Perhaps one of the more common tasks a hydrogeologist will be involved with is obtaining subsurface information, which can be found through a variety of methods, including geophysical (Chapter 4), hand tools, and drilling methods. This chapter presents the common drilling methods and explains how monitoring and production wells are installed. A hydrogeologist does not need to know how to run a drill rig but should be familiar with drilling methods, terms, and well-completion strategies so that meaningful subsurface information can be obtained. Also, the hydrogeologist with some guidance will be better informed to make decisions in the field.

Hydrogeologists need to be able to work safely with the drill crews in obtaining subsurface information. It is helpful to know the basics of drilling methodologies, how to describe drill cuttings, and what is involved in well completion. The approach taken here is to familiarize entry-level hydrogeologists or professionals unfamiliar with drilling operations with what they should know to safely proceed.

Understanding the geology of an area (Chapter 2) is helpful in knowing which drilling methodologies would be most productive and result in obtaining the best subsurface information. Examples of drilling in different geologic settings are presented throughout to show applications of the appropriate drilling method in a given geologic environment.