Groundwater flow and contaminant transport models - a short review

Abstract
Over the last century, the impact of wide varieties of human activities on groundwater has grown intensely in many ways. As a consequence, groundwater quality and quantity are getting deteriorated with each passing year. Groundwater has become an essential commodity and is the most threatened resource nowadays due to its overexploitation by rapidly growing urbanization and industrialization. Many researchers, all around the globe, are taking initiatives to protect this important resource. A thorough study on some of the important contributions (theoretical and experimental) for the 50 years (i.e., 1950-2000) that laid the foundation for 21st-century researchers in the field of groundwater flow and contaminant transport modeling are discussed in this review. Based on the study, issues that remain unclear or unaddressed are listed out to simplify the future research guidelines and/or changes to advance technology for a better understanding and more wide-ranging analysis of the subject matter.