High infiltration rates can cause the development of perched water tables above water-restricting horizons. The perched water results in fairly rapid subsurface flow (interflow) to streams. Subsurface flow may also contribute to gully formation and streambank failure.

The subsurface flow experiment at Little Topashaw Creek aims at two objectives:

• Quantify subsurface flow processes and the physical and hydrologic soil properties resulting in bank failure.
  
  
• Expand bank failure research to include both overland and subsurface flow