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Monday, November 2, 2009: 2:30 PM
Convention Center, Room 407, Fourth Floor
Abstract:
Water flow and solute transport in soils are invariably affected by heterogeneity and often by preferential flow, mostly occurring within 1 m2. Paradoxically, we need to grasp flow and transport at this small scale to quantify them at the field and regional scales. This paradox arises from the fact that the scale in the direction of the flow is orders of magnitude smaller than the scales perpendicular to it. We present a package of experimental and theoretical tools to observe and analyze small-scale (0.1-1 m2) water and solute fluxes.
Multicompartment samplers can measure small-scale water and solute movement in space and time. The latest generation of samplers allows repeated extraction of percolate samples in situ under controlled suction to minimize disturbance of the unsaturated flow field. We developed a method to estimate the required total sampling area of a sampler from the degree of flow convergence in a soil.
We improved our ability to analyze the data produced by multicompartment samplers. The spatial solute distribution curve as the spatial equivalent of the breakthrough curve was parameterized and physically interpreted. Both curves were unified in the leaching surface, which has tremendous potential for detailed interpretation.
Recently, the theory of solute dilution was extended to multicompartment sampler data. It transpired that dilution theory can be used to determine the predominance of a convective-dispersive or a stochastic-convective transport regime from multicompartment sampler data.
Multicompartment samplers can measure small-scale water and solute movement in space and time. The latest generation of samplers allows repeated extraction of percolate samples in situ under controlled suction to minimize disturbance of the unsaturated flow field. We developed a method to estimate the required total sampling area of a sampler from the degree of flow convergence in a soil.
We improved our ability to analyze the data produced by multicompartment samplers. The spatial solute distribution curve as the spatial equivalent of the breakthrough curve was parameterized and physically interpreted. Both curves were unified in the leaching surface, which has tremendous potential for detailed interpretation.
Recently, the theory of solute dilution was extended to multicompartment sampler data. It transpired that dilution theory can be used to determine the predominance of a convective-dispersive or a stochastic-convective transport regime from multicompartment sampler data.