Thursday, May 21

When water conservation is counterproductive: "Waste, paradoxically, is a kind of reservoir"

Now they tell us.  Below, passages from a New Yorker article (May 25 issue) Where the River Runs Dry: The Colorado and America’s water crisis by David Owen.  While the article focuses on problems with the Colorado River water, Owen addresses some little known or poorly understood water issues that aren't specific to the river. I nearly fell off my chair when I read about the problems with water efficiency. All these months I've been wracking my brain about how to conserve water, as have a great many other people.  Turns out there's a "Damned if you do, damned if you don't" aspect to efficiency in this case.                                                

I've added a few notes after the New Yorker quotes. With no further introduction:  

In the Grand Valley, the principal crops include peaches, alfalfa, and grapes. I visited Brooke and Brad Webb, who worked in finance in Denver until 2009, when they bought Mesa Park Vineyards, in Palisade. Brooke showed me their headgate and the communal irrigation canal that feeds it. 

“When we moved in, the water wasn’t being managed well,” she said. “So we started cutting new furrows every year, and we’ve cleaned out our ditches and lined them with plastic, to keep them from leaking, and now we actually manage the wastewater for about five different properties.” 

The Webbs draw much less water than their right entitles them to, and they have eliminated a wet area at the bottom of their property, where excess irrigation water used to pool.

Reducing waste seems like an obvious solution to overuse, but it can actually make the problem worse. Bradley Udall, a scientist at Colorado State University’s Colorado Water Institute -- his family has been prominent in conservation and in regional and national politics for decades -- told me that water use can be divided broadly into two categories: consumptive and non-consumptive. 

When a farmer irrigates a field with river water, he said, some of the water is consumed by whatever the farmer is growing and by evaporation, but some is returned to the stream. The ditch system in the Grand Valley carries runoff and surplus irrigation water back to the river, and that water is used again, mainly by other farmers. (Kent Holsinger told me that, on average, river water is used more than half a dozen times before it leaves the state.) 

Excess irrigation water also soaks into the earth, replenishing groundwater and, eventually, feeding surface streams.

Udall said, “Efforts to improve water efficiency in agriculture almost always lead to increases in the consumed fraction. On an individual field, they make it look like we are using water better, but they actually move us in exactly the wrong direction.” 

Modern, efficient irrigation techniques can cause crop yields per acre-foot to rise, but also increase water consumption, so downstream users who relied on excess from upstream -- the non-consumed fraction -- now have to find water somewhere else. Increasing efficiency also does nothing to address over-allocation. Indeed, it can make over-allocation more dire, by allowing uses, and even the total number of users, to grow. 

Waste, paradoxically, is a kind of reservoir. If the residents of a suburb routinely water their lawns, they can stop during a drought. But once they’ve replaced their Bermuda grass with cacti and gravel, and once the water that formerly ran through their sprinklers has been redirected to bathrooms and kitchens in brand-new subdivisions, the enlarged system is more vulnerable in dry periods, because it contains less slack.

Cox drove me past a field in which one of his employees was planting lettuce, and parked by another ditch. “This is some of our citrus, here,” he said. “It’s grapefruit. It’s been flood-irrigated in the past, but we’re switching it all to micro-sprinkler.” 

Doing that will reduce Cox’s water need, but it will also have the perverse efficiency effect that Bradley Udall described, by turning a non-consumptive use (irrigation runoff) into a consumptive one (more grapefruit). That’s an especially complicated issue in the Imperial Valley, because runoff from farms like Cox’s is the only source of water, other than modest amounts of rainfall and mountain runoff, for the Salton Sea, an immense but shrinking and increasingly threatened lake at the northern end of the valley. [He means water in addition to water received from the Colorado for irrigation.]

Conservation has had other negative effects in the region. Water from the Colorado is transported to the valley by the All-American Canal, which was completed in 1942. It used to leak tens of thousands of acre-feet a year into the desert along its route. In 2010, as part of the Quantification Settlement Agreement, a concrete-lined replacement for the most porous section was completed. 

But it turned out that the leakage had sustained a fragile Mexican wetland, which dried up when the leakage stopped; leakage had also provided irrigation water for Mexican farms near the border. 

Lining the canal didn’t reduce water use or turn waste into a new resource; instead, it transferred an existing resource from Mexico to Southern California, creating a shortage that then had to be relieved with water from somewhere else.


Pundita Notes

1.  The entire writing is important but I wish Owen or another reporter would dedicate an article to the conservation issue he raised. I'd especially like to know whether any study has been done yet to determine when/if use of a large volume of water in a concrete-paved environment (cities) outweighs concerns about zealous conservation.   

2. I have a question about another part of the article, which discusses how water rights are allocated in the western states: “Water law in Colorado and most states in the West is based on what’s called the doctrine of prior appropriation." ...  “first in time, first in right.”

I'm trying to understand how this law squares with the "use it or lose it" rule, which was discussed in a National Geographic article about exporting Colorado River water to Asia via alfalfa feed.  (See reference below.)
"There's a lot of water being wasted growing alfalfa in the summer," [Robert Glennon] said. "The [Imperial Valley farmers] do it because they don't have anything else to do with the water, and because they fear they'll lose their rights to it if they don't keep using it. That's a rule that could be changed."
It's possible the rule (and the "first in time" rule) is governed by states and has nothing to do with interstate water law; e.g., the water compact governing how California and other states use the Colorado River water, but I wanted to raise the question.

3.  Three articles that are excellent background to Owen's discussion of problems connected with the drain on the Colorado:

The American Nile (photo essay/video/text), Jonathan Waterman, February 14, 2014, National Geographic
(Stunning, 1 pix worth 1,000 words 'then and now' photos of Colorado tributaries.  

Exporting the Colorado River to Asia, Through HayBen Jervey, January 23, 2014, National Geographic

Water's Edge (5 part video/text series), Steve Baragona, February 12, 2015, VOA News
"Baragona co-wrote a documentary on the impacts of the 2012 drought in the U.S. Midwest that won four awards."
Very interesting comment on the VOA series:
 Matt Colver ·  Top Commenter · California State University, Long Beach
There's one simple solution to add over 300,000 acre feet of water each year. That's more than Las Vegas uses each year. The answer is to lower Lake Powell to almost dead pool depth. Lake Powell is in sandstone and also has a huge surface area. More than 300,000 acre feet of water is lost to evaporation and into the sandstone each year in Lake Powell. Lake Mead is a deeper reservoir made of volcanic rock. It's a better place to store water. Lake Mead should be kept full at the expense of Lake Powell. The dam at Powell would still work to keep silt from filling up Lake Mead. It's a simple thing that can also be reversed if for some reason people change their mind. It's also a lot cheaper than the billion dollar straw they're digging for Mead or better than screwing over the Native Americans one more time by taking their water.  [Feb 23]
 [The remark about Native Americans is a reference to one of the articles in the series]
4.  Don't forget the 2013 Supreme Court decision in Tarrant Regional Water District v. Herrmann (Red River Compact) and the possible implications for renegotiation of old water compacts between states.  Here's a succinct analysis of the implications by two attorneys.  (PDF) The Court's decision, while narrowly applied to a specific dispute, will take on increasing import the longer the drought in the West drags on, and the more populations in the states grow.    


1 comment:

Lorenzo said...

Central Washington also exports irrigated "meadow" hay (timothy) to Japan where it is, for some non-nutritive reason, highly valued.