G07 Geohazards Monitoring

IAG (Geodesy)



26-Jun-2015, 15:00 - 16:30


 
Abstract content:

Application of terrestrial laser scanning for fluvial transport monitoring in riverbed: Case study Lomniczka River, Karkonosze Mts.

The fluvial transport is the main surface process responsible for the contemporary dynamic change of the relief in the Sudetes Mts. (Poland). The knowledge of this process is usually gathered by the hydrological measurements what gives a good understanding of the river flow, however, the information of the bedload movement in the rivers is still insufficient. Particularly, this applies to the largest clasts persisting in the riverbeds, i.e. boulders over 256 mm. The question therefore arises, to what extent this fraction is a mobile component of the bottom of the mountain streambeds.
The answer to that question is presented in this work as the case study Lomniczka River (Sudetes Mts.). The investigation was carried out by monitoring 30 m long steep section of the river using terrestrial laser scanning (TLS). TLS was performed annually using Leica ScanStation C10 scanner in the period 2011-2014. In order to eliminate the systematic errors and assure the best accuracy of the data, all four measurement campaigns were carried out with the same geometrical conditions.
High accuracy of the data was proven by the small RMSE of the simultaneous georeferencing and point cloud registration, and achieved 2-6 mm depending on the campaign. Dense point clouds were compared to each other using the Iterative Closest Point (ICP) algorithm to produce high resolution Digital Elevation Models (DEMs), and finally to detect displaced stones. The highest dynamic of the fluvial process resulting in the boulder displacement up to 2.3 m was observed between years 2012-2013. Obtained differential DEMs shown the alternating zones of erosion and deposition of the finer fractions of sediment in the local sedimentary traps. TLS confirmed its potential to monitor the fluvial transport in the riverbed.

 
Author(s):
A. Borkowski1, M. Ziaja1, G. Józków2, M. Kasprzak3.
1Wroclaw University of Environmental and Life Sciences, Institute of Geodesy and Geoinformatics, Wroclaw, Poland.
2The Ohio State University, Department of Civil- Environmental and Geodetic Engineering, Columbus, USA.
3University of Wroclaw, Institute of Geography and Regional Development, Wroclaw, Poland.

 

Keywords:
terrestrial laser scanning     fluvial transport     monitoring     mountain area