Colorado River Compact: Rethinking Southwest Water Management Amid a Changing Climate
Climate change is affecting the Colorado River, highlighting the need for local, resilient water sources such as recycled wastewater and stormwater capture.
March 28, 2024
Justin Breck, LA Waterkeeper Climate Resilience Fellow
Since time immemorial, the Colorado River has in many ways been the lifeblood of what is now known as the Southwestern United States, including and especially California. Currently the Colorado provides around 1 million acre-feet of water per year to the Metropolitan Water District of Southern California (MWD), the water wholesaler that provides water to municipalities and retail water agencies throughout the Los Angeles region. Aside from providing drinking water to the Los Angeles region, the Colorado River also irrigates millions of acres of farmland and supports many bird and native fish species as well as recreation and tourism activities. In addition, the Colorado River Aqueduct, which pumps water from the river to the LA region, has the capacity to deliver a whopping 1.2 million acre-feet of water per year.
However, climate change and its impacts – including extended periods of drought and reduced snowpack melt and runoff into the river – are placing undue stress on the river (and the infrastructure that transports its water). Several years ago, this caused the federal Bureau of Reclamation – the federal agency responsible for managing and protecting the Colorado River for the states that rely upon it – to declare the first ever water shortage for the river, triggering some cuts to users in Arizona. The effects of climate change on the Colorado River and the unpredictability of water cuts and unreliability of the river as a source to users in the LA region has made it imperative to find more local, resilient sources of water – such as recycled wastewater, stormwater capture, and nature-based solutions more broadly.
The History of The Colorado Water Compact
World Water Day is an annual United Nations Observance focused on the importance of freshwater. This year, the theme was "Leveraging Water for Peace.” Per the UN, water “can be a tool for peace when communities and countries cooperate over this precious shared resource.” Similarly, it is crucial that the Colorado River is managed in a way that benefits all users in an equitable manner.
With this in mind, we wanted to take a minute to quickly examine the history of the Colorado Water Compact, its challenges, and what the conflict over Colorado River water means for the future of water supply in the Southwestern United States.
The Colorado River Compact of 1922 divided the river into two basins: the Upper Basin – comprising the states of Colorado, New Mexico, Utah, and Wyoming – and the Lower Basin – comprising Arizona, California, and Nevada. The Compact set a limit of 7.5 million acre-feet of water each year for both the Upper Basin and the Lower Basin. This was to ensure that all states had enough water for their present and future needs.
Outdated Allocations
However, the water allocations made to the basin states under the 1922 compact were based on hydrologic data that anticipated much higher average annual water flows than we have seen over the past 100 years. This in part led to high profile legal battles and a series of court cases spanning over 70 years among different states, tribes, and the federal government over the rights to Colorado River water. Moreover, the growth of many cities in Arizona and Nevada – including Phoenix, Las Vegas, and others – has meant that those Lower Basin states started using their full allocations of Colorado River water, and thus California has had to cut back its use of those states’ excess, unused water.
Historically, California overshot its allowance of Colorado River water, but under a 2003 agreement (known as the Quantification Settlement Agreement, or QSA), each California party’s share of Colorado River water was allocated (or “quantified”), creating the ability for transfers of water between those parties – including large, long-term east-to-west transfers of water from the agriculture- and farmland-rich Imperial Irrigation District to the coastal and heavily urban Metropolitan Water District of Southern California.
More recently, in early 2023, the Bureau of Reclamation considered the possibility of further intensifying water reductions to the Lower Basin states. This was to halt the continual decline in water levels at Lake Powell and Lake Mead, two crucial reservoirs along the Colorado River. The Bureau’s goal was to “maintain congressionally authorized infrastructure, operations, water deliveries, and power generation.” Then, in May 2023, to try to head off these cuts, California, Arizona, and Nevada submitted a proposal agreeing to conserve an additional 3 million acre-feet of Colorado River water per year. Finally, just last month, the Bureau of Reclamation chose to adopt this proposal and integrate it into the Bureau’s guidelines for managing Lower Basin water shortages and operations of Lake Mead and Lake Powell through the end of 2026.
Short-Term Solutions for Long-Term Problems
While this cooperation between basin states is a positive development, it is only a short-term solution to a very long-term problem. As climate change exacerbates drought and dwindles California’s supplies of Colorado River water, the previous and current challenges and conflicts over water highlight the need to develop more sustainable, local water supplies urgently and proactively.
Water agencies in the LA region must create new sources of water supply that promote and protect natural local ecosystems while minimizing the emission of greenhouse gases that contribute further to climate change.
Nature-based stormwater capture projects that integrate bioswales and rain gardens into the landscape are beneficial because they gather water and allow it to infiltrate through the earth into groundwater – thus helping to filter pollutants while also creating additional sources of water supply.
Agencies should also promote the develop of wastewater recycling projects that reuse current infrastructure and minimize the creation of additional, redundant, and unnecessary infrastructure that leads to increased costs and carbon emissions. Wastewater recycling involves extensive treatment, resulting in treated water which is actually purer than our current water supplies. It is also a great way to help reduce our reliance on unreliable imported supplies – such as those from the Colorado River – as well as the additional and upgraded infrastructure necessary to transport that imported water to the LA region. Solutions like these can help water agencies wean themselves off the Colorado River in a sustainable way.
Toward True Equity and Sustainability
It's been over a century since the original compact was established. As we contemplate the legacy and enduring challenges associated with the Colorado River, it becomes evident that clinging to antiquated solutions is untenable in the face of escalating water scarcity exacerbated by climate change. More strategic, forward-thinking, and equitable approaches are needed. In line with the ethos of World Water Day, attaining true peace requires us to acknowledge and rectify past mistakes. Moreover, none of this even begins to touch on how the diversion and management of water from the Colorado River have wrought significant environmental injustices on Indigenous peoples.
In charting a course towards sustainability, nature-based strategies such as stormwater capture and wastewater recycling offer one potential path forward. These methods not only diminish dependence on the Colorado River but also fortify local resilience while curbing environmental degradation. By prioritizing such initiatives, we can alleviate the pressure on the Colorado River and pave the way for a more harmonious relationship with our water sources, and more equitable cooperation and sustainable water supplies for all.