| In this study, a practical and physically based methodology for estimating groundwater recharge is developed using the hydrologic model HELP3 in conjunction with a Geographic Information System (GIS).; The developed flexible and versatile recharge methodology is applied to two main study areas. A study area in Toms River, New Jersey, is used to investigate the impact of recharge in the context of groundwater modelling, while the Grand River watershed, located in southern Ontario, is used to explore issues related large scale applications, as well as to demonstrate the advantage of the methodology in overall groundwater resource management. The methodology is also used to assess the impact of climate change and urbanization on groundwater recharge in the two study areas. A comprehensive sensitivity analysis is also conducted in order to determine the relative impact of each of the model input parameters on the estimated recharge rates.; The results of the study not only demonstrate the many strengths of the developed recharge methodology, but also identify some weaknesses and limitations associated with the method. The results from the Toms River study illustrate a much improved calibration of the transient groundwater flow model, which would be exceedingly difficult to obtain using other traditional methods. The results from the Grand River watershed analysis, on the other hand, provide valuable information for overall water resources management in the watershed.; The results from the climate change studies indicate that global warming will generally result in increased recharge rates in the two study areas. The increase is mainly due to an overall reduction in ground frost, which allows more water to infiltrate into the ground in wintertime. Land use change due to urbanization is found to be highly dependent on site-specific conditions, resulting in both marginally increased and decreased recharge rates in the study areas. (Abstract shortened by UMI.)... |
