Say goodbye to the Colorado River as you know it

As the U.S. Southwest is expected to heat up faster than the world average during the coming decades of global warming, what’s that mean for the lifeblood of the Southwest, the Colorado River?

The U.S. Geological Survey says it could hit a 500-year low in its flow.

Between that and reduced snowpack in the Sierras, 40 percent of SoCal’s water supply could become vulnerable in the next 20 years. Farmers will either get pressured to sell more water rights to cities (which I contend is illegal under the Newlands Act, which established the Bureau of Reclamation; read Marc Reisner’s excellent “Cadillac Desert” for more on this in particular and Desert Southwest water issues in general), or else pony up the money (which SoCal’s big corporate farms can easily afford) to get more efficient with irrigation, like folks like the Israelis do.

Remember, the Colorado is NOT the Mississippi or even close to it. In fact, it’s closer in size (and geographic setting) to the Amu Darya and Syr Darya rivers of (the former Soviet) Centra Asia, the Oxus and Jaxartes of Alexandrine fame. (The Amy Darya is shown at right, on the Afghanistan/Tajikstan border; doesn’t that just look like the Colorado Plateau?) And we all know what has happened to the Aral Sea as a result of too much tapping of these two rivers.

The USGS has predicted a 25-30 percent chance of a basin-wide water shortage by 2020. That’s the basis of the prediction, made last month, that Lake Mead could dry up by that date.

USGS scientist Gregory McCabe, the author of the report, is due to testify to Congress next month. Stay tuned.