According to a press release from Arizona State University that was picked up early this week by Mike "Aquadoc" Campana for his own blog as well as the blog of the American Water Resources Association (with both blogs under Mike's editorial leadership), several researchers have realized and explained that Mark Reisner's Cadillac Desert was correct about the sustainability of water resources in the American Southwest. This news comes only 25 years after the publication of Reisner's popular work, to say little of John Wesley Powell's assertion (dutifully cited by Reisner) of the same concept in 1878. Cadillac Desert, first published in 1986, was principally an historical work and was followed closely by Reisner's less-known Overtapped Oasis, a collaboration with Sarah Bates on the more present state and future of water in the American West, in 1990. Taken together, these two works by Reisner have overshadowed much of what came before and after in both popular histories and technical accounts of water management in the western U.S. That's not to say that the others are not good in the own right, just not as stark and brutally honest in their depictions of what has happened to get the West into this mess and the vast sacrifices it may take to get out.
This recent journal article is titled "Reclaiming freshwater sustainability in the Cadillac Desert" and was just published in the Proceedings of the National Academy of Sciences (PNAS). I know two of the co-authors on the article, Mr. Campana by e-mail correspondence (outside of his blog), and Ms. Wohl only by her reputation and the quiet intellectual power of her books on western rivers and streams. In the criticism that I offer here, I mean not to offend friends or colleagues. However, both of those people are hydrologists, and Mr. Campana offered quotes to ASU in support of the press release on the paper's publication, and as such might have exerted some scientific influence on the wording of the release. I certainly understand that the scientists cannot control all of the information that is promulgated in more traditional media about their work--in the academic journal system, we at least have recourse to formal comments and the opportunity to reply in official publication. To its credit, there is Paragraph 6 in the press release, which leads me to believe that the study and paper are well-founded:
"At the core of their analysis, Sabo and his colleagues applied the best available tools to data on water, soil, salt, dams, fish and crop yields. 'Our data and analyses confirm with numbers and maps what Reisner deftly described with words,' Sabo said."So, when it's not the journal article, but instead the press release, that I believe to be in error, even from an institution acting on the authors' behalf and in their interests, I have little more than this. Maybe I'm just being picky here, but some things in the press release just don't seem to do justice to the study that is being promoted for public consumption. So, let me begin with...
"Researchers applying modern scientific tools and mapping technologies, unavailable during Reisner’s time, find his conclusions for the most part to be accurate scientifically correct. As a result, current water practices are not sustainable and many dramatic initiatives will be needed to correct the current unsustainable path the West is on."While the mapping and data-relation technologies of GIS have been with us for quite a while, it took the advance of the other "modern scientific tools" to make such a study truly possible: distributed hydrological modeling is still a toy in the academic community, despite the efforts of yours truly and like-minded progressive individuals with whom I've had the pleasure to work over the years, and the operational community (such as the 13 regional River Forecast Centers in the National Weather Service) doesn't come close to trusting it yet. Don't let them tell you otherwise--I've worked with several of the forecasters, with even more of the researchers and bureaucrats, and with the models that they suggest will make the transition to distributed use, and I know that they just don't have it yet. But that's a rant for another time...
However, it is not the eventual efforts at scientific validation of Reisner's assertions and conclusions that have made "current water practices" unsustainable--those water policies were not sustainable practices long before this study, before Reisner's work, well before Reisner was born for that matter. The water policies in the American West were unsustainable long before science told us just exactly how and why they left us in this mess. The point of Reisner's work was to demonstrate with historical evidence and a keen analytical eye those conclusions about Western (oh, I almost wrote "wastern" there--a Freudian slip?) water policy that the present study has reinforced with a more "modern" scientific approach using mapping technologies, distributed hydrological models, and basin-level water accounting practices.
As such, the press release suggests that "many dramatic initiatives will be needed to correct the current unsustainable path the West is on." This is something that we have certainly known for a long time. The present drought in the western U.S. is not a new phenomenon, and the work of Reisner and many others have pointed out exactly what was wrong and some of the ways that we might correct the "current unsustainable path" of western water management. For that, this study was not necessary at all--we had all of that knowledge, information, understanding and warning already. The history of water in the West is full of more focused and storied histories in their own right. As we have ignored this history of evidence, we are doomed to its repetition, however more learned and thorough each iteration may become.
Paragraph 7a, regarding some of the study findings:
"Currently, the desert Southwest uses 76 percent of its total surface water to support its population. This will rise to 86 percent with a doubling of urban population (expected in 50 to 100 years). Sustainable balance for the region is achieved when 40 percent of total surface water is used."I will be very interested to see how the study authors arrived at these numbers, likely by numerical simulation of the Colorado River and tributary/distributary systems in the region. Of greater interest to me is how that number for "sustainable balance" was determined. I wonder if groundwater extraction is balanced with its own recharge, and overall just how the whole surface/subsurface water system of the Southwest can become both balanced and sustainable at a single value with climate, people and agriculture all in the mix. Alas, it is a shortcoming of the press release to provide such provocative information and then hold us in suspense...oh, yes, that's called marketing.
"Salt, which results from the application of large quantities of water to grow drought intolerant food crops on desert farmlands, has likely caused about $2.5 billion in reductions in crop revenues in the Western U.S."Hello, science? Salt results from the evaporation of saltwater, such as seawater; it is an evaporite mineral deposit. The "application of large quantities of water" is needed primarily to offset the meteorological conditions and biological imperatives of crops grown "on desert farmlands..." Where the weather is hot and dry, the same species of plant needs more water to survive and grow than it would in a warm and humid weather regime. The same corn crop that grows "knee-high by the 4th of July" under rain-fed farming conditions in Iowa would wilt and wither upon sprouting in southern California. The same cotton that thrives in the humid Mississippi delta region needs artificial irrigation measured in meters in southern Arizona. For that matter, many species of crops grown in the dry Southwest have been selected for their drought tolerance, and Pima cotton was propagated by Native Americans and the USDA in southern Arizona more than a century ago, just for that reason.
What I think the press release is trying to explain here, but does not succeed, is the widespread issue of soil salinization on irrigated farms in the American Southwest. When the irrigation water is untreated, as for much of the water taken directly from streams and rivers, it contains a salt content that is near the tolerance for many crops, beyond which the plant can no longer process the water properly as its biology "clogs up" with the salt load. To counteract this build-up of salts in the upper soil layers and the consequent clogging of plant vascular systems, farmers learned to over-water their crops in an effort to flush the salts out of the root layer. As if this overuse of water was not enough, the problem actually comes when so much water is applied that the water table, traditionally far below the surface, rises with this excess input and floods the plant roots from below. The rising groundwater brings with it even more salts, those in solution and those that had previously deposited and dried well below the root layer. To flush the saline from the waterlogged soils, farmers applied still more water, not recognizing that drainage had been the key problem all along but instead exacerbating the problem of soil salinization. Eventually, whole farms perished as the salt deposits left crop soils barren and sterile.
Now about that $2.5B in losses--is that annual, or over all the history of irrigated agriculture in the American Southwest? What area, specifically, does that cover--for example, are the earliest irrigation communities in Utah included? Are these losses due to soil salinization and the overwatering that came with and caused that problem, or due to climatic impacts such as heat and drought that remained beyond human control and led to additional irrigation simply for crop viability? Are farm and water subsidies, sizable sums in their own right, calculated into those losses? The press release is mute on these points of clarification.
"The water footprints of Los Angeles, Las Vegas and Phoenix are the top three in the U.S. The footprint of Los Angeles alone is larger the seven largest eastern U.S. cities (including New York, Chicago and Washington, D.C.)."However the study authors have defined water footprint, it remains a fact of geography that Chicago is not an eastern U.S. city. The seven largest eastern cities by population in the United States are all in states that border the Atlantic Ocean. In order, these are: New York City NY, Philadelphia PA, Jacksonville FL, Charlotte NC, Boston MA, Baltimore MD, and Washington DC. To include Chicago IL in this list, as the third largest city in the country, Washington DC would have been bumped, and there are several cities more "eastern" than Chicago that would need to be counted. As it is, the population of New York City is almost three times that of Los Angeles CA, the second largest city in the U.S. by population, so I am eager to see the elements of the water footprint calculated by the study authors, and that the press release does not make clear.
"'We suggest an initially modest target of a 16 percent reduction (to 60 percent total) in the fraction of stream flow withdrawn,' the researchers state. This alone would require the seven states that make up the West to do several things they have yet to do, including improving urban water use efficiency, implementing a desalinization system by coastal cities, improvements in land-use practices that minimize erosion and sediment infilling of the region's reservoirs, and implementing modified crop portfolios that include only salt tolerant and cash crops."The quote from the study is interesting, in that I am eager to see how they calculate these resource withdrawal numbers--do they include groundwater extraction, agricultural and municipal return flow, the relative locations of stream withdrawals, and both spatial (meteorological) and temporal (climatological) variations in supplies? As for the "several things [the seven states] have yet to do..." I can only suggest that the writers of this press release should have searched on those terms in Wikipedia and Google News before making such an statement:
- the widespread movement to improve water efficiency in urban settings is now into (and in some places beyond) its second decade, and is already being worked into international LEED building certification requirements;
- coastal desalination plants are under consideration and construction in San Diego CA and along a sizable portion of the southern California megalopolitan region, and the inland desalination plant at Yuma AZ is in a process of re-commissioning for use in part to fulfill international treaty obligations with Mexico regarding the quality of Colorado River water that passes over the border;
- land-use practices to minimize erosion have been in place since the Dust Bowl of the early 20th century, and the Southwestern U.S. has not ignored the recommendations and activities of what was first the USDA Soil Conservation Service (SCS) that arose from that semi-natural disaster and is now, encompassing water and forest lands as well, the Natural Resources Conservation Service (NRCS). For that matter, hydrology as an engineering practice is littered with studies using the far-outdated, highly-parameterized SCS curve number method for land-use-based runoff modeling;
- "sediment infilling of the region's reservoirs," while it can be addressed to a certain extent with land-use reform, is more a function of meteorology and hydrology over the vast pristine and undeveloped lands of the western U.S. Reservoir sedimentation is, in fact, an inevitability of design that is taken into account in the more thorough of engineering studies when a dam-and-reservoir system is considered. The problem of sedimentation, not of construction durability or infrastructure maintenance, is why dams have a "usable lifespan" in practice; it is also one of the few aspects of the current state of infrastructure quality in the U.S. that is not explicitly considered in ASCE evaluations, even though the time since the last surge in American dam construction is exactly in line with the expected usable lifespan of those projects...
- "modified crop portfolios that include only salt tolerant and cash crops" is an interesting turn of phrase, as I certainly agree with the adoption of salt-tolerant crops where those are needed for farm viability (which is not everywhere, as drainage quality varies widely), but a reliance on "cash crops" is the very problem we are attempting to overcome. Farmers simply should not be planting crops that bring in cash just because of their market value, and regardless of the cost in water use demanded by such crops. What we want to encourage are salt- and drought-tolerant crops, despite their smaller value on the market, in the arid southwestern U.S. while other regions with more hospitable and sustainable climates take over the "cash crops" for which the specialty farms of the Imperial Valley are known. These are, as farming in that area has evolved, increasingly market-oriented crops with high water demand, while other areas of the country should be taking on (or retaining) those responsibilities: corn, cotton, alfalfa, lettuce, fruits and vegetables, etc. At least we aren't seeing that last and most profitable refuge of the cash crop movement, tobacco, in water-poor southern California--at least, not that I know of...
"'The water crisis in the West is a regional one,' Sabo said. 'This suggests that local conservation efforts (shorter showers, banning lawns, installing a gray-water recycling systems) are necessary but not sufficient for a solution. Regional and national policy changes are called for,' he added.
"'The cards are stacked high against freshwater sustainability in the West,' Sabo added. 'Something will have to give, and it likely will be the price of water and high quality produce. If water were priced appropriately (by market forces or policy mandates), we would become much more efficient with water use in cities and on farms, and we would likely do agriculture completely differently than we do it now in the Western U.S.'"Wow, a shift out of our agency-controlled regime of combined water supply and power generation operations and negotiated distribution, into a market system? Talk about jumping from the frying pan to the fire...the states and established commercial interests in the American West will not go quietly. My fellow blogger and friend over at Aguanomics is far better qualified to address the potential issues there, but with some education maybe I will soon give it a shot as well.
To the authors of the study and their researchers who likely contributed immeasurably, I say well done and kudos to you all! To the PR office at ASU, I suggest you bring the publishing scientists into your draft process, and retain some editors with subject matter expertise, or you'll continue to do a disservice to your researchers and programs.