A Model for Splash and Retention of Sediment and Soil-Borne Contaminants on Plants

Abstract

ABSTRACT RAINDROPS striking exposed soil detach and splash soil particles onto nearby plants, a process that can also transfer soil-borne radioactive contaminants to plants. Following field experiments at the Los Alamos National Laboratory, we developed a model to describe this process. The model estimates sediment and contaminant retention and their distribution with height on plants as a function of rainfall intensity and amount, soil erodibility, sediment size, plant spacing, leaf area and its distribution on plants, and plant surface properties affecting retention of sediment. The model has components for: (a) detachment of soil by raindrop impact, (b) splash of sediment toward plants, (c) interception of sediment by plants, and (d) washoff of sediment already on plants. Many parameter values for the model were derived from analysis of data from previous experiments on rainfall characteristics, raindrop impact, soil detachment and splash by raindrops, and retention of aerially deposited particulates on plants. Validation of the model with data from the Los Alamos field experiments showed that the model adequately represents many of the factors affecting the transport of soil and contaminants to plants by raindrop splash.