DC, April 7, 2004 (ENS): Additional permits
for water to be diverted from the Columbia River for
farm irrigation should be granted only if the withdrawals
can be stopped if river flows become critically low
for endangered and threatened salmon, according to a
federal panel of experts.
In a report released last week, the committee of the
National Academies National Research Council warned
that salmon are at increased risk during periods of
low flows and high water temperatures, conditions that
are most likely to occur during the summer months when
demand for water by farmers is greatest.
"Whether or not to issue additional permits is
a decision to be made by the public and policy-makers,
but if the withdrawals are allowed, there should be
enough flexibility to halt them if river conditions
become too severe for the salmon," said Ernest
Smerdon, chair of the committee that wrote the report,
and retired vice provost and dean, College of Engineering
and Mines, University of Arizona in Tucson.
The report was requested by the Washington State Department
of Ecology, which asked for an evaluation of the effects
of additional water withdrawals of approximately 250,000
acre-feet to 1.3 million acre-feet per year. The latter
amount is roughly the volume sought in currently pending
applications for additional water withdrawals.
An acre-foot is the quantity of irrigation water that
would cover an acre to a depth of one foot -- equal
to 325,851 gallons.
Over the course of the 20th century, salmon runs on
the Columbia River dwindled from around 16 million per
year to only 1 million per year.
Numbers have rebounded slightly in recent years, mainly
because of favorable conditions in the Pacific Ocean,
to which young salmon migrate before returning upstream
The committee reviewed many competing scientific hypotheses
and models that attempt to explain the effects of various
environmental conditions on Columbia River salmon.
There is no scientific consensus on which environmental
factors pose the greatest threat to salmon, the committee
said, but scientific evidence does show that when extremely
low flows or excessively high water temperatures occur,
pronounced changes in salmon migratory behavior and
lower survival rates can be expected.
Because the Columbia River basin extends across seven
states, many Indian reservations, and one Canadian province,
the committee urged the jurisdictions involved to convene
a forum for documenting and discussing the potential
effects of proposed water diversions.
Making decisions about diversions on a case-by-case
basis without considering the basinwide cumulative effects
will contribute to degraded conditions for salmon, the
Several water management approaches being considered
by the state's department of ecology were reviewed by
It recommended against any conversion of current water
rights to so-called uninterruptible status - an approach
in which a farmer gives up rights to a certain volume
of water in exchange for a guaranteed minimum level
of water every year - because this method would decrease
flexibility in times of low flows or high water temperatures.
The committee also found the department's market-based
proposals appealing because the trading of water rights
could lessen the need for further water diversions.
The committee stressed that regardless of the approaches
it chooses, the department of ecology should adopt the
principles of adaptive management, where decisions are
made and adjusted based on continuous scientific experimentation