Mountain snowpack and rainfall are the primary sources of water for the southwestern United States, and water allocation institutions determine how that water gets distributed among competing uses. This includes agriculture, which accounts for approximately 80 percent of water diversions in Colorado.
The “Arid West,” which includes Arizona, California, Colorado, Idaho, Nevada, New Mexico and Utah, receives precipitation in the mountains far from agricultural fields, or during winter months when crops are not grown.
Climate change, population growth and other factors mean that Western water allocation strategies may benefit from changes over the long term. The availability and seasonal timing of mountain snowpack runoff, for example, are predicted to change with a warming climate. And everyone, from farmers to municipal managers, is going to have to adapt.
To bring scientific veracity to these inevitable changes, researchers at Colorado State University, in partnership with the University of Nevada, Reno; Desert Research Institute; Northern Arizona University; and Arizona State University have received a $4.9 million grant from the USDA National Institute of Food and Agriculture.
The five-year project will aim to predict which entities in the West will be most impacted by changing water quantities and availabilities under current water laws. In addition, the researchers will evaluate the impact of potential adjustments to existing water laws, and evaluate the possibilities for new laws and regulations.
Over the next five years, the interdisciplinary team that includes hydrologists, resource economists and sociologists will evaluate the following:
- How changes in mountain snowpack affect available water;
- Which basins in the arid West are most at risk;
- The effectiveness of existing water allocation laws and regulation in managing these changes, in comparison with proposed modifications;
- And how changes in available water, and laws and regulations, affect the economic well-being of various groups in society – including the sustainability of agricultural production in the arid West.
CSU’s role
Bringing their expertise to the team will be CSU associate professor Christopher Goemans, and assistant professor Dale Manning, both in the Department of Agricultural and Resource Economics in the College of Agricultural Sciences. Together, Goemans and Manning will develop an economic model that identifies how, over the next 30 years, different groups who use water in the West could gain or lose water access, depending on the timing and amounts of water available within seasons.
The CSU researchers’ ultimate goal is to help water managers, farmers and other users plan for the future by modeling various scenarios of water availability and allocation. For example, their model could help inform decisions about water release versus storage on a seasonal basis, or how water rights within existing laws might benefit from change.
“While infrastructure investment can improve the timing of water deliveries, designing allocation rules and regulations that account for the multiple values of water can be equally important to getting the most out of scarce water resources in the face of uncertain supply,” Manning said. “As snowmelt patterns change, both junior and senior water rights holders may be adversely affected. In this context, inflexible laws and regulations could result in rights holders wasting water, or being reluctant to adopt conservation technology to avoid the risk of losing water rights.”
Water management will change
Water policy analysts predict that water management in the western U.S. will undergo extensive changes to adapt to mountain snow melt patterns. The speed and extent to which these changes can occur depend on water allocation rules and regulations. This has caused recent conflicts where existing water allocation laws and regulations have failed to distribute water in accordance with all rights holders’ expectations. Given existing laws and the risk of over-allocating limited supplies, states and regional water authorities have intervened to limit permitted water rights.
“Water rights laws may hinder adaptation to climate change in the arid western U.S.,” Goemans said. “If senior water rights holders – namely food-producing and cash crop agriculture customers – are unable to get the water they need, the economic viability of irrigated agriculture could decline significantly.”
The impacts of changing volume and timing of snow melt on water rights users are profound, according to Kim Rollins, a University of Nevada, Reno economics professor and the grant’s project director. “Increased risk is involved with private decisions to sell irrigation water rights and lands, causing permanent losses in the capacity for food production in the arid West,” Rollins said. “Decision-making can be improved with a better understanding of how changes in water flows influence agricultural producer decision-making and how laws and regulations can exacerbate or relieve constraints from these changes.”
Information gathered will aim to inform three sets of decision-makers. The first are the regional, state and federal water policymakers that create the legal infrastructure for allocating water. The second are the local water district managers as they determine where and when to divert water flows from the various sources through their systems to end users, given existing law. The third set of decision-makers includes the individual agricultural producers and other water rights holders that decide how they will use water and how they will respond to changes in their water rights.
