Anyone implementing a Source Water Protection Plan should understand some basic scientific principles about groundwater. Among them are the hydrologic cycle, basic groundwater principles, different types of aquifers and groundwater movement. Two additional documents accompany this guide that do a good job of summarizing basic groundwater concepts and conditions in Pennsylvania. These PDF documents include The Geology of Pennsylvanias Groundwater (Fleeger, G.M., 1999, 4.7 MB download) and Groundwater, A Primer for Pennsylvanians (League of Women Voters (LWV) of Pennsylvania Citizen Education Fund, 2000, 4.1 MB download).
The reader may become familiar with hydrologic terms and concepts using these publications. However, because the practice of geology is regulated in the state of Pennsylvania and because groundwater flow is often complex, the public water supplier may need to obtain the services of a professional geologist to gather and interpret information on local groundwater conditions and test results.
More detailed documents that may be used as guides on hydrogeology for source water protection work include two U.S. Geological Survey publications: Risser and Madden, 1994 and Risser and Barton, 1995 (see references)