More recent studies in the Willamette River v/ere reported 

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

 (1945) o Insofar as the main stem is concerned, their studies 

 were conducted dovm to the Sellwood Bridge between Aup;ust and 

 Decembers lS44j with bi-monthly samplings at the critical stations 

 continued until the I'ollowing Marcho Merryfield and Wilmot demon= 

 strated that the oxygen block extended upstream to approximately 

 river mile 60 at the time their studies were undertaken in late 

 August of 1944c. The block had been forced dovmstream to river mile 

 44j presumably by increasing water flows, by October and it disappeared 

 entirely sometime late in the snme month* 



Fish and Rucker (1950) reported a reconnaissance of the main stem 

 Willamette from Springfield to the Steel Bridge (river mile 12) in 

 Portland during mid^October, 1948o They obtained no evidence of 

 an oxygen block at that time, the lowest dissolved oxygen concentra- 

 tion obtained on the survey being 7*4 ppmo at the Steel Bridge* 



It is apparent from the studies made to date that the pollution 

 burden of the Willamette River is of sufficient magnitude to over-" 

 load the lower reaches during periods of low flows and high temper>= 

 atureso The lowest reach of the river is degraded to the point where 

 oxygen deficiency precludes any movement of migratory fishes through 

 the affected areao Because the Willamette River currently supports 

 important runs of salmon and steelhead trout -- fishes of high conrni" 

 ercial and recreational value — the impact of pollution upon the 

 fishery resources is of considerable importance o 



The impact of pollution upon the fisheries resources of the 

 Willamette Valley is of major conseauence not only under existing 

 conditionSj, but it bids fair to become increasingly more so in the 

 near futureo Increasing population and industrialization of the 

 Willamette Basin -- with an accompanying additional pollution burden 

 to the already overloaded main stem — appears inevitable » Some loss 

 of potential dilution water through evaporation has accompanied the 

 great increase in the quantity of main stem water diverted for the 

 irrigation of croplands during the past decade o This trend undoubted^ 

 ly will continue, and probably steepen, with the obvious shifting of 

 agriculture in the Valley from grain and pasturage to truck and specialty 

 farmingo 



Perhaps the greatest crisis of all, insofar as the fisheries of 

 the immediats future are concerned, lies in the acute need for the main 

 stem and certain tributaries of the Willamette as spawning and nursery 

 areas for fall-chinook salmon relocated from the main Columbia Rivero 

 A serious threat to the upper Columbia River salmon runs is forming in 

 the multiple -purpose programs of water development currently in progress 

 by the Corps of Engineers, the Bureau of Reclamation, and by private 

 interests The Fish and Wildlife Service, together with the fishery 

 agencies of Oregon and Washington, are engaged in a 20-million dollar 

 "Lower River Program" designed to perpetuate the Columbia River salmon 



4 



