- Two lawsuits challenge a federal right-of-way for the Cadiz water project.
- The cases raise concerns about groundwater, desert springs and tribal cultural resources.
- The Bureau of Land Management approved the pipeline right-of-way on July 8, 2026.
- The project could pump an average of 50,000 acre-feet of groundwater each year.
- The same groundwater is being considered as a possible future water supply for Arizona farmers.
Thursday, August 20, 2026 — A long-running fight over groundwater beneath California’s Mojave Desert is back in federal court, and this time the dispute could have implications beyond California.
Two separate lawsuits filed July 28, 2026, challenge the U.S. Bureau of Land Management’s renewed approval of a right-of-way needed to move water through the Northern Pipeline, a former oil and natural gas pipeline that is part of the Cadiz water project.
One lawsuit was filed by the Fort Mojave Indian Tribe, Chemehuevi Indian Tribe, Native American Land Conservancy and National Parks Conservation Association
. The other was filed by the Center for Biological Diversity and Sierra Club.
Both cases challenge the federal government’s environmental review of the pipeline approval. The allegations in the complaints have not yet been decided by the court.
At the center of the dispute is a basic question: How much of the larger groundwater project did the Bureau of Land Management need to study before allowing water to cross federal land through the pipeline?
That question has become particularly important to Arizona. In July, the Central Arizona Irrigation and Drainage District announced plans to explore purchasing up to 10,000 acre-feet of water per year from the Mojave Groundwater Bank for possible use through an interstate exchange.
A Large Water Supply Beneath the Desert.
Cadiz owns land over an aquifer system in the eastern Mojave Desert. The company’s water project, also known as the Mojave Groundwater Bank, calls for pumping groundwater and moving it through pipelines to water customers.
According to the Center for Biological Diversity and Sierra Club complaint, the project proposes to extract an average of 50,000 acre-feet of groundwater per year for 50 years. That equals about 16.3 billion gallons annually.
The Northern Pipeline is an important part of that system.
The tribal complaint states that the pipeline is 217 miles long. Of the 162 miles involved in the case, 83 miles cross federal lands, including 65 miles managed by the Bureau of Land Management. The right-of-way covers about 455 acres of federal public land.
Converting the former oil and natural gas pipeline into a water pipeline would require more than simply turning on a valve.
According to the complaints, the work includes replacing at least 16 miles of pipeline, constructing as many as seven pump stations and installing as many as 140 air and vacuum relief valves and 140 blow-off facilities.
The Center for Biological Diversity and Sierra Club complaint says the overall construction corridor would disturb about 1,346 acres and include access roads and other facilities.
The Federal Government Approved the Pipeline.
On July 8, 2026, the Bureau of Land Management approved a federal right-of-way allowing Fenner Gap Mutual Water Company to convert and use the Northern Pipeline to transport water.
The agency supported its decision with an environmental assessment and a finding of no significant impact, according to the tribal complaint.
The federal government’s review recognized potential benefits from the project.
According to language from the Bureau of Land Management’s finding quoted in the tribal complaint, the pipeline could provide access to a new reliable water supply and greater flexibility for Southern California water deliveries. The agency said the infrastructure could improve water reliability for more than 100 public water systems.
The plaintiffs do not dispute that the pipeline could move water. Their lawsuits instead focus heavily on what they contend the federal government failed to study before approving it.
The Fight Is Really About the Pumping.
Both complaints argue that the Bureau of Land Management considered the pipeline too narrowly.
The Center for Biological Diversity and Sierra Club say the agency treated groundwater pumping as outside the federal action under review, even though the pipeline is needed to transport and sell the groundwater.
The groups argue that the federal government therefore failed to fully evaluate what could happen to the aquifer, desert springs and other groundwater-dependent resources if large-scale pumping proceeds.
The environmental groups allege that groundwater levels could fall substantially and that some freshwater springs could be affected. They also raise concerns that drying desert lakebeds could contribute to windblown dust and air pollution.
Those are allegations made by the plaintiffs, not findings by the court.
The tribal complaint also points to earlier U.S. Geological Survey work. According to the complaint, the federal scientific agency found Cadiz’s estimates of natural groundwater recharge were “not defensible” and concluded that the proposed extraction rate could exceed natural recharge by as much as 25 times.
Tribes Say More Than Water Is at Stake.
For the Fort Mojave and Chemehuevi tribes, the dispute also involves cultural resources.
Their complaint describes groundwater-fed springs, seeps and other water sources as part of a larger cultural landscape connected to tribal stories, songs and ceremonies.
The tribes say these water sources also support desert wildlife, including bighorn sheep, mountain lions, bobcats and kit foxes. They contend that preserving the landscape is important to maintaining traditional knowledge, language and cultural practices.
The complaint says both tribes requested government-to-government consultation after the Bureau of Land Management notified them of the right-of-way application in 2025.
The tribes raised concerns that groundwater depletion could affect sacred desert springs, traditional cultural landscapes and living cultural practices, including the Salt Song Trail.
Their lawsuit alleges that the federal review did not adequately address those concerns.
This Dispute Has Been to Court Before.
The litigation also has an unusual history.
The Bureau of Land Management previously approved rights-of-way connected with the pipeline during the first Trump administration. Those decisions were challenged in federal court.
During that earlier litigation, the agency acknowledged that its review had been too narrow and that it had not adequately considered groundwater pumping associated with transporting the water.
The court ultimately vacated the earlier right-of-way approvals.
The new lawsuits argue that the Bureau of Land Management has now repeated much of the same problem.
The plaintiffs contend that despite the previous litigation, the agency again approved the pipeline without adequately considering the broader effects of groundwater withdrawal.
The Bureau of Land Management’s current position, as described in the Center for Biological Diversity and Sierra Club complaint, is that groundwater pumping associated with the larger Cadiz project was not part of the federal action being considered in the pipeline right-of-way review.
That disagreement is now one of the central issues before the court.
Environmental Groups Also Raise Air Quality Concerns.
The Center for Biological Diversity and Sierra Club lawsuit adds another issue: air pollution from construction.
The complaint alleges that the Bureau of Land Management did not properly evaluate emissions associated with converting the pipeline.
The groups point to calculations in the agency’s own supporting materials that they say show construction-related nitrogen oxide emissions exceeding a significance threshold used in the analysis. They argue that the agency nevertheless failed to conduct the federal air-quality review they believe was required.
Again, these are allegations in the lawsuit and have not been resolved by the court.
Why the Fight Matters to Arizona.
Although the lawsuits concern a California groundwater project, the water has recently attracted attention in Arizona.
On July 2, 2026, the Central Arizona Irrigation and Drainage District and Cadiz announced a memorandum of understanding under which the Pinal County irrigation district could purchase up to 10,000 acre-feet of Mojave Groundwater Bank water each year.
The concept involves an interstate exchange rather than physically piping Mojave groundwater directly to Arizona. Cadiz would deliver water into the Colorado River system in California, while an equivalent amount of Colorado River water could potentially be credited for use in Arizona.
The proposal remains subject to additional agreements and government review. No water is yet being delivered under the arrangement.
That connection gives the California court battle added significance for Arizona agriculture.
Pinal County farmers have already experienced reductions in Colorado River supplies delivered through the Central Arizona Project. The proposed Cadiz arrangement represents an effort to bring a water source developed outside the Colorado River system into the regional supply picture through an exchange.
What the Lawsuits Ask the Court to Do.
The two lawsuits take somewhat different legal paths, but both seek to stop the federal approval from moving forward in its present form.
The tribal plaintiffs allege violations involving the National Environmental Policy Act, National Historic Preservation Act, Federal Land Policy and Management Act and other federal requirements. They ask the court to vacate the environmental review and right-of-way approval and prevent use or modification of the pipeline for water transportation until the federal government complies with applicable laws.
The Center for Biological Diversity and Sierra Club similarly ask the court to set aside the right-of-way and prevent Cadiz or Fenner Gap Mutual Water Company from undertaking activities within it until the Bureau of Land Management complies with federal requirements. Their claims also include alleged violations of the Clean Air Act.
As reported by Edvard Pettersson for Courthouse News on July 28, representatives of the U.S. Department of Justice, which represents the Bureau of Land Management in the litigation, did not immediately respond to the publication’s request for comment.
For now, the lawsuits leave the future of the Northern Pipeline in another round of federal litigation.
The underlying dispute is broader than a pipeline. It involves how a large new desert groundwater supply can be developed, what environmental and cultural effects federal agencies must consider when approving infrastructure needed to move that water, and whether the government’s latest review satisfies federal law.
Those questions will now be decided in court.
