Irrigation in the American Southwest

1. Irrigation in the American Southwest

2. U.S. Government Irrigation • Small scale irrigation continued even as the southwest became part of the United States. Towards the end of the 19th Century irrigation became somewhat of a political issue. Up to this point the federal government stayed out of irrigation projects. With the many failures of private enterprise attempts, however, momentum for government backed projects grew.

3. What is Irrigation? • To supply dry lands with water • As you will see methods of irrigation can take many forms • For a historical look at irrigation, click Here

4. Why was irrigation necessary in the American Southwest? • This area of the country is exceptionally arid or lacking in water. • Less than ten inches of rain per year qualifies as a desert climate • Less than twenty inches of rain per year qualifies as a steppe climate • Annual rainfall for select cities in the Southwest Phoenix, AZSanta Fe, NM

5. How have the inhabitants dealt with this lack of rainfall? • By necessity they irrigated the land. • The groups of people who have lived in the American Southwest have a history of using irrigation projects to make their land more productive. • Let us look at three groups of inhabitants (two historic and one modern) who have irrigated this land.

6. Pre-Colonial Group: The Hohokam • Hohokam is a Pima word meaning “those who are gone.” It is used to describe an indigenous group that lived in the Sonoran desert, one of the four major deserts in the United States. • Click here to see where it is located

7. The Hohokam • Because the Hohokam mostly disappeared by 1450, scant few primary source materials remain on their existence. Due to this, historians rely on archeological evidence to piece together the story of the Hohokam. This is what we shall use to discover there methods of irrigation.

8. The Hohokam Irrigation System • The irrigation system of the Hohokams mainly consisted of building canals. The technology used to build these canals consisted of stone tools and large pools of human labor. Primitive as these were they managed to enhance the landscape enough to make it sustainable. • Irrigation allowed the Hohokam to practice agriculture.

9. Hohokam • Archaeologist Emil Haury surmises, • “It was unreasonable to believe that a settled village could exist in the desert without some form of water technology… in the arid environment of the Gila valley, a sizeable clumping of people could not survive as a village without farming; farming could not be pursued without an advanced knowledge of arid land agriculture; and arid land agriculture could not be effectively practiced without irrigation” (Haury) 121

10. Hohokam A mural depicting Hohokam irrigation agriculture. This mural is displayed at the Arizona Museum of Natural History.

11. The Hohokam

12. Hohokam • Modern remains of a Hohokam irrigation canal.

13. Spanish Colonial Acequias • As the Spanish colonizers migrated north from Mexico in the 16th and 17th centuries, they also realized the need for irrigation. • Jose Rivera of the University of New Mexico discusses the role of acequias in the Spanish settlement of New Mexico. Read This • You only need to read the first four paragraphs. • As Rivera notes, the Spanish drew upon their experiences in the arid regions of the Iberian Peninsula to enhance their irrigation projects.

14. Spanish Colonial Acequias • Juan de Torquemada, a Franciscan friar and historian, wrote of the success of these irrigation projects. • “San Gabriel… is situated at thirty-seven degrees latitude, and its sides consist of two rivers, one of which has less water than the other. The small one [the Rio Chama] irrigates all the varieties of wheat, barley, and corn, in cultivated fields, and other items that are planted in gardens, because those lands produce cabbage, onions, lettuce and beets, and other small vegetables than in this one: producing many good melons and watermelons. The other river is very large; they call it [Rio] del Norte, which provides a lot of fish.” (Monarquía Indiana por Fray Juan de Torquemada, published in 1615.) 

15. Spanish Colonial Acequias Image from On a Mexican Mustang, Through Texas, from the Gulf to the Rio Grande, by Alex E. Sweet and J. Armoy Knox, 1883. Notice the armed Spanish guards posted to keep the Indian laborers from abandoning their duty.

16. U.S. Government Irrigation • “The western half of the United States would sustain a population greater than that of our whole country to-day (sic) if the waters that now run to waste were saved and used for irrigation. The forest and water problems are perhaps the most vital internal questions of the United States.” President Theodore Roosevelt 1901

17. U.S Government Irrigation • In 1902 the U.S. government passed the Reclamation Act. This act allowed for, “the examination and survey for and the construction and maintenance of irrigation works for the storage, diversion, and development of waters for the reclamation of arid and semiarid lands” in the American west.

18. U.S. Government Irrigation • The first dam completed with funds from the Reclamation Act was the Truckee-Carson Dam. Completed in 1905 it diverted water from the Truckee River to arid regions of Nevada.

19. U.S Government Irrigation • Truckee–Carson Dam 1905

20. U.S. Government Irrigation • Arguably the most famous dam constructed with funds from the Reclamation Act is the Boulder Canyon Dam, later renamed the Hoover Dam. • Hoover Dam Video

21. U.S. Government Irrigation • Follow this link to see pictures and primary documents on the Hoover Dam. • Hoover Dam

22. Conclusions • Generations of inhabitants in the American Southwest deemed irrigation necessary to their quality of life. • Irrigation systems in the arid southwest did not occur in a historical vacuum. Successive groups built upon the foundations of their predecessors and enhanced the projects with available technology. • While the scope and size of their undertakings differ, each group altered the landscape for their own gain.