dowsing from the sky

The NYT’s reports on a NASA study that can detect groundwater depletion by satellite! After nine years in orbit, the Gravity Recovery and Climate Experiment (GRACE) has been mapping “all of the change in ice, all of the change in snow and water storage, all of the surface water, all of the soil moisture, all of the groundwater,” says Dr. Famiglietti director of the University of California’s Center for Hydrologic Modeling.

Grace data, like the information in a corresponding visual image, has its limits. Gravitational data gets sparser as the area examined gets smaller, and in areas smaller than 75,000 square miles it gets more difficult to reach conclusions about groundwater supplies. Most aquifers are far smaller than that — California’s 22,000-square-mile Central Valley overlies several different groundwater basins, for example.

The policy implications and international status quo are challenged by the big picture, as water wars are a serious danger faced in the arid regions of the world such as the middle-east and africa. Science can’t ignore politics any longer! Dr. Famiglietti says:

“Look, water has been a resource that has been plentiful, but now we’ve got climate change, we’ve got population growth, we’ve got widespread groundwater contamination, we’ve got satellites showing us we are depleting some of this stuff.

“I think we’ve taken it for granted, and we are probably not able to do that any more.”

Just one more fact that we must act on.