The record snowpack and long, late runoff this year would seem like an unlikely harbinger of future conditions in a warming world.

But the U.S. Bureau of Reclamation’s climate scientists and its Pacific Northwest regional director Karl Wirkus say this spring followed the kind of extreme conditions their models predict — and it already is posing new challenges in how to handle both extremely wet and extremely dry conditions.

The bureau’s recent West-wide climate report predicts warmer, but on average wetter, conditions for the Snake River.

That means this region will have far more water than the Southwest, increasing the chance that water managers from the urban areas there may want to look north to divert water south, Wirkus said.

But the bigger challenge will be to manage river flows in times of growing climatic uncertainty.

Models show the Snake River will have generally higher flows in the spring and the early summer, and lower flows in the fall at the end of irrigation season.

But they also show increased variability — so while reservoirs are full now, Wirkus is convinced the region will face back-to-back drought years in the future that could be even worse than we’ve seen in the past.

“You may very well see the other end of this, so the ’50s droughts or the ’70s or ’90s droughts don’t describe what the really dry conditions can be,” Wirkus said.

The balancing act between preventing floods and filling reservoirs for irrigation will get even harder. “We’re going to have to figure out how to manage the flood risk around the risk of filling,” Wirkus said.

ALREADY UNPRECEDENTED

Wirkus’ agency couldn’t use history to guide it through the long effort this year to keep the Snake River from flooding from Jackson, Wyo., to Payette.

Reservoirs like Jackson Lake and Palisades filled in late July, long after they are usually full.

Yet just a few months earlier, Palisades was down more than a million acre-feet, and farmers were worried it wouldn’t fill. By comparison, all three Boise River reservoirs hold less than 900,000 acre-feet together.

By May, Wirkus’ flood experts were telling him to release even more water into the South Fork of the Snake on the Wyoming border to capture the additional snow that had fallen in the mountains.

And the week before Memorial Day, a full inch and a half of rain fell on midelevation snow on the west slope of the Tetons drained by the Henrys Fork of the Snake River that joins the South Fork near Idaho Falls. Already, the riverside communities of Shelley and Firth downstream were beginning to flood.

Bureau veterans urged Wirkus to shut down Palisades flows so the “slug” of water moving down the Henrys Fork would not combine with high South Fork flows to make Shelley’s flooding worse. Once that high water moved downstream, bureau engineers increased flows from Palisades.

Yet even with more water to move, the bureau was able to ensure there was less flooding than there had been in the last big flow year, 1997.

Some of that, Wirkus acknowledged, was luck.

“I think the Bureau of Reclamation did as good a job as they could with the weather conditions we had this spring,” said Jeff Raybould, a Rexburg farmer and a member of the Idaho Water Resources Board.

NEW CLIMATE, NEW NEED FOR STORAGE

It used to be that farmers like Raybould and the irrigation community in general were the major constituency of the bureau. But today, the agency must balance irrigation with flows for resident fish, recreation such as the whitewater rafting businesses around Jackson, and downstream salmon and steelhead.

As Pacific Northwest region director, Wirkus is in charge of the Columbia River Basin, which includes Idaho, Washington, most of Oregon, and parts of Montana and Wyoming.

He has under his charge 54 reservoirs that hold 18 million acre-feet. Power production facilities at Grand Coulee Dam are among the largest in the world.

More reservoirs would make it easier to manage a future where there is less snow in the mountains to store water. But Wirkus is skeptical the federal government will finance new dams in a time of budget cuts and calls for smaller government.

Twin Falls Canal Co. manager Brian Olmstead doesn’t disagree. Instead, he looks underground for the tool that could have captured for future uses some of the more than 2 million acre-feet of water that ran down the Snake this year in flood flows.

“We think the answer is the Eastern Snake Plain Aquifer — by far the biggest reservoir we’ve got,” Olmstead said. “We just haven’t had the consensus to develop that.”

The Lake Erie-sized aquifer underlies southern Idaho from Ashton to King Hill. Canal companies like Olmstead’s ran their systems full this spring in hopes some of the water would leak below the surface and recharge the underground reservoir.

But Olmstead acknowledges this practice only increases storage near the recharge sites and has little permanent impact. That would take more ambitious and expensive programs like the one Arizona is implementing with money from Las Vegas.

The Central Arizona Water Conservation District has constructed six recharge projects to recover more than 200,000 acre-feet of water by filling basins with treated water and letting it seep back down.

Even environmental groups like Idaho Rivers United, which oppose new reservoirs, support aquifer recharge projects that protect the health of the river, said the Boise group’s Kevin Lewis. But they want more water conservation, as well, a tool Wirkus supports, too.

Despite the current political climate, Idaho Water Users Executive Director Norm Semanko doesn’t rule out that Idaho irrigators or urban residents facing floods will try to build more reservoirs in the future.

“If people really want water, and they’re ready to finance it, they’ll do it,” he said.

A COMING BATTLE?

Today, the Colorado River drains 12 million to 15 million acre-feet of water for the states of Colorado, Wyoming, Arizona, Nevada and California. The Columbia has 135 million acre-feet in a good year — and that’s going up while the Colorado is going down.

“Twenty years from now, there is going to be even worse Northwest envy than there is now,” Wirkus said.

Historically, California and Nevada have expressed interest in diverting some regional water south, and regional lawmakers have even placed a law banning such diversions. But water planners will have to find a way to continue to support the 25 million people who live in the Los Angeles area — as their traditional sources of water dry up.

“There has always been that sort of weird engineering optimism that we can solve our problems by moving water around,” said John Freemuth, a Boise State political science professor and fellow at the Andrus Center for Public Policy.

But he thinks today that is tempered by the recognition that water conservation is a more efficient tool. He recommends that upstream states like Idaho work with downstream states on water programs that benefit both.

Raybould is one of the pioneers of working collaboratively with anglers and others in the Henrys Fork basin to resolve water issues. The Henrys Fork Watershed Council formed after the bureau’s communication broke down between irrigators and fishermen over a dam release.

Things are better now between everyone, he said.

“I think we are seeing river operations run with more flexibility to meet an increasing amount of needs,” he said.

Rocky Barker: 377-6484