Hydrogeological Methods for Estimation of Spatial Variations in Hydraulic Conductivity

Virtually every hydrogeologic investigation requires an estimate of hydraulic conductivity (K), the parameter used to characterize the ease with which water flows in the subsurface. For water-supply investigations, a single estimate of K averaged over a relatively large volume of an aquifer will usually suffice. However, for water-quality investigations, such an estimate is often of limited value. A large body of work has demonstrated that spatial variations in K play an important role in controlling solute movement in saturated flow systems (e.g.,

Sudicky and Huyakorn, 1991

;

Zheng and Gorelick, 2003

). Numerous studies have shown that information about such variations is required to obtain reliable predictions of contaminant transport and to design effective remediation systems. Varieties of methods have been used in efforts to acquire this information. The primary purpose of this chapter is to describe these methods and assess the quality of the information that they can provide. Later chapters will discuss how geophysics can augment the information obtained with these approaches.