By Sarah Jane Keller | High Country News
Mike Conway of the Arizona Geological Survey started getting phone calls from realtors a several months ago. With the Phoenix-area real estate market heating back up, they needed to know if their clients are looking at land run through with cracks that might open up and damage their homes, or worse. In 2008, a fissure known as the Y-crack became famous when it split open in the wake of heavy summer rains and swallowed a horse southeast of Phoenix.
Gaping cracks and collapsing land are the legacies of a century of steadily mining water in Arizona. That history of groundwater depletion is one of 40 detailed in a recent U.S. Geologic Survey report on how we’re over-drafting groundwater in many places, and on the whole doing it faster than ever. The author, Leonard Konikow, a USGS hydrologist, wanted to know how much water has been removed from underground since the U.S. began developing, so he assembled data from 1900 to 2008 for 40 different basins. The results are sobering.
Looking at a national scale, since 1900, there’s been enough water pumped from underneath the U.S. to fill Lake Erie twice over. In a related 2011 study, Konikow calculated that it’s enough water to raise sea level by about 2.8 millimeters, accounting for a little over two percent of global sea level rise between 2000 and 2008 (this happens because taking water from underground puts it into the water cycle, where most paths lead to the ocean, and not back underground).
