Numerical Methods for Modelling Leaching of Pollutants in Soils and Groundwater

摘要

Pesticides used in crop production and herbicides used for weed control are the major source of nonpoint-source pollutants to groundwater. The movement and degradation of pesticides residues in soils and groundwater are complex processes affected by soil physical, (bio)chemical and hydrogeological properties, climatic conditions and agricultural practices. This paper presents two physically-based models suitable for equilibrium and two-sites/two-regions non equilibrium models. The mathematical problem arising is basically an unsteady linear convection-diffusion-reaction equation. Different stabilization techniques to avoid the instabilities arising from the convection-dominated regimes are presented, including the more recent of Link-Cutting Bubbles, which gives the best numerical results. Some experiments based on real data are presented as applications.