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"Natural flow patterns in the McKenzie River have been altered by dams, diversions, water
withdrawals, roads, and changes in the landscape vegetation. Average annual river flows for the McKenzie are 454 cubic feet per second (cfs) at the
outlet of Clear Lake and 5,809 cfs near its confluence with Willamette River at Armitage Park (USGS,1995). Stream flows in the watershed approximate the
seasonal precipitation patterns, peaking in February at approximately 10,200 cfs
in the McKenzie River near Armitage Park and dropping to 2,020 cfs in September
(USGS, 1993). The relatively high stream flow in the
McKenzie is sustained during the early summer months since the
porous lava beds of the high Cascades tend to release water from
snowmelt gradually and at a uniform rate (State Water Resources
Board, 1961).
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McKenzie River south of Goodpasture Rd.
10/99
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In addition, the summer flows are roughly
one-third higher than normal due to the releases of Cougar and Blue
River Reservoirs. There are indications that there may be significant
groundwater sources discharging into the lower reaches of the
McKenzie River as flows are 20 percent higher at Armitage Park than
would be expected solely from overland sources (USGS, 1995)." |
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