A battle over water related to Colorado River drought is looming, as states in the upper basin are expected to work to retain more flow despite the needs of Arizonans and Californians to preserve existing water levels.
The 1,450-mile Colorado River is a major source of water in seven states — the upper basin of Utah, Colorado, Wyoming and New Mexico and the lower basin on California, Arizona and Nevada — and most of that flow is dedicated to agriculture. But water levels are expected to diminish in coming years: the current management plan was developed during a plan of high water levels, and with the levels going down in coming decades, there will surely be a battle for the water remaining. From The New York Times:
The once broad and blue river has in many places dwindled to a murky brown trickle. Reservoirs have shrunk to less than half their capacities, the canyon walls around them ringed with white mineral deposits where water once lapped. Seeking to stretch their allotments of the river, regional water agencies are recycling sewage effluent, offering rebates to tear up grass lawns and subsidizing less thirsty appliances from dishwashers to shower heads.
Studies now show that the 20th century was one of the three wettest of the last 13 centuries in the Colorado basin. On average, the Colorado’s flow over that period was actually 15 percent lower than in the 1900s. And most experts agree that the basin will get even drier: A brace of global-warming studies concludes that rising temperatures will reduce the Colorado’s average flow after 2050 by five to 35 percent, even if rainfall remains the same — and most of those studies predict that rains will diminish.
Already, the drought is upending many of the assumptions on which water barons relied when they tamed the Colorado in the 1900s.
Now, it’s not hard to see a scenario where upper-basin states are pressured to use less water. And with these discussions will be larger discussions of climate change and whether it exists. Lower water levels associated with the Colorado River drought, alas, are physical realities and not subject to the abstractions you find in the midst of climate-change debates.