La two-phase riverine spill model

Abstract

This paper presents a riverine spill model that computes the concentration of oil components in both the oil phase and the water phase by mathematically simulating the processes that affect the fate of the spilled oil. Processes simulated by the model include evaporation from the slick, dissolution of the slick into the water, volatilization from the water, and longitudinal dispersion in the river. The model also computes the location and size of the slick as it drifts downstream and spreads across the water surface. The model is versatile yet relatively simple and easy to use. The model requires minimum information on the river and oil, and it can be applied whenever the assumption of a laterally well-mixed river is acceptable. Most applications can be solved in several minutes on a 486-based personal computer. Sample applications show that the concentration of a compound in the water phase is strongly linked to its concentration in the oil phase and to its aqueous solubility. Concentrations in the water phase were also found to be most sensitive to variations in the dissolution rate. Concentrations were much less sensitive to variations in the volatilization rate, slick evaporation rate, and longitudinal dispersion.