HR: 1340h
AN: H53C-1392    [Abstracts]
TI: Rainsplash as an Advection-Dispersion Process, With Implications for Plant-Soil Interactions
AU: * Childs, E M
EM: elise.m.childs@vanderbilt.edu
AF: Vanderbilt University, Earth and Environmental Sciences Vanderbilt University 2301 Vanderbilt Place Station B 35-1805, Nashville, TN 37235,
AU: Furbish, D J
EM: david.j.furbish@vanderbilt.edu
AF: Vanderbilt University, Earth and Environmental Sciences Vanderbilt University 2301 Vanderbilt Place Station B 35-1805, Nashville, TN 37235,
AB: Raindrops falling on loose sediment transfer part of their momentum to the sediment grains, which are ejected radially outward from the impact site. This process, referred to as rainsplash, plays an important role in sediment transport and landscape evolution. Describing rainsplash within the framework of the Master Equation and the Fokker-Planck Equation suggests that the transport of grains is an advection-dispersion process. By taking into account the intermittency of grain motions activated by raindrop impacts, the formulation indicates that gradients in raindrop intensity, and thus grain activity, can be as important as gradients in grain concentration and surface slope in effecting transport. Outdoor lab tests simulating rainfall over loose sand, on both flat and sloped surfaces, provide evidence to support this advection-dispersion model of rainsplash. Furthermore, sheltering a portion of the test surface from rain causes differential rainsplash to occur. As a result, sediment builds up as a mound beneath the shelter. The behavior of the shelter imitates that of plant canopies, which suggests that rainsplash contributes to the development of sediment mounds beneath shrubs in desert environments. These conclusions are consistent with observations of natural mounds at the Sevilleta Long Term Ecological Research station and Bandelier National Monument in New Mexico.
DE: 1625 Geomorphology and weathering (0790, 1824, 1825, 1826, 1886)
SC: Hydrology [H]
MN: 2007 Fall Meeting