Although hillslope-scale experimental studies of rainfall-runoff behavior in humid regions date back to the early work of Hoover and Hursh (1943), subsurface stormflow remains a poorly understood and poorly conceptualized runoff process. While there have been scores of studies in different climate, topographic and geological settings (see Weiler et al., 2005 and Beven, 2006, for reviews), few of these datasets are available for use by the scientific community/wider public. Some surface processes can be identified such as infiltration excess overland flow from infiltration tests and saturation excess overland flow from labor-intensive mapping of saturated areas. In contrast, subsurface stormflow is something of a runoff enigma — it is very difficult to observe and seemingly different at locales with contrasting driving conditions. Part of this enigma relates to the extreme difficulty in acquiring subsurface stormflow data — intensive site investigations, such as a hillslope trench and internal water-level measurements, are a pre-condition for defining internal controls on flow generation. We argue that a need exists to compile hillslope datasets from different settings around the world and to make datasets easily available for re-interpretation by other scientists to allow: (1) intercomparison with other sites, (2) model structural development or parameter identification with opportunities to test process descriptions, (3) evaluation of data and model uncertainties, and (4) assessments of model performance.

In this datanote, we present a high resolution spatial and temporal rainfall-runoff dataset generated from the Panola Mountain Research Watershed (PMRW) experimental trenched hillslope, henceforth called the PMRW hillslope. This dataset has provided new insights into the role of subsurface topography on hillslope-scale runoff generation (McDonnell et al., 1996; Freer et al., 1997, 2002), the role of hillslope subsurface stormflow in stream runoff (Burns et al., 2001), the link between subsurface stormflow and solute flushing (Burns et al., 1998; Burns, 1999), the identification of threshold responses (Peters et al., 2003; Tromp-van Meerveld and McDonnell, 2006b), the fill-and-spill theory (Uchida et al., 2005; Tromp-van Meerveld and McDonnell, 2006c), the link among soil depth, soil moisture, and plant transpiration (Tromp-van Meerveld and McDonnell, 2006a), and new modeling approaches to describe subsurface stormflow emergent behavior (Lehmann et al., 2007).

In this datanote, we provide a description of the PMRW hillslope dataset for the period January to June 2002, during which rainfall-runoff response was monitored at the permanently excavated trench face and during which detailed, high-resolution internal hydrologic measurements were made. This dataset is the first of its kind to be made available and we encourage other researchers with similar datasets to make them available for intercomparison.

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