Order in the Court: USC experts on Navajo Nation’s interstate fight for water rights

Hoover Dam in Colorado River
Water laws in the Western U.S. follow prior appropriation, wherein the first people to tap into a water source for ‘beneficial use’ — a legal term encompassing irrigation, mining, and other purposes — are given priority control. (Hunter James | Unsplash)

This article is part of an ongoing series investigating Supreme Court cases slated for the current term and their impacts on the USC community. 

As the Southwestern United States continues to suffer a historical drought, legal battles rage on over the hierarchy for control of the water supply. In Arizona v. Navajo Nation, the Supreme Court will hear arguments Tuesday regarding what water rights the Navajo Nation is entitled. The Daily Trojan spoke with USC’s experts in law and western U.S. history about the case’s impacts on major Arizona cities, the Diné people and interstate relations surrounding the Colorado River Basin. 

Water laws in the Western U.S. follow what is known as prior appropriation, a first-come-first-served system wherein the first people to use a certain quantity of water from a source for “beneficial use” — a legal term encompassing irrigation and mining, among other purposes — are bestowed water rights over that quantity. Under the legal doctrine of prior appropriation, Indigenous tribes hold the most senior water rights. Yet, for many tribes, these rights have not been recognized nor quantified. 

“It’ll be an interesting case, because the trust that the United States owes to tribal nations has been ill-defined in law,” said Robin Craig, Robert C. Packard Trustee Chair in Law at the Gould School of Law. “The Navajo Nation, in particular, has been left without water for a very long time.” 

Arizona v. Navajo Nation came before the Supreme Court Nov. 4 after the states of Arizona, Nevada and Colorado and the Metropolitan Water District of Southern California — collectively called “Arizona” in the case’s title — appealed a U.S. Court of Appeals for the 9th Circuit decision to the Supreme Court. The appellate court’s ruling in 2021 provided that the Navajo Nation had a claim for breach of trust against the U.S. in accordance with an 1868 treaty that had promised sufficient land and water for the Diné. The 9th Circuit decision allows the Navajo Nation to continue to appeal their case and push for water rights. 

But despite the fact that Indigenous reservations have typically been established before the creation of the Western states, California currently holds the most senior water rights and is also entitled to the most water from the Colorado River — 4.8 million acre-feet worth. 

“Tribal water rights tend to be very senior,” Craig said. “When [tribal reservations] finally get their water rights acknowledged and quantified, they step in at the head of the line. That’s one reason why Arizona has not been anxious to settle these water rights, because it would put Tucson and Phoenix and all of Arizona agriculture way down the line in terms of who got water.”

Some of the doctrines concerning water rights today are as old as the states themselves,such as the prior appropriation doctrine and the Winter’s Doctrine. Over time, a patchwork of interstate compacts, treaties, Supreme Court cases, congressional statues, drought contingency plans and more have formed to create what is called the “Law of the River,” Craig said.

The 1922 Colorado River Compact, which initially overestimated the amount of available water, set the stage for water allotments to the lower basin states — California, Nevada and Arizona — and the upper basin states — New Mexico, Utah, Colorado and Wyoming — and of Mexico. Tribal nations were not taken into consideration.

“It’s a question of, how do we reallocate the water when there’s less of it, but also honor the sovereign rights of either international nations like Mexico or the U.S., or sovereign nations like tribal entities, and then of course, many states that fall into the Colorado watershed?” said William Deverell, director of the Huntington-USC Institute on California and the West.

Mining activities contaminated Diné water sources with arsenic and lead, among other toxins. Nuclear testing near tribal lands after World War II also rendered residents as ‘downwinders’ due to the radioactive materials and waste. (Lyntha Scott Eiler | U.S. National Archives and Records Administration)

Regardless, the Colorado River is in trouble. The Southwestern U.S. has been in a drought for the past 22 years, which would affect the 19 million people who get their supply from the Metropolitan Water District of Southern California, Deverell said.

Residents of Diné lands have long faced environmental vulnerabilities spanning beyond droughts and climate change. Nuclear testing near Diné tribal lands after World War II rendered those living within them as ‘downwinders,’ because radioactive materials and waste floated “into the lungs, bodies, water streams [and] animals” of the Diné people, Deverell said. Compensable diseases and conditions for downwinders, as listed by the Health Resources and Services Administration, include leukemia, multiple myeloma and primary cancer of the pharynx, brain, stomach, thyroid, pancreas, liver and lung. 

“They get the short end of the environmental stick,” Deverell said.

Mining activities spanning over a century have also contaminated water sources flowing through Diné communities with selenium, among other toxins.

“This is an environmental and public health issue,” Deverell said. “There’s deep poverty on the Navajo reservation. These are very poor circumstances for the vast majority of these Indigenous people.”

The basin states have attempted — and failed — to agree upon one set plan to ration the water in recent months. Six of the states agreed upon a proposal, but California objected, citing its status as a senior water rights holder. The federal government requested that all states agree upon a proposal by Jan. 31. The impasse, however, has resulted in the federal government taking matters into its own hands. 

“Arizona has the largest concentration of tribes in the United States and the largest concentration of tribes that still do not have quantified water rights,” Craig said. “So it’s entirely possible that, if the Supreme Court decides in the Navajo Nation’s favor, there’s going to be a lot of lawsuits in Arizona that will result in some effective reallocation of water.” 

This Supreme Court case is expected to not split purely down ideological lines. Justice Neil Gorsuch, for example, has clashed with other conservative justices on expansion of tribal authority, of which he has consistently ruled in favor.

“We’ve got a little bit of a wild card in some of our justices who are normally thought of as conservative justices but tend to vote on the side of tribes,” Craig said. “The majority and dissent may not be the normal lineup.”

The current battles over water have major implications for the nearly 170,000 people living on the Navajo Nation, which Craig said is a “civil rights issue.”

“[It’s] not the ones we tend to focus on here in L.A. because we’ve erased the tribal presence here, but these are the original inhabitants of the U.S. and a lot of tribes like the Navajo Nation do not have the water they need to survive,” Craig said.

Correction: An earlier version of this article misstated Justice Neil Gorsuch’s position on tribal authority. He has consistently ruled for the expansion of tribal authority, not sometimes for and sometimes against. The article also misstated the number of people living on the Navajo Nation. The Daily Trojan regrets these errors.