Because Arizona is arid by nature, we are tempted to think it has no water. Since ancient times. residents of this desert land have been ingenious in harnessing the water resources needed for life. As it was for the ancients, our main renewable resource for water is surface water in streams.
For almost 1500 years the Hohokam people inhabited central Arizona, farming near the Gila and Salt Rivers. In about 600, the Hohokam began to dig canals up to twelve feet deep to bring water to their 110,000 acres of fields.
Their amazing irrigation system made it possible to support a population of about 80,000 people. We do not know what finally disrupted their civilization in about 1450, but they left petroglyphs on hilltops throughout the region. Their descendants live on as the Tohono O’odham Nation.
In the 1870s, settlers to the central valley followed the lines of the ancient canals and brought water from the same Salt River to their own fields. Those canals are no longer in use, but newer canals criss-cross the valley bringing water from the river and from new projects. Arizona has developed one of the most sophisticated water management programs in the world. (The Arizona Experience)
Beginning in the early 1900s, Arizona began building a series of dams along the streams and creeks of the state. Lakes behind these dams provide recreational use as well as water supplies for drinking water, irrigation and industry.
As it was for the ancient people, the surface water today is not dependable season to season or year to year. Additional resources currently are Ground Water, Colorado River Water, and Effluent. Water from the Colorado River is brought into the middle of the state with the Central Arizona Project, CAP, and used to fill the lakes and recharge the groundwater. With careful management, Arizona is not so dry after all.