Arizona’s Colorado River Cut: What It Really Means for Yuma

Arizona could lose 760,000 acre-feet of Colorado River water annually under the federal government’s new operating plan. That works out to roughly 27% of the state’s basic river allocation.

For Yuma, that number deserves attention. But it does not mean every farmer, water district, business or household in the area is facing a 27% cut.

The reason comes down to something Arizona has spent decades fighting over: water rights.

Yuma-area water users operate under different contracts, different legal priorities and different rules. Some hold rights that are senior to the Central Arizona Project (CAP). Others hold rights in the same general priority category as CAP.

And despite the federal government announcing its decision in August, Arizona’s own planning documents left one particularly important question unanswered: how much water would be available to on-river Priority 4 users?

The records reviewed by Yuma Informed support neither a blanket 27% reduction for Yuma nor a guarantee that local water deliveries will remain untouched.

Here is what the documents actually tell us.

Washington’s Decision and Arizona’s Share

On August 21, 2026, the Department of the Interior announced new Colorado River operating guidelines for 2027 and 2028. The plan calls for reducing the Lower Basin states’ annual water supply by 1.25 million acre-feet.

For perspective, an acre-foot is enough water to cover one acre of land to a depth of one foot. It is the standard unit used to measure large water supplies, particularly in agriculture.

Under the federal operating guidelines, the proposed annual reductions would be divided among the three Lower Basin states:

• Arizona: 760,000 acre-feet
• California: 440,000 acre-feet
• Nevada: 50,000 acre-feet

Together, those reductions total 1.25 million acre-feet.

There is a qualification buried in the paperwork that matters quite a bit.

Section 5.3.A of the guidelines ties that particular division of water reductions to the execution of implementing agreements. If the necessary agreements are not completed, the Secretary of the Interior determines the apportionment under applicable law.

The Lower Basin states submitted a proposal on May 1, but a proposal is not the same thing as a completed set of binding agreements.

Yuma Informed's review through September 22 did not establish that every required agreement had been executed. The 760,000-acre-foot figure therefore needs to be understood as the proposed Arizona share under that conditional arrangement.

The federal government also adopted a broader Record of Decision covering a 2027–2036 framework. The specific operating guidelines examined here govern 2027 and 2028. The broader decision framework does not settle every operational question for the years that follow.

Why the 27% Figure Can Be Misleading

Arizona's basic Colorado River apportionment is 2.8 million acre-feet.

Divide 760,000 by 2.8 million, and the result is approximately 27.14%.

The arithmetic is correct. The assumption that every Arizona water user must absorb that same percentage is not.

Colorado River water is distributed through a complicated system of legal entitlements and priorities. Those rights determine where different water users stand when supplies become limited.

Yuma is a geographic area, not a single water customer with one contract.

The City of Yuma, agricultural irrigation districts, tribal water users and neighboring municipalities hold different rights. Some rights cover the volume diverted from the river. Others concern consumptive use, meaning water that is consumed rather than returned to the river.

Those distinctions matter when officials determine who receives water and how much.

The Bureau of Reclamation's Arizona priority rules help explain why.

Priority 1 includes present perfected rights, a category of established rights recognized under the governing legal framework. Priority 2 covers certain earlier rights, while Priority 3 includes qualifying contracts dating from before September 30, 1968.

Reclamation treats Priorities 2 and 3 as coequal.

Priority 4 includes the Central Arizona Project contract and later on-river contracts. Its treatment involves proportional allocation provisions, subject to applicable law, regulations, decisions by the Secretary of the Interior and approved sharing agreements.

That creates an important distinction for Yuma.

Some local rights have stronger legal priority than CAP. Others fall into Priority 4, where the relationship is considerably less straightforward.

Anyone claiming that all Yuma water automatically comes ahead of CAP is skipping over part of the federal government's own priority system.

Who Holds Yuma’s Colorado River Water?

The Bureau of Reclamation maintains separate entitlement lists for Arizona's water users. Those records provide a more useful picture of Yuma's position than a statewide percentage.

They also reveal how easily the numbers can be misunderstood.

Yuma County Water Users’ Association

The association appears on Reclamation's Priority 1 entitlement list with 254,200 acre-feet of annual diversion under Present Perfected Right No. 4.

It also appears on the Priority 3 list, but that entry does not specify an additional quantity.

That distinction prevents treating the second listing as some unknown amount of extra water.

Wellton-Mohawk Irrigation and Drainage District

Wellton-Mohawk appears under Priority 3 with an annual entitlement of 278,000 acre-feet of consumptive use.

That figure describes consumptive use, not the total volume diverted from the river. Those are different measurements and should not be used interchangeably.

Source: Reclamation Priority 3 entitlements

Yuma Mesa Division

The Yuma Mesa Division has a combined Priority 3 entitlement of 250,000 acre-feet of annual consumptive use.

That total is distributed among three districts: 41,203 acre-feet for North Gila Valley Irrigation District, 67,278 for Yuma Irrigation District and 141,519 for Yuma Mesa Irrigation and Drainage District.

Those three figures add up to 250,000 acre-feet. They are portions of the same entitlement, not additional water on top of it.

North Gila Valley also holds a separate Priority 1 entry covering 24,500 acre-feet of diversion.

The entries appear in Reclamation's Priority 1 and Priority 3 records.

City of Yuma

The City's water rights illustrate why reading only one line in the federal records can produce the wrong conclusion.

Its Priority 1 entry lists 1,478 acre-feet of consumptive use and 2,333 acre-feet of diversion, subject to a limiting footnote in the entitlement document.

A Priority 3 entry provides the balance needed to reach a combined annual consumptive-use entitlement of 50,000 acre-feet.

The City's legal entitlement is not 50,000 plus 1,478. The smaller amount is already included in the combined total.

Those figures are documented in Reclamation's Priority 1 and Priority 3 lists.

Yuma Auxiliary Project

The Yuma Auxiliary Project, also identified as Unit B, has a Priority 1 entry for 6,800 acre-feet of diversion.

Its Priority 3 entry describes the diversion reasonably necessary to irrigate 3,305 acres.

There is a small but important difference between those numbers. An acre measures land. An acre-foot measures water volume. The 3,305-acre figure cannot be treated as an additional 3,305 acre-feet of water.

The entitlement records also use the Yuma Auxiliary Project name, while federal accounting documents refer to a Unit B district. Those descriptions should not automatically be treated as identical legal entries without examining the underlying records.

Priority 1 records | Priority 3 records | Federal accounting schedules

Cocopah Water Rights

Cocopah-related entries appear under more than one priority.

Reclamation's Priority 1 list includes separate diversion entries of 7,681 and 1,140 acre-feet. The Priority 4 list includes another 2,026 acre-feet of diversion and cross-references the Priority 1 entries.

This is particularly relevant because Arizona's preliminary shortage presentation assigns a percentage to CAP Indian Priority water.

That percentage should not be mistaken for a specific reduction in Cocopah water rights.

The federal entries establish that different Cocopah-related rights have different listed priorities. They do not establish the complete scope of tribal holdings or a final allocation for the Tribe.

Priority 1 entries | Priority 4 entries

City of Somerton

Somerton appears on the Priority 4 list with an entitlement of 750 acre-feet of annual diversion under contract 03-XX-30-W0419.

That entry identifies an entitlement. It does not establish how much water Somerton currently uses or what its 2027 delivery will be.

Source: Reclamation Priority 4 entitlements

There is another geographic wrinkle worth remembering.

The federal Yuma Project extends into California.

According to Reclamation's project description, it covers 68,091 acres, including 53,415 acres in Arizona's Valley Division and 14,676 acres in California's Reservation Division.

Those figures describe the project, not necessarily the acreage currently planted.

The name Yuma Project does not mean every acre or every water entitlement associated with it belongs to Arizona.

Taken together, these records show why applying a single statewide shortage percentage to the Yuma area produces an unreliable answer.

They are also not a complete legal inventory. The reviewed entitlement lists carried revision dates ranging from August 2024 to December 2025, and the records examined through September 22, 2026, do not rule out subsequent amendments.

Water Rights Are Not the Same as Water Deliveries

A water entitlement establishes a legal right. It does not necessarily tell us how much water will actually be delivered in a particular year.

Reclamation's annual accounting records distinguish between approved diversions, forecast diversions and forecast consumptive use.

The City's own numbers offer a useful example.

In the 2026 Colorado River water forecast dated September 21, Reclamation listed these figures for the City of Yuma:

• Approved diversion: 32,600 acre-feet
• Forecast diversion: 31,242 acre-feet
• Forecast consumptive use: 18,646 acre-feet

All three describe different aspects of the same year's water operations.

None replaces the City's combined 50,000-acre-foot legal consumptive-use entitlement. Nor does any of them establish how much the City will receive in 2027.

The September forecast was provisional, with monthly use-to-date figures updated through July.

This is where comparing water numbers without checking what they measure can lead readers badly astray.

An entitlement, an approved annual diversion and a forecast are three different things. Even two numbers expressed in acre-feet may be measuring different aspects of the water supply.

Arizona's Own Planning Documents Leave a Major Question Open

On August 24, the Arizona Reconsultation Committee presented an illustrative shortage scenario for 2027.

Slide 39 of the presentation outlined several proposed shortage levels for Central Arizona Project water.

The CAP Agricultural Pool and CAP Non-Indian Agricultural Priority categories were shown with 100% shortages.

CAP Municipal and Industrial Priority was shown at 14%, while CAP Indian Priority was shown at 10%.

Then came the entry especially relevant to Yuma's on-river users.

On-river Priority 4: TBD.

To be determined.

That leaves a substantial unanswered question for an area whose water users include Priority 4 entitlement holders.

The presentation was explicitly preliminary and illustrative. Those percentages were planning assumptions, not final delivery notices to individual customers, districts or tribes.

The 10% CAP Indian Priority figure, for example, cannot be applied to Cocopah's listed entitlements simply because both concern tribal water.

Likewise, the document does not establish that all on-river Priority 4 users will face the same treatment as CAP.

When Yuma Informed checked the committee's public records on September 22, the August 24 meeting was still the latest listed. The review did not identify a later final determination for on-river Priority 4 users.

Nor did it establish individual 2027 delivery orders for Yuma-area water holders. The federal accounting index examined contained 2026 schedules and approvals.

That does not prove the missing decisions or documents do not exist. It means the reviewed records did not establish them.

For farmers, water districts and municipalities trying to prepare for 2027, the distinction matters.

Planning percentages can indicate where officials expect shortages to fall. Actual delivery orders and governing agreements establish what an individual water user is authorized to receive.

Will the Central Arizona Project Take the Biggest Hit?

Arizona's priority system gives some Yuma-area users a stronger position than CAP, and the state's preliminary scenario shows severe shortages for certain CAP categories.

That provides a reasonable basis for expecting important differences between CAP deliveries and deliveries under some senior on-river rights.

But it does not establish that CAP will absorb Arizona's entire proposed reduction.

Priority 4 includes both CAP and later on-river contracts. How those rights are treated depends on the applicable legal framework, federal decisions and any approved sharing arrangements.

Reservoir conditions, future operating decisions and litigation could also affect the outcome.

There is a meaningful difference between saying some Yuma water rights have senior priority and promising that Yuma is protected from reductions.

The first statement is supported by the federal entitlement records.

The second goes further than the available evidence allows.

Another 700,000 Acre-Feet Through Conservation

Water shortages are only part of the federal plan.

Section 5.3.B of the 2027–2028 operating guidelines provides for an additional 700,000 acre-feet of voluntary conservation across 2026, 2027 and 2028.

That is 700,000 acre-feet over the three-year period, not 700,000 acre-feet annually.

Voluntary conservation is different from a mandatory shortage. It involves agreements under which participating water contractors conserve water according to negotiated terms.

The May 1 Lower Basin proposal discusses minimum conservation contributions of 300,000 acre-feet each from Arizona and California and 100,000 from Nevada, dependent on appropriate funding.

Those state-level figures do not tell an individual Yuma farmer or district whether participation will be required, offered or financially worthwhile.

The practical questions are considerably more specific.

Will a particular district participate? What conservation measures would be required? Would growers receive compensation? How would the saved water be measured and verified? And when would any agreement take effect?

The records examined did not establish participation by specific Yuma water users in the new 700,000-acre-foot program.

Existing conservation figures in the 2026 federal forecast do not answer that question either.

For Yuma agriculture, the difference between a compulsory shortage and a compensated conservation agreement could be substantial. The governing terms would matter as much as the volume of water involved.

Mexico Has a Separate Agreement

The Colorado River does not stop at the international border, and neither do the negotiations.

On September 2, the United States and Mexico signed Minute 334, a new binational agreement addressing Colorado River cooperation through December 31, 2028.

Both governments approved it on September 8.

According to Reclamation's September 9 announcement, the agreement concerns water-use reductions, salinity and evaluation of additional water sources.

The agreement, available through the International Boundary and Water Commission, is separate from the Lower Basin states' proposed sharing arrangement.

Mexico is not one of the three U.S. Lower Basin states.

Its treaty-related obligations should therefore not be added to Arizona's proposed 760,000-acre-foot reduction or treated as another portion of Arizona's allocation.

The agreement adds another piece to the broader Colorado River picture, but it operates through a different legal and governmental framework.

Why Yuma City Council Is Considering Legal Action

Yuma officials have already taken steps to protect what the City considers its water rights.

On September 16, the Yuma City Council passed motion MC 2026-173, authorizing exploration of possible legal action concerning the federal government's August operating decision.

The Council report sets out the City's objections to how the decision treats Lower Basin water users and explains its position on relative priority rights.

The authorization allows the City to explore litigation, retain legal counsel and potentially participate in a court challenge.

It does not establish that litigation has been filed.

Nor does it mean a court has accepted the City's interpretation of federal water law.

Those are the City's legal arguments, which could eventually become issues for judicial consideration.

The report carries administrative signatures dated September 9. The Council's actual action occurred September 16, when the motion passed.

Yuma Informed's review did not verify a subsequent City-specific court filing.

That distinction matters because authorizing litigation and pursuing a case are separate events. A court ruling would be another step beyond either one.

What Yuma Still Needs to Know

The federal government's August decision established a major change in Colorado River operations for 2027 and 2028.

It did not establish a uniform reduction for every Yuma-area water user.

The available records identify senior local rights, shared entitlements, Priority 4 contracts and planning assumptions that could affect users differently.

Several details remained unresolved in the records reviewed through September 22.

Among them were whether every required Lower Basin implementing agreement had been executed, how on-river Priority 4 rights would ultimately be treated, what individual Yuma-area delivery orders would authorize for 2027, and which local water users might participate in the new voluntary conservation program.

Any later litigation filings, federal orders, reservoir determinations or changes to entitlement records could also affect the picture.

Those are specific gaps in the available evidence. They are not proof that no additional decisions have been made.

The next documents worth examining are the actual implementing agreements, final priority determinations and individual delivery orders. Those will tell Yuma water users considerably more than a statewide percentage.

For now, the 27% figure describes the size of Arizona's proposed reduction compared with its basic Colorado River apportionment. It does not establish a 27% cut to every Yuma water user.

Yuma's senior rights matter. So do its Priority 4 contracts, the final federal decisions and the agreements that put those decisions into practice.

Until those pieces are established, promising that Yuma will lose 27% is unsupported. Promising that Yuma will lose nothing is equally unsupported.

And with the Colorado River facing another round of difficult decisions, neither assumption is a sound basis for planning.

Sources and Review Date

Last reviewed: September 22, 2026.

This article is based on official records examined September 21–22, 2026. It does not represent a new verification of subsequent agreements, delivery orders or litigation developments.

Principal documents include:

• Department of the Interior's August 21 announcement
• Final 2027–2028 Colorado River Operating Guidelines, particularly Sections 5.3.A and 5.3.B
• Federal Record of Decision
• Arizona Reconsultation Committee's August 24 presentation, particularly Slide 39
• Arizona's Colorado River water priority rules
• Reclamation's Priority 1, Priority 3 and Priority 4 entitlement lists
• Reclamation's September 21, 2026 water forecast
• International Boundary and Water Commission Minute 334
• Yuma City Council motion MC 2026-173

These records document the entitlements, proposed operating arrangements and government actions described above. They do not, by themselves, establish final 2027 delivery quantities for individual Yuma-area water users.