Subsurface stormflow is important in semiarid karst shrublands

Abstract

In this paper we describe hillslope‐scale, rainfall‐simulation experiments on karst shrublands dominated by Ashe juniper. These simulations, designed to mimic flood‐producing rainfall events, were carried out at two sites separated by 206 km within the Edwards Plateau of Central Texas. Five hillslope plots were instrumented—two shrub‐covered (canopy) plots and three intercanopy plots measuring 12–14 m in length. We repeated the experiments on the canopy plots after removing the shrubs. For the canopy plots, both before and after shrub removal, 50% or more of the water applied exited the plots as subsurface stormflow and no overland flow occurred. For the intercanopy plots, subsurface stormflow amounted to less than 10% of the water applied and overland flow was between 10 and 50%. These experiments demonstrate the importance of subsurface stormflow in semiarid karst shrublands during flood events, and more generally highlight the fact that subsurface stormflow is important in some semiarid landscapes.