The Colorado River

The Environmental and Energy Study Institute (EESI) held a briefing highlighting strategies for improving the resilience and restoring the health of the Colorado River and its tributaries. The Colorado River basin serves as an essential source of agricultural, residential, and commercial water for communities and tribes in Wyoming, Colorado, Utah, Arizona, New Mexico, Nevada, and California as well as our neighbors across the border in Mexico. However, the river faces severe water stress, resulting in dwindling reservoirs. This water stress, exacerbated by climate change, threatens to degrade the river and jeopardize the ecosystems dependent on it.

This briefing focused on the role of federal policy in supporting stakeholders across the West as they addressed the impacts of drought and water stress through effective water conservation, measurement, and allocation. Panelists discussed the importance of collaboration between tribes, industry, communities, and local and federal government to restore river vitality and ensure equitable water availability for generations to come.

Caitlin Ochs photos are copyrighted. 

Highlights

KEY TAKEAWAYS

One out of every 10 people living in the United States relies on the Colorado River for drinking water. Most people who use water from the Colorado River do not live on the river.  About 52% of the Colorado River’s water is used for irrigated agriculture, while 18% is consumed in urban areas. The rest supports natural vegetation (19%) and evaporates from reservoirs (11%). No water reaches the ocean. Cities in the Colorado River Basin have reduced water use by 18% since 2000, despite a 24% population increase, through measures like outdoor water use reduction, efficient plumbing fixtures, tiered pricing, and leak detection. The Colorado River’s current usage exceeds its natural replenishment, making agricultural and urban water conservation strategies critical for long-term water security.

 

Caitlin Ochs, Visual Storyteller and National Geographic Explorer, National Geographic Society 

• The Colorado River is a snow-fed system that begins in the Rocky Mountains.
• The Colorado River flows through a mostly arid environment that receives under 20 inches of rain each year and is currently experiencing a megadrought—the hottest and driest period in the last 1,500 years.
• The river's natural flows since 2000 are 20% lower than average flows in the previous century. The river has lost an estimated 10 trillion gallons of water due to hotter, drier conditions driven by climate change.
• One out of every 10 people living in the United States relies on the Colorado River for drinking water. Its resources are shared among 30 federally-recognized, sovereign tribes and seven western states: Colorado, New Mexico, Wyoming, Utah, Arizona, Nevada, and California.
• The Colorado River supports life in major western cities such as Denver, Phoenix, Los Angeles, and San Diego.
• Many tribal communities in the Colorado River Basin are still working to access water that is legally theirs or are in the process of navigating complex settlement processes to secure their water rights.
• Every year, half the river is diverted to irrigate five million acres of farmland, which contribute to 15% of U.S. agricultural production.
• The basin’s major reservoirs, including Lake Mead and Lake Powell, are at critically low levels. This has caused federal, state and tribal officials to engage in negotiations over how to distribute long-term water cuts after certain drought agreements expire in 2026 in order to stabilize water levels.
• Under current Western water law, the oldest water users have the most secure water rights. During times of water shortage, newer water users (e.g., new farms) face cuts first.
• As one example, the Ute Mountain Ute Tribe Farm and Ranch Enterprise in Colorado received only 10% of their normal water delivery in 2021 and had to fallow 6,000 acres of the farm and lay off half of their staff. In 2022, the farm received 40% of a normal supply. Farms find out what their water allocation will be each spring. Ute Mountain Farm wrote a climate adaptation plan and is working to implement it through strategies such as replacing irrigation nozzles to eliminate water leaks. 
• Farmers in the Imperial Valley, who hold some of the oldest water rights, receive the largest allocation of water of any farming community in the Colorado River Basin. In fact, the valley receives about the same amount of water as Arizona and Nevada combined. To reach the valley, water is moved through complex canal systems in the desert. 
• The Imperial Valley is feeling some pressure to cut water use and help bear the burden of climate change, but that will mean reducing the amount of area farmed.
• The Colorado River delta is now dry, but it used to be deep enough for steam ships to pass through.
• The binational coalition Raise the River is rebuilding areas of critical natural habitat in the river's former delta. They have restored over 1,500 acres of land across several sites using less than one percent of the river's annual flow. Species populations in these restored sites are 80% greater than in the surrounding depleted areas.
• Nearby mining waste and other industrial contaminants also threaten the Colorado River ecosystem.

 

Jack Schmidt, Director, Center for Colorado River Studies, Utah State University

• Most people who use water from the Colorado River do not live on the river. The largest U.S. city on the banks is Yuma, Arizona, with a population of only 100,000.
• The size of the Colorado River Basin reservoirs, primarily Lake Mead and Lake Powell, are larger in proportion to the natural flow of the river than any other watershed in North America. Thirty percent of the Colorado River Basin’s water is stored in Lake Mead, 30% in Lake Powell, 30% in the Upper Basin, and 10% in the lower river.
• People constructed dams on the river to even out the annual river flow and support agriculture.
• Twelve million acre-feet of water runoff from the Rocky Mountains flows south into the Colorado River (An acre-foot is equal to about 326,000 gallons.)  Four million acre-feet of water arrives in reservoirs and is used within the Upper Basin. Over one million acre-feet evaporates off the surfaces of Lake Powell and Lake Mead. About 800,000 acre-feet of water enters the Colorado river within the Grand Canyon through springs. Water released from the Hoover Dam and David Dam is almost entirely diverted to Arizona and California, specifically the Imperial Valley. Approximately 1.5 million acre-feet of water crosses the Mexican border and is diverted to farm fields. No water makes it to the ocean.
• Lake Powell and Lake Mead reservoirs experienced significant water loss from 2000-2005 and 2020-2022. The reservoirs were the lowest they have ever been in 2023. This occurred as a result of consumption exceeding natural supply and a decline in watershed runoff due to the warming climate.
• There has been a 31% decline in flow at Lees Ferry (the location where the Upper Basin ends and the Lower Basin begins) since the early 20th century.
• The laws that govern the Colorado River are complex and include two interstate compacts, a binational treaty, Supreme Court rulings, records of decisions, and administrative agreements.
• The key areas of environmental concern are the Upper Basin, Grand Canyon, and the delta.
• For the latest water use negotiations, stakeholders need to figure out how to rebuild the water supply to balance consumption with supply and who is going to take the brunt of water shortage or drought.

 

Brian Richter, President, Sustainable Waters; Senior Freshwater Fellow, World Wildlife Fund

• About 52% of the Colorado River’s water is used for irrigated agriculture, while 18% is consumed in urban areas. The rest supports natural vegetation (19%) and evaporates from reservoirs (11%).
• Nearly three-quarters of all Colorado River water consumed by humans is used for farming, with 62% of that water supporting the growth of cattle feed like alfalfa and grass hay.
• Cities in the basin have reduced water use by 18% since 2000, despite a 24% population increase, through measures like outdoor water use reduction, efficient plumbing fixtures, tiered pricing (i.e., as more water is consumed, the price per unit of water increases), and leak detection.
• Las Vegas, Nevada, is a leader in water conservation efforts, such as incentivizing residents to switch from grass lawns to drought-resistant landscaping.
• Encouraging water-efficient plumbing fixtures like low-flow toilets, dishwashers, and washing machines has contributed to a 20% reduction in U.S. water use, with cities achieving major savings through these measures.
• Improving farm irrigation efficiency can save water, but the “irrigation efficiency paradox” often leads to farmers using those savings to expand production rather than reducing overall water consumption.
• Encouraging farmers to grow less water-intensive crops and reduce total harvests (e.g., cutting alfalfa fewer times per season) can lead to significant water savings.
• Temporary fallowing programs, where farmers are compensated to stop farming certain fields for a period of time, have received billions of dollars in funding from the Inflation Reduction Act (IRA) (P.L. 117-169).
• Permanently retiring some farmland may be necessary for sustainable water use. While not in the Colorado River Basin, California is proposing a similar plan for its Central Valley that would retire 20% of irrigated land.
• The depletion of the Colorado River currently exceeds its natural replenishment. A combination of agricultural and urban conservation strategies is critical for long-term water security.

 

Q&A

 

Q: What federal policy levers can be used to strengthen the resilience of the Colorado River and the surrounding communities?

Ochs

• Reliable federal funding that supports farmers trying to adapt their practices is critical. For example, the U.S. Department of Agriculture received $3.1 billion from the IRA and made it available for climate-smart initiatives such as the Rural Energy for America program and the Environmental Quality Incentives Program.
• Federal funding can continue to support farmers who are trying to make difficult sustainable transitions and also fund under-researched areas in agricultural science, such as the study of forage crops.
• Making changes on farms takes time, especially when you have to work within the parameters of what is possible during a growing season.

Schmidt

• There are two parts to this answer. The first is that the Colorado River is a federally-managed system, and therefore the federal government is obligated to play a role in its management.
• The second part is that the federal government funds hydrologic measurements and other climate science. This is the data that is essential for resource management.
• Looking at the big picture, the problem of high levels of greenhouse gases in the atmosphere must be addressed.
• In terms of the Colorado River negotiations, the federal government might need to play a more significant role to negotiate settlements between U.S. states and Mexico.

Richter

• There is no full Colorado River Basin commission, the creation of which could help to foster more holistic discussion. This work is currently split into an Upper and a Lower Basin commission.
• The discussions now are reactive, and they need to be more future-focused. For example, we could ask stakeholders about what they want the basin to look like 10 or 20 years from now.
• In Richter’s book, Chasing Water, he emphasizes the importance of setting a limit on resource usage in line with the reliable volume of water in the system now and looking ahead. We must live within nature’s limits.

 

Q: Would rebuilding soil health to allow the ground to hold more water in the root zone allow production to continue with lower levels of irrigation?

Richter

• A review of field studies from around the world on efforts to conserve water in irrigated agriculture did identify soil health as a potential way to reduce irrigation needs. More definitive scientific data on soil’s relative ability to hold moisture is needed, including detailed studies that can document moisture retention in different soil types and under different crop conditions to get this strategy up to scale.

Ochs

• Building soil health to increase system resilience could be a part of the long-term solution, but the most pressing thing is shifting from disaster response to stabilizing the system in order to deliver water to people.

 

Q: Are there solutions out there that deserve more attention or solutions that are not as effective as they are perceived to be?

Richter

• We already have diverse and effective solutions for reducing water use in cities and on farms. The issue is that these tools are not being applied at the necessary scale to meet the crisis in the Colorado River system.
• Over a billion dollars a year goes to farms to incentivize farmers to fallow and save water. This reduces water use by about one million acre-feet of water per year, but stakeholders in the basin need to reduce water consumption by three to four million acre-feet a year. More investments must be made.

Schmidt

• There are not yet policies in place that will rebuild reservoir storage. We are living on the brink of disaster.
• There is talk of manipulating forests or eliminating forest cover to increase runoff. However, data does not support that as a strategy for increasing water supply.
• The main debate right now is between the Upper Basin and the Lower Basin, but the real problem is that over half of the water is used to grow livestock feed.
• Marc Reisner, the author of Cadillac Desert, said that the American West does not have a water supply crisis, but a water allocation crisis.

Ochs

• Ali Montazar has done deficit irrigation work with Palo Verde District citizens north of the Imperial Valley. Deficit irrigation is a strategy whereby farmers reduce water usage during summer months to find the point at which the soil can be kept healthy with minimal watering.
• There is discussion about importing water, but there is no reliable water source mentioned in these conversations. There is also interest in desalination as a source of water, but that process is very energy-intensive.

 

Compiled by Whitney Orloff and Raneem Iftekhar and edited for clarity and length. This is not a transcript.