1,075: What a Lake Mead “shortage” would mean in practice

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update, June 24, 2015: Since this post was written in April 2015, a wet spring has reduced the chance of a “shortage” in 2016. It now appears 2017 is the earliest this could happen. The situation described in rest of the post, detailing what happens when a “shortage” is declared, remains the same.

previously

tl;dr There is a clear possibility of a shortage declaration on Lake Mead in August, which would force a reduction in Lower Colorado River water deliveries, primarily to Arizona, in 2016. Nevada and Mexico would also see small shortages. Neither California, nor the states of the Upper Basin (New Mexico, Utah, Colorado and Wyoming) will see any curtailments.

This is a big deal, but it is almost entirely an Arizona big deal. Arizona currently has the slack in its system to absorb the reductions, including possibly deeper cuts if Mead continues to drop, without major disruptions. The Phoenix and Tucson metro areas are not going to dry up and blow away.

Longer details below:

Continue reading ‘1,075: What a Lake Mead “shortage” would mean in practice’ »

The water efficiency of California ag

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Some interesting stats from Charles Fishman (whose book The Big Thirst is a timely read):

As I’ve said, farmers are clever.

On the Rio Grande drought, not exactly optimism, but not pessimism either

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Michael Wines in Monday’s New York Times:

The perils of drought are on ample display along the Rio Grande, where a rising thirst has tested farmers, fueled environmental battles over vanishing fish and pushed a water-rights dispute between Texas and New Mexico to the Supreme Court.

But you can also see glimmers of hope. Albuquerque, the biggest New Mexico city along the Rio Grande, has cut its water consumption by a quarter in 20 years even as its population has grown by a third. Irrigation districts and farmers — which consume perhaps seven of every 10 gallons of river water — are turning to technology and ingenuity to make use of every drop of water given them.

John Fleck, a journalist and scholar at the University of New Mexico Water Resources Program who is finishing a book on the Colorado River, said no one should dismiss the gravity of the West’s plight. But neither is it necessarily ruination.

“This whole running-out-of-water thing isn’t really doom,” he said. “When water gets short, farmers get very clever.”

With which, it goes without saying, I agree.

 

The interior West’s disappearing snowpack

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Checked in this evening on the snowpack map, which I haven’t been watching closely. Yow, what I missed! On the left is percent of average for March 1, on the right is this morning’s percent of average:

declining snowpac

declining snowpack

Here’s what that looks like summed up across the Colorado River Basin above Lake Powell:

Snowpack above Lake Powell

Snowpack above Lake Powell

Water in the desert, Wellton-Mohawk edition

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Preparing the field. Wellton-Mohawk Valley, Arizona

Preparing the field. Wellton-Mohawk Valley, Arizona

The Wellton-Mohawk Valley is one of those places where you can feel the desert pressing in around you, a ribbon of irrigated green no more than 3 miles wide along the Gila River in southwestern Arizona. The last of the winter vegetables are done, and farmers are getting the ground ready for their spring-summer cover crops. This is Colorado River water, diverted at the east side of Imperial Dam into the Gila Main Gravity Canal.

San Diego displeased with state water mandate

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The San Diego County Water Authority is displeased with the state of California’s decision to set the starting point for its water conservation mandate at 2013, arguing that it rewards communities that ignored the need to conserve until recently, and  penalizes those that have been at the conservation game for a while:

For example, water use in San Diego declined 20 percent from 2007 to 2013. By failing to account for this conservation, the proposed regulations punish those who have conserved and rewards communities that did not make such early and sustained commitments to conservation.

Fallowed ground: 21st century water institutions on Yuma Mesa

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Fallowed field on Yuma Mesa, April 2015, by John Fleck

Fallowed field on Yuma Mesa, April 2015, by John Fleck

This is a field fallowed under a 2013 agreement between Yuma Mesa Irrigation and Drainage District and the Central Arizona Groundwater Replenishment District.

The deal is small, but it raises all kinds of fascinating issues of both water management and culture down here in Arizona’s southwestern corner, where water is both economically critical and culturally of profound importance.

The economics makes sense. Farmers up on the mesa’s sandy soil pretty much exclusively grow citrus, which has had its ups and downs in recent years. Every 15 or 20 years, they pull out groves and rest the land for a few years to kill the cooties (not the technical term) that build up in the soil before planting new fruit trees. Typically they’ll plant alfalfa as a cover crop to generate a bit of income during this cootie-killing phase. But CAGRD came down here a few years ago with an offer: $750 an acre to simply fallow the land. (update in response to reader question: It’s $750 per acre per year, currently a three-year agreement, with farmers able to move in an out of the program in one year increments during that time.) (Brett Walton did a good story back in 2013 explaining the deal in more detail.) That’s more than the farmers would have made with the alfalfa, so a bunch signed up – 1,420 acres’ worth, a bit less than 10 percent of the irrigated land on the mesa. The unused water, which preliminary calculations put at a bit less than 5 acre feet per acre, is held in Lake Mead.

It’s not a lot of water. This was as much about learning how to do a deal like this in Arizona as it was about the water saved. California is much further along in this sort of thing, with ag->urban transfers from Palo Verde and Imperial Valley to coastal Southern California. But this is new territory here in Arizona.

I’m not sure yet what lessons have been learned. There are, as one ag water person down here told me, a lot of people in Yuma that don’t want any water leaving Yuma. It’ll be interesting to see if the agreement is renewed.

The groundwater-surface water connection

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Sharlene Leurig:

We dug through a ton of data to learn what we could about how much water in Texas rivers comes from groundwater. We were really amazed to find that in an average year, not a drought year, anywhere between 15 and 40 percent of a river’s flow comes from the water below ground.

During times of drought, like what we have been experiencing in the past few years, the amount of water in a river in Texas that comes from below ground can be as high as 80 percent of total flow. So it is a really critical interaction, but it is one that is poorly understood in terms of data and monitoring. It is poorly managed in terms of state water plans, projections of future availability, the impact of our desired future conditions.

 

Palm trees and durum wheat

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Palm trees and durum wheat, Gila Valley east of Yuma

Palm trees and durum wheat, Gila Valley east of Yuma

One of the things we do with Colorado River water is grow durum wheat in the Gila River Valley. Durum is used to make pasta. Here in the valley around Yuma, where the Gila River meets the Colorado in Arizona’s southwestern corner, durum is planted as a cover crop in spring on land that derives its primary income from winter vegetables.

The growth of a winter vegetable agricultural base here over the last four decades has been extraordinarily lucrative, and it also uses less water than the old days when they irrigated cotton and alfalfa during the crucible that is summer in the Lower Colorado River desert. Total annual water use here is about 20 percent less than it was in the 1970s, when the shift to winter lettuce began. (The Yuma County Agriculture Water Coalition has much more background on water use here, including an interesting report arguing the case for the efficiency of their water use.)

Most U.S. durum wheat is grown in North Dakota, with California, Arizona and Montana also contributing. (source pdf)