How to increase Colorado’s water supply


President Barack Obama gave a speech last week in California, which is enduring the worst drought in its recorded history, and he called on the country to rethink how it deals with water.

“We’re going to have to stop looking at these disasters as something to wait for. We’re going to have to start looking at these disasters as something to prepare for,” he said.

“Water has been seen as a zero-sum game: agriculture against urban, north against south. We’re going to have to figure out how to play a different game,” he said.

“We can’t afford years of litigation and no real action,” he added.

Good points. So here’s a different way for Colorado to secure its water supply against the horrors of global warming: Build some seawater desalination plants.

It wouldn’t take very many of them to make a huge difference.

The world’s largest desalination plant is the Sorek plant, located in Israel about 10 miles south of Tel Aviv. It became fully operational last October. Its annual output is 150 million cubic meters of drinking-quality water, or 121,600 acre-feet. The output of two such plants could produce enough water to nearly fill Dillon Reservoir (capacity 257,000 acre-feet), the Denver Water Board’s largest. Six of them could fill all of Denver’s reservoirs (which hold about 658,000 acre-feet) and Boulder’s (which hold about 26,000 acre-feet) with some to spare.

The plant was built in less than three years. Construction costs came to about $400 million.

In other words, for an investment of $2.5 billion, Colorado could desalinate enough sea water to double Denver and Boulder’s water supply in a normal year or to completely replace it in a period of extreme drought.

Of course, there are two small complications: Colorado is about 1) 1,000 miles and 2) a mile uphill from the Pacific Ocean. This would make getting the desalinated water from the Pacific to Colorado, well, challenging.

However, Colorado wouldn’t have to move a drop of desalinated water to Colorado.

That is because in a normal year about 8.66 million acre feet of water flow out of Colorado toward the Pacific Ocean, almost all of it via the Colorado River and its tributaries. This represents more than half of the total amount of water in the Colorado River Basin in a normal year (about 16.5 million acre-feet). Under the Colorado River Compact of 1922, which allocated the water among the seven states in the Colorado River Basin and Mexico, Colorado currently gets to keep 3.86 million acre-feet of the 16.5 million. California’s allocation of Colorado River water is 4.4 million acre-feet.

So the way to augment Colorado’s water supply with Pacific Ocean desalinated water is to cut a deal with California. Swap the water produced by Colorado-built desalination plants on the Pacific coast for an equal amount of California’s Colorado River allocation and reduce the amount of water that leaves Colorado accordingly. Better yet, swap the desalination plants themselves for an equal amount of California’s Colorado River allocation. That way California becomes responsible for running the plants.

It’s a win-win deal for both states. As of today, desalinated water is too expensive for agricultural use and municipal users still pay a premium for it, but unlike water from conventional sources, desalinated water is a drought-proof resource. That could be a big deal, if drought turns into California’s new normal — as some think it may.

Nobel laureate and former Energy Secretary Steven Chu repeatedly cited studies predicting that California’s Sierra-Nevada snowpack could decline by as much as 90 percent by the end of the century; if that happens California’s annual water shortfall could be as much as 35 million or 40 million acre-feet, so any drought-proof source of water would be a godsend.

Colorado, for its part, would get a big addition to its water supply, and while the water rights obtained in the swap wouldn’t be as drought-proof as desalinated water, the water they yielded would be cheap enough for agricultural use.

And if continued drought in the Colorado River Basin were to cut the annual flow in the river by a couple million acre-feet a year (as it has for several years) and thus reduce the size of everyone’s draw, the extra water would be especially valuable to Colorado.

But could desalination plants be built in California for as little as the Sorek plant ($400 million)? Not bloody likely.

As they used to say on late-night TV, prices vary, slightly higher in the West. OK, a lot higher.

The Israeli company that built the Sorek plant, IDE Technologies, is currently building a plant one-third the size of Sorek in Carlsbad, Calif. (Nonetheless, it will be the largest desalination plant in the Western Hemisphere when completed in 2016.) That plant is expected to cost close to $1 billion. There are a lot of factors that have contributed to the cost difference — not least of which was that California’s problem-perpetuating eco-cranks managed to delay the project for 20 years through litigation and gaming the regulatory system. Doing anything in California costs more and takes longer.

Even so, the cost of desalinating water is dropping quickly as technology improves. The amount of electricity needed to desalinate a gallon of water has been cut in half in the last few years, for example. If present trends continue, the cost of increasing a California city’s water supply with desalinated water will be competitive with new water from conventional sources (if there’s any to be had) within a decade.

Moreover, water projects that produce sticker shock when they’re built have a way of looking like incredible bargains within a decade or two — especially if they are financed and paid off in inflated dollars. It cost $49 million to build the Hoover Dam in 1936.

Ensuring that it has an adequate water supply is probably the single most important thing Colorado can do to meet the threat of global warming-induced drought of, say, Anasazi-era proportions.

Building desalination plants on the Pacific and engineering water swaps with California may be the only realistic way to do that.


This opinion column does not necessarily reflect the views of Boulder Weekly.