History of man’s taming of the powerful Colorado River
to control flooding, obtain water and power, irrigate farmland
and create recreational spaces, with unintended consequences along the way
The Colorado River begins in the mountains of Colorado and snakes southwest for 1,450 miles towards the Gulf of California. Over a century ago, the river ran free from the Rocky Mountains to Mexico. The river delta covered over two million acres, with wetlands and waterways extending from the southern U.S. to the Gulf of California in Mexico. Today, the river dries up before the U.S./Mexico border and no longer reaches the ocean. Plant, animal and marine life have disappeared. Seven western states and Mexico share water from this heavily managed river, but the river is shrinking due to drought conditions over the past 15 years and there is concern about the future of this water supply.
The history of the taming and harnessing of this powerful river and the story of current restoration and conversation efforts are fascinating.
Before dams were constructed up and down the Colorado River, its course was unpredictable from season to season. It ran fast and deep and stretched wide in places. At what would become Yuma, Arizona, granite outcroppings squeezed the river into a narrower channel. Yuma Crossing became known as the safest and easiest place to cross the river. A settlement developed at Yuma in the mid-1800s. With its close proximity to the river, the town was prone to frequent flooding.
The Yuma Project was initiated in 1904 to create a dam and irrigation canals. Laguna Dam, the first dam on the Colorado River, was completed in 1909. It was based on successful weir systems in India. In a weir system, water flows freely over the top instead of being released in measured amounts. Backed up water forms a pool and can be diverted into canal systems.
The dam ended the steamboat era. Steamships and barges operated in the lower Colorado in the late 1800s, killing off native cottonwoods and willows to fuel their boilers. At Yuma, a U.S. Army Quartermaster Deport stored goods brought by steamboat from Mexico for later shipment by stagecoach to posts in California. The Depot was in operation from the 1860s to the 1880s. It is now Yuma Quartermaster Depot State Historic Park. Information on the Colorado River story is one of the displays at the park.
Because of the location of the Laguna Dam, water to supply canal systems in the Yuma Valley needed to cross either the Gila River or the Colorado River. The Yuma Project chose to go under the Colorado River. The inverted Colorado River Siphon is a large u-shaped tunnel formed by three concrete shafts. Water flows through the system by gravity. Today the Yuma Valley is a thriving agricultural area, thanks in part to the canal system. The area produces 90% of the leafy green vegetables grown in the U.S. in winter months.
The success of the Yuma Project led to other dam projects. The Hoover Dam was built in 1936 to control floods and generate hydro-electric power. It also created the Lake Mead recreational area. The Parker Dam was built in 1938 to supply water and power to Los Angeles, San Diego, Phoenix and Tucson. It created Lake Havasu, which is 45 miles in length and the deepest dam in the world.
The Imperial Dam, also built in 1938, delivers irrigation and drinking water to Yuma, Imperial, Coachella and Gila Valleys. It irrigates 600,000 acres of rich farmland. The Morelos Dam was built in 1950. It is Mexico’s only dam on the river and provides irrigation and drinking water to the Mexicali Valley. Building of the Davis Dam began in 1942, was temporarily suspended due to World War II, and completed in 1951. The dam regulates water flow to Mexico through integration with the Hoover Dam and supplies power for California, Nevada and Arizona.
The last dam, built in 1968 amid growing environmental concerns, was the Glen Canyon Dam. It regulates the amount of water to the lower Colorado Basin and generates over 3.4 billion kilowatt-hours of energy annually. It created Lake Powell and the popular Glen Canyon Recreational Area.
The dams provide water and power to millions of people, irrigate hundreds of thousands of acres of farmland and control flooding, but there have also been unintended consequences. Ecosystems have been altered with negative impact to native species. Wetlands have disappeared.
See Part 2 of the Colorado River Story for information about current conservation and restoration projects.