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What Could A 'Water Bank' Withdrawal Cost Lake Mead?


Lake Mead

Lake Mead stores the water Las Vegas and other cities use.

It’s a practice that’s been around for decades but few know about it. It’s called water banking.

Water banking is when a water district doesn't take its water allotment, instead it takes payment for it. The district that paid for the water then must pay back by not taking its allotment in the future.  

The Southern Nevada Water Authority board will decide whether to enter into an agreement with the Metropolitan Water District of Southern California Thursday.

The way the arrangement would work: Nevada would receive $45 million from California. Nevada – in return - would give 150,000 acre feet of water to California, enough for 300,000 homes.

That 150,000 acre feet is half of Nevada's annual share of the Colorado River.  

However, in a time of need, Nevada would get back that acre feet from California's water share.

John Entsminger, General Manager of the Southern Nevada Water Authority, talked to KNPR’s State of Nevada about the water banking deal. 

"We actually have a large portion of this water already in a bank account. It's in our Lake Mead bank account," Entsminger said.

One of the big problems with holding water in Lake Mead and other reservoirs is evaporation. The SNWA is charged an evaporation fee of about 3 percent a year. In addition, the water authority couldn't get extra water when it is needed, like not having a savings account for emergencies. 

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"By moving it from this account to an account in California, we solve both of those problems," Entsminger said. "The water won't be evaporating out from underneath us and we'll be able to call on it when we really need it."

The $45 million raised by the deal would go to the water authority's rates stabilization fund. 

"We're only in a position to do a banking arrangement like this with California because of the extraordinary conservation efforts of our community," Entsminger said.

He said the water that is going to California wouldn't needed by people in Southern Nevada for another 10 or 15 years, which could mean a higher evaporation rate. 

In California, the water will be used right away, which is why he said the deal is in "the best interest of Nevada and California."

The deal will not impact Lake Mead's elevation, according Entsminger.

"Lake Mead would be at the exact same elevation it would have been whether this deal is entered into or not," he explained. 

Entsminger also said Southern Nevada has banked millions of acre feet of water through out the West and even in Mexico. 



John Entsminger, general manager, Southern Nevada Water Authority

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