Central Idaho water outlook is average
Most South Idaho reservoirs won’t fill
By GREG STAHL
Express Staff Writer
With near-average snowpacks in its central
and northern mountains, Idaho appears to be entering another year of drought.
Though precipitation in March was far
above average in most of the state, water experts are warning that reservoir
storage across the state’s central and southern regions is far below normal.
Magic Reservoir, which is fed primarily by the Big Wood River, was only 19
percent of its 191,500-acre-foot capacity March 31.
"Mother Nature has not been kind to us,"
said Big Wood Canal Company Manager Lynn Harmon.
Harmon predicted that Magic will supply 35
to 45 days of water this summer, "maybe a little better." Last year, the
reservoir supplied 73 days of water to farmers near Richfield.
In order to fill the reservoir, snowpacks
would need to climb to about 150 percent of average, Harmon said, and that is
unlikely. Though mountain weather is unpredictable, April 1 is generally
considered to be the transition between winter and spring. It’s also the
traditional start of the Idaho irrigation season.
However, Magic Reservoir’s status is a
gloomy look at what has been, after a near normal winter for precipitation in
much of Idaho, barring the southernmost regions. According to the Idaho
Department of Water Resources, the Big Wood River basin was 88 percent of
average April 1. The Salmon and Payette basins were 98 percent of average, and
the Clearwater River basin was 97 percent of average.
"If we forget about southern Idaho for a
minute, it’s a definite improvement over the last month," said Natural Resources
Conservation Service Hydrologist Phil Morrisey.
Morrisey said March precipitation in the
Clearwater basin was 200 percent of average, and the upper Snake River and Big
Wood River basins received 10 percent more precipitation than the average March.
"It’s a lot better news than last month.
We’re getting close to that normal range," he said.
In Idaho and across most of the arid West,
however, normal isn’t enough.
"More people claim water rights than what
an average runoff would be," Morrisey said. "So, the reservoirs are there to
catch the extra. If it was just normal, normal, normal year after year, I’m not
sure the reservoirs would be able to stay full."
Unfortunately, it hasn’t been normal the
last several years. It’s been slightly below normal each year, and some of the
reservoirs, Magic included, are not even close to filling.
Does it fit the definition of a drought?
"Drought kind of creeps in slowly as a
result of a couple of years of dryness," Morrisey said. "When does it start? We
don’t really have a good definition. The term drought means different things to
different people. People who have good water rights below a good reservoir, they
might not perceive a drought."
Morrisey added that other drought
indicators include soil moisture and spring flows. He said reports indicate that
both are suffering from several years of below-normal precipitation.
"Those are kind of the cumulative effects
of the ground water and soil moisture being depleted, and that take a few years
to recover," he said.
Irrigation and farming aside, Idaho’s
winter precipitation can help predict the severity of the summer wildfire season
to come.
Federal experts are predicting that 2003
will not be as severe as last year, but still more fire-prone than an average
year.
Fire forecasters said consecutive dry
years coupled with early snowmelts could result in an extended fire season. They
also said drought-stressed or insect-damaged vegetation will increase the
potential for large, destructive wildfires.
"Nationally, it won’t be as severe as
2002, but it still will be more severe than average," said Rick Ochoa, national
fire weather program manager. "As a whole, the Great Lakes area and the
Northwest may have a more significant fire season than the Southwest."
The Southwest and Colorado, which had a
severe fire season last year, will have an "above average season, but not as
intense as last year," Ochoa said.