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Gila River

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The Gila River is a significant waterway in the American Southwest. It is a tributary of the Colorado River. This means it flows into the Colorado River to help form it. The river drains a very large watershed. Most of this land is in Arizona, which accounts for 91.5% of the area. About 5.7% of the watershed is in New Mexico. The remaining 2.8% sits in northern Sonora, Mexico.

Gila River at Komatke Arizona
Gila River at Komatke Arizona

The river begins its journey in western New Mexico. Its source is in the Black Range of the Sierra County area. Specifically, it starts on the western slopes of the Continental Divide. From there, it flows southwest through several protected areas. These include the Gila National Forest and the Gila Wilderness. It also passes the Gila Cliff Dwellings National Monument. The water moves through many canyons before entering Arizona near Safford. Eventually, it reaches Yuma, Arizona, to join the Colorado River.

Many different rivers join the Gila to increase its volume. The main stem is formed near Gila Hot Springs by the East and West Forks. As it moves, the San Francisco and San Simon rivers join the flow. The San Carlos River also flows into the system at San Carlos Lake. Further downstream, the San Pedro and Santa Cruz rivers add their water. The Salt River is the Gila's most important tributary. It joins the Gila near the Phoenix metropolitan area. Finally, the Agua Fria and Hassayampa rivers join the river near its end.

Indigenous peoples have a very deep connection to this river. The Akimel O'odham, or Gila River People, have lived here for at least 2,000 years. They consider the river to be holy. They have even used sand from the riverbanks as an exfoliant for bathing. Between 600 and 1450 AD, the Hohokam people built complex civilizations here. They relied on irrigated agriculture. To do this, they constructed over 500 miles of canals. In the upper Gila, the Mogollon culture lived in settlements like the Gila Cliff Dwellings.

European explorers arrived in the region during the 16th century. Juan de la Asunción may have been the first European to see the river in 1538. In 1540, Hernando de Alarcón sailed up the river. His expedition called the river the Miraflores or Brazos de la Miraflores. Later, the river served as a border between the United States and Mexico. This lasted until the 1853 Gadsden Purchase expanded American territory. In 1944, the river played a role in a famous escape. German prisoners of war tried to flee using a handmade kayak. They used a map that showed the Gila as a healthy blue waterway. In reality, the river was mostly a dry rut.

Modern engineering has changed the hydrology of the Gila River significantly. The river was once a perennial stream, meaning it flowed all year. It was even navigable by large riverboats. Today, much of the water is diverted for human use. The Coolidge Dam is the main dam on the river. It creates the large San Carlos Lake. The Ashurst-Hayden Diversion Dam also moves much of the water. These projects provide water to over 6 million people in Phoenix and Tucson. Because of these diversions, the river's flow has dropped. The historic natural discharge was much higher than the modern flow. Near its mouth, the average flow is now just 10 cubic feet per second.

Despite these changes, the river system remains a place of biological diversity. There are 36 different fish species in the system. These include the largemouth bass and the channel catfish. The Gila trout is another notable species found here. The river can also be used for recreation. During spring snowmelt or after big storms, parts of the river are navigable. It features whitewater ranging from Class I to Class III. People also enjoy boating and fishing on San Carlos Lake and other reservoirs. However, visitors must be careful of the desert weather. The river is known for erratic flows and sudden flash floods.

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File:Gila River at Komatke Arizona.jpg
Gila River at Komatke Arizona.jpg
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