Movement of Nonpoint‐Source Contaminants through Heterogeneous Soils

Abstract

Due to the widespread use of ground water as a supply of drinking water in the United States, predicting the effect that nonpoint sources of contamination have on the quality of nearby ground‐water supplies is an important element in ensuring that public health standards are met. A variety of methods have been developed to simulate this phenomenon, but most assume that the soil system can be simulated as a homogeneous environment, which in many cases is not true. Thus, a probabilistic modeling piocedure is developed that simulates the average movement of contaminants from nonpoint sources of contamination toward an underlying aquifer's water table through a heterogeneous soil environment. The proposed modeling procedure is applied to a hypothetical nonpoint‐source contamination problem, and the results are compared to those of a conventional deterministic contaminant transport model. The results of this application demonstrate that the proposed procedure provides superior simulation results as compared to the deterministic model, which emphasizes the need to account for heterogeneous soil conditions found in natural environments when simulating nonpoint‐source contamination problems.