The Willametta River has constituted a serious pollution problem 

 of many years standings 



Routine samples were collected from the Willamette by the Portland 

 City Health and City Enp;ineering Departments at seven stations located 

 between Sellwood Bridge (River Mil© ISsS) and the confluence with the 

 Columbia over a 27=month period between Octoberj 1926, and December, 

 1926o During the month of August. 1927, and during both August and 

 September, 1928, the oxygen content of the river was fotjnd to be less 

 than three parts per milliono 



Rogers, Mockmorej, and Adams (1930) made more critical studies 

 when surveying the Willamette and major tributaries during July and 

 August, 1929 o They continued sampling at key stations on the main 

 stem between the city of Cottage Orove and the Sellwood Bridge, 

 Portland, at monthly intervals between October, 1929, and May 1930 o 



Gleeson (1936) made an intensive study of the pollution and tidal 

 comples in the Portland Harbor area of the 'Willametteo Gleeson's studies 

 were made betT'/een the Sellwood Bridge and the Columbia River, September 5 

 to 27, 1934o 



Craig and Tovmsend (1946) report a series of seven spot samplings 

 at Sellwood Bridge and at Sto Johns Bridge, Portland, between February 

 4, and July 28, 1941, and four samplings between May 2, and August 21, 

 1942, Their data indicate that an oxygen block (i.e., less than 5 ppm.) 

 formed in the Willamette River at Ste Johns Bridge sometime between 

 March 18 and May 1, 1941 o Likewise, an oxygen block developed upriver 

 at Sellwood Bridge between May 29 and July 17, 1941 « An oxygen blocjk 

 developed at both sampling stations sometime betv/een May 2, and early 

 August in 1942c 



Tne most recent pollution studies in the Vllillamette Basin were 

 reported by Merryfield and Wilmot (1945) and by Dimick and Merryfield 

 (194c) o These studies included both the major tributaries and the 

 main-stem Willamette (downstream to Sellwood Bridge) and were conducted 

 between August and December,, 1944 -- with bi-monthly sampling at critical 

 main-stem stations extending until March 1945o Insofar as the main-stem 

 Willamette is concerned,, Merryfield and V/'ilmot demonstrated that an oxygen 

 block extended upstream co approximately river mile 60 at the time their 

 studies were undertaken in Augusts The block had been forced downstream 

 to river mile 'si by October and disappeared entirely late in that month. 



It is quite obvious from the studies that have been made to d ate 

 that pollution constitutes a serious fisheries problem in the Willamette 

 Basin and one which cannot be fully evaluated vfith existing datao Cer- 

 tain facts are knovm concerning the migratory-fish runs of the Willamette 

 and also about the lov;=oxygen barrier in the lower reaches of the main 

 stem. Neither are sufficiently well known, hov;ever, to evaluate the 

 effect of pollution upon the fish runs. 



