Understanding evolving drought risks in the Southwest

The 2020–21 drought in the Southwest set new records for low rainfall and high temperatures. The 18 months from January 2020 to June 2021 were the driest 18-month period on record for Nevada, Utah, and Arizona; the third driest on record for California and Colorado; and the eighth driest for New Mexico. During the same period, Arizona experienced the second-hottest 18-month period on record. The hot season (April–September) of 2020 was also the hottest such season on record for California, Arizona, and New Mexico (www.ncdc.noaa.gov/cag/). Following the extreme heat of the summer season, the fall soil moisture was at record-low levels. The winter snowpack remained below average for most of the Southwest, and what snow had accumulated then melted earlier than usual (Mankin et al. 2021).

The high temperatures induced a high vapor pressure deficit. A NIDIS-funded report by NOAA’s Drought Task Force on the 2020–21 southwestern U.S. drought highlighted this point. The precipitation deficit of 2020 was extremely low, but within known natural variability, whereas the mean vapor pressure deficit for 2020 would have been impossible in the 1950–2000 climate and fits more closely with climate model projections for the 2030–50 climate (Mankin et al. 2021).

The 2020 drought represents a single data point in the context of a much longer dry period that spans approximately the last 20 years (Mankin et al. 2021). This megadrought (Williams et al. 2020) may be like megadroughts in the paleo record, and will eventually have an end, but considering the relative permanency of increased temperatures globally and in the American Southwest, policy makers, land managers, and community leaders face shifting paradigms as they consider the potential permanent aridification of the Southwest region (Mankin et al. 2021).

Drought in the American Southwest is interconnected with other natural hazards and impacts, such as wildfire, heatwaves, low river flow, and ailing agriculture. Before tackling drought as a broad-scale natural hazard, it is important to recognize that the actual impacts of drought manifest themselves as secondary and tertiary issues, and risk management practices should acknowledge the broad diversity of impacts to livelihoods and ecosystems. Here are some key areas, identified in the forum, where drought is impacting the economy and livelihoods across the Southwest region.

Impacts from decades of drought in the Southwest on agriculture have been significant. The region has seen five severe droughts since 2000 with associated growing wildfire risk, heat waves, dust storms, and diminished farm productivity. According to the Colorado Cattlemen’s Association, by 2050 drought may cost Colorado an additional $830 million in annual damages, with $511 million from agriculture alone. To adapt to drought risk, the Colorado Cattlemen’s Association recommended 1) state and local policies (e.g., state water plans) that advance agricultural priorities; 2) interagency and interindustry coordination to support community-led response efforts; 3) relief programs that can provide direct adaptation support for agricultural communities such as mental health resources, conflict resolution assistance, and risk management guidance; 4) changes to disaster aid to ensure it is promptly available based on drought and climate indicators; 5) incentives for ecosystem markets, 6) disaster-specific recovery funding for multi-hazard resilience; and 7) built and green infrastructure solutions for future water management.

The drought is also impacting previously built infrastructure. The Central Arizona Project (CAP; www.cap-az.com/) is a 540-km (336-mi) aqueduct system that runs from Lake Havasu to Tucson, Arizona. Each year, the CAP delivers more than 500 billion gallons of water to customers in central Arizona. The 2021 water restrictions from Lake Mead mean less water is available for the CAP as per the Lower Basin Drought Contingency Plan (www.usbr.gov/dcp/). Looking forward, the CAP is considering drought adaptation actions that include a broader climate adaptation plan, research and development of improved hydrologic forecasting and data tools, and partnering with the other largest water utilities in the United States through the Water Utility Climate Alliance (www.wucaonline.org).

Ten tribal nations sit within the Colorado River basin and these, too, are responding to decades of drought in the Southwest. The Navajo Nation sits at the heart of the Colorado River basin and it relies on hydropower from Lake Powell, as well as agricultural and potable water from Colorado River tributaries and from aquifers. The exceptional drought of 2020 impacted agriculture on tribal lands where water-limited livestock producers resorted to using potable water for their livestock, thus putting additional strain on the community water systems. The tribal recreational economy at Lake Powell is also at risk due to dropping water levels. The Navajo Nation has worked to settle water rights along the San Juan River and to enhance coordination among other water users.

The $788 billion outdoor recreation and tourism industry, which accounts for about 5.2 million jobs nationwide and 2.1% of the U.S. GDP (https://recreationroundtable.org/economic-impact-by-state/), experienced a drop to both supply (recreational opportunities) and demand (patrons) in the Southwest during the 2020 drought. Changes in outdoor recreational supply are manifested as low reservoirs for boating access, low rivers and warmer river water limiting angler access, forest closures due to wildfire risk, etc. Changes in recreational demand were seen in 2020 when smoke from California wildfires created air quality alerts in western national parks. Many tourists canceled trips when they learned that iconic vistas were shrouded in a haze of smoke. The outdoor recreation industry is adapting to these changes by promoting and protecting public lands and waters, attracting new visitors by installing electric vehicle charging stations, proposing tax credits for e-bikes, and promoting a more diverse outdoor industry and encouraging new participants in the outdoors.

Drought also impacts human health outcomes, degrades air and water quality, increases incidence of disease, increases mental health stresses (www.cdc.gov/nceh/drought/default.htm), and, combined with intensifying heat waves, leads to increases in mortality and morbidity. Over the last 20 years, heat-related deaths across the western United States have increased, including 494 documented mortalities in Arizona in 2020, and deadly heat waves in the Pacific Northwest and southwestern Canada in summer 2021 (Popovich and Choi-Schagrin 2021; Lapoint 2021).

The last two decades of drought in the Southwest has challenged municipal water providers by decreasing reservoir storage, which acts as a buffer at times of drought. Looking forward, water providers are looking for new ways to stretch existing water supplies, including water recycling projects, and desalination projects.

Diverse economic sectors and communities are being impacted by increasing aridification in the Southwest (Manning et al. 2021). Representatives from these sectors have called for mitigation efforts to address anthropogenic climate change. In the near term, communities and businesses are being forced to adapt to this new paradigm.

Do more opportunities exist? Current efforts and outstanding needs

Facing a new paradigm of aridity in the Southwest, some groups have identified and begun implementing new adaptation and mitigation strategies. These ongoing efforts to address drought in the Southwest are novel and deliberate. Here are some of the key opportunities and needs identified throughout the forum.

While the U.S. federal government has long-established drought response mechanisms in place across agencies that help farmers, water managers, cities and towns, and businesses withstand and recover from otherwise crippling drought, state and local entities are also taking action.

Coconino County, Arizona, is an example of forward-thinking planning to address issues of increasing aridity in the Southwest. Coconino County has identified wildfire and post-wildfire erosion, flooding, and debris flow as its primary drought-related hazard. Mitigation activities have included forest restoration efforts to limit the amount and severity of wildfires and postfire erosion.

Colorado agriculture is thriving in a region that can experience frequent and prolonged droughts. Droughts and associated high temperatures, high evapotranspiration, and soil moisture deficits create a year-round cycle of problems for producers, which can also create supply chain issues. A decreasing winter snowpack and increasing population has created competition between municipal and agricultural water users. The Colorado Department of Agriculture is promoting resilience through initiatives supporting projects benefiting soil health in crop and livestock production and enhancing water, wildlife, and vegetation; increasing water use efficiency through groundwater management and providing multiple user benefits through flood irrigation; and applying lessons learned through previous water administration experiences.

Extending beyond Colorado, agriculture across the West is facing similar challenges and looking for similar solutions. Recent work from the Union of Concerned Scientists has shown that high temperatures and reduced air quality are as equally concerning as water availability concerns for farm workers in California’s Central Valley (Fernandez-Bou et al. 2021). These concerns are increasing due to hot droughts, which have been getting hotter in recent decades. The Union of Concerned Scientists is working to address research gaps and bring attention to the issues faced by food systems in a hotter, drier Southwest.

The nonprofit group WaterNow Alliance has called for improved federal funding for infrastructure. Currently, 95% of water infrastructure is paid for by the local rate payer, and most state and federal financial support comes in the form of loans that the local government or utility has to pay back. Drought resilient water infrastructure can be in the form of decentralized, onsite solutions and initiatives that affordably put water-use decisions in the hands of the consumer. Centralized and built infrastructure should emphasize efficiency and reuse.

Future thinking: Decision-making in the face of a new paradigm

“As Engineers, we have to judge the future by the past …. About the time we got [the Hoover Dam] built and started operating, nature demonstrated to us that there was a [drier] ten-year period [than had been planned for] …. I don’t know what the future is going to hold.” – Randy Ritter, 1948¹

Planning for the future in an increasingly arid Southwest requires innovative frameworks and leveraging existing resources and programs, such as philanthropic initiatives, water markets, and cooperative agreements. Among the ideas for a drought-resilient future was an underlying theme of ethics and equitability in new water projects. One example of this provided by the Community Water Center (www.communitywatercenter.org/) is that drought impacts water availability for shallow wells first, and when wells dry up some people cannot afford to drill deeper wells. This means that many poorer communities and smaller farm businesses are the first to feel the impact of encroaching drought. The following are projects and groups that are working toward a future of ethical, sustainable and drought resistant water.

As a global beverage manufacturer, The Coca-Cola Company is heavily reliant on water availability and the communities in which it operates. The company’s commitment to increasing water security has three parts: 1) reduce local shared water challenges through regenerative water use; 2) improve watershed health and sustainable supply chains, including through watershed stewardship plans and green-infrastructure projects; and 3) enhance community water access and resilience with a focus on women and girls, as they are often the most affected by water scarcity and sanitation challenges (www.coca-colacompany.com/news/2030-water-security-strategy).

In the Colorado River basin, the Walton Family Foundation is committed to ensuring a healthier watershed with improved flows that help the region adapt to climate change. Their strategies for climate resilience in the Colorado River basin (www.tenstrategies.net/) include three that employ a forward-thinking mindset using existing technologies. These include 1) forest management and restoration practices to maintain system functionality and biodiversity; 2) regenerative agriculture practices that enrich soils, enhance biodiversity, restore watershed health, and improve overall ecosystem function and community health; and 3) natural ­distributed storages that restore highly degraded natural meadow systems to improve local aquifer recharge, water retention, reconnect historic floodplains, and support productive meadows and riparian ecosystems.

Another future-thinking approach to building drought resilience in forests includes financial mechanisms such as the Forest Resilience Bond (www.blueforest.org/forest-resilience-bond). Blue Forest Conservation is a non-profit organization that leverages financial innovation to create sustainable investment solutions to environmental challenges. They administer the Forest ­Resilience Bond, a public–private funding mechanism that overcomes the funding gap for forest restoration by allowing private capital to play a role in supporting public land management.

Through regional cooperation, the Del Puerto Water District (www.delpuertowd.org), on the west side of the San Joaquin Valley in California, built a pipeline that allowed recycled municipal water to supplement agricultural water needs in the region. This is one example of public policy supporting and implementing novel solutions to water sharing.

Addressing growing challenges: Moving forward together

Drought and aridification are interconnected with many hazards, such as wildfire, and require a shared vision to address these challenges in a changing environment. The Southwest Drought Forum provided a unique platform to highlight the important role of the private sector in addressing drought and aridification risk. Both the public and private sector have vital roles to play in addressing drought issues, and public–private partnerships are essential to harnessing the full capabilities of both sectors.

Will Sarni, CEO of the Water Foundry and CEO of the Colorado River Basin Fund, phrased the challenge for the private sector this way: “How do companies with ambitious growth strategies secure the water they need to fuel business growth in a world where paying more for water will not work?” Consumers are placing increasing pressure on businesses to be good water stewards. New and emerging financial tools and services, such as the Colorado River Basin Fund (www.coloradoriverbasin.com/), water markets, and drought-aware insurance products can support a business’s desire to be water-conscientious while still working within its risk thresholds.

Water utilities and other public or semipublic water-providing organizations have to approach drought risk differently from private companies. For these, the drought risk is twofold: 1) the risk for water users of not having enough water to meet their needs and 2) the financial risk for a water supply organization—especially an organization supplying urban water users—of not being able to sell enough water to bring in revenue to cover the organization’s fixed costs. To manage these risks, states have the authority to legislate rules governing water ownership, use, reuse, transfer (lease or sell), and storage. For cross-boundary water resources, water sharing compacts are put in place to ensure equitable access to shared water resources (Olmstead et al. 2007).

To conclude, the 2020–21 drought highlights an extreme low period in nearly two decades of drought in the southwestern United States. The Southwest Drought Forum allowed researchers and decision makers to come together to talk about the innovations needed in order to support communities in the new paradigm of increased aridity in the American Southwest. Some key takeaways from the meeting include the following:

• The U.S. Southwest is a bellwether of climate change in arid regions. These drought periods are more representative of the future climate than the past climate in the region, primarily due to a background warming of mean global temperatures.

• A single very bad year in the midst of a decades-long drought crisis has exacerbated ongoing environmental and water availability issues.

• Deep uncertainty is now a new reality and existing water management practices were designed for historic variability and uncertainty that has now changed.

• Water reuse and recycling led by companies and communities offer solid opportunities to identify new sources of local water and better plan for and respond to droughts going forward.

• Any new solutions to enhance drought resilience must consider water ethics and equity.

• Effective coordination and water governance require timely, accessible drought and climate information; cost-benefit analyses to support evidence-based decision making; consistent and inclusive federal, state, local, and tribal engagement; and trust built through shared values and social connectedness.

A more in-depth report on the outcomes of the forum will be forthcoming. To learn more about this event and watch recorded presentations, visit the NIDIS YouTube page at https://bit.ly/3Diz460