We’ve talked a lot about drought in the US, and although it seems to be lessening in many areas, we’re still drawing heavily on groundwater for irrigation and drinking water supplies—so much so that the ground is subsiding.
We’re not alone, however, and as this article describes, the Middle East—particularly the area around the Tigris and Euphrates river basins—is losing groundwater faster than just about anyplace else in the world. (India claims first place in this contest no one really wants to win.) Scarce rainfall and rising temperatures have hurt the region’s agriculture, leading to a migration of people out of parts of Iran, Syria, and Iraq. To try to make up for the lack of precipitation, millions of acre-feet of freshwater have been pumped from the ground. In all, counting groundwater, surface water, and snowpack, the area lost 117 million acre-feet of its stored water—a volume equivalent to that of the Dead Sea—between 2003 and 2010.Are you subscribed to Erosion Control magazine? Click here for a free subscription!
Here in the US, Arizona—particularly the area between Tucson and fast-growing Phoenix—is pumping groundwater the most quickly, but places you might not expect are also pumping more than is being replaced, including many parts of the Atlantic coast, west-central Florida, the Gulf Coast, and the Chicago area. In addition to subsidence, loss of groundwater eventually lowers the level of lakes and rivers, contributing to shoreline and streambank erosion and, depending on the geology of the area, can lead to saltwater intrusion into the water table, threatening a source of drinking water.
Researchers in the Middle East and a team at the University of California at Irvine are collaborating on possible solutions, sharing satellite data to measure groundwater depletion as well as other research. They talk of possible solutions such as better water management, clearer international water laws and cross-border water-use treaties, and other management efforts, but as one NASA researcher notes, “Groundwater is like your savings account. It’s okay to draw it down when you need it, but if it’s not replenished, eventually it will be gone.” Dwindling supply and higher demand from growing populations seems to be leading in just one direction.
Laura Sanchez’s blog this week looks at one solution that’s working in Colorado’s San Luis Valley—fees for farmers who pump groundwater, which in turn are used to pay other farmers to fallow their fields.
Is your area experiencing higher-than-normal groundwater withdrawals, and if so what management strategies are in place or being considered?