Why The Colorado River Basin Project Act of 1968 Matters

The Colorado River Basin project Act of 1968
© marekuliasz/Shutterstock.com

Written by Michael Steinkirchner

Updated: July 21, 2023

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The Colorado River Basin Project Act of 1968 is a historic piece of legislation that allowed for the construction of the Central Arizona Project or CAP. The CAP is an impressive feat; a 336-mile system that helps divert water from the Colorado River throughout southern and central Arizona via aqueducts, Lake Havasu, and a series of dams and canals.

Infographic about the Colorado River.
The Colorado River runs through several states and carved the Grand Canyon.

What is The Colorado River Basin Project Act of 1968?

The Colorado River Basin Project Act of 1968 created the groundwork for the $4 billion construction of the Central Arizona Project (CAP), which contributes significantly to Arizona’s state economy and water supply.

The CAP was helped through Congress by Arizona state Representative Carl Hayden, a politician and popular member of the Democratic party. They later became the first to serve seven consecutive terms on the United States Senate.

The aims of this wide-reaching project became steadily more necessary as the 1950s developed. Arizona was experiencing a population boom with the advent of air-conditioning, and several manufacturing plants moved to the state from all over the country. By 1960, half of the population of Arizona lived in and around the city of Phoenix.

According to the Act, the project’s goal was to provide a system for regulating flood waters. In addition, the project aimed at storing and moving water from the Colorado River for land reclamation, raising the quality of drinking water, raising the standard of living for fish and other wildlife, supplying water to recreation facilities, and helping create and sell electrical power for the state.

Carl Hayden represented Arizona for forty-two years, from 1927 to 1969. In the final stages of Hayden’s career, he was able to help bring water from the Colorado River to industrial centers, farmland, and various business, parks, and public works all over Phoenix. Water was also brought to Pinal, Pima, and Maricopa counties. The CAP was officialized with the signing of the Colorado River Basin Project Act of 1968 on September 30.

By the year 1960, half of the population of Arizona lived in and around the city of Phoenix.

Phoenix, Arizona.


Why Is The Colorado River Important?

The Colorado River is one of the most important rivers in America because it provides water to Mexico and the following seven states: Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming. In addition, this 1,450-mile river helps many hydropower plants create electricity. These include the famous Glen Canyon Dam (immortalized in Edward Abbey’s 1975 cult classic, “The Monkey Wrench Gang”) and the Hoover Dam.

Farms from all over the states mentioned above also depend upon a steady influx of water from the Colorado River to help them keep their soil and animals healthy. This, in turn, has massive repercussions for the food supply, environmental health, and restaurant and tourism industries of these 7 states.

A third and equally important facet of the Colorado River is implicit in its simple presence as a habitat for mammals, birds, and fish all over the country. The planet’s health is often reflected in the health of its species and the natural environments they rely upon for food, shelter, and everyday life. Even the natural regulatory effects of runoff for mountains and rivers is a significant feature of the Colorado River that helps keep nature in balance.

Carl Hayden

The Carl Hayden Visitor Center at Glen Canyon Dam.

©Deva Kaiser/Shutterstock.com

Where Does the Water From The Colorado River Go?

The Colorado River originates in Lake Granby. It is a body of water within the Poudre Pass in America’s largest mountain range, The Rocky Mountains of Colorado. From there, it makes its way (mostly uphill) across the southwest and flows 17 miles along the US-Mexico border. 

40 million Americans are benefitting from the water supply of the Colorado River is estimated. In addition, it helps irrigate totals of upwards of 5 million acres. The Colorado River also supplies water to Mexico and is responsible for 40% of Colorado’s total water supply.

The river runs for about 3,000 square miles and covers 246,000 square miles. This takes up the entirety of Arizona and parts of the other seven states it flows through.

It is divided into two main areas, the Upper Basin and the Lower Basin. The Upper Basin is Colorado, Utah, Wyoming, and New Mexico. The Lower Basin is designated as California, Arizona, and Nevada.

At Lake Havasu, the water is pumped 824 feet upwards via the Mark Wilmer Pumping Plant. This plant was dedicated to the attorney who helped guarantee Arizona’s specific share of water from the Colorado River. 

Arizona Vs. California

The Glen Canyon Dam (forever immortalized in Edward Abbey’s 1975 cult classic, “The Monkey Wrench Gang”) and the Hoover Dam.

The Glen Canyon Dam is a true icon of the American Southwest.


The Supreme Court case Arizona v. California was the longest-running case in United States history. Initially, it started in 1952 and reached its conclusion 11 years later in June 1963. 

The decisive argument for the Arizona v. California case came from Wilmer. He referenced an earlier project act (the Boulder Canyon Project Act of 1928) as a legal precedent for Arizona’s rights to water from the Colorado River. The BCPA was the act that allowed for the creation of the Hoover Dam and the All-American Canal.

From the Mark Wilmer Pumping Plant, water is transported via a 7-mile-long tunnel. It is then lifted continuously by another 14 pump plants before spreading out across seven other states. 

The Imperial Valley in California relies heavily on the Colorado River for its agricultural water needs. Multiple municipal projects in Albuquerque, San Diego, Los Angeles, Salt Lake City, and Denver also draw from the river.

Every year the canals of the Colorado River transport more than 1.6 million-acre feet of water. This provides clean drinking water to more than 3 million households. 

The Colorado River Basin project Act of 1968

Aerial view of Franklin Eddy Canal, part of the Closed Basin Project to extract groundwater in San Louis Valley (Colorado) and deliver it to Rio Grande River.


What Are The Dams Along The Colorado River?

The Colorado River has fifteen dams (the highest number along one river in America) and several form man-made lakes such as Lake Powell and Lake Mead. Some of these dams occur along tributaries. They are included as long as they are more than 50,000 acres and above 250 feet. Dams on tributaries are separated into two tiers, the Upper Basin above Lee’s Ferry, Arizona, and the Lower Basin below. 

While these dams and reservoirs were constructed and financed by multiple institutions, state governments, and organizations, they are all bound under the Law of the River. This law was established by all seven Colorado River beneficiary states in 1922.

Upper Basin Vs. Lower Basin Dams

The main tributary dams of the Upper Basin are the San Juan dam (New Mexico), the Morrow Point/Gunnison dam (Colorado), and the Green/Flaming Gorge dam (Utah). The Lower Basin’s most notable tributary dams are the Gila Dam (Arizona), the Virgin Dam (Utah), and the Little Colorado Dam (Arizona).

The primary dams along the Colorado River are the Glen Canyon Dam, the Hoover Dam, and the Parker Dam. All of these dams help provide water for irrigation and also create electricity.

Glen Canyon Dam

The Glen Canyon Dam was built from 1956 to 1966 by the United States Bureau of Reclamation. It also helped make Lake Powell a reservoir in Arizona and Utah, which holds around 25 million acre-feet of water and is visited by more than 2 million tourists annually.

Glen Canyon Dam

Glen Canyon Dam.

©Alex Papp/Shutterstock.com

During and after its construction, the Glen Canyon Dam became a controversial structure when it flooded the Glen Canyon. This event (along with the Edward Abbey novel “The Monkey Wrench Gang”) is credited with starting the American environmental movement. The more radical/violent sections of this movement (Earth Liberation Group, Animal Liberation Group, Earth First! etc.) have been classified as eco-terrorist groups by the United States government.

Hoover Dam

The Hoover Dam in the Black Canyon is perhaps the most famous dam and the largest of the three main dams. The Hoover Dam was created during the Great Depression. It took 6 years to finish, with work starting in 1931 and reaching its conclusion in 1936.

Lake Mead was formed after the completion of the Hoover Dam. It is the largest artificial lake in America when not facing drought. All of the electricity for private and public utilities in Arizona, California, and Nevada are supplied by generators from the Hoover Dam. Hoover Dam is also a massive tourist spot, drawing in roughly 7 million visitors annually.

Parker Dam

The Parker Dam is the deepest in the world and was built by the Bureau of Reclamation from 1934 to 1938. It lies only 155 miles south of the Hoover Dam, and only 85 of its 320 feet are above water. The Parker Dam passes through Arizona and California state borders and primarily serves as a reservoir and source of hydroelectricity.

Lake Havasu was created by forming the Parker Dam, and it can hold 619,400 acre-feet of water. Lake Havasu is named after the Mojave Indian word for “blue” and is a popular attraction for tourists all over the country. 

Six of the fifteen Colorado River dams only help with irrigation needs and do not provide electricity. The remaining nine dams generate around 9 million kilowatts of power annually, with a little less than half of this coming out of the Hoover Dam and 3.5 million kilowatts generated from the Glen River Dam.

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