5 Methods to Investigate Groundwater-Surface Water Exchange

This section presents the general methods used to qualitatively and quantitatively describe groundwater-surface water exchange with streams, lakes and wetlands. Included are examples of applying methods and interpreting the exchange processes in natural and modified groundwater and surface-water systems. Characterizing exchanges requires a number of approaches including calculating exchanges using water budgets, applying hydrogeological principles and modeling, physical instrumentation, remote sensing, and geochemical analyses (Figure 53). In some cases, these procedures are intertwined as analyses overlap. Some methods provide a broader view of exchange (e.g., water budgets) and other methods characterize conditions at a specific location (e.g., seepage meters). Rosenberry and LaBaugh (2008) provide an excellent public-domain book describing methodologies applied to characterizing exchange sites, magnitudes and durations. They address the use of streamflow records; wells, piezometers and seepage meters; methods to characterize karst hydrology; and, the application of temperature to assess exchanges. Once data are obtained, field and remote sensing data sets require multiple levels of analysis and interpretation. A variety of modeling tools are also used to build conceptual models, test uncertainty, and quantify exchange conditions and timing (e.g. Anderson et al., 2015).