Drought impacts popular Magic Reservoir
Water level declines in face of dry summer
"I don’t think we’re going to be as low as we were in
the worst of the drought, but I’m a little concerned about next year unless we get
some good rainfalls or significant snowpack over the winter, because, as everybody knows,
it’s powder-house dry out there."
Lynn Harmon, Big Wood Canal Co. manager
By GREG STAHL
Express Staff Writer
On Friday afternoon at Hot Springs Landing boat launch at the north end of
Magic Reservoir, not a boat was put in the water. The reservoir was stagnant and low,
perhaps 50 feet below the high water mark, and well below the bottom end of the concrete
boat launch.
"This fall’s the lowest the water will have been in seven
years," said Jim Brown, a 20-year Magic Reservoir boater, over a Friday afternoon
beer at West Shore Lodge in West Magic.
The
level of Magic Reservoir has been dropping steadily for the past several weeks. By the end
of the irrigation season, in early October, the reservoir could be nearly dry. Express
photo by Willy Cook
Brown said the usually 40-foot-deep waters at Hot Springs are about six
feet deep most of the way across the reservoir. They’re 11 to 14 feet deep at the
deepest, he said.
Brown had been fishing the area early Friday morning and checked the
depths with a fish finding sonar system. The dry years in the late 1980s and early 1990s,
he said, were the last time he remembers Magic’s waters descending as low as they are
now.
According to Magic Reservoir dam tender Mike Childs, the reservoir’s
primary purpose is for irrigation and secondly as a hydroelectric power source. And
it’s managed as such, which sometimes leads to very low levels in dry years like this
one.
"This is a dry year, but I’ve seen it where it was a lot
drier," Childs said during a conversation at his home, which is perched between the
dam and its spillway. "We’re just a little over half full right now."
According to Childs, the reservoir can hold a maximum of 191,500 acre feet
of water.
Right now it’s holding 95,800 acre feet "and dropping
fast," the dam’s power plant supervisor, Mike Nielsen, said in a Monday
telephone conversation.
The typical irrigation season eats up 270,000 acre feet of
water—about a reservoir and a half of water. Power generation, flood control
and public use come as tertiary priorities to irrigation in managing the level of the
reservoir, Nielsen said.
Childs confirmed Brown’s prediction for extremely low water levels
later this fall, though neither he or Nielsen attempted to predict precisely just how low
the water will get.
If water continues to be drained at current rates, however, the reservoir
could be dry by the end of September.
"We can drain it out," Childs said.
Childs said he measures the reservoir’s water level every day at
about 6:30 a.m. It dropped 8.5 inches from the previous day when he measured on Friday
morning, he said, and that’s been pretty typical over the past three weeks.
Childs said the reservoir will continue to be tapped for irrigation until
early October, though the rate of discharge will lessen as the demand for irrigation
waters decreases.
Much of the northern Snake River Plain is irrigated using the Richfield
Canal, which is formed about three miles downstream from the reservoir at an irrigation
diversion. The dam regulates the flows of water that can be diverted into the canal,
Childs said.
In typical years the dam holds a fair amount of water from one year to the
next. The amount of water that remains after the irrigation season is called carryover.
"We’re not going to have really good carryover this year,"
Childs said.
Ultimate decisions on water levels and irrigation releases come from
Shoshone-based Big Wood Canal Co.
Canal company manager Lynn Harmon said in a Monday telephone conversation
that the company is predicting between 12,000 and 15,000 acre feet of water for this
winter’s carryover. That’s about one sixteenth of the reservoir’s capacity.
But this year, Harmon said, isn’t nearly as bad as some.
He recalled the summer of 1992, the driest in recent history, when the
canal company only released irrigation water for 39 days. In typical years, including this
summer, irrigation releases last four months.
"I don’t think we’re going to be as low as we were in the
worst of the drought," he said, "but I’m a little concerned about next year
unless we get some good rainfalls or significant snowpack over the winter, because, as
everybody knows, it’s powder-house dry out there."
After irrigation is shut off in early October, the dam will be nearly
plugged up and will begin to refill.
It won’t completely fill, however, until the Camas Prairie melts and
flows into the reservoir via Camas Creek next spring, Nielsen said. Runoff from the Big
Wood River generally comes later, usually in late May and June, and helps keep the
reservoir full late into the season.
Bureau of Land Management (BLM) park ranger Miles Aslett said the BLM
manages several boat ramps and camping facilities at Magic Reservoir.
He said the number of people using those facilities tends to drop off as
the water level slips.
"We see more use there when the water’s higher," he said.
"Most of our sites are built at the high water mark."
Magic Reservoir was formed when construction of Magic Dam was completed in
1910. In 1916 the dam was raised 10 feet to accommodate an additional 19,500 acre feet of
water.
