This award will provide supplementary support for a long-term research stay by Dr. Roy Sidle of the USDA Forest Service to conduct collaborative research with Dr. Makoto Tani of the Forestry and Forest Products Research Institute in Tsukuba, Japan. They will investigate how soil pipes in forest hillsides influence the subsurface water flow regime, and thus affect initiation of landslides. Soil pipes and macropores are recognized to be important conducts for subsurface water during intense rainstorms. The rapid transport of large quantities of water into unstable soil mantles during storms can create zones of water pressure buildup, resulting in landslide initiation. Existing models of subsurface flow and groundwater response do not adequately address the influence of pipeflow. The research work of Dr. Tani's lab on the effects of soil physical properties on groundwater accretion will complement Dr. Sidle's research background on subsurface flow processes and landslide modelling.
