Non‐Point‐Source Pollution from Interrill Flow Areas

Abstract

This paper presents a procedure for estimating the total pollutant mass loss resulting from the interrill component of agricultural runoff. The procedure involves successive applications of a flow model and a mass transport model. The two‐dimensional flow model developed by Limback et al. in 1985 provides depth and velocity distributions in the interrill flow domain, where the flow is longitudinally uniform. These distributions are used as input for a diffusional mass transport model to estimate pollutant losses from soil interstices into the overland flow. Empirical relationships are used in the mass transport model to express dispersion coefficients as functions of overland flow and soil parameters. The procedure, based on the interrill flow model, can be used with other mass transport models instead of the diffusion model presented here. Such models might include infiltration, adsorption, convection, or other pertinent physical processes.