Humans greatly affect ground water.
However, the availability and quality of this resource are influenced directly by the properties of the geologic formation that holds water. The chemical and physical nature of these formations varies from area to area, creating a wide range of water yields and quality at different depths. This publication contains information about the ground-water resources underlying Marion County. Its purpose is to help the reader better understand the factors that influence the quantity and quality of ground water. Water resources terminology used in this publication is included in Surface and Ground Water Terminology , fact sheet AEX-460, which provides a listing of generally accepted water resource definitions.