Where did the water go?

Newcomers to the Phoenix Arizona area may cross over the Salt or Gila rivers and see a dry ditch, a gravel quarry, a junk yard, or a landfill. Perhaps they remark on how something can be called a “river” if it lacks its most important component – water. The dry climate even fools long-time residents into thinking local rivers were always and supposed to be this way. After all, a desert may go months between rains.

Historical records reveal a different story. The oldest residents remember fish caught from these rivers during the Great Depression. Early pioneers document abundant beaver and other aquatic animals. But, another local legend from World War Two tells how German POWs escaped from a local prison and planned to float the Gila River to the Gulf of California and freedom – only to find the river dry! If pioneers and Depression-era residents have stories about flowing water, yet WWII prisoners found not enough water to float in, where did the water go?

The numerous canals that traverse the valley reveal the answer. Canal diversions and groundwater pumping intercept all of the Salt and Gila Rivers’ baseflow. In other words, humans use all of the natural surface water in the Phoenix area. The only water currently in either of these rivers results from storm water runoff or effluent discharge.

A variety of users partition water from the main canals, including municipal treatment plants and agricultural fields. Older neighborhoods in central Phoenix and Mesa retain a water right, and canals and pipelines deliver water to many residences for domestic irrigation. These older neighborhoods exist in the wake of agricultural fields. Residential neighborhoods retained the irrigation conveyances and water rights for domestic irrigation as developers converted farmland to residences. Every two weeks during the summer, canal water floods these yards several inches deep, providing water for lush lawns and large shade trees.

Is this sad? Possibly. While ugly scars now remain in the Salt and Gila River beds, others point to the beautiful agriculture fields and domestic gardens made possible by water diversion. Humans have diverted the water of the Salt River for over one thousand years. Irrigation is part of the local culture, and part of what makes the region unique.