rodgers, C. A. Mockmore, and C. D. Adams, A Sanitary Survey of the Willamette Valley, Bulletin Series, No. 2. Corvallis: Oregon State Agricultural College Engineering Experiment Station, 1930, p. 29.
 John H. Lincoln and Richard F. Foster, Report on Investigation of Pollution in the Lower Columbia River, Salem, Oreg.: Interstate Technical Advisory Committee, 1943, p. 111.