EGU21-14276
https://doi.org/10.5194/egusphere-egu21-14276
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Hydromorphological monitoring of individual river reaches with UAV-data – image-based measurement of bathymetry and flow velocity

Anette Eltner1, László Bertalan2, and Eliisa Lotsari3
Anette Eltner et al.
  • 1Department of Geosciences, Technische Universität Dresden, Germany (anette.eltner@tu-dresden.de)
  • 2Department of Physical Geography and Geoinformatics, University of Debrecen, Hungary
  • 3Department of Geographical and Historical Studies, University of Eastern Finland, Finland

Unmanned Aerial Vehicles (UAV) have become a commonly used measurement tool in geomorphology due to their affordable cost, flexibility, and ease of use. They are regularly used in fluvial geomorphology, among other fields, because the high spatiotemporal resolution of UAV data makes it possible to assess the continuum rather than relying on single samples.

In this study, UAV data are used to hydro-morphologically describe three different river reaches of lengths between 150 and 1000 m. Specifically, the surface flow velocity and bathymetry of the rivers were reconstructed. The flow velocities were calculated using the Particle Tracking Velocimetry (PTV) method applied to UAV video sequences. In addition, UAV-based imagery was acquired to perform 3D reconstruction above and below the water surface using SfM (Structure from Motion) photogrammetry, taking into account refraction effects as well as frame processing to increase the visibility of underwater features. Reference data for flow velocities were generated at selected positions using current meters as well as ADCP (Acoustic Doppler Current Profiler) readings. The image-based calculated bathymetry was compared with RTK-GNSS sampling depth measurements and also ADCP data.

The developed workflow enables rapid and regular measurement of hydrological and morphological data of river channels. This ultimately enables multi-temporal assessment and significantly improves hydro-morphodynamic modelling, in particular their calibration.

How to cite: Eltner, A., Bertalan, L., and Lotsari, E.: Hydromorphological monitoring of individual river reaches with UAV-data – image-based measurement of bathymetry and flow velocity, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14276, https://doi.org/10.5194/egusphere-egu21-14276, 2021.

Corresponding presentation materials formerly uploaded have been withdrawn.