Idaho seeks to add water storage

By Sean Ellis, Idaho Farm Bureau Federation
Friday, June 6, 2008 3:16 PM CDT

POCATELLO, Idaho - If it’s true that the era of dam building is over, Dave Tuthill didn’t get the memo. Neither did the governor, legislators, irrigators, municipalities, and several other major water users in Idaho.

Tuthill, director of the Idaho Department of Water Resources, has been around the state recently beating the drum on the need to store more water.

He’s recommended building some new dams, but he’s also advocated doing other things such as raising existing dams, building off-site “mini-reservoirs” and recharging the important Eastern Snake Plain Aquifer.

Anything that increases Idaho’s water storage capacity, which is especially critical for agriculture.

“There are many, many opportunities for storage,” Tuthill said. “If we want to maintain agriculture as an important part of the economy in Idaho, we’re going to need more storage.”

“There’s no question water is a limiting factor in the state of Idaho,” said Albion farmer Tom Geary, chairman of Idaho Farm Bureau Federation’s water committee. “We need to save every drop of water we possibly can.”

Tuthill’s pitches on the dire need for Idaho to store more water may be getting through. There seems to be a growing awareness by a large number of Idahoans that it will be absolutely necessary to capture and store a lot more water in the coming years.

Farmers, of course, have known this for a long time. But now the rest of the state seems to be awakening to the need.

“I think we’re to the point where people throughout the state realize we can’t keep going merrily along our way and ... squandering our water resources,” said Rep. Dell Raybould, R-Rexburg. “I think the time is ripe to be looking at these opportunities.”

“The attitude is substantially changing compared to what it was 20 years ago,” said Geary, who has dealt with water issues for decades and is the immediate past president of IFBF. “People are recognizing water is a limiting factor and a very important thing in the state of Idaho.”

“The governor fully supports additional storage opportunities; the Legislature, water users and the populace have a heightened level of awareness about water,” Tuthill said. “My sense is many people are in favor of these projects.”

The need for more water is only going to continue to grow as Idaho’s population increases, along with urbanization, the drought years continue and more water is needed to meet Endangered Species Act requirements. Disputes between surface- and ground-water users over water that comes from the Eastern Snake Plain Aquifer also threaten to disrupt Idaho’s economy. Curtailment of ground-water pumping always seems to be just around the corner.

“There are all kinds of things we need water for,” Raybould said.

Irrigation in southern Idaho and federally mandated fish-flow requirements offer a good example of how much water is needed.

The 1 million acres of irrigated land along the ESPA require 2 million acre-feet of water each year. And 487,000 acre-feet of water must be used each year to aid endangered fish species.

So ground-water pumping by irrigators and fish flush alone use 2.5 million acre-feet of water each year. By comparison, the entire upper Snake River reservoir system can only hold 4 million acre-feet.

Down the river

According to the IDWR, about 34 million acre-feet of water from the Snake River basin leaves the state each year. There is only 8 million acre-feet of capacity to store water from the basin. So the state can store about 1 acre-foot of water from the Snake River basin for every 4 acre-feet that it loses.

“Obviously, there is a lot of potential there for additional storage,” says Norm Semanko, executive director of the Idaho Water Users Association.

“If we had another 4 million acre-feet, that would not be too much storage,” Tuthill said. “We could put that water to good use.”

There is only 1 million acre-feet of storage capacity in the Boise River basin, which produces 2 million acre-feet of flow in a normal year.

By comparison, the Missouri River basin has the capacity to store 400 percent of its annual flow, and the Colorado River basin can store 200 percent of its annual flow.

“We’re just sending that water downstream and not capturing it,” said Boise water attorney Scott Campbell. “I’d say we need double (the capacity) we currently have. Long term, what are we going to do for water supplies?”

Tuthill said 2006 and 2007 served as good examples of how fragile Idaho’s water situation has become, especially for agriculture. Even though 2006 was a good water year, 2007 wasn’t - and it was almost a catastrophe.

“One year of drought in 2007 and ground-water users barely had enough water,” he said. “If we have two years of drought in a row, there would be serious ramifications on ground-water users. We no longer have a situation where we can survive multiple years of drought.”

If only some of that vast amount of water that leaves Idaho unused every year could be stored, it would help. It can be done, and that’s Tuthill’s message.

Possibilities

There have been several proposals for adding more water capacity. They include:

• Raising Minidoka Dam on Lake Walcott near Rupert 5 feet, which would add about 50,000 acre-feet more capacity. This year’s Legislature approved $1.4 million to study enlarging the dam. This proposal is especially timely because the Bureau of Reclamation is about to begin preliminary design and environmental work on replacing the dam’s spillway. Including the study to raise the dam at the same time would save money.

Everyone contacted for this story agreed this project is the one most likely to happen.

“That one has quite a bit of enthusiasm ... and support behind it,” Semanko said.

• Adding a water storage site in the Teton River basin, which could include rebuilding Teton Dam, which burst in 1976 and claimed 11 lives while killing thousands of livestock and causing hundreds of millions of dollars in damage.

Skeptics say the dam near Rexburg will never be rebuilt because of alleged opposition by local residents. But the proposal to add more water storage in the Teton River basin doesn’t necessarily mean rebuilding the dam at the prior site. It could also mean such things as building off-site mini-reservoirs to store water until it’s needed.

“We’ll be exploring all the options,” Tuthill said. “Rebuilding the Teton Dam is not the only alternative.”

“There are a whole lot of options up there, and we ought to take a look at them,” Raybould said.

The 2008 Legislature approved $400,000 to study this idea.

• Constructing Twin Springs Dam on the Boise River and Galloway Dam on the Weiser River. These proposals may seem to be new ideas to many people, but they’re not. Both have been around for years. If built, the Galloway Dam would hold upward of 500,000 acre-feet of water, while the Twin Springs Dam would hold about 300,000 acre-feet.

There is a lot of interest from various sources in creating additional storage on the Boise River.

“Flood control is a very big issue in the Boise basin,” said Lisa Stark, programs manager with the Bureau of Reclamation.

Though the need there is mainly for flood control, the water could also be used for irrigation and municipalities.

Evaluations by the Army Corps of Engineer and University of Idaho have shown the next great flood in the Boise River valley will cause millions of dollars in damage and potential loss of life. The Corps is working with IDWR on a study that would look at a flood-control project in the Boise basin, and the hope is to get it started next year.

Besides flood control, a recent study predicted the water needs of the Boise Valley will increase by 74 percent by 2025.

There are some environmental issues involved with Twin Springs, Stark said, but geographically, it’s a site that has good qualities for a dam.”

The Galloway would also serve flood-control needs and could offset the water used for fish flow. The Corps of Engineers did studies on this proposal in the 1990s.

• Raising Idaho Power’s Swan Falls Dam on the Snake River near Kuna by 50 feet. Doing that would provide more than 300,000 acre-feet of additional storage and vastly increase the dam’s electrical production.

• Creating more off-site storage areas near rivers and creeks that would serve as mini-reservoirs where water is diverted during high water times. When it’s needed, it would be moved back to the main channel. Most of these off-site storage areas would probably require pumping, though gravity could be used in the right place.

Stark said an example of this type of project is Banks Lake, which has water pumped to it from Washington’s Grand Coulee Dam.

Lake Lowell, 5 miles southwest of Nampa, is an example of an off-site storage area that has water moved to it using gravity. Water from the Boise River moves down a canal and into the lake.

IDWR has a map that shows a lot of sites where this can be done.

• Finding more ways to recharge the ESPA, which would take some of the pressure off the annual dispute between ground-water and surface-water users who get their water from that massive aquifer.

“We need to figure out some way to take excess water when we have it and put that into the ground,” Geary said.

• Conservation will play an increasingly important role this century, Tuthill said, but the reality is that it alone isn’t enough to solve the problem.

“There are many, many opportunities for storage,” Tuthill said.

Meeting the challenge

Accomplishing any of the dam projects will require complying with a mound of federal environmental regulations. Any such facility would have to meet the requirements of the National Environmental Policy Act, Clean Water Act and Endangered Species Act.

“There are all kinds of obstacles and hurdles” involved with dam building, Stark said. “There are all kinds of issues that we face and have to work out.”

Any proposal to build a new dam or enlarge a current one will inevitably meet with opposition from some environmental groups.

Campbell said certain groups will always be opposed to these types of projects but he believes if the public understands the situation, it will support these projects.

“I think if you can get the information out there, people will understand,” he said. “The increase of water storage in Idaho has to happen.”

Assuming the public gets on board and some of these projects proceed, there will be the not-so-small matter of determining how to pay for them, because dams aren’t cheap and the federal government is not likely to pick up most of the tab as it once did.

The funding outlook for these types of projects is not as bright as it used to be, Stark said.

When talking about dams, “You could get into the hundreds of millions of dollars easy, very easy,” she added.

“The reality is these things cost money. Dams aren’t cheap,” Semanko said. “I think that’s going to be one of the great challenges moving forward - who’s going to pay for all of this? - because it will not be cheap.”

The bill could be divvied up between a variety of sources, including the federal government, state, municipalities, irrigators, utilities, and other big water users. Because any new dam would likely produce power, that could help offset the cost.

As the value of water increases, however, the projects will become more feasible, Tuthill said. Already, the value of water has risen “to the point a project not feasible 20 years ago might be feasible today.”

Several western states are pursuing these types of projects and in various ways. Stark said Wyoming is an interesting example of a state that is pursing them without the aid of the federal government. While that precludes a potentially important funding source, it also means they don’t have to meet NEPA and CWA requirements.

Sean Ellis is publications editor for Idaho Farm Bureau Federation.

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