High-resolution topography to measure and model river channel morphodynamics

Fluvial environments are fragile landscapes, which can change rapidly, e.g. due to  climatic  impacts,  with  potential  ecological  as  well  as  socio-economic consequences. To understand and model processes of fluvial morphodynamics monitoring  with  spatio-temporal  high  resolution  are  necessary.  A  better comprehension  of  these  landscapes  can  help  to  improve  their  management regarding  the  risk  of  flood  events  and  to  enhance  their  ecological  functions. However,  high-resolution  topographic  data  for  river  morphology  change detection and modelling are still difficult  to achieve. In  this  project,  multi-temporal field  campaigns  of  river  channel  morphological surveys are to be performed at Sajó River to test several devices to improve the data density regarding river bank geometry and bathymetry. Thereby, a survey-boat integrated with laser scanner, echo sounder and red-green-blue (RGB) as well  as  near-infrared  (NIR)  cameras  is  utilized  to  measure  the  topography. Furthermore,  unmanned  aerial  vehicles  (UAVs)  equipped  with  RGB,  multi-spectral and thermal cameras are used to test their suitability to measure flow velocities  and  sediment  load.  Thus,  boat  and  aerial  observations  of  complete river  reaches  complement  each  other  to  enable  a  holistic  topographic  river description.

 The performance of the multi-sensor and multi-platform data is evaluated with reference  data  acquired  by  terrestrial  laser  scanner  (TLS)  and  boat measurements  with acoustic  Doppler  current  profilers  (ADCP)  to  test  the achievable accuracy.  Another aim of the project is the implementation of the newly acquired data in hydrological  modeling of  selected  meandering  reaches  of  Sajó  River  to  better understand seasonal as well as annual channel morphodynamics. Thereby, data suitability  is  verified  and information  gain  for  the  models  themselves  is investigated.

This project is sponsored by the Federal Ministry of Education and Research and performed in co-operation with the Department of Physical Geography and Geoinformatics, Institute of Earth Sciences, University of Debrecen, Hungary.

Publications

• Eltner, A., Bertalan, L., Perks, M., Grundmann, J., Lotsari, E. (2021): Hydro‐morphological mapping of river reaches using videos captured with unoccupied aerial systems. Earth Surface Processes and Landforms. 10.1002/esp.5205 (Link ESP&L).

• Eltner, A., Mader, D., Szopos, N., Nagy, B., Grundmann, J., Bertalan, L.  (2021): USING THERMAL AND RGB UAV IMAGERY TO MEASURE SURFACE FLOW VELOCITIES OF RIVERS. Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLIII-B2-2021, 717–722 (Link ISPRS Archives).