Author(s): Tabea Broecker, Jonas Schaper, Fatima El-Athman, Mikael Gillefalk, Sabine Hilt, Reinhard Hinkelmann
Linked Author(s): Reinhard Hinkelmann
Keywords: Hyporheic exchange, computational fluid dynamics (cfd), openfoam, fluid mechanics, bank filtration
Abstract: Almost all types of surface water are interrelated with the groundwater. Therefore, the knowledge of interactions between ground- and surface water is very important for understanding processes within the whole water cycle. This paper presents surface water-groundwater interactions from different perspectives and with various emphases including investigations of flow processes, the impact on the ecosystem functioning, the local biota and chemical turnover rates. The application and extension of an integral single-domain model for flow and transport processes in the groundwater - surface water interaction space is the objective of one research project. Most numerical investigations consider ground- and surface water as separate environmental compartments or couple the corresponding models. For the integral model concept, the three-dimensional Navier-Stokes equations are extended by the consideration of porosities using the open source CFD software OpenFOAM. In a further project, the retention of chemical compounds in hyporheic reactors of urban freshwater systems is examined. Biogeochemical factors that affect retention and dynamics of micropollutants as a function of flow characteristics in hyporheic zones are determined with the help of laboratory experiments and field approaches. A simple one-dimensional transport and reaction model will be extended for the quantitative prediction of trace compounds such as organic micropollutant dynamics in sediments. Furthermore, various effects of bank filtration are investigated in two projects. Passing the soil layers, different purification processes and chemical reactions are taking place resulting in a modified water quality and changed properties. The reductive metabolism of iodinated X-ray contrast media as important organic pollutants in urban surface water as well as changes in groundwater seepage including effects on lake ecosystems are examined. This contribution gives an overview on different research activities with special emphasis on the integral model concept for the surface water-groundwater interaction space
Year: 2017