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Scale effects of Hortonian overland flow and rainfall‐runoff dynamics: laboratory validation of a process‐based model
Author(s) -
Stomph T. J.,
de Ridder N.,
Steenhuis T. S.,
Van de Giesen N. C.
Publication year - 2002
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.356
Subject(s) - surface runoff , kinematic wave , storm , hydrology (agriculture) , infiltration (hvac) , environmental science , runoff curve number , hydrograph , soil science , geology , meteorology , geotechnical engineering , ecology , geography , biology , oceanography
Hortonian runoff was measured in the laboratory from uniform slopes of lengths of 1·5, 3·0, and 6·0 m for steady, high‐intensity rainstorms with durations of 1·0 to 7·5 min. A clear reduction in runoff per unit slope length was found as slope lengths were increased. This effect becomes more pronounced with decreasing storm duration. The runoff data were used to validate a simple process‐based model that combines the Philip‐two‐term infiltration equation with the kinematic wave overland flow principle. The predicted and experimental results agreed well. Laboratory findings were extrapolated with the aid of the model to slopes and rainfall durations similar to those found under West African conditions. The calculated reduction of runoff per unit length is similar to reported observations. Thus, this process‐based model can largely explain the phenomenon of runoff reduction with increasing slope length. Copyright © 2002 John Wiley & Sons, Ltd.