Precious Water for the Southwestern U.S.

June 28, 2012


Thomas McGuire
Summary Author: Thomas McGuire

Seven states of the American west and a portion of Mexico depend upon the water of the Colorado River for agricultural, industrial and domestic use. No other major river in the United States is so thoroughly depleted by human consumption. In fact, the Colorado River has not flowed as far as the Gulf of California (Sea of Cortez) for two decades. Before it reaches its delta, the river usually runs dry.

The Colorado River Compact of 1922 specifies how much water can be used by each state and Mexico. Unfortunately, the terms of the Compact were based upon river flow during the previous 30 years, a period of unusually abundant river discharge. Storage behind the Glen Canyon Dam and Hoover Dam help even out the supply water in years of drought. But if storage in the reservoirs falls below an established trigger level, which nearly occurred in 2010, the Compact also specifies how states must cut back on water usage. This stream gauging station near Phantom Ranch in the Grand Canyon is one of the locations where river flow is closely monitored. A cable across the river carries a cage from which a hydrologist can lower instruments into the water to measure a variety of parameters, including water height and velocity. Note also the commercial raft

Photo Details: Camera: OLYMPUS C2100UZ; Focal Length: 7mm; Aperture: f/5.0; Exposure Time: 0.0020 s (1/500); ISO equiv: 100; Software: Adobe Photoshop CS5 Windows.