Southern #Nevada #Water Authority manager says #ColoradoRiver out of easy solutions — The Las Vegas Review-Journal #COriver #aridification

Las Vegas Lake Mead intake schematic, courtesy SNWA.

From The Las Vegas Review-Journal (Blake Apgar):

John Entsminger walks a fine line as Southern Nevada’s top water official.

On one side, he has to explain the seriousness of a shrinking Colorado River to climate change skeptics and people who are content with not immediately handling the West’s water woes.

On the other, he has to quell concerns of crisis on a river that supplies water to 40 million people in the U.S. and Mexico.

“That’s a delicate balance,” he said.

How we got here

How Lake Mead got to its lowest levels in history — enough to trigger a water shortage — isn’t a mystery. Part of it is basic math.

Historically, the lower basin has used more water than has been released to Lake Mead by the upper basin, largely because there is no agreement between the lower basin states on how to cut allocations to account for evaporation.

Couple that with decades of unfavorable hydrology, and Lake Mead begins to decline.

But Southern Nevada has lived within its means in recent decades, using less than its legal entitlement of water every year since 2002, Entsminger said.

Entsminger said he wishes water use had been brought into balance with the river’s flows sooner, but he’s part of a generation of water managers that has addressed the deficit.

He said agreements that have been signed since 2007 seek to create an equilibrium. Lower basin states last week signed a new deal with the federal government that will conserve water beyond those existing agreements to protect Lake Mead from crashing to critical levels.

Brad Udall: Here’s the latest version of my 4-Panel plot thru Water Year (Oct-Sep) of 2021 of the Colorado River big reservoirs, natural flows, precipitation, and temperature. Data (PRISM) goes back or 1906 (or 1935 for reservoirs.) This updates previous work with

Southern Nevada ‘immunized’ from crisis

Entsminger doesn’t think the Colorado River is in a crisis, but it is out of easy solutions.

If the river experiences two more years of hydrology like what it just experienced, it could become a question of how much water the federal government will be able to send downstream from the Glen Canyon Dam, he said.

But even in that case, Entsminger doesn’t see a crisis on the horizon for Southern Nevada.

“And that’s because we’ve essentially immunized ourself from that by the construction of new infrastructure on the shore of Lake Mead,” he said.

About $1.5 billion in local money has gone to ensuring Las Vegas can pump water from Lake Mead, even when the federal government can’t send it downstream to others.

Entsminger said he thinks Southern Nevada is “the most water-secure municipal area in the Colorado River Basin.”

Sustainability in the basin depends on agricultural efficiencies, he said. Locally, Entsminger continues to push for conservation as a way out of a dire situation.

Growth in Las Vegas is possible, he said, but it requires driving down existing water demands and tightly controlling new demands, something he said Southern Nevada has a track record of doing successfully.

One method of meeting conservation goals is through a law signed this year that bans nonfunctional grass in coming years. Another is increased enforcement of compliance with seasonal watering restrictions.

Those measures will be able to save about 15 percent of Southern Nevada’s allocation of Colorado River water under a nonshortage year and help provide the water for additional growth.

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