The successful investigation of the hydrogeology of an area depends on the collection of reliable field data. First, the available existing information must be identified and used to develop a preliminary conceptual understanding of the groundwater system in the area. This conceptual model is then used to identify the gaps in the available information and to plan a fieldwork programme to obtain the necessary data required to verify and improve the model. This book follows this systematic approach to completing a hydrogeological study and explains how to decide on the measurements which are needed and on the instruments and techniques used to make them. Measurements of groundwater levels, rainfall and evaporation, spring and stream flows and the use of groundwater tracer techniques are covered. There is a great deal of practical information on all aspects of planning and completing field investigations and on the interpretation of field evidence. Advice on safety aspects of field work is also included. This second edition has been fully revised and updated to cover advances in the use of electronic instruments and the needs of the environmental regulators. The scope has been widened to include the design and execution of pumping tests, and groundwater sampling methods to meet the protocols adopted by national environmental regulators. A chapter on report writing and the presentation of information is included. Field Hydrogeology is designed to assist anyone who is involved in the collection and interpretation of hydrogeological data. It is suitable for undergraduate and postgraduate students of geology, hydrogeology, environmental sciences and engineering, as well as a wide range of professionals working in the water resources and environmental protection fields.