Horizon, Host: Ted Simons

March 3, 2011


Host: Ted Simons

Water in the West


  • Using modern scientific tools, a team of researchers led by John Sabo, an ASU Professor in the School of Life Sciences, tested assertions, from the 1986 book “Cadillac Desert”, that the American West was running out of water. Sabo discusses the group’s findings.
Guests:
  • John Sabo - Professor, ASU School of Life Sciences
Category: Sustainability

View Transcript
Ted Simons: In his -- in his 1986 book "Cadillac Desert," author Marc Reisner warned of water scarcity in the western United States. In essence he said our water supply cannot keep up with our growing population. Now using the best available data and the latest tomorrow, researchers have tested the author's conclusions. Their report, "Reclaiming Freshwater Sustainability in the Cadillac Desert" has been published in the proceedings of the national academy of sciences. Joining us now is the lead researcher, John Sabo, he's a professor in the school of life sciences at Arizona State University. Thanks for joining us. We appreciate it.

John Sabo: Thank you for having me.

Ted Simons: Give us a synopsis. What did Cadillac desert say?

John Sabo: Every scientist or every reader of the book would probably have a different take than I do. But my take from a scientist perspective is Reisner had four messages. The first of them is what I call the prophecy, the idea that the U.S. West of the hundredth Meridian is a desert and that reclamation, the building of dams would not change that fact. That's the first one. The second one has to do with sediment. So rivers have silt in them and they deliver that silt downstream and eventually ends up in reservoirs. And Marc Reisner thought that that sediment would have an immediate impact on the ability to deliver water to cities and farms. The third one is salt. And it's salt is the idea that salt accumulation on farmlands as a result of irrigation in a desert region would eventually poison the farmland that it was intended -- that reclamation was intended to supply water to, and so it would no longer help the crops and resources it was intended to in the beginning. As water scarcity increases it will pit cities and farms against each other in this epic struggle for the west's most limiting resource.

Ted Simons: OK. Before we get to answers on all four, what kind of -- how did you do research to find out if these kinds of prognostications are really coming true?

John Sabo: Well, it required a really diverse team, and a lot of kudos to the 12 or 13 coauthors that I had on the paper, because they brought a rich experience and training in three or four different disciplines. The data that I think weren't available to Reisner at the time of the book were simply geospacial data sets, things that describe salt concentrations in soils, water availability in soil, precipitation, all of these things, GiS was just coming to fruition as a tool to allow scientists to look at maps of these big geospacial data sets and now we have the tools to do that as well as really sophisticated models of hydrology that allow us to understand at big scales what virgin flow and rivers would be like without reservoirs.

Ted Simons: The concept, I guess we can agree we still live in a desert. How do you measure something like that? I guess what surface water were you looking at mostly? What were you looking senate.

John Sabo: We looked mainly at surface water, so in the paper we quantified what's called the water scarcity index. And it's essentially the ratio between the amount of water that is -- the amount of surface water extracted -- the amount of water humans use divided by the total amount of surface water available. And in the west the region that we think that Reisner meant for the Cadillac desert, we appropriate 76% of all surface water in that region, which includes seven states and three or four major river basins. So on the answer to that question, yes unequivocally, I think science would set the sustainable limit of about 40%, currently our withdrawals are about 76% of stream flow in the region.

Ted Simons: What about silt and reservoirs?

John Sabo: Silt had kind of an interesting twist. Not unequivocal support, I think most people knew from the outset that the answer was yes, eventually these reservoirs will fill up, but it's just a question of when. What we found was it's going to take longer than the impression that you get from reading the book. So on the order of a century and a half for most reservoirs, but even much longer for some of the big ones. The flip side, sediment has already impacted the capacity for big reservoirs to deliver water to cities and farms on the order as -- the same order as major aqueducts in the area, like SRP cap, Los Angeles aqueduct.

Ted Simons: The concept of salt, and you're talking about growing food on desert farmland with water that has increasing amounts of salt 90, that's what was written in "Cadillac Desert." What did you find?

John Sabo: In the point in "Cadillac Desert" was we're bringing water from outside and putting it on the field and desert areas and there's high evaporation which leaves behind the salt and a lot more than would normally be there, because we're putting surface water in a place where there isn't supposed to be surface water. What we found pretty strong support, I would say unequivocal support for that assertion.

Ted Simons: OK. The last one is city versus farms. What did he say, what did you find?

John Sabo: Reisner said eventually water shortages would pit farms against cities, and I think in the paper we don't measure this explicitly, but you can already see the signs of that in the newspaper, for example, you see cities growing and wanting more water and asking why can't we get that water from farms? Farms use 80% of the water in the west, there's got to be some give there. We could use some of that to grow our cities a little further. On the flip side, farmers are saying those cities are just growing enormously, they're the problem, we need to grow our crops, otherwise we can't feed the people. I think there's hope in that conflict. And that hope is trying to get people to cooperate a little bit more and focus on sort of establishing creative trading markets for water between, for example, cities and farms, or between -- farm water to city water or farm water to environmental organizations who want to put that water back in the stream or to the delta.

Ted Simons: Real quickly, I know back when "Cadillac Desert" was written it was controversial from the beginning, it got a lot of people's attention. All the way up till now when you are doing this research and we're hearing some pretty dire consequences unless something changes here, people will -- heard it then hear it now and say, yeah, but things seem like they're going pretty well. The state's grown, the west is growing like crazy, Colorado river water means my water bill isn't all that high anyway, it's just a bunch of people complaining about stuff, let's live it up and not be so concerned about these issues. How do you respond to that?

John Sabo: Well the first thing I'd point people to is the recent controversy in newspaper issue about lake Mead, which had dropped to levels that were about seven feet from levels that would trigger all drought restrictions in Arizona. And those would have pretty significant impacts at least at the farm, not at the tap in cities. So there's I think a very tangible example of being at the upper limit of how we can stretch the water supply in the west. So that's the first way I would respond to that.

Ted Simons: And other ideas, I know increasing price of water, you increase something and folks start conserving it and they do a better job. Is that what has to be done? It seems like for most folks when they look at this issue, they always say, water is too cheap.

John Sabo: I think that the answer is yes. And I think it has to increase -- that price has to increase at the tap in cities. But it has to be done in a wise way. In a tiered structure so that people get what they need for basic need, but beyond that, it's considered a luxury and people pay more for that luxury. And a lot could be done with that revenue. Some of these markets I talked to could be established with that revenue.

Ted Simons: Do you think people are ready for no lawns, higher water price, shorter showers, trying to grow salt tolerant plants? Are we ready for that sort of thing?

John Sabo: They would be able to make the choice in that system. So they'd say, OK, my water costs this much for my dishes, my laundry, and my basic need. If I want a lawn I have to pay that much more it. And some will choose to do it, some won't.

Ted Simons: A book that's 25 years old often especially a book that deals with current issues, social issues, environmental issues, can get old. Were you surprised that so much of what was written in 1986 seems relevant today?

John Sabo: Definitely. From the onset of this project I thought we were going to find a lot of weak support for a lot of the arguments that are made in the book, and to my surprise there were only a few wrinkles, and little and minor nuances to his messages. I think more impressively the response I've gotten from the paper, from people who knew Reisner, is that Reisner was essential a visionary and was way ahead of his time, so I think that speaks for why the book still stand as a treaties on the topic in the west.

Ted Simons: John, thanks for joining us. We appreciate it.

John Sabo: Thank you for having me.

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