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Subsurface flow velocities in a hillslope with lateral preferential flow
Author(s) -
Anderson A. E.,
Weiler M.,
Alila Y.,
Hudson R. O.
Publication year - 2009
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2008wr007121
Subject(s) - surface runoff , subsurface flow , geology , flow (mathematics) , storm , tracer , antecedent moisture , flow velocity , antecedent (behavioral psychology) , hydrology (agriculture) , soil science , geotechnical engineering , mechanics , groundwater , runoff curve number , psychology , ecology , developmental psychology , oceanography , physics , nuclear physics , biology
Our understanding of hillslope subsurface flow relies on assumptions about how storm characteristics affect the hillslope runoff response. Experiments in hillslopes dominated by preferential flow features often show that runoff is dynamic and is affected by antecedent conditions, rainfall conditions, and position of the slope. We applied tracers to a hillslope under natural and steady state flow boundary conditions to determine the relationship between lateral tracer velocities and various hillslope lengths and storm indicators. Tracer velocities were similar to the fastest velocities measured in other similar experiments. The velocities were dependent on the boundary conditions and slope length, and the subsurface flow velocity was most closely related to the 1‐h rainfall intensity. Unlike some studies, there was little correlation between our measured flow velocities and storm volume or antecedent conditions. We attributed this to the hillslope characteristics and the relatively consistent wet antecedent conditions during the experiments. This experiment showed that the connectivity of the hillslope preferential flow network is an important factor governing the average subsurface flow velocity.