Aerial view of the Colorado River
This aerial view of the Colorado River was shot with a GoPro camera. Credit: waterdesk.org/lighthawk.org, CC BY-NC-ND 4.0

The Colorado River stretches from Rocky Mountain headwaters in Wyoming and Colorado more than 2,400 kilometers to the Gulf of California in Mexico. On its way, the river supplies water to the residents of the Colorado River Basin and millions of hectares of irrigated farmland and serves to generate affordable power for municipal and rural customers.

Soil moisture probes are a type of sensor that measure or estimate the amount of water in soil. The portable probes can measure soil moisture at several locations. Credit: Colorado Department of Agriculture

In the past couple of decades, however, severe drought has plagued the Colorado River Basin, and the current period is the driest in the past 1,200 years. The situation is so dire that on 14 June, the U.S. Bureau of Reclamation commissioner Camille C. Touton told a U.S. Senate committee that states within the region will need to cut usage by between 2 million and 4 million acre-feet in 2023 to protect the Lake Mead and Lake Powell reservoirs.

“Right now, we find ourselves at a crossroads,” said Karen Kwon, associate project director at the Colorado River Sustainability Campaign (CRSC). “We have an immediate crisis that we need to address.”

In the past 20 years, various stakeholders have already been exploring pathways to resilience to dwindling water resources. Urban water authorities have increased water efficiency and are experimenting with changing city landscapes in Colorado, farmers are reducing their water use, and conservation groups are exploring how to keep fish habitat stable with reduced streamflow.

“The goal is to try and persist through the short term, adapt through the long term, and transform or transition to where we need to be,” Kwon said.

Efficiency Is Key

Denver Water might serve about a quarter of Colorado’s population, but thanks to decades of efforts to step up water efficiency and conservation, it uses less than 2% of the state’s water. The agency has curtailed outdoor watering, requires indoor fixtures to be water efficient, and is pushing for water-saving green building codes.

The payback of such measures is that Denver, with a population of just over 715,000, has rolled back its water use by 50 years. “The customers in our service areas are using the same amount of water as in the mid-70s, despite adding half a million people and half a million jobs to our service area,” said Greg Fisher, manager of demand planning at Denver Water.

This waterwise demonstration garden illustrates the native grasses and species that thrive in Colorado and don’t require watering. Credit: Colorado Springs Utilities

Colorado Springs Utilities can boast a similar statistic: The city of more than half a million uses the same amount of water as it did in the 1980s despite 92% growth in the past 4 decades. One step the utility has taken has been to rebate the conversion of nearly 167,225 square meters (1.8 million square feet) of turf grass to native species. The city’s water conservation team also has two “waterwise” demonstration gardens where they test many plant species, including 11 grasses, to determine water use and climate adaptability. “We have a large educational outreach component to all our work which is critical to customer engagement,” said Julia Gallucci, water conservation supervisor at Colorado Springs Utilities.

Although the water savings of cities have been impressive, it’s the agricultural sector that uses 80% of the water in the Colorado River. Consequently, in light of prolonged drought conditions and climate change, farmers and conservation professionals have developed the Saving Tomorrow’s Agriculture Resources (STAR) initiative. The goal of STAR is to encourage soil and water conservation and to provide technical and financial assistance to help farm operators and landowners evaluate their current practices and make decisions to reduce the nutrient and soil losses on their fields.

“If you increase soil health, you increase the water-holding capacity of the soil,” said Les Owen, the Conservation Services Division director of the Colorado Department of Agriculture. Other department programs promote strategies such as improving irrigation practices to increase efficiency and reduce leaching of salts into the Colorado River.

Soil health specialist Ryan Taylor demonstrates the installation of soil moisture probes. Credit: Colorado Department of Agriculture

“Looming deadlines for interstate compacts threaten the ability to irrigate a significant number of acres if we don’t really adapt and be flexible,” Owen said. “So agricultural producers are hungry for alternatives.”

Caring for the Environment

While the Colorado River community explores how to withstand the immediate crisis and navigate the “new abnormal,” it is important not to overlook caring for the environment, Kwon said. Consequently, the CRSC supports conservation groups that strive to sustain healthy populations of fish and wildlife in the basin, such as Trout Unlimited (TU).

In Wyoming, a headwater state of the Colorado River, TU works with landowners and other stakeholders to protect important habitats, reconnect degraded waterways, and restore trout populations in the rivers. Its focus in the state is on improving the infrastructure of irrigation—such as getting rid of the push-up dams that have impacts on the surrounding wetlands and installing more efficient structures in their place. “We do whatever we can to improve water delivery while maintaining fish passage,” said Cory Toye, the TU Wyoming water and habitat program director.

TU considers the whole environment when attempting to build resilience, incorporating the needs of rivers, wildlife, and people who use river water. It’s an approach modeled by the many Native American tribes that have lived sustainably in the Colorado River Basin for millennia.

In addition to providing water to more than 40 million people in two countries and seven states, the Colorado River also supplies water to 29 federally recognized Native American tribes. The river and its tributaries supply these tribes with water for domestic, commercial, and agricultural use; power generation; and cultural and religious activities. Combined, the tribes hold rights to roughly 20% (or 2.9 million acre-feet) of the water in the Colorado River Basin.

“I understand we have completely different value systems, but we all need water, and we need to do this not just for ourselves but for future generations.”

On the Hopi Reservation in northeastern Arizona, Indigenous farmers have used a myriad of techniques to preserve soil moisture in the high desert and make the most of every single drop of water. Their agriculture, like that of most Native American farmers, also preserves biodiversity. “Without biodiversity, we have no true sustainability,” said Michael Kotutwa Johnson of the Indigenous Resilience Center at the University of Arizona, who is also a Hopi farmer.

Given that they have some of the oldest water rights in the basin, the tribes have the legal authority to play a significant role in balancing the water demand and supply in the region. Their extensive experience in living sustainably and stewarding the environment will be vital to efforts to ensure the future health of the Colorado River Basin in the face of climate change.

In addition, Native American communities have always talked to each other and are well practiced at trying to reach a consensus about major decisions, Johnson said. Building a resilient future for the Colorado River will require a similar approach and will involve all the different parties coming to the table and working to have a better understanding of each other’s needs. “I understand we have completely different value systems, but we all need water,” Johnson said. “And we need to do this not just for ourselves but for future generations.”

—Jane Palmer (@JanePalmerComms), Science Writer

Citation: Palmer, J. (2022), Building resilience in the face of a dwindling Colorado River, Eos, 103, https://doi.org/10.1029/2022EO220376. Published on 5 August 2022.
Text © 2022. The authors. CC BY-NC-ND 3.0
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