Oregon State Sanitary Authority calls for the treatment of the 

 oxygen-cons uning industrial wastes, principally sulphite liquor 

 and cannery offal, as rapidly as feasible methods can be developed. 



Primary treatment of domestic sewage will reduce its subsequent 

 oxygen demand in the order of thirty percent. When effected, this 

 measure woijld improve lower river conditions materially although it 

 still appears insufficient to lift the o::ygen block all the way to 

 the Columbia River. Insofar as the migratory fishes are concerned, 

 an oxygen block several hundred yards in length probably would prove 

 just as effective a barrier as one of many miles in extent. 



Gleeson, it will be recalled, found that 7.6 days were required 

 for the Willamette River water to flow from Sellv/ood Bridge to the 

 Columbia when river discharge was 4,000 second feet. The assumption 

 appears tenable, therefore, that the full oxygen demand indicated by 

 the 5-day biochemical oxygen determimttion of water at the Sellwood 

 Bridge will be consumed — at least during the low flow periods — before 



that water reaches the Columbia. 



» 



Using the 1949 determinations obtained at the Sellwood Bridge 

 on August 29, September 5, and September 12 (which represent the 

 approximate time when relocated runs of fall-chinook salmon would be 

 entering the lower Willamette) as exsnnpleB, the future river conditions 

 between the Sellwood Bridge and the Columbia that may be grossly antici- 

 pated under conditions comparable to the 1949 river flows and tempera- 

 tures and with various degrees of pollution abatement can be calculated 

 as follows : 



Date of Determination ----------- Aug« 29 Sept» 5 Sept. 12 



River flow at Sellvrood Bridge, second feet 5,260 5,080 5,476 



River water temperatures (°C.) 21 23 20.5 



Dissolved oxygen available, 1949 conditions; 



ppra. 2,8 2.0 3.3 



pounds per day 79,531 54,864 97,583 



dissolved oxygen deficit, lbs/day 175,819 183,244 170,980 



Dissolved oxygen available: 



with 1949 deficit reduced 60% (lbs/day) 1^2,564 109,837 148,897 



with 1949 deficit reduced 50?? (lbs/day) 167,728 146,486 183,073 



16 



