Subsurface storm flow formation at different hillslopes and implications for the ‘old water paradox’

Although many studies over the past several decades have documented the importance of subsurface stormflow (SSF) in hillslopes, its formation is still not well understood. Therefore, we studied SSF formation in the vadose soil zone at four different hillslopes during controlled sprinkling experiments and natural rainfall events. Event and pre-event water fractions were determined using artificially traced sprinkling water and 222Rn as natural tracer. SSF formation and the fraction of pre-event water varied substantially at different hillslopes. Both intensity of SSF and fraction of pre-event water depended on whether SSF in preferential flow paths was fed directly from precipitation or was fed indirectly from saturated parts of the soil. Soil water was rapidly mobilized from saturated patches in the soil matrix and was subsequently released into larger pores, where it mixed with event water. Substantial amounts of pre-event water, therefore, were contained in fast flow components like subsurface storm flow and also in overland flow. This finding has consequences for commonly used hydrograph separation methods and might explain part of the ‘old water paradox’. Copyright © 2007 John Wiley & Sons, Ltd.

[1]  A. Jenkins,et al.  The contribution of old and new water to a storm hydrograph determined by tracer addition to a whole catchment , 2000 .

[2]  F. Adler.  A Case , 1863, The Lancet.

[3]  R. Gillham,et al.  A deterministic-empirical model of the effect of the capillary fringe on near-stream area runoff 1. Description of the model , 1996 .

[4]  S. Uhlenbrook,et al.  Hydrograph separations in a mesoscale mountainous basin at event and seasonal timescales , 2002 .

[5]  A. Skowronek,et al.  Hydrological parameterization of piping in loess‐rich soils in the Bergisches Land, Nordrhein‐Westfalen, Germany , 2002 .

[6]  J. Buttle,et al.  Isotope hydrograph separations and rapid delivery of pre-event water from drainage basins , 1994 .

[7]  J. Kirchner.  A double paradox in catchment hydrology and geochemistry , 2003 .

[8]  R. Allan Freeze,et al.  Role of subsurface flow in generating surface runoff: 2. Upstream source areas , 1972 .

[9]  Brian L. McGlynn,et al.  A review of the evolving perceptual model of hillslope flowpaths at the Maimai catchments, New Zealand , 2002 .

[10]  Tim Burt.  A third paradox in catchment hydrology and biogeochemistry: decoupling in the riparian zone , 2005 .

[11]  F. Stauffer,et al.  Radon-222 as a groundwater tracer. A laboratory study , 1992 .

[12]  Jeffrey J. McDonnell,et al.  Using numerical modelling to evaluate the capillary fringe groundwater ridging hypothesis of streamflow generation , 2006 .

[13]  J. Hewlett.  Factors affecting the response of small watersheds to precipitation in humid areas , 1967 .

[14]  D. Genereux,et al.  Quantifying uncertainty in tracer‐based hydrograph separations , 1998 .

[15]  J. McDonnell,et al.  A Case Study of Shallow Flow Paths in a Steep Zero-Order Basin , 1991 .

[16]  Jeffrey J. McDonnell,et al.  Virtual experiments: a new approach for improving process conceptualization in hillslope hydrology , 2004 .

[17]  J. A. A. Jones,et al.  A semi-distributed simulation model for natural pipeflow , 2002 .

[18]  Felix Naef,et al.  A decision scheme to indicate dominant hydrological flow processes on temperate grassland , 2003 .

[19]  S. P. Anderson,et al.  Subsurface flow paths in a steep, unchanneled catchment , 1997 .

[20]  Malcolm G. Anderson,et al.  Process studies in hillslope hydrology. , 1993 .

[21]  Comment on “A deterministic—empirical model of the effect of the capillary-fringe on near-stream area runoff. 1. Description of the model” by Jayatilaka, C. J. and Gillham, R. W. (Journal of Hydrology vol. 184 (1996) 299–315) , 1998 .

[22]  Jeffrey J. McDonnell,et al.  The role of event water, a rapid shallow flow component, and catchment size in summer stormflow , 1999 .

[23]  R. Harriman,et al.  A case study in catchment hydrochemistry: conflicting interpretations from hydrological and chemical observations , 1994 .

[24]  A. Pearce,et al.  Storm runoff generation in humid headwater catchments 1 , 1986 .

[25]  M. Weiler.  Mechanisms controlling macropore flow during infiltration , 2001 .

[26]  Kevin Bishop,et al.  Resolving the Double Paradox of rapidly mobilized old water with highly variable responses in runoff chemistry , 2004 .

[27]  A. Faeh.  Understanding the processes of discharge formation under extreme precipitation , 1997 .

[28]  J. McDonnell,et al.  Functional intercomparison of hillslopes and small catchments by examining water source, flowpath and mean residence time , 2006 .

[29]  Robert C. Wolpert,et al.  A Review of the , 1985 .

[30]  John F. Dowd,et al.  A new interpretation of kinematic stormflow generation , 2002 .

[31]  H. Surbeck.  A Radon-in-Water Monitor Based on Fast Gas Transfer Membranes , 1996 .

[32]  M. Sklash,et al.  The Role Of Groundwater In Storm Runoff , 1979 .

[33]  Felix Naef,et al.  Simulating surface and subsurface initiation of macropore flow , 2003 .

[34]  S. P. Anderson,et al.  Unsaturated zone processes and the hydrologic response of a steep, unchanneled catchment , 1998 .

[35]  Jeffrey J. McDonnell,et al.  The role of lateral pipe flow in hillslope runoff response: an intercomparison of non-linear hillslope response , 2005 .

[36]  P. Burlando,et al.  Hydrograph separation of runoff components based on measuring hydraulic state variables, tracer experiments, and weighting methods , 1999 .

[37]  Jeffrey J. McDonnell,et al.  A rationale for old water discharge through macropores in a steep, humid catchment. , 1990 .

[38]  Todd C. Rasmussen,et al.  Tracer vs. pressure wave velocities through unsaturated saprolite , 2000 .

[39]  Young-Jin Park,et al.  An assessment of the tracer‐based approach to quantifying groundwater contributions to streamflow , 2006 .

[40]  Peter Kienzler,et al.  Vectors of subsurface stormflow in a layered hillslope during runoff initiation , 2005 .

[41]  E. Hoehn,et al.  Radon in groundwater: A tool to assess infiltration from surface waters to aquifers , 1989 .

[42]  Jeffrey J. McDonnell,et al.  Where does water go when it rains? Moving beyond the variable source area concept of rainfall‐runoff response , 2003 .

[43]  N. Chappell,et al.  Preliminary analysis of water and solute movement beneath a coniferous hillslope in Mid-Wales, U.K. , 1990 .

[44]  J. Gerring.  A case study , 2011, Technology and Society.

[45]  James M. Buttle,et al.  Coupled vertical and lateral preferential flow on a forested slope , 2002 .

[46]  P. Mulholland,et al.  Use of radon-222 and calcium as tracers in a three-end-member mixing model for streamflow generation on the West Fork of Walker Branch Watershed , 1993 .