On the surface, it’s pretty obvious how humans have altered lakes and rivers over the past century; dams have turned rivers into strings of reservoirs, the Mississippi River is more or less a concrete-lined sluice, and artificial ponds have proliferated by the thousands. Less apparent, but perhaps just as important, is how tapping into the groundwater systems that underlie the United States has impacted those streams and lakes as well. Now, a new detailed study in the journal Science Advances shows how much groundwater pumping has impacted those water bodies, in some cases reducing their flows by half.
Researchers have mapped the impact of groundwater pumping on surface water in individual watersheds before. But it’s only recently that computing power has improved enough to look at groundwater’s interaction with surface water, known as integrated modeling, on a scale as large as the United States. | 
