US stream flows reduced by groundwater pumping

Groundwater pumping has caused marked aquifer storage declines over the past century. In addition to threatening the viability of groundwater-dependent economic activities, storage losses reshape the hydrologic landscape, shifting groundwater surface water exchanges and surface water availability. A more comprehensive understanding of modern groundwater-depleted systems is needed as we strive for improved simulations and more efficient water resources management. Here, the authors of a new paper in Science begin to address this gap by evaluating the impact of 100 years of groundwater declines across the continental United States on simulated watershed behavior. Subsurface storage losses reverberate throughout hydrologic systems, decreasing streamflow and evapotranspiration. Evapotranspiration declines are focused in water-limited periods and shallow groundwater regions. Streamflow losses are widespread and intensify along drainage networks, often occurring far from the point of groundwater abstraction. Their integrated approach illustrates the sensitivity of land surface simulations to groundwater storage levels and a path toward evaluating these connections in large-scale models. 


2019.06.23 eaav4574.800acrobat icon Simulating the sensitivity of evapotranspiration and streamflow to large-scale
     groundwater depletion


Groundwater pumping in the last century has contributed as much as 50% to stream flow declines in some US rivers. This is the first study to examine the impact of past groundwater pumping across the entire US. Previous research examined how groundwater pumping affected surface waters, but at smaller scales. The researchers compared what US surface waters would have been like without consumptive uses with changes since large-scale groundwater pumping began in the 1950s.