Groundwater and surface-water interactions in riparian and lake-dominated systems
This chapter presents an overview of the application of isotope tracers (primarily the isotopes of water) to further the understanding of hydrologic processes occurring in riparian areas contiguous with stream systems and in hydrologic systems dominated by lakes. The chapter begins with a discussion of the spatial distribution of lake-dominated systems and a general discussion of the dominant hydrological processes occurring in these systems. Next, a brief overview of previous research in this area is presented, which focuses on investigations of recharge processes in riparian areas and studies examining the hydrologic components of lake systems. A more detailed quantitative discussion of groundwater/lake interactions follows, including the application of stable isotopes for estimating groundwater/lake exchange and the development of an index-lake method for simplifying estimates of groundwater/lake exchange. Finally, We present a case study describing qualitatively the current research being conducted forested catchment in northern Wisconsin. This work focuses on the use of multiple isotopic tracers to examine hydrologic processes as the stream flows from the headwaters to its confluence with a large lake. We conclude with suggestions for future directions in applying stable-isotope tracers to understanding hydrologic processes in riparian areas and lake-dominated systems, including the importance of spatial and temporal heterogeneity, the importance of groundwater flow and reaction paths for understanding these complex systems, and the use of multiple isotopic tracers.
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