The Eastern Southland Plains is situated between the Oreti and Mataura Rivers, and the area of approximately 45 km2 under investigation in this study includes the Morton Mains, Waimatua, and Kapuka coalfields. Farming is the principal land use in the region, particularly dairying, and groundwater resources are utilised widely. This thesis provides a detailed investigation of the Early Quaternary and Gore Lignite Measures aquifer systems by delineating the hydrogeological setting, groundwater trends and fluctuations, groundwater yields and water chemistry issues with specific reference to potability.