EGU2020-981
https://doi.org/10.5194/egusphere-egu2020-981
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Management and analysis of high resolution multibeam sonar surveys for geometry characterization of riverbed material

Simone Rover1, Gabriele Avancini2, and Alfonso Vitti1
Simone Rover et al.
  • 1DICAM, University of Trento
  • 2ETS S.r.l., Roma

The geometric characterization of riverbed material is fundamental piece of information for the management of river basins because it allows, for example, the determination of bed-load and hydrodynamics roughness and the study of geo-morphological phenomenona.
However information such the grading curve are not easily achievable by means of traditional field sampling methods, mostly intrusive, and to the hydraulic conditions of rivers that may have high water levels and strong flows.

Multibeam sonars represent an important alternative to traditional survey methods. Nowadays, thanks to advanced scientific knowledge, it is possible to make full use of an equipment increasingly accurate and precise. State of the art solutions have dimensions compact enough to be installed on remotly piloted vehicles and allow to obtained high resolution digital surface models of river beds. The feasibility of having models of such quality and the possibility to conduct surveys more frequently, allowing the monitoring of sedimentation and erosion phenomena as well as the dynamics of the armouring layer, have motivated the development of advanced and innovative technology to analyse these models.

The aim of this work is the development of a workflow that provides an effective method to characterize riverbed material. In order to achieve this target we start from an advanced and original survey technique, that allows to obtain high resolution digital surface models, and use an appropriate post-processing procedure.
We introduce first some results obtained from the analysis of digital surface models produced in laboratory or relative to well known site. In particular advanced techniques for the study of 3D model and the detection and geometric characterization of forms are investigated.
Then we present some data acquired at high resolution (few centimeters) with a multibeam sonar mounted on a remote controlled vessel. Field surveys were conducted in real fluvial environment with the aim of produce qualitative and quantitative information about the surface layer of riverbed.
Even considering some sources of uncertainty that may be present from field survey to modeling, the obtained results show how it is possible to identify and geometrically characterize several of the forms present on the surfaces analyzed. 

How to cite: Rover, S., Avancini, G., and Vitti, A.: Management and analysis of high resolution multibeam sonar surveys for geometry characterization of riverbed material, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-981, https://doi.org/10.5194/egusphere-egu2020-981, 2019

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  • CC1: Comment on EGU2020-981, Joseph Jonke, 04 May 2020

    Congratulations for the research. I found it quite interesting and hope it will be incorporated in standard procedures for hydraulic risk. I would like some info on the possible application (seabed, riverbed, dams, ecc.) and where do you find this device/procedure more suitable in. Thank you.

    • AC1: Reply to CC1, Gabriele Avancini, 04 May 2020

      Hi Joseph,

      thank you for the appreciation.

      The research has been made in order to provide a practical tool for the management of river basins and this include certainly the issue you raised about hydraulic risk.

      The developed procedure is meant for the geometric characterization of riverbed material, information very useful for hydraulic modelling and other tasks, but the very accurate bathymetry we obtain is sutable for many other applications. Just to mention some example let us think at the monitoring of the sedimentation rate of material inside a reservoir or the study of scour at a bridge site.

      Among the many possible applications, we think that the ideal use of such devices is in rivers or small water basins where bigger vessels and payloads, design for sea applications, could not operate.

  • CC2: Comment EGU2020-981, Fabio Treglia, 05 May 2020

    Very interesting research. Can you tell me how this research can support the management of a river basin?

    • AC2: Reply to CC2, Simone Rover, 05 May 2020

      Hi Fabio, thank you for the question.

      From an engineers point of view the knowledge of the riverbed granulometric composition is fundamental for hydraulic model simulations because it allows, for example, an estimation of hydraulic roughness and helps in understanding sediment transport phenomena.

      A correct boulder detection can also help in judging the ecomorphological state of a river by highlighting the presence or absence of the geo-habitats needed for an high biodiversity and benthic production.

  • CC3: Comment on EGU2020-981, Andrea Dellai, 06 May 2020

    Great research, what are the practical application of this research? Thanks

    • AC3: Reply to CC3, Gabriele Avancini, 06 May 2020

      Hi Andrea, thank you for the question.

      An innovative methodology for geometric characterization of riverbeds, through the use of sonar Multibeam technology, allows to acquire new data sets with a repetitiviness that is unthinkable today.

  • CC4: Comment on EGU2020-981, Carmine Foglia, 07 May 2020

    Congratulations for your research! Your study shows that the advantages of this technology are evident: the multibeam echo sounder links quality (high resolution) to quantity (high sampling rate), making sampling operations very lean and practical thanks to compact size and light weight of the instrumentation.

    From a strictly engineering point of view, I am very interested in understanding how the connection between the geometric parameters and the classification curve of the sediments of the surface layer of the rivers takes place through numerical analysis, that you mentioned in your conclusions. Could you briefly explain it to me please?

    • AC4: Reply to CC4, Simone Rover, 08 May 2020

      Hi Carmine, thank you for the consideration.

      We are developing a numerical model that, given many real granulometric curves, simulate possible distributions of riverbed material. In this way we could derive some statistical properties for the surface layer and compare them to the geometric parameters estimated with our procedure.