The role of bedrock topography on subsurface storm flow

Water Resources Research
By: , and 



We conducted a detailed study of subsurface flow and water table response coupled with digital terrain analysis (DTA) of surface and subsurface features at the hillslope scale in Panola Mountain Research Watershed (PMRW), Georgia. Subsurface storm flow contributions of macropore and matrix flow in different sections along an artificial trench face were highly variable in terms of timing, peak flow, recession characteristics, and total flow volume. The trench flow characteristics showed linkages with the spatial tensiometer response defining water table development upslope. DTA of the ground surface did not capture the observed spatial patterns of trench flow or tensiometric response. However, bedrock surface topographic indices significantly improved the estimation of spatial variation of flow at the trench. Point‐scale tensiometric data were also more highly correlated with the bedrock surface‐based indices. These relationships were further assessed for temporal changes throughout a rainstorm. Linkages between the bedrock indices and the trench flow and spatial water table responses improved during the wetter periods of the rainstorm, when the hillslope became more hydrologically connected. Our results clearly demonstrate that in developing a conceptual framework for understanding the mechanisms of runoff generation, local bedrock topography may be highly significant at the hillslope scale in some catchments where the bedrock surface acts as a relatively impermeable boundary.

Publication type Article
Publication Subtype Journal Article
Title The role of bedrock topography on subsurface storm flow
Series title Water Resources Research
DOI 10.1029/2001WR000872
Volume 38
Issue 12
Year Published 2002
Language English
Publisher American Geophysical Union
Description 16 p.
First page 5-1
Last page 5-16
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