Hillslope run‐off thresholds with shrink–swell clay soils |
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| Authors: | Ryan D Stewart Majdi R Abou Najm David E Rupp John W Lane Hamil C Uribe José Luis Arumí John S Selker |
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| Affiliation: | 1. Crop and Soil Environmental Science Department, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA;2. Biological and Ecological Engineering Department, Oregon State University, Corvallis, OR, USA;3. Civil and Environmental Engineering, American University of Beirut, Beirut, Lebanon;4. Oregon Climate Change Research Institute, College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA;5. Branch of Geophysics, Office of Groundwater, US Geological Survey, Storrs, CT, USA;6. Instituto Nacional de Investigaciones Agropecuarias, Quilamapu, Chile;7. Departamento de Recursos Hidricos, Universidad de Concepción, Chillán, Chile |
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| Abstract: | Irrigation experiments on 12 instrumented field plots were used to assess the impact of dynamic soil crack networks on infiltration and run‐off. During applications of intensity similar to a heavy rainstorm, water was seen being preferentially delivered within the soil profile. However, run‐off was not observed until soil water content of the profile reached field capacity, and the apertures of surface‐connected cracks had closed >60%. Electrical resistivity measurements suggested that subsurface cracks persisted and enhanced lateral transport, even in wet conditions. Likewise, single‐ring infiltration measurements taken before and after irrigation indicated that infiltration remained an important component of the water budget at high soil water content values, despite apparent surface sealing. Overall, although the wetting and sealing of the soil profile showed considerable complexity, an emergent property at the hillslope scale was observed: all of the plots demonstrated a strikingly similar threshold run‐off response to the cumulative precipitation amount. Copyright © 2014 John Wiley & Sons, Ltd. |
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| Keywords: | hillslope hydrology vertisols shrink– swell soils run‐off infiltration |
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