Tuesday, January 15, 2019

The West’s Great River Hits Its Limits:  Will the Colorado Run Dry?

As the Southwest faces rapid growth and unrelenting drought, the Colorado River is in crisis, with too many demands on its diminishing flow.  Now those who depend on the river must confront the hard reality that their supply of Colorado water may be cut off.  First in a series.

The Colorado flows 1,450 from its source in Colorado to the southwest, ending just short of the Gulf of California. (Map Credit:  David Lindroth) Click to Enlarge.
The Colorado River gathers momentum in western Colorado, sea-green and picking up a good deal of steam in its confluence with the Fraser, Eagle, and Gunnison rivers.  As it leaves Colorado and flows through Utah, it joins forces with the Green River, a major tributary, which has its origins in the dwindling glaciers atop Wyoming’s Wind River Mountains, the second largest glacier field in the lower 48 states.

The now sediment-laden Colorado (“too thick to drink, too thin to plow” was the adage about such rivers) gets reddish here, and earns its name – Colorado means “reddish.”  It heads in a southwestern direction through the slick rock of Utah and northern Arizona, including its spectacular run through the nearly 280-mile-long Grand Canyon, and then on to Las Vegas where it makes a sharp turn south, first forming the border of Nevada and Arizona and then the border of California and Arizona until it reaches the Mexican border.  There the Morelos Dam — half of it in Mexico and half in the United States — captures the last drops of the Colorado’s flow, and sends it off to Mexican farmers to irrigate alfalfa, cotton, and asparagus, and to supply Mexicali, Tecate, and other cities and towns with water.

While there are verdant farm fields south of the border here, it comes at a cost.  The expansive Colorado River Delta — once a bird- and wildlife-rich oasis nourished by the river that Aldo Leopold described as a land of “a hundred green lagoons” — goes begging for water.  And there is not a drop left to flow to the historic finish line at the Gulf of California, into which, long ago, the Colorado used to empty.
The hard lesson being learned is that even with the Colorado’s elaborate plumbing system, nature cannot be defied.  If the over-allocation of the river weren’t problem enough, its best flow years appear to be behind it.  The Colorado River Basin has been locked in the grip of a nearly unrelenting drought since 2000, and the two great water savings accounts on the river — Lake Mead and Lake Powell — are at all-time lows.  An officially announced crisis could be at hand in the coming months.
The bill for a century of over-optimism about what the river can provide is coming due.  How the states will live within their shrinking water budget will depend on how severe the drought and drying of the West gets, of course.  But however the climate scenario plays out, there is a good deal of pain and radical adaptation in store, from conservation, to large-scale water re-use, to the retirement of farms and ranches, and perhaps an end to some ways of life.  Worst case, if the reservoirs ever hit “dead pool” — when levels drop too low for water to be piped out — many people in the region could become climate refugees.

“I hate to use the word dire, because it doesn’t do justice to the good-thinking people and problem solvers that exist in the basin, but I would say it is very serious,” said Brad Udall, a senior scientist at the Colorado Water Institute.  “Climate change is unquantifiable and puts life- and economy-threatening risks on the table that need to be dealt with.  It’s a really thorny problem.”

Read much more at The West’s Great River Hits Its Limits:  Will the Colorado Run Dry?

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