Sediment and Pesticide/Herbicide Transport Relationships: Entrainment of Interstitial Pore Water by Overland Flow

摘要

The study examined the entrainment of interstitial soil pore water by overland sheet flow. A series of laboratory experiments were performed in which water was passed at various velocities and depths over a soil bed. The soil was saturated with a sodium bromide solution prior to each experiment and the runoff water was sampled at the end of the flume. The samples were analyzed for bromide concentration then concentration and mass loss rate curves were developed. A diffusion model was formulated and used to describe mass transfer across the soil surface. The experimental data was fitted to the diffusion model with a procedure developed to determine diffusion parameters from empirical data. In general, the experimental data conformed quite well to the diffusion model, with the diffusion coefficient depending on velocity and soil surface roughness.