Western states buy time with a 7-year Colorado River drought plan, but face a hotter, drier future
Posted by admin on 10th July 2019
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As Midwest states struggled with record spring flooding this year, the Southwest was wrestling with the opposite problem: not enough water. On May 20, 2019, federal officials and leaders from seven states signed the Colorado River Drought Contingency Plan, a sweeping new water management agreement for this arid region.

The plan is historic: It acknowledges that southwestern states need to make deep water use reductions – including a large share from agriculture, which uses over 70% of the supply – to prevent Colorado River reservoirs from declining to critically low levels.

But it also has serious shortcomings. It runs for less than a decade, through 2026. And its name – “Drought Contingency Plan” – suggests a response to a temporary problem.

As scholars who have spent years researching water issues in the West, we know the Colorado River’s problems are anything but temporary. Its waters have already been over-allocated, based on a century of false optimism about available supply. In other words, states have been allowed to take out more than nature puts back in.

Now the river is being further depleted by climate change-driven aridification. The next steps, post-2026, require a recognition that Arizona, Nevada and California will likely have to come to terms with permanent reductions in their Colorado River supply. For their part, Wyoming, Utah, Colorado and New Mexico must abandon dreams of taking ever-larger gulps from the Colorado River to support future growth.

The Colorado River flows 1,450 miles from Colorado south into Mexico, where it empties into the Gulf of California.
USGS

Draining western reservoirs

The Drought Contingency Plan is an important step in that direction. By creating a new layer of rules that temporarily reduces water allocations, it significantly reduces the chance of emptying Lake Mead, the massive reservoir on the Arizona-Nevada border that supports residents of Arizona, Nevada, California and Mexico. Without the plan, the lake conceivably could have been sucked dry – a devastating prospect for 40 million people who live in the Colorado River Basin.

As a seven-year stopgap, the plan comes just in time. After 19 years of unprecedented low flows, the nation’s two largest reservoirs – Lakes Mead and Powell – collectively contain only 40% as much water as they held in 2000. And while the winter of 2018-2019 was a big snow year, it merely balances the previous year, when record-setting warm and dry weather in large parts of the basin lowered water levels in Lake Powell by over 40 feet.

Dry years like 2018 are the far more likely future. From 2000 through 2004, annual runoff totaled only 65% of the 20th-century average. And in 2012-2013, it was just 60% of the 20th century average. More episodes like these would seriously compromise the system’s ability to provide water to the seven Colorado River Basin states and Mexico.

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