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Study Shows That Klamath River Temperatures – Not Klamath
Project Operations – Are Likely Reason for 2002 Fish Die-Off, by David Vogel
3/03
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Traditional advocates of high mainstem Klamath River flows quickly concluded
last fall that the fish die-off was due in large part to Klamath Project
operations, despite the fact that the fish died below the confluence of the
Klamath and Trinity rivers, 200 miles downstream of the Klamath Project.
Dave Vogel, a fisheries biologist with 28 years of experience (see attached
biography), believes that Klamath River water temperatures are extremely
important in this issue because of the adverse impact high water
temperatures can have on salmon (such as causing disease outbreaks). The
topic is also important because of how water project operations can, or
cannot, affect water temperatures in riverine areas important to salmon.
2002 Findings
During late summer and early fall of 2002, Dave Vogel conducted a field
investigation to assess water temperatures in the main stem Klamath River:
Main stem water temperatures were measured hourly just prior to and during
the fall-run Chinook salmon migration season.
Vogel found that water temperatures in the upper Klamath River downstream
of Iron Gate Dam during September 2002 were unsuitable for adult salmon.
This finding was similar to that of previous studies.
As expected, a normal seasonal cooling trend at the end of September and
early October provided the moderating influence lowering Klamath River
temperatures to tolerable levels for salmon.
Vogel also found that large numbers of salmon entered the lower Klamath
River earlier than usual and were exposed to two dramatic and
uncharacteristic cooling and warming conditions causing disease outbreak
from warm water and crowded conditions.
The combination of these factors was chronically and cumulatively stressful
to fish and is probably the most plausible reason for the fish die-off.
Past Studies Support the 2002 Investigation Results: Iron Gate Dam
Releases Are Too Warm for Salmon in Late August and Early September
Preliminary Assessment of Increased Klamath River Flows for Salmon During
the Late Summer and Fall of 1994. D.A. Vogel and K.R. Marine, Red Bluff,
California (November 1994)
In 1994, fisheries biologist David Vogel co-authored a technical report
which concluded that:
Any increased flows from Iron Gate Dam, pulsed or otherwise, to benefit
adult salmon should only occur during late September or early October to
coincide with normal seasonal declines in air temperatures and concomitant
cooler river flows.
Earlier seasonal increased releases from Iron Gate Dam are unlikely to
provide biological benefits because the water is naturally too warm.
Based on his research in 2002, Vogel’s conclusions remain the same.
Assessment of Alternatives for Flow and Water Quality Control in the
Klamath River Below Iron Gate Dam. M.L. Deas and G.T. Orlob, Center for
Environmental and Water Resources Engineering, University of California,
Davis. December 1999.
Vogel’s conclusions concerning the effect of Iron Gate Dam releases and
upper main stem Klamath River water temperatures in the fall are similar to
the findings of other researchers. For example, Deas and Orlob (1999) found
the following:
“During early fall, mean daily measured water temperatures are fairly
uniform throughout the river system. However, by late fall it is apparent
that temperatures are decreasing in the downstream direction by late fall,
i.e., after October 1. During this period, releases from Iron Gate Dam are
generally at temperatures above equilibrium and the reservoir is acting as a
heat source to the river.”
Study Shows That Klamath River Temperatures – Not Klamath
Project Operations – Are Likely Reason for 2002 Fish Die-Off
Conclusion
It appears that large numbers of salmon entered the lower Klamath River
earlier than usual, were exposed to two dramatic and uncharacteristic
cooling and warming conditions that were chronically and cumulatively
stressful to fish.
At the same time, riverine conditions in the upper Klamath River were
unsuitably warm for salmon because the normal seasonal cooling trend had not
yet occurred.
These data indicate that September 2002 was unique, but not for the
reasons portrayed by the California Department of Fish and Game.
Until additional data is acquired on the topic, Vogel’s opinion is that
the combination of those factors is probably the most plausible reason for
the fish die-off.
“In my opinion, the best available scientific data and information indicate
that the continued operation and maintenance of historical flows at Iron
Gate Dam will not jeopardize coho salmon. Furthermore, in my opinion the
operations of Iron Gate Dam during the summer and fall of 2002 did not cause
and could not have prevented the fish die-off in the lower Klamath River.”
Dave Vogel, March 2003
Klamath Water Users Association
2455 Patterson Street, Suite 3
Klamath Falls, Oregon 97603
Phone (541) 883-6100
FAX (541) 883-8893
kwua@cvcwireless.net |