Extreme Drought Effects on the Colorado River in Grand Canyon

             

Will Long-Term Regional Drought and Climate Change Affect My

Grand Canyon Rafting Adventure?

                    

By Sharon Hester-Updated 04/24/25

If you have heard about the long-term extreme drought and effects of climate change on the Southwest region and Colorado River system, and have concerns, you are not the only one. We at Arizona Raft Adventures are also worried for the communities and ecosystems of the region that all rely on Colorado River water to survive.  Much will have to change, such as water conservation practices and water regulations/law for the regions that rely on Colorado River water to continue to thrive.    

We hear the question, “will the river be too low to raft?” a lot from our rafting participants. With the current information available, not having enough water to raft the Colorado River in the near future due to regional drought is not a concern for us. You may ask how can that be, we have heard so much about drought and climate change? Let us explain!  

The Colorado River and the Colorado River Compact 

The Colorado River is a large volume and heavily regulated river system. The 100-year-old federal act, the Colorado River Compact (CRC) originally mandated that the upper basin states (CO, WY, UT, NM), where most of the water is created by snowpack, deliver 7,500,00 -acre feet annually to the lower basin states (CA, NV, AZ).  Figure in mandated water delivery to Mexico and Indigenous Tribes’ allocations and the total amount was 8,230,000-acre feet annually. That amount was to be averaged out over a 10-year period. With the original CRC regulations, even in a heavy shortage year scenario, 7,000,000 acre-feet/year (7maf) must still flow down through Grand Canyon from the upper basin states to the lower basin states. However, in May of 2023, the Lower Basin states agreed to cut their water use by 3 million acre-feet from then until the end of 2026 in exchange for federal funding for water infrastructure projects, called the  Interim Guideline Modification. The first 1.5 million of which would be completed by the end of calendar year 2024. This interim flow regime to the Colorado River Compact has had the effect of stabilizing the Colorado River system but is likely to be modified in 2026 when it expires. 

 For a bit of perspective, the previously required 8.23maf (million acre-feet/year) equates to a median water release of about 12,000 cubic feet per second (cfs) per day from Glen Canyon Dam/Lake Powell. That includes both the higher flows in mid-summer and the lower flows in the shoulder months and winter. In 2022, the lower basin water users saw a reduction of flow from 8.23maf to 7maf.  At the 7maf, this averages out at about 10,615cfs per day spread out over the year. The 2023 rafting season saw the lowest consumptive use in the Lower Basin States at about 5.8 million acre-feet, the lowest consumptive use since 1984. This equated to flows between 5,200cfs to almost 20,000cfs. With the average flows being about 13,000cfs between April and Oct 2023. While flows below 6,000cfs present more challenges for rafters, those lower flows are short-term lows. Flows above 6,000 are fine flows for rafting through the Grand Canyon. For perspective, the river has been successfully navigated (in both motor and oar rafts) at flows as low as 3,000cfs. It is interesting to note that prior to Glen Canyon Dam being built (prior to 1963), the average annual flow of the river was about 8,000cfs.  

The Colorado River supports over 40 million people, making it a critical resource for various stakeholders and interest groups. Changing the parameters of the Colorado River Compact is a massive legal challenge, affecting many water municipalities in both upper and lower basin states. Ensuring adequate flows for power demands, cities, agriculture, and the environment will undoubtedly be a long and challenging process, requiring sacrifices from everyone reliant on the river. 

Water allocations under the Colorado River Compact might be further reduced in 2026 due to insufficient stored water in the upper basin states. However, it is highly unlikely that these reductions would prevent rafting through the Grand Canyon. As long as snow continues to melt from the Rocky Mountains, water will flow through the Grand Canyon to meet the needs of southern cities and farmlands, and to ensure power generation by flowing through the dam’s turbines. The river remains navigable even at exceptionally low flows, so rafting in the Grand Canyon is not at risk of stopping due to water reductions. Fortunately, the winters of 2022/23 and 2023/24 saw above-average snowpack in the Colorado River watershed, providing a reprieve from potentially more extreme water cuts that could be mandated with the 2026 Interim Guideline Modifications. 

If the Colorado River through Grand Canyon National Park were to become too low for navigation, it would signify severe issues for southwestern communities, making rafting concerns secondary for residents of the region. This dire scenario could happen with continued drought and climate change if necessary conservation measures and changes to water allocations are not implemented. However, with careful planning and effective water conservation efforts, we hope that people can continue to live in the region and enjoy rafting adventures on the Colorado River for generations to come. 

UPDATE and Current River Flows for the 2025 Season

Update: Due to the extremely high snowpack of 2022/2023 and the slightly above average snowpack during the winter of 2023/24, the Department of the Interior projects that the Interim Water Conservation measures adopted recently in the Southwest will keep supplies stable for at least a couple more years. It is likely that at some point in the future, flows will have to be reduced further, but when and how much remains to be seen. Further cuts will be big news again in the future. It will be a painful and expensive change for states and cities that rely on Colorado River water. However, if there is enough water to sustain those cities and humans residing in the southwest, there will be enough water for rafting.  

Projected April 2025 Flows: Recent emails from the Bureau of Reclamation (BR) state that hourly releases during April 2025 will fluctuate from a low of approximately 8,000 cfs during the early morning hours to a high of approximately 13,400 cfs during the afternoon and evening hours.  The anticipated monthly release volume for May is 598,000 acre-feet and will be confirmed with a subsequent notification toward the end of April. 

Projected May 2025 Flows: Recent emails from the Bureau of Reclamation (BR) state that hourly releases during May 2025 will fluctuate from a low of approximately 8,900 cfs during the early morning hours to a high of approximately 14,275 cfs during the afternoon and evening hours.  The anticipated monthly release volume for June is 676,000 acre-feet and will be confirmed with a subsequent notification toward the end of May. We will update this flow information upon receiving email updates from the BR. For current and historical flows/temperatures at Lees Ferry (Mile 0 for Grand Canyon rafting trips) go to  USGS Water Data.

NOTE: Flooding from side streams in Grand Canyon can add to the dam releases. Those side stream floods are temporary and usually do not have a significant effect on river levels, but occasionally can create a sharp short-term spike in the base flow from the dam. Also, dam operators may deem it necessary to decrease flows at any time for emergency operations procedures. 

The Effects of Lower Water Flows: Pros and Cons 

The information below remains valid for future years when flows will need to be further reduced due to low water storage in reservoirs. Every trip also experiences daily low and high flow regimes, so the details below apply to any rafting adventure. 

When all is done, even with projected lower volume water flows, there should still be plenty of water to raft through the Grand Canyon in the future. Many rapids in the Grand Canyon become more challenging at lower flows. Some rapids have waves that are largest at lower flows, while others become washed out at higher flows. Grand Canyon rapids remain exciting at any given water flow! 

Benefits of Lower Water Flows Due to Lowered Lake Levels: 

Larger and More Plentiful Beaches: Lower water levels create bigger beaches, providing better camping options overall. 

Warmer Water: The water will be warmer, making it nicer for dipping, playing, splashing, and bathing. This is because the warmer surface waters of Lake Powell are drawn into the dam intake pipes due to the lower lake level. Previously, when lake levels were higher, the intakes were deeper, resulting in colder water temperatures. 

Drawbacks of Lower Water Flows: 

Slower Water Speed: Lower water means slower water speed, which could result in less time for hiking at the lowest flows. However, this can often be mitigated by starting earlier in the mornings. It will also require more effort to row or paddle rafts downriver in the flat sections. This is not an issue on motor trips, where hiking time should remain similar regardless of the flow. 

Warmer Beverages: Warmer water means that beverages chilled in “mesh drag bags” hanging off the raft into the water may not be as cold as in previous years. 

Ecological Changes: Warmer water will create ecological changes in the already modified environment (due to Glen Canyon Dam and other upper basin dams). Historically, the river was warm and muddy most of the year. After the dams were constructed, the flows became very cold and less muddy, altering the habitat for many plants and animals. Reintroducing warm water into a now colder river will induce further ecological changes, as some species have adapted to the colder flows. An observed change includes an increase in foot infections on trips. Learn how to prevent foot maladies from happening on your river trip. 

Possible Absence of Dories: There is a possibility that dories may not be available on some Classic Adventures if they are damaged, or the water is too low. 

We’re still rafting!

In summary, despite drought and potential future reductions, current and anticipated water flows in the Colorado River remain adequate for an enjoyable rafting experience. So, rest assured and get ready for an unforgettable Grand Canyon rafting adventure! 

NOTE: According to normal operating procedures, river flows during the commercial operating season are typically lower in April, May, September, and October due to decreased power demands in the cooler spring and fall seasons. The highest flows typically occur in June, July, and August, with the peak releases usually in July or August. 

For the most updated flows, more information, scholarly articles, and more, please refer to the links provided below. 

Current and historical water flows and temperatures in the canyon  

Projected releases from Lake Powell/Glen Canyon Dam     

Want to dig deeper and learn more from the experts?  Below are a few publications that we would like to draw your attention to: 

• Management of the Colorado River: Water Allocations, Drought, and the Federal Role a Congressional Research Service Report prepared for members of Congress. (Updated March 2025)  

• Bureau of Reclamation 24-Month Study April 2025 Study of the projected outcomes for the next 24 months of the Colorado River System   

• Latest Updates in the Post-2026 Colorado River Operations Process: Post-2026 Alternatives Submitted From the University of Boulder, School of Law April 2024. Addresses issues with the Short-Term Coping, Post-2026 Operations, and Beyond For many years, full reservoirs on the Colorado River made for relative peace and stability among the basin’s major water users, despite lingering concerns over environmental degradation, unfulfilled promises to Tribal Nations, and the eventual consequences of water over-allocation and overuse. That era has abruptly ended, challenging the authors of modern Colorado River policy to quickly draft new chapters stabilizing the system through 2026, directing post-2026 reservoir operations, and articulating the long-term vision and strategies for achieving a healthy, sustainable, and equitable river system. 

• The Colorado River Water Crisis, Its Origin and the Future, by Jack Schmidt, Charles Yackulic, and Eric Kuhn. Updated April 2023. Note: I found this an informative publication. The decisions about which reservoir, Powell, or Mead, will be preferentially assigned storage will have profound ecosystem, recreational, and hydropower impacts on Grand Canyon and Glen Canyon. As those of you who attended the GTS will remember, Jack Schmidt stressed this difficult choice, and we will all have to decide what we value most. Those tradeoffs are discussed clearly in this article. Suffice it to say, there are no easy answers and tough decisions will need to be made through the EIS process that has just begun.)

• What will it take to stabilize the Colorado River? Policy Form as published in Science, by Wheeler, Udall, Kuhn, Schmidt, et al. (Note: this article and White Paper #6 above both express the consensus idea of the Future of the Colorado River Project about managing Lake Powell and Lake Mead as one facility instead of two.  Some of the best water, science, and climate change minds produced this concept, so it is best to pay attention.  The new metric will focus attention of the public and managers on the resource being managed — the stored available water supply. Currently, just Lake Mead is used to trigger consumptive use reductions to the Lower Basin and Mexico. 

 Please note in any given year there is always the possibility of temporary emergencies, extreme low flows due to power grid issues or other emergencies. 

 

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