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Mechanisms responsible for streamflow generation on a small, salt‐affected and deeply weathered hillslope
Author(s) -
George Richard J.,
Conacher Arthur J.
Publication year - 1993
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.3290180402
Subject(s) - throughflow , streamflow , surface runoff , ponding , infiltration (hvac) , hydrology (agriculture) , geology , aquifer , interflow , erosion , antecedent moisture , saturation (graph theory) , environmental science , groundwater , soil science , geomorphology , drainage basin , geotechnical engineering , runoff curve number , ecology , drainage , physics , cartography , mathematics , combinatorics , geography , biology , thermodynamics
This paper considers the contributions of overland flow, throughflow and deep seepage to the generation of streamflow in a salt‐affected, deeply weathered landscape. Runoff mechanisms on a small hillslope in south‐western Australia were dependent on the extent and development of variable source areas. In winter, streamflow generation was controlled by returnflow, saturation overland flow and throughflow. In summer, post‐ponding, infiltration‐excess and saturation overland flow dominated. The extent of the variable source area and the magnitude of streamflow were due to antecedent soil moisture, rainfall and slope morphology. Concave hillslope sections accumulated soil moisture due to both saturated and unsaturated lateral flow processes. Throughflow provided the mechanism and vehicle for solute movement from the groundwater discharge area to the stream. However, discharge from the deep aquifer was the primary mechanism responsible for soil salinity and maintaining the core of the variable source area. Estimates of throughflow which only take account of soil‐water movement and disregard returnflow, will underestimate the magnitude of throughflow.