Below Ground Changes Affect Rainfall Partitioning at the Surface 

In many areas of the world, the surface of the earth is changing rapidly. These changes affect the soils below them, which in turn affects the hydrological response of hillslopes and catchments. The soil hydrological effects of land cover change can be slow or fast, and affect many processes. The feedbacks between these processes are not well understood. In this talk, I will provide examples from two very different climates to highlight the need to better understand the effects of land cover change on soil hydrological properties. I will show how tropical deforestation and reforestation affects infiltration rates, the partitioning of precipitation into overland flow, subsurface flow, and groundwater recharge, and the response of headwater streams to rainfall events. I will also highlight how the retreat of glaciers results in newly exposed land surfaces and how the establishment of vegetation and soil development affect the partitioning of rainfall into overland flow, subsurface flow, and deeper drainage, and how it affects erosion and solute transport.