Part of a continuing series about complexity science by the Santa Fe Institute and The Christian Science Monitor, generously supported by Arizona State University.
Last summer, it was hard to miss news about California’s drought, caused by the four driest years in the state’s history. Its impact on California’s economy in 2015 alone was estimated at $2.7 billion dollars and 21,000 jobs lost. Thanks to El Niño, this drought has eased some, but 42 percent of the state is still in a condition of extreme drought.
In 2007, there was a drought that didn’t garner quite the same national attention: Atlanta, Georgia was in a state of exceptional drought from September to December and came within a few months of running out of water. A large American metropolitan area running out of water almost certainly would have required driving in massive trucks of water every day just so that people could wash their hands, drink, and use the bathroom.
To address the impending disaster, Georgia’s governor led several hundred people in prayer, without leading an official effort to reduce water demand or increase supply.
Unlike California’s drought, Atlanta’s was not unprecedented. Droughts of equivalent severity occur about once a decade, but the region’s population had grown by 25 percent in the previous decade, and an increase in water-intensive agriculture was putting stress on the system even before dry weather limited Atlanta’s supply.
Growing urban populations and increasing demand are likely to make water scarcity much more common, not just in Atlanta and California, but across the US and in most arid parts of the world. What’s worse is that these expectations do not take into account the effects of continuing climate change, which will put additional stress on water supplies in many regions.
Unpredictable or complex?
But we are not helpless observers. We can use ideas from complex systems science to find ways to improve the water supply system we have so that it better serves today’s needs. First, it helps to think about what we control and what we don’t.
Droughts are an expression of natural conditions: lower than usual precipitation, drier soil, and low stream flow. They result from normal and recurring weather variations. We can’t predict when a drought will begin or end or how bad any given drought will be, but we do know from hundreds of years of meteorological records how often droughts of a given severity can be expected to occur.
Water scarcity, on the other hand, occurs when people want more water than is available. This distinction matters: droughts often cause water scarcity, but the social and economic disruptions that follow from drought are a result of how water is managed, not because droughts can’t be anticipated.
This is not to say that water managers are doing their jobs badly. Our water system relies on close couplings between the hydrological and ecological contexts and the water distribution infrastructures we have built, as well as the social, economic, and legal institutions that have developed in this context. No single group or perspective can address all these features simultaneously.
This multifaceted complexity is why water allocation problems today are so wickedly difficult to solve. But solve them we must. Uncertainty over water access is inhibiting innovation, damaging ecosystems, and limiting economic growth.
Water is not gold
If the system isn’t working but it’s no one’s fault, how did we get here? The core ideas of the legal infrastructure that allocates water in the Western US were developed during the Gold Rush era of the mid-1800s and relied on legal precedents that determined allocation of mineral rights. This system gave ownership of the land and any minerals thereunder to the first person that invested the hard physical labor of digging for gold on that claim.
If a claim was abandoned, the next miner who started digging earned the right to any minerals he found there. This requirement, that a resource be used to maintain ownership, prevented miners from “staking their claim” to more land than they could reasonably work. It also provided a legal mechanism that allowed somebody else to use the resource if a miner disappeared or died. The two underlying legal principles that resulted from this system are known as “prior appropriation” and “beneficial use.”
But water is not gold. Unlike gold, water quickly moves from claim to claim through rivers and underground aquifers. This fluidity makes owning water much harder than owning gold. As a consequence, we define water use rights based on the expectation that there will be water in a stream, lake, or well during a given season if it has been there in the past.
When hydrological and human water use patterns are consistent over a period of many years, understanding the detailed hydrology doesn’t matter much, because water rights can be granted based on expected conditions. This is how the principle of prior appropriation is applied to water: if water is generally available in a place and time, the first claimant is granted the right to use water there as long as they maintain continuous use.
Crucially, once a water right has been established, any change in use from the right holder is only permitted if it doesn’t damage other established users. If a pair of water users would like to arrange a water transfer between themselves, they need to demonstrate that this transfer won’t harm any other users.
Water transfer is why the Salton Sea in California still exists. In 1905, an engineering accident led to the Colorado River overflowing into irrigation canals and from there into a dry prehistoric lake bed; for almost two years thereafter, nearly the entire flow of the Colorado River was diverted, creating today’s 350 square mile Salton Sea.
The lake was quickly put to beneficial use, even though its only continuing water source was wasted irrigation runoff from those same irrigation canals. People drawn to the new inland lake quickly made the Salton Sea a tourist and recreational destination, and migratory birds and endangered fish have incorporated the lake into their ecological niches.
In recent decades, thirsty cities like San Diego have looked to the Salton Sea as a water source, but based on the legal principle of prior appropriation and beneficial use, any claim they make is junior to the lake’s established users.
Despite this, in 2003 the Imperial Irrigation District and San Diego agreed to a water transfer. San Diego would pay for efficiency improvements in Imperial’s irrigation systems, and the city could then use the water saved to support its rapidly growing population.
But the agreement, which seemed like a win-win, presented a conundrum. By using more efficient irrigation technology, the Imperial Irrigation District would have reduced the agricultural runoff that had fed the Salton Sea. This reduction would have, in turn, damaged the lake’s ecosystem and thus the users, who argued that they had been putting the ignored agricultural runoff to beneficial use for decades.
This, in turn, made it much more difficult for the irrigation district to invest in more efficient irrigation technology and sell the savings to a thirsty city. San Diego and Imperial’s agreement did eventually get modified and approved, but only after a long legal battle with the lake’s user groups.
Complex and tangled social-legal-economic circumstances like these are why water transfers are contentious, uncertain, and rare. Still, transfers are the only way to allow our allocation system to adapt to changing use patterns as the population continues to grow and new industries rise, fall, and evolve.
Put another way, the complex system of water supply, demand, and use is evolving, but the legal system by which it is managed is locked rigidly in place.
Where might we go from here?
The doctrine of prior appropriation worked well while there was still unclaimed water available, but that era is over. Severe droughts like California’s and increasing demand like Atlanta’s, both ubiquitous features of our modern water climate, highlight the two faces of scarcity.
Thanks to increasing population, climate variability, and changing demand patterns, water scarcity will be a significant constraint in the Western US for the foreseeable future. There is no new water to allocate, and so the water management task now is to make the best possible use of the water resources that are available.
Most conventional thinking about the water system ignores the deep complexities of water scarcity; as a society we think of taking shorter showers. Other oft-proposed solutions are big infrastructure projects to import water from somewhere else or investments in expensive water supply technologies such as desalination plants.
Water conservation and new technology will help us make better use of our resources. They are necessary components of any solution. But measures like these don’t address the underlying cause of the water scarcity we face. One way or another, we need to figure out how to transfer water from one use to another more critical use in a reliable and consistent way so that users not involved in the trade are not damaged by it, and so both agricultural and urban users can plan and make investments with reasonable confidence in the volume of water they’ll be able to access – and the price they will have to pay to get it.
These problems are complex, but they are also solvable. Water management lies at the intersection of economic, legal, political, hydrological, climatological, ecological, agricultural, and engineered systems. It can be difficult for existing institutions to understand all of the disparate perspectives. But we can use the frameworks of complex systems to begin to analyze water supply and demand.
Interdependency clearly plays a role in the systems we have and the systems we need to build, as does path dependence (in physics, a system whose state depends on the path taken to achieve it). The concept of scale helps us understand the spatial mismatch between the laws of physics that govern hydrology and the local, state, and federal laws that govern water allocation. Understanding the drivers and effects of institutional hysteresis (lag in response to forces) can help us break down impediments to better water supply systems. These are but a few examples of complex systems concepts that can help us think more deeply about water.
In turn, the knowledge that emerges from this deeper thinking can facilitate a broader understanding of the social and political tools that we already use to manage societal challenges. Further, the science-based solutions developed by applying a complex systems perspective to water management may also generalize to address many of the other intractable social and political challenges we face today: from addressing global poverty to mitigating climate change.
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Christa Brelsford is a postdoctoral fellow of the Arizona State University-Santa Fe Institute Center for Biosocial Complex Systems. Her research focuses on urban infrastructure systems.
Complexity, a partnership between The Christian Science Monitor and the Santa Fe Institute, generously supported by Arizona State University’s Global Security Initiative, seeks to illuminate the rules governing dynamic systems, from electrons to ecosystems to economies and beyond. An intensely multidisciplinary approach, complexity science draws from mathematics, physics, biology, information theory, the social sciences, and even the humanities to seek out the common processes that pervade seemingly disparate phenomena, always with an eye toward solving humanity's most intractable problems. To get this coverage in your inbox, sign up for our weekly newsletter here.