Pollutants

The objective is to develop a groundwater flow model of the Surficial Aquifer System in the area of Plantation, Broward County, Florida, using the U.S. Geological Survey MODFLOW code and to make a comparison between the use of two supplementary contaminant transport models: MODPATH code and the MT3D code. The advantages and limitations of the two solute transport models are described and an evaluation is made of their accuracy with respect to delineation of traveltime related to capture zones of wells. Final results of the computer simulations indicate that this study area is sensitive to river bed hydraulic conductivity and the stress of the continuous pumping at a nearby wellfield. Therefore, a critical factor in selecting an appropriate flow model for delineating the traveltime-related capture zone of a well is a model which simplifies the flow system while still preserving hydrogeologic characteristics of the flow system.

This thesis addresses the groundwater contamination problem from a probabilistic point of view. The objective of this study is to obtain analytical solutions for the backward type Kolmogorov equations governing certain crucial variables in the case of a two-dimensional medium. These include the rate at which pollutants enter the protected zone and the length of time that a pollutant particle takes to travel from a given location to the boundary of the protected zone. It is assumed that the groundwater flow is horizontal and uniform, and that a protected zone is located downstream. Analytical solutions are obtained by using the techniques of Laplace transform and separation of variables. Numerical results are given for two cases, one with flow coming from a boundary which is imperious to the pollutant, and another with flow coming from infinity.