Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 11 2 2007 10.5194/hess-11-907-2007 http://www.hydrol-earth-syst-sci.net/11/907/2007/ http://www.hydrol-earth-syst-sci.net/11/907/2007/hess-11-907-2007.html http://www.hydrol-earth-syst-sci.net/11/907/2007/hess-11-907-2007.pdf 907 922 2007-02-23 Formation of runoff at the hillslope scale during intense precipitation S. Scherrer info@scherrer-hydrol.ch F. Naef A. O. Faeh I. Cordery Scherrer AG, Basel, Switzerland Institute of Hydromechanics and Water Resources Management, Swiss Federal Institute of Technology, ETH, Zurich, Switzerland Basler & Hofmann, Consulting Engineers, Zurich, Switzerland School of Civil and Environmental Engineering, University of New South Wales, Sydney, Australia On 60 m² hillslope plots, at 18 mainly grassland locations in Switzerland rain was applied at rates of 50–100 mm/h for between 3 and 6 h. The generated flows were measured, including overland flow, near surface and subsurface flow 0.5–1.3 m below the surface. At some locations less than 2% of the rain flowed down the slope either on or below the surface, whereas at some others more than 90% of the rain ran off. At the majority of sites most runoff was overland flow, though at a few sites subsurface flow, usually via macropores was dominant. Data collected during each of 48 high intensity sprinkling experiments were used to distinguish, which processes were dominant in each experiment. Which dominant and subsidiary processes occurred depended on interactions between infiltration rate, change in soil water storage and drainage of the soil water. These attributes were often not directly linked to parameters usually considered important like vegetation, slope, soil clay content and antecedent soil moisture. 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