Hydrogeophysical Case Studies at the Local Scale: The Saturated Zone

Abstract

Modern geophysical methods provide significant promise for estimating subsurface aquifer properties of the saturated zone in a minimally invasive manner. Mapping aquifer boundaries and internal stratification, estimating spatial distribution of hydrogeologic parameters, or monitoring tracer and contaminant plumes are examples of geophysical tools successfully applied. A general benefit of geophysical methods is the ability to collect high-resolution data in the horizontal dimension, where core/borehole data is nearly always limited. The complementary nature of core/borehole data and 2-D or 3-D geophysical data promises to help improve the accuracy and resolution of aquifer characterization at a variety of scales. However, one significant remaining difficulty is transforming geophysical parameters into flow and transport properties. A series of approaches and petrophysical models have been developed to help in this transformation (e.g., see Chapter 4 and Chapter 9 of this volume), but often complex and non-unique parameter relationships complicate data analysis and interpretation.