Interactions between groundwater and surface water can significantly influence contaminant transport, biogeochemistry, subsurface ecology, and the approach to remediation in environmentally sensitive areas at groundwater discharge locations. Complexities in understanding groundwater-surface water interactions (GSIs) are created by the presence of subsurface heterogeneities, the dynamic hydraulic nature of groundwater discharge zones, and the fact that much of the subsurface is inaccessible due to economic, geopolitical, and technological constraints. Furthermore, adequate understanding of GSIs in environmental hydrogeology and site remediation requires a multidisciplinary approach, drawing from the fields of hydrogeology, geochemistry, surface water hydrology, sediment processes, microbiology, ecology, toxicology, and engineering. Consequently, presentations of these perspectives are scattered widely across several disciplines, potentially limiting broader exposure and discussion. This session presents papers relating to a variety of disciplines that describe: • New theory, techniques, and methods for evaluating GSIs in environmentally important areas • Their application to site remediation • Interesting case studies.