The Western United States, heavily dependent on mountain snowpacks for water storage and supply, faces significant challenges due to climate change. A recent study led by scientists at the Desert Research Institute (DRI) suggests that expanding reservoir capacity alone will not suffice to prevent future water crises in agricultural communities.
Published in Earth’s Future, the research identifies at-risk agricultural communities affected by changing snowfall and snowmelt patterns. The study finds that adapting crop types and extents could be more effective than increasing reservoir capacity. By century's end, some areas may have less than half their historical water supply for reservoirs. However, altering crops could restore about 20% of reservoir capacity.
Beatrice Gordon, lead author and sociohydrologist at DRI, emphasizes the importance of local-level water management decisions. "A lot of decisions about water are made at the local level," Gordon notes. She adds that understanding future scenarios is crucial for community-scale resource management.
Mountain snowpacks traditionally act as natural water towers by storing winter precipitation and releasing it during drier months. Existing water management systems are challenged by altered snowmelt patterns due to climate change. Irrigated agriculture, a major freshwater user globally, is particularly vulnerable.
While strategies like expanding reservoirs aim to augment supply, they become less effective with unpredictable precipitation patterns. In contrast, conservation measures such as reducing crop acreage or shifting to higher-value crops can mitigate risks.
The researchers developed a risk assessment framework using data from 13 communities on irrigation supply and demand dynamics through 2100 projections. "We gathered all these data together and looked at the picture of risk," says Gordon.
Gabrielle Boisramé, assistant research professor at DRI and co-author of the study praises Gordon's work: “Dr. Gordon assembled a very impressive dataset linking agricultural water supply and demand across the Western United States.”
The selected communities are located in headwaters areas sensitive to climate changes and serve as indicators for broader regional impacts. Some lie within the Upper Colorado River Basin which supports over 40 million people downstream.
"A lot of these areas provide downstream water," explains Gordon. Adrian Harpold from the University of Nevada commends Gordon’s insights: “Her insights are helping apply our best available science for sustainable water management.”
Study results indicate significant declines in reservoir refill capacities within decades—a critical issue for smaller reservoirs holding only a year’s worth of water.
Gordon stresses immediate action: “It shows how important it is to dedicate effort now...to figuring out how we support communities.” She concludes that conservation remains vital across many Western U.S regions facing warmer climates with reduced snowfall.
For further details on this study titled "The Essential Role of Local Context in Shaping Risk and Risk Reduction Strategies for Snowmelt-Dependent Irrigated Agriculture," visit Earth’s Future journal online.