Opinion: We’ve known that a shortage is coming for years, but it’s alarming how quick the conditions are changing. The Colorado River system was not set up for this.
This warm, dry weather we’ve been having may be good for moving activities outside.
But it’s bad news for our water supply.
The chances are growing – and quickly – that a warm, dry winter could push Lake Powell to a trigger point about a year from now that could result in significantly less water for Lake Mead, which supplies about 40% of Arizona’s water supply.
That likely would push Mead into a first-time shortage declaration. And if the same thing were to happen the following year, it would likely plunge Mead into a more severe shortage – a depth from which the lake is unlikely to recover any time soon.
Like I said, bad news.
Why would Mead get less water?
The 2007 operational guidelines lay out how much water is released from the upstream Powell to the downstream Mead. In “normal” years (and yes, I use quotes because nothing about the Colorado River is normal these days), Mead gets about 8.23 million acre-feet.
That drops to 7.48 million acre-feet once Powell’s levels fall below a certain depth. This occurred once before, in 2014, and luckily, Mead was nowhere close to a shortage then.
But lake levels plunged that year and never recovered, even in wet years and despite millions of acre-feet of water that Arizona and others have stored in Mead.
The lake is currently less than 10 feet above its shortage elevation trigger of 1,075 feet. Yet a 7.48 million acre-feet release in water year 2022, which begins in October 2021, could drop levels on Lake Mead by nearly 20 feet.
That could plunge us into shortage
That would place us solidly into a Tier 1 shortage – which for Arizona, means no more Colorado River water for Pinal famers and some water lost from the non-Indian agricultural (NIA) pool, which is a rung higher on the priority list and despite its name, mostly supplies tribes and cities.
Should conditions persist and Mead get another 7.48 million acre-feet release in water year 2023, that would likely plunge us deep into a Tier 2 shortage, nixing most of the NIA water that some cities use for existing development and others had wanted to shore up their long-term supplies.
Without that water, cities will need to find other, more secure sources. Which means if the battle to transfer water from on-river communities to Queen Creek is fierce now, new ones are likely to get a lot fiercer.
How likely is this 7.48 scenario?
We’ve known for years that a shortage would eventually come to Lake Mead, and that when that happens, Arizona – the state with junior water rights – would be the first to face more severe consequences.
But it’s alarming how quickly the conditions are…