Groundwater Contamination Problems and Numerical Simulation

Abstract

In the last few decades, due to the overuse of groundwater resources and human mismanagement, groundwater quality has been severely affected. If the quality is not safe, even if it is abundant, it is not useful. This chapter essentially deals with the nature and movement of contaminants in groundwater due to the transport mechanisms such as advection, dispersion, retardation, and other chemical reactions and its numerical modeling. The numerical modeling refers to the process of simulation where approximate solutions to the governing equation of contaminant transport are obtained. The numerical modeling of groundwater contamination had undergone much advancement over the past half century. The driving factors behind this continuous progress are due to the alarming change in groundwater quality due to different anthropogenic reasons leading to the need for more accurate and efficient groundwater remediation and management models. Further, due to the rapid development in computational techniques and powerful data processing systems, groundwater contamination modeling is made more easily available to hydrogeologists and engineers. This chapter gives an insight into the groundwater contamination process, from discussing contaminant transport mechanisms to challenges faced in its numerical modeling. The details of the governing partial differential equations and the evolution of the methodology in obtaining these approximate solutions using different numerical techniques are presented. The process of numerical simulation is demonstrated with the help of example problems, and the results are discussed and compared with solutions from different numerical models. The chapter highlights the need for the qualitative and quantitative reasoning behind the simulation of any contaminant transport problem and how the numerical modeling helps in identifying the best way of solving it. Finally, a field case study is given in which the numerical simulation provides an integrated framework wherein the conceptual principles are applied to the observed data and investigative and predictive calculations are done which helps in developing management and protection policies.