Prediction and uncertainty analysis of a parsimonious floodplain surface water‐groundwater interaction model

Abstract

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). To overcome the problem of large computation times, we simplified the surface water equation. 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 and investigate its parameter uncertainty using Latin hypercube sampling. Behavioral model runs were selected based on a threshold criterion of a mean root‐mean‐square error that was smaller than 0.26 m. All the simulated groundwater wells show an individual RMSE between 0.17 and 0.41 m for the calibration period. Regarding the parameterization, the model shows rather large variance in parameters that are capable of generating good simulations: a range of saturated conductivity of 2793 m/d, porosity of 0.4 m3/m3, residual wetness of soil of 0.2 m3/m3/soil and range of soil thickness of 2.9 m.

Multi-Source Uncertainty Analysis in Simulating Floodplain Inundation under Climate Change

“…The same results have also been observed in other applications of the HBV model for the Rhine River (e.g., [43]). We found that the water level of the Rhine River is the primary driving variable for the groundwater-surface water model, as the Rhine River is known to be directly connected with the groundwater of the floodplain and is mainly responsible for the groundwater level changes [34].…”

“…For this study, we modified a previously-developed parsimonious, physically-based surface water-groundwater model to simulate flood characteristics in the floodplain [34]. The model is built with the catchment modeling framework (CMF), version v0.1315 [35,36] and includes the interaction between surface water and groundwater flow.…”

“…Precipitation and modeled evapotranspiration using the FAO guidelines [38] complement the system boundaries. More details about the study area and the model set up, including the surface water routines, can be found in Maier et al [34].…”

“…A subsequent recalibration of the model resulted in similar optimal parameter sets and an increase of the RMSE of less than 0.1 m in the active floodplain. We tested several CMF parameter sets from Maier et al [34] for numerical stability. Due to the numerical stability and computation effort, we selected only one parameter set.…”

Incremental model breakdown to assess the multi-hypotheses problem

“…It 15 can be used for subsurface and surface water fluxes, surface-atmosphere exchange and solute transport. So far, it has been applied in studies to better understand hydrological processes (Holländer et al, 2009;Maier et al, 2017;Orlowski et al, 2016;Windhorst et al, 2014), to simulate solute transport (Djabelkhir et al, 2017;Kraft et al, 2010) and to capture hydrological lateral and vertical transport processes in coupled complex ecosystem models (Haas et al, 2013;Houska et al, 2014Houska et al, , 2017Kellner et al, 2017). 20…”