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When interflow also percolates: downslope travel distances and hillsclope process zones

Formally Refereed

Abstract

In hillslopes with soils characterized by deep regoliths, such as Ultisols, Oxisols, and Alfisols, interflow occurs episodically over impeding layers near and parallel to the soil surface such as low-conductivity B horizons (e.g.Newman et al., 1998; Buttle and McDonald, 2002; Du et al., In Review), till layers (McGlynn et al., 1999; Bishop et al., 2004), hardpans (McDaniel et al., 2008), C horizons (Detty and McGuire, 2010), and permeable bedrock (Tromp van Meerveld et al., 2007). As perched saturation develops within and above these impeding but permeable horizons, flow moves laterally downslope, but the perched water also continues to percolate through the impeding horizon to the unsaturated soils and saprolite below. Perched water and solutes will eventually traverse the zone of perched saturation above the impeding horizon and then enter and percolate through the impeding horizon. In such flow situations, only lower hillslope segments with sufficient downslope travel distance will deliver water to the riparian zone within the time scale of a storm. Farther up the slope, lateral flow within the zone of perched saturation will act mainly to shift the point of percolation (location where a water packet leaves the downslope flow zone in the upper soil layer and enters the impeding layer) down the hillslope from the point of infiltration. In flatter parts of the hillslope or in areas with little contrast between the conductivities of the upper and impeding soil layers, lateral flow distances will be negligible.

Citation

Jackson, C. Rhett; Bitew, Menberu; Du, Enhao. 2014. When interflow also percolates: downslope travel distances and hillsclope process zones. Hydrological Processes. 28(7): 3195-3200. DOI: 10.1002/hyp.10158
Citations
https://www.fs.usda.gov/research/treesearch/46484