Out of the need to maintain and grow, Arizona has become a renowned leader in water management. Thanks to careful planning over the years and effective decision-making, we have been able to benefit from our most valuable resource. The history of Arizona water is one that dates back centuries as lawmakers worked to ensure that our state is efficiently and intelligently using our water.

Events That Shaped Arizona’s Water History

1864 — The First Arizona Territorial Legislature Adopts The Howell Code

The code establishes prior appropriation for surface water, establishing that the first to take use of the water has the priority to use the water for the same purpose, over newer water users.

1885 – The Buckeye Canal Is Founded

Situated in the central part of Maricopa County, the Buckeye Canal brought settlers to the area and provided the essential water they would need to thrive in their new home.

1902 — President Theodore Roosevelt Signs The National Reclamation Act

The Act recognizes that a key component to Western growth and development is constructing a system of irrigation works for the storage, diversion, and development of water. The Act provides funding for irrigation projects in the Western states including construction of the Roosevelt Dam, and results in the creation of the U.S. Reclamation Service (later the Bureau of Reclamation).

1903 — Creation of the Salt River Project

Salt River Project, based in Phoenix, is established as the nation’s first multipurpose federal reclamation project authorized under the National Reclamation Act. Today, SRP is one of the Arizona’s largest water suppliers to the Phoenix Metropolitan area.

1911 — Construction of the Roosevelt Dam Is Completed

The structure is built by the Bureau of Reclamation. It is operated and maintained by the Salt River Project.

1917 — Benson Allison Decree

Decreed surface water rights for the lands in the BWCDD district.

1919 —Arizona Legislature Adopts The Public Water Code

This law requires that a person apply for and obtain a permit to appropriate surface water, rather than the previous method of merely asserting beneficial use.

1922 — Colorado River Compact Is Established

The compact among Arizona, Colorado, New Mexico, Utah, Wyoming, Nevada, and California, divided the Colorado River Basin into an Upper and Lower River Basin, and appropriates 7.5-million-acre feet of Colorado River water per year to each basin. Arizona refuses to ratify the Compact over concerns about the allocation of water among states.

1922 – Founding of The Buckeye Water Conservation & Drainage District (BWCDD)

The founding of the BWCDD assisted with agricultural endeavors by supplying irrigation water and power throughout Maricopa County.

1928—Congress Passes The Boulder Canyon Project Act

The Act designates the Secretary of the Interior as the contracting authority for the Colorado River, approves construction of the Hoover Dam on the condition that the Colorado River Compact is ratified, and authorizes approval of the Colorado River Compact without Arizona’s approval.

1935 — Completion of The Hoover Dam/creation of Lake Mead

The dam stores water for use by the Lower Basin states, controls flooding, improves navigation, regulates the flow of the Colorado River, and generates hydroelectricity. The reservoir created by the dam is Lake Mead.

1944 — The Mexican Water Treaty Is Signed

The United States and Mexico sign a treaty providing for an annual allocation of Colorado River water to Mexico of 1.5 million acre-feet.

1944 — Arizona Approves The Colorado River Compact

Governor Sidney Preston Osborn announces a policy shift in Arizona’s position on matters relating to the Colorado River leading to the State’s approval of the Colorado River Compact. This action clears the path for delivery of Colorado River water to central and southern Arizona (Central Arizona Project). Arizona contracts with the Secretary of the Interior for the annual delivery of the State’s full entitlement of 2.8 million acre-feet of Colorado River water. Contracts between the Secretary of the Interior and all Arizona water users are subject to the terms of this contract.

1945 – 1948 — Arizona Legislature Passes First Groundwater Code Legislation

In response to warnings by the Bureau of Reclamation that the Central Arizona Project would not be approved without restrictions on groundwater use. The legislation requires the registration of wells throughout the State (1945) and prohibits the drilling of new irrigation wells in ten designated Critical Groundwater Areas (1948).

1963 — Supreme Court Upholds The Boulder Canyon Project of 1928

The Court rules in favor of Arizona in a lawsuit filed by Arizona against California disputing California’s claims to Colorado River waters in the Lower Basin. The decision allowed each state exclusive use of their respective tributary water, a key reason Arizona did not initially ratify the Colorado River Compact.

The decision also secured water rights for Indian Reservations and other federal lands. Finally, the decision establishes the Secretary of the Interior as the Water Master of the Colorado River below Lee Ferry, granting the Secretary broad discretion, including the discretion to reduce the Lower Basin states’ allocations during times of shortage with some limitations.

1966 — Congress Passes The Land And Water Conservation Fund Act

President Lyndon B. Johnson signs the Act championed by Arizona Congressmen Mo Udall, which protects federal land and water and incentives states to develop public parks and recreation. Since passage, the Fund has resulted in over 2.7 million acres of land protected and the creation of over $40,000 public parks throughout the nation.

1966 — Completion of Glen Canyon Dam/creation of Lake Powell

The dam regulates the flow of Colorado River water from the Upper Basin to the Lower Basin, controls floods, stores water and produces hydroelectricity. The reservoir created by the dam is Lake Powell.

1968 —Congresses Passes The Colorado River Basin Project Act

Following persistent leadership by Arizona Congressmen John Rhodes and Mo Udall and Arizona US Senator Carl Hayden, President Lyndon B. Johnson signs the Act authorizing the Central Arizona Project (CAP). Upon signing, the President proclaimed the day “Carl Hayden Day” at the White House to commemorate the passage. In exchange for gaining California’s support of the Act, Arizona agreed that the Central Arizona Project would be the first to take reductions during times of shortage.

1971 – Arizona Legislature Creates The Central Arizona Water Conservation District (CAWCD)

The CAWCD is created to repay the federal government for the State’s share of the cost of the Central Arizona Project (CAP) and to operate the CAP canal.

1980 — Arizona Legislature Passes The Groundwater Management Act

Governor Bruce Babbitt signs the Act, championed by legislative leadership including Stan Turley, Burton Barr, and Alfredo Gutierrez, implementing the recommendations of the Groundwater Management Study Commission, composed of city, mine, and agriculture stakeholders.

The Act establishes the Arizona Department of Water Resources (ADWR) to administer the provisions of the Act and gives ADWR jurisdiction over surface water and responsibility for representing the State on Colorado River issues.

1993 — Establishment of The Central Arizona Groundwater Replenishment District (CAGRD)

Legislation requires CAWCD to replenish groundwater used by new subdivisions in Maricopa, Pinal and Pima Counties consistent with the 1980 Groundwater Management Act. In this role, CAWCD is referred to as the CAGRD.

1995 – Assured and Adequate Water Supply Rules Adopted

ADWR establishes criteria requiring a developer to demonstrate 100-year assured or adequate water supply, before land is sold for housing subdivisions in areas where groundwater depletion is most severe, designated as Active Management Areas (AMAs).

1996 – Establishment of The Arizona Water Bank Authority

The AWBA is established to protect Arizona’s cities, towns, and tribes from shortages to their Colorado River allotments by storing unused water underground. The AWBA is also the sole entity authorized by the Arizona Legislature to store Colorado River water on behalf of California and Nevada.

2004—Congress Passes The Arizona Water Settlements Act

President George W. Bush signs legislation led by Arizona US Senator Jon Kyl, approving an agreement for the amount of Arizona’s CAP repayment obligation. The Act also settles water rights claims of the Gila River Indian Community and the Tohono O’odham Nation and reallocates 67,300 acre-feet of unallocated CAP water to the Secretary of the Interior for use in future Indian water rights settlements in Arizona. 

2007—Arizona Legislature Enacts Mandatory Water Adequacy

Governor Janet Napolitano signs a bipartisan measure authorizing counties and cities outside of AMAs to adopt a requirement that new subdivisions demonstrate a 100-year adequate water supply, similar to the assured water supply requirement in the AMAs. Cochise and Yuma Counties, as well as several cities, subsequently adopt the requirement.

What Does The Future Hold?

Arizona’s water is essential to ensuring the stability of our state. As we continue facing the challenges of climate change and the Colorado River Shortage, it is essential that we learn from previous events in order to protect the future of Arizona. By taking action today, we can ensure the future of Arizona for years to come.