USGS Scientific Investigations Report 2010–5016 Development of an Environmental Flow Framework for the McKenzie River Basin, Oregon

Table 10. Significant changes to environmental flow components in the McKenzie River basin as a result of upstream dams.

[Reaches 8 and 10 were not evaluated for changes because of the Leaburg and Walterville canal diversions, respectively]

Reach No.	Large floods	Small floods	High flows	Low flows	Extremely low flows	Monthly distribution
1	Less frequent	Less frequent	No significant change	No significant change	No significant change	No significant change
2	No significant change	No significant change	No significant change	No significant change	No significant change	No significant change
3	Eliminated	Decreased magnitude,  less frequent	Decreased magnitude	Increased magnitude	Increased magnitude, shift in timing from September to March	Decreased streamflow from February to May, increased streamflow from July to November
4	Decreased magnitude	Decreased magnitude	No significant change	Increased magnitude	Increased magnitude,  no significant change in timing.	Decreased streamflow from February to May, increased streamflow from August to November
5	Eliminated	Eliminated	No significant change	Increased magnitude	Increased magnitude, shift in timing from September to March	Decreased streamflow from February to May, increased streamflow from July to November
6, 7	Decreased magnitude, less frequent	Decreased magnitude, less frequent	No significant change	Increased magnitude	Increased magnitude, no significant change in timing.	Decreased streamflow from March to May, increased streamflow from July to November
9, 11, 12	Decreased magnitude, less frequent	Decreased magnitude, less frequent	No significant change	Increased magnitude	Increased magnitude, no significant change in timing.	Decreased streamflow from March to May, increased streamflow from July to November