Adjusted values consider dilution effect frcm difference In flows. 



values unadjusted and adjusted for tbs 

 differences in flow in April and September. 

 When the September vsLLuee are adjusted by 

 a dilution factor of 1.94 for the differ- 

 ence in flows, it will be noted that the 

 water quality (or total content of impuri- 

 ties) is about the same in April and in 

 September. From observing the flows and 

 quality values in the other months, it is 

 evidence that the quantity of Impurities 

 discharged by the Yakima River to the 

 Columbia River is about the same each month 

 of the yeair, regardless of other factors. 



If the 1910-11 water quality data 

 for the Yakima River at Prosser in Septem- 

 ber are adjusted for the differences in 

 flow between I9IO-II and 1953-54, a com- 

 parison can be made of the change in water 

 qu€LLity due to an increased irrigated 

 acreage of 240,000 acres and an added total 

 population equivalent of 216,000 persons. 

 Table 29 shows this ccnnparison in the last 

 column. Ftgoi an actual weight basis then, 

 the irrigation of an additional 240,000 

 acres and the addition of a population 

 equivalent of 216,000 persons between I9IO 

 and 1950 has resulted in the following 

 percentage Increases in constituents : 

 Alkeilinlty - 6IO; hardness - 435; sulfate 

 - 100; dissolved solids - 400; calcium plus 



magnesium - 4^0; sodium plus potassium - 

 39O; silica - 775j chlorides - 166; and 

 nitrates - 6,250 percent. These are very 

 large increases and are representative 

 only of a change in the maximum yearly con- 

 stituent values in September for the years 

 compared. 



IXaffiSTIC SEWAGE AND INDUSTRIAL 

 WASTE DISCHARGE 



Present conditions : 



The Colimibia River Basin has been 

 growing in population at a rate comparable 

 to the entire Pacific Northwest. Table 30 

 shows that^ in 1950, the Columbia River 

 Basin population (which includes portions 

 of seven states and a portion of British 

 Colvmibia) was about three and one-quarter 

 million persons of which close to one and 

 one-half million lived in cities having a 

 population in excess of 1,000 persons and 

 where their dcmestic sewage was discharged, 

 treated or untreated, to the Columbia Ri'ver 

 system. Table 32 lists by number the sig- 

 nificant industries as of about I950 that 

 discharge waste waters to the Columbia 

 River system. These are industries whose 

 waste waters have a potential damaging 



90 



