H016-04
An estimate of temporal variation of discharge and its accuracy for the River Rhine

Monday, 7 December 2020: 07:16
Virtual
Luciana Fenoglio-Marc1, Elena Anatolievna Zakharova2, Matthias Gärtner3, Salvatore Dinardo4, Quang Duong5, Marcus Hatz5, Peter Krahe5, Thomas Artz5 and Juergen Kusche3, (1)University of Bonn, Bonn, Germany, (2)Maynooth University, Maynooth, Ireland, (3)University of Bonn, Institute of Geodesy and Geoinformation, Bonn, Germany, (4)CLS (Collect Localisation Satellites), Toulouse, France, (5)Federal Institute of Hydrology, Koblenz, Germany
Recorded Presentation
Abstract:
Quantification and monitoring of the river height and river flow is needed both for sustainable management of this valuable resource and for prediction of its future states, both for short and medium range warning and forecasts as well as for long term changes. Measurements of both river width and water velocity are provided by the optical/SAR imaging sensors, and the altimetric radar measures the water height. Upcoming SWOT wide-swath altimeter will measure water level, river width and water surface slope.

In this study, we assess the accuracy of discharge algorithms for the river Rhine by using water level and discharge from a large network of fiducial reference measurements and by using satellite data.

First approach is based on daily water level height and on approximated river widths. We found that, the MetroMan algorithm (Durand et al. 2016) estimates the discharge with good accuracy of 11% (expressed as RRMSE). The accurate implementation of the Manning-based algorithms requires additional ground information on river fluvial geomorphology (depth, bed roughness, floodplain characteristics) and the accuracy of the discharge obtained including this information is assessed. Further on, model data of the hydrodynamic Sobek 1D-Model of the River Rhine running at BfG serve as input to the discharge algorithm and results are evaluated.

We consider Sentinel-3A/3B measurements and finally simulated SWOT data of the 1-day phase generated from the model.

Our research questions are: (1) Is the accuracy of the discharge algorithms depending on the approximations made? (2) Do sparse SAR-altimetry measurements contribute to the discharge estimation? (3) What are the main sources of uncertainties?

The dense ground monitoring network of the River Rhine enables us to understand the factors affecting the accuracy of different approaches of discharge retrievals and to evaluate the role of the different parameters and methods for their approximation.

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