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Shallow subsurface storm flow in a forested headwater catchment: Observations and modeling using a modified TOPMODEL
Author(s) -
Scanlon Todd M.,
Raffensperger Jeff P.,
Hornberger George M.,
Clapp Roger B.
Publication year - 2000
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 - 10.1029/2000wr900125
Subject(s) - piezometer , subsurface flow , hydrology (agriculture) , geology , surface runoff , hydrograph , storm , groundwater , baseflow , infiltration (hvac) , groundwater flow , groundwater recharge , drainage basin , environmental science , geomorphology , aquifer , streamflow , geotechnical engineering , meteorology , oceanography , cartography , geography , ecology , physics , biology
Transient, perched water tables in the shallow subsurface are observed at the South Fork Brokenback Run catchment in Shenandoah National Park, Virginia. Crest piezometers installed along a hillslope transect show that the development of saturated conditions in the upper 1.5 m of the subsurface is controlled by total precipitation and antecedent conditions, not precipitation intensity, although soil heterogeneities strongly influence local response. The macroporous subsurface storm flow zone provides a hydrological pathway for rapid runoff generation apart from the underlying groundwater zone, a conceptualization supported by the two‐storage system exhibited by hydrograph recession analysis. A modified version of TOPMODEL is used to simulate the observed catchment dynamics. In this model, generalized topographic index theory is applied to the subsurface storm flow zone to account for logarithmic storm flow recessions, indicative of linearly decreasing transmissivity with depth. Vertical drainage to the groundwater zone is required, and both subsurface reservoirs are considered to contribute to surface saturation.