EGU2020-8954
https://doi.org/10.5194/egusphere-egu2020-8954
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Physiographic controls on pre-event hydrological states and hydrological response to extreme precipitation in the Alzette River Basin, Luxembourg

Carol Tamez-Melendez1, Judith Meyer1,2, Audrey Douinot1, Günter Blöschl3, and Laurent Pfister1,2
Carol Tamez-Melendez et al.
  • 1Environmental Research and Innovation department, Catchment and eco-hydrology research group, Luxembourg Institute of Science and Technology (carol.tamezmelendez@list.lu)
  • 2University of Luxembourg, Faculty of Science, Technology and Medicine
  • 3TU Vienna, Institute of Hydraulic Engineering and Water Resources Management

The hydrological regime of rivers in Luxembourg (Central Western Europe) is characterised by summer low flows and winter high flows. In winter, large-scale floods are typically triggered by long-lasting sequences of precipitation events, related to westerly atmospheric fluxes that carry wet and temperate air masses from the Atlantic Ocean. In recent years, several flash flood events have been observed in Luxembourg. While being a common feature of Mediterranean river basins, this type of flooding events is uncommon at higher latitudes. The design of the hydro-meteorological monitoring and forecasting systems operated in Luxembourg is not adapted to this type of extreme events and there is a pressing need for a better mechanistic understanding of flash flood triggering mechanisms.

Here, we explore two lines of research – focusing on (i) the spatio-temporal variability of flash flood generation across a set of 41 nested catchments covering a wide range of physiographic settings (with mixed land use, soil types and bedrock geology) and (ii) the responsivity (resistance) and elasticity (resilience) of these catchments to global change.

Our area of interest is the Sûre River basin (4,240 km2), characterised by a homogenous climate (temperate oceanic), as well as various bedrock (e.g. sandstone, marls, shale) and land use (e.g. forests, grassland, crops, urban areas) types. Based on 8 years’ worth of daily hydrological data (precipitation, discharge and potential evapotranspiration) we computed the increments of the water balance to determine the maximum storage capacity and pre-event wetness state (expressed as storage deficit). Based on the relationship between storage deficit and discharge we first estimated total storage at nearly zero flow conditions. Second, we compared event runoff ratios (Q/P) to pre-hydrological states (as expressed to storage deficit prior to a rainfall-runoff event) in order to assess each catchment’s sensitivity to antecedent wetness conditions. Third, we assessed the responsivity (resistance) and elasticity (resilience) to climate variations – as expressed through the PET/P and AET/P deviations from the Budyko curve – for each individual catchment. Finally, we investigated potential physiographic controls on catchment responsivity and elasticity across our set of 41 nested catchments.

How to cite: Tamez-Melendez, C., Meyer, J., Douinot, A., Blöschl, G., and Pfister, L.: Physiographic controls on pre-event hydrological states and hydrological response to extreme precipitation in the Alzette River Basin, Luxembourg, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8954, https://doi.org/10.5194/egusphere-egu2020-8954, 2020.

Displays

Display file