So much of the country has been experiencing drought for so long that you’d think, by now, we’d have learned some strategies to cope with it. As this blog from the Arizona Municipal Water Users Association points out, some of us have. It details how Arizona is planning ahead and making sure it gets—and keeps—its fair share of water from the Colorado River.
Water rights in the West have often been contentious. A couple decades ago, Arizona was taking less water from the Colorado River than it was legally entitled to, letting the excess flow on to California. Realizing that if it didn’t take what it was due, other states might want to claim the water permanently, Arizona decided to start taking, and saving, its full share in anticipation of future population growth. The state adopted a new policy: “Leave no water on the river.” It began storing its unused portion of the river water underground to use in times of drought or greater demand.
Today there are several large constructed recharge basins throughout central and southern Arizona that allow water to percolate into the aquifer, from which it can be pumped when needed. To help preserve the underground supply, the state also allocates river water to farmers to irrigate crops, and in exchange, they promise to reduce the amount they pump from the aquifer.
As expected, the state’s water use has increased since the plan was launched in the early 1990s, despite some model conservation efforts. Today, Arizona is banking only about 65,000 acre-feet a year of excess water, down from a peak of about 250,000 acre-feet a year. But it still has about 3.4 million acre-feet stored, which will become critical if the ongoing drought leads the US Department of Interior to declare a shortage of Colorado River water. Lake Mead, the reservoir on the river, is at its lowest-ever level, and the declaration could come as soon as 2018.
California is starting to stockpile water in a similar way, diverting stormwater into recharge ponds to replenish the groundwater the state has pumped for decades. This article from Stormwater magazine looks at some of that state’s efforts.
Are large-scale water stockpiling efforts underway in your area, and if so, how much of what’s captured is stormwater runoff?
Janice Kaspersen
Janice Kaspersen is the former editor of Erosion Control and Stormwater magazines.