Water 

Four Corners Water (and Lack Thereof)


In an ocean or
In a glass,
Cool water is such a gas.
Brian Wilson


Almost everything environmental in the Four Corners region concerns water in some way. Whether it is the availability of water or its quality, no single issue captures as much attention in regional environmental circles. And to say that water is a political issue understates the situation as much as saying that summers in the southwestern deserts are warm.


The cliché is that, in the southwest, “Water flows uphill toward money.” One basis for this cynicism is the extraordinarily complex system of water law in the various states, a topic far too difficult to tackle here.


However, one generality that is common to the various political jurisdictions of the region is the notion of water rights, and the principle of seniority, a concept based in the precept “first in use, first in right.” Basically, this means that people who laid claim to water resources first have the most senior right of use. In most jurisdictions, there is an additional requirement that right of use be exercised in a “beneficial” manner. It is the legal interpretation of “beneficial” that is controversial. In addition, the question of Native American water rights (they were here first, after all) complicates water law even further.


Because of this complexity, and because of the scarcity of water, the challenge of water resources is the one that overwhelms all other environmental challenges facing the Four Corners states.


The problems posed in meeting this challenge depend on your point of view. First and foremost is the fact that this is a semi-arid region, so there is simply not enough water to do everything that we want to do. Our society’s aspirations depend on abundant fresh water supplies, and the scarcity of water thwarts those aspirations and challenges our management of water resources. Of course, it may be argued that we need to adapt our aspirations to match the available resources. But this approach merely presents a different set of problems to be solved.


Historically, water has always been a challenge for human society in this region. The early development of irrigation systems—the traditional acequias—allowed agriculture to flourish by bringing mountain water to the lowland desert where it was needed. Reservoirs, long before the Bureau of Reclamation’s mega-projects, were build to retain runoff from summertime thunderstorms. And early societies adapted to the regional conditions by treating water as a precious resource not to be wasted.


With the development of water projects on vast scales—the two river basins of the southwest are now essentially elaborate plumbing systems, controlled from headwaters to the oceans—society has developed a slightly different view of water resources. Golf courses in the desert, open-air fountains, warm-water lakes, and large-scale flood irrigation techniques are all profligate in their usage of water. In particular, they all lead to huge amounts of waste, in the form of evaporation. Water that could be put to another use simply floats away in the atmosphere.


It is not possible here to present a comprehensive overview of water resources in the southwest. Entire books, including technical textbooks and more popular narratives such as Cadillac Desert* are devoted to the topic. Some of the background material for the discussion here is included on other pages (e.g., the Four Corners Climate overview).


The commentary here is concerned with two topics, the water cycle of the Four Corners region and how our society has chosen to allocate water resources.




*Reisner, M., 1993 (Rev.): Cadillac Desert: The American West and Its Disappearing Water, Penguin USA, ISBN: 0140178244, 528 pp.


The Water Cycle


Water for next summer

In a discussion of water, political boundaries become arbitrary. A more useful approach is to consider the water cycle within river basins. This was recognized more than a century ago by John Wesley Powell. In the Southwest, the Colorado River and the Rio Grandé basins are of primary interest.


Figure 1 shows a schematic representation of the water cycle. All of the water that is naturally available in a basin falls as precipitation; for the two southwest river systems, this occurs as mountain snow in the winter and, in the desert, as rainfall during the winter and during the summer monsoon season. (In between, such as here in Santa Fe, we get both, but it’s still very dry.)


The water on the ground, whether liquid or solid, either stays put (creating a lake), runs off, soaks in, or evaporates. (Snow can sublime—that is, turn directly to water vapor—but it has to melt before the water can soak in or run off.) The runoff eventually collects in rivers; along the way, some of it also soaks in or evaporates. And evaporation is also complex, because water that soaks into the soil can be taken up by plants and then transpired, which augments surface evaporation. The net result of plant transpiration and surface evaporation is called evapo-transpiration. Finally, the water that soaks in can flow underground and either re-surface (in a spring) or contribute to acquifer recharge.



Figure 1: Click for full size

In Figure 1, there are several places where society enters the picture. The first of these, the “diversions” on the left, represents inter-basin water transfers, part of the plumbing system referred to above. For example, the Rio Grandé system receives water from the Colorado system via the San Juan-Chama diversion; and the Colorado system also contributes water to the Platte system to serve the cities of the Colorado Front Range. (Note that both of these water transfers move water across the Continental Divide.) Other societal usage in Figure 1 removes water from the system and returns (some of) it; this represents agricultural, municipal, and industrial water usage.

With a conceptual diagram such as Figure 1, it is possible to quantify the behavior of the water cycle in a basin given precipitation amounts and other parameters affecting the movement of water through the river system. Parts of the problem, particularly representing the surface and sub-surface process, are highly complicated, but scientists are making progress on computer simulations of the water cycle.


Allocations


As noted above, water law is a topic far too arcane and complex to even attempt to understand unless that’s what you do for a living. To complicate matters further, the Four Corners states of Colorado, New Mexico, Arizona, and Utah have different laws concerning water. There are, however, two common principles, seniority of rights and the requirement of beneficial use discussed previously. Traditionally, beneficial use has been associated with agriculture (or ranching), municipalities or businesses. Consequently, it is not possible to establish water rights for the purpose of just letting the river flow. This has become controversial in recent years, because it is increasingly recognized that the riverine ecosystem, and the riparian community along it, need a certain amount of water to survive. The existence of endangered species within these communities has brought this controversy to the public’s attention.


With increasing numbers of people coming to appreciate the benefits of the rural environment, appreciation of rivers and streams is on the increase. This means that the definition of “beneficial use” is evolving. Maintaining minimum stream flow sufficient to support a trout population, for example, is becoming part of the definition. Such changes will allow special interest groups to purchase and use senior rights for purposes other than traditional agricultural or industrial water needs.


Water Resources: Quantity and Quality


To the extent that water is scarce, it is valuable. Providing enough water to meet society’s demands means some combination of finding more or making the best use of what we have. The second of these implies that we should work hard to avoid wasting water.


The schematic diagram of the water cycle in Figure 1 suggests that the main “waste” of water is due to evapo-transpiration. Other pathways provide water for use either locally or downstream (after the societal uses return it to the river, for example), or by pumping acquifers. Therefore, minimizing evapo-transpiration is a way to conserve water resources. Drip irrigation, rather than sprinklers, is one way to do this.


Finally, it is worth emphasizing that water quantity is only half the story. Water quality is the other half. Some indications of water quality issues are included in Figure 1. Generally these issues are associated with societal use or with historical problems such as mine tailings. For example, the Alamosa River in southern Colorado and the Red River of northern New Mexico are both contaminated with heavy metals from nearby mining activities. Agriculture is also problematic, because the water returned to the river after irrigation can be highly saline. This is a problem especially in the lower reaches of the Colorado River.



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