Insights from a surface water‐groundwater interaction model to simulate floodplain characteristics

Nadine Maier1, Lutz Breuer1, Philipp Kraft1, Tobias Houska1
1 Uni Giessen

3.6 in Groundwater-Surface Water Interactions – from the river reach to the catchment

27.03.2020, 12:00-12:15, Telemann-Saal

Floodplains provide a variety of hydrological and ecological functions and are therefore of great importance. The flooding frequency, as well as the height and duration of inundations are particularly relevant for ecosystem states and are dependent on the exchange between surface water and groundwater. In this study, we developed a fully distributed model approach to simulate distributed groundwater levels in a floodplain in Hesse, Germany (14.8 km2). This function calculates the distribution of the surface water at steady-state for each day, based on the water level of the Rhine River. Thus, the water surface of flooding is at the same level everywhere and the dynamic effect of the flooding is ignored. In this way, it was possible to run the model 5000 times using Latin hypercube sampling. We will report on model performance and parameter uncertainty and will give insights, how such a calibrated model can be used to investigate the potential impact of climate change on the inundation characteristics. Here a cascading uncertainty introduced through climate projections, climate model structure, and parameter uncertainty will be shown. The established modeling framework integrates projections of two general circulation models (GCMs), three emission scenarios, a rainfall–runoff model (HBV), and a coupled surface water–groundwater model (CMF). Our results indicate large spatial and quantitative uncertainties in the simulated inundation characteristics, which are mainly attributed to the GCMs. Overall, an increase in inundation extent are simulated. This can cause significant changes in the habitats of species adapted to these highly-endangered ecosystems, where we will show examples of effected plant species.

Maier, N., Breuer, L. and Kraft, P.: Prediction and uncertainty analysis of a parsimonious floodplain surface water-groundwater interaction model, Water Resour. Res., 53(9), 7678–7695, 2017.

Maier, N., Breuer, L., Chamorro, A., Kraft, P. and Houska, T.: Multi-Source Uncertainty Analysis in Simulating Floodplain Inundation under Climate Change, Water, 10(6), 809, doi:10.3390/w10060809, 2018.

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