Groundwater–Surface Water Interaction: Process Understanding, Conceptualization and Modelling (Proceedings of Symposium HS1002 at IUGG2007, Perugia, July 2007). IAHS Publ. 321, 2008, 21-29.

Interactions between near-surface groundwater and surface water in a drained riparian wetland

BRITTA SCHMALZ, PINA SPRINGER & NICOLA FOHRER

Dept. Hydrology and Water Resources Management, Ecology Centre, Kiel University, Olshausenstr. 75, D-24118 Kiel, Germany

bschmalz@hydrology.uni-kiel.de

Abstract Lowland hydrology is characterised by a strong impact of near-surface groundwater which demands an analysis of the interaction between groundwater and surface water. Additionally, a high fraction of agricultural land in lowland catchments is drained and therefore influenced by fast water transport towards discharge systems. A riparian wetland situated in the lowland catchment area “Kielstau” in the north of Schleswig-Holstein, Germany, was investigated. Groundwater, ditch water and river water levels were measured to assess the interactions between these systems. Besides weekly measurements, some data were logged at hourly intervals since September 2005. The results show a high seasonal variability in water levels and flow dynamics in the groundwater as well as in the ditches and the river. Far from the river, at the ditch origin, the interactions in the riparian wetland are characterised by continuous effluent conditions which originate from positive differences in groundwater heads. Close to the river, at the mouth of the ditch, lower differences in groundwater heads are observed. They are partially negative, or change between positive and negative differences and result in a change between influent and effluent conditions.

Key words interaction groundwater–surface water; riparian wetland; lowland catchment