October 6, 2008

Study: Water Table Depth Tied to Droughts

U.S. scientists say whether another Great Plains 1930s-type "dust bowl" again develops depends on underground water storage depth.

Recent modeling results show the depth of the water table, which results from lateral water flow at the surface and subsurface, determines the relative susceptibility of regions to changes in temperature and precipitation.

"Groundwater is critical to understand the processes of recharge and drought in a changing climate," said Reed Maxwell, an atmospheric scientist at Lawrence Livermore National Laboratory.

Maxwell and Stefan Kollet of Bonn University in Germany studied the response of a watershed in the southern Great Plains in Oklahoma using a groundwater/surface-water/land-surface model. The southern Great Plains are an important agricultural region that has experienced severe droughts during the past century, including the "dust bowl" of the 1930s.

The researchers discovered that while the onset of droughts in the region might depend on sea surface temperature, the length and depth of major droughts appears dependent upon on soil moisture conditions and land-atmosphere interactions.

The research and findings are detailed in the Sept. 28 edition of the journal Nature Geoscience.