Water in the Desert

11/6/11

Roosevelt canal

It's odd to think of a drought in the desert, but we've had one this year.  We normally get about 8 inches of rain, but have only gotten about 2 inches so far this year.

But that's not to say there is no water in the desert.  The Phoenix area has 8 major canals running through it, and several minor ones.  We have a minor canal near our home called the Roosevelt canal.  Much of Phoenix was founded on a network of canals inherited from the Native Americans (Hohokems) who farmed this land from about 500 CE to 1450 CE.



 The Native American system utilized at least 1,000 miles (1600 km) of canals and irrigated over 100,000 acres of land.  Many of the canals running through Phoenix are based on the Hohokem system, and most of the early development of the Phoenix area was agricultural.

Most of the water comes from the rain and snow in the mountains to the east and north.  The runoff is dammed, collected in reservoirs, and released into the canals, so the three rivers that run through the Phoenix area (Aqua Fria, Salt and Gila) are dry except following downpours.




dry Gila riverbed

 In addition to the main canals, Phoenix has 924 miles of laterals, which are ditches that take water from the large canals to various delivery points in irrigated areas.  The major crops grown here are alfalfa hay, cotton, citrus, melons, spinach, broccoli and cauliflower.

lateral ditch

cotton field nearing harvest time

These canals also irrigate golf courses (over 150 in the Phoenix area), and, of course, provide drinking water.

The Phoenix area also has a superabundance of swimming pools (I would guess at least one million), and most of them are part of private homes.  There are pools in many of the backyards of our neighborhood.

Most people think we have no mosquitoes here with our dry desert climate, but because of all this water lying around in canals, laterals and pools, and because many older homes use flood irrigation to water their land, Arizona had the most cases (167) of West Nile virus of any state in the nation last year according to the Centers for Disease Control.