Title of Monitoring and Modelling Runoff in Semi-arid Areas from the Hillslope to the Watershed Scale

Response of the landscape to intense rainfall events is a complex and poorly understood problem. An understanding of the spatial variability of runoff generated by such storms at the hillslope scale is a necessary goal if patterns of runoff and soil erosion are to be understood at the field and catchment scale also. In recent years, it has been recognised that linking these scales of runoff may provide an approach by which accurate predictions may be made at all scales from the small hillslope to the large catchment (Wainwright et al. 2001). Furthermore, by studying the way in which patterns of runoff vary with spatial scale a better understanding of sediment delivery problems and the dynamic connectivity of systems at a variety of scales can also be made. To address the issue of scaling within runoff, a series of nested experiments was carried out to monitor the flux of runoff after intense, natural rainfall events at a range of scales at the Walnut Gulch Experimental Watershed in the semi-arid south western US. Data from these experiments were used to evaluate a distributed, dynamic, process-based model