An analytical solution for the lateral transport of dissolved chemicals in overland flow-varying soil surface concentration

摘要

The role of overland flow dynamics on the lateral transport of soil-dissolved chemicals toward an outlet is studied herein using the solutions of the mass conservation equations for overland flow and transport. The transfer of soil chemicals to the overland flow is a rate-limited process proportional to the chemical concentration at the soil surface which is time dependent. Some simplifying conditions are considered, to develop an analytical solution for both equations. The rainfall rate f, the infiltration rate i, and the mass transfer coefficient k are assumed constant. The analytical solution is based on the characteristic method for the two main stages of overland flow, namely, the rising and falling stages. The first stage occurs from ponding time to the time when rainfall ceases, at which point the second stage begins.