Print Email Facebook Twitter Bank erosion processes measured with UAV-SfM along complex banklines of a straight mid-sized river reach Title Bank erosion processes measured with UAV-SfM along complex banklines of a straight mid-sized river reach Author Duro, G. (TU Delft Rivers, Ports, Waterways and Dredging Engineering) Crosato, A. (TU Delft Environmental Fluid Mechanics; IHE Delft Institute for Water Education) Kleinhans, Maarten G. (Universiteit Utrecht) Uijttewaal, W.S.J. (TU Delft Environmental Fluid Mechanics) Date 2018-10-25 Abstract We apply structure from motion (SfM) photogrammetry with imagery from an unmanned aerial vehicle (UAV) to measure bank erosion processes along a mid-sized river reach. This technique offers a unique set of characteristics compared to previously used methods to monitor banks, such as high resolution and relatively fast deployment in the field. We analyse the retreat of a 1.2 km restored bank of the Meuse River which has complex vertical scarps laying on a straight reach, features that present specific challenges to the UAV-SfM application. We surveyed eight times within a year with a simple approach, combining different photograph perspectives and overlaps to identify an effective UAV flight. The accuracy of the digital surface models (DSMs) was evaluated with real-time kinematic (RTK) GPS points and airborne laser scanning of the whole reach. An oblique perspective with eight photo overlaps and 20 m of cross-sectional ground-control point distribution was sufficient to achieve the relative precision to observation distance of ∼ 1 : 1400 and 3 cm root mean square error (RMSE), complying with the required accuracy. A complementary nadiral view increased coverage behind bank toe vegetation. Sequential DSMs captured signatures of the erosion cycle such as mass failures, slump-block deposition, and bank undermining. Although UAV-SfM requires low water levels and banks without dense vegetation as many other techniques, it is a fast-in-the-field alternative to survey reach-scale riverbanks in sufficient resolution and accuracy to quantify bank retreat and identify morphological features of the bank failure and erosion processes. Improvements to the adopted approach are recommended to achieve higher accuracies. To reference this document use: http://resolver.tudelft.nl/uuid:86ab202c-7cdc-4fa2-a027-f3a8f1912152 DOI https://doi.org/10.5194/esurf-6-933-2018 ISSN 2196-6311 Source Earth Surface Dynamics (ESurf), 6 (4), 933-953 Part of collection Institutional Repository Document type journal article Rights © 2018 G. Duro, A. Crosato, Maarten G. Kleinhans, W.S.J. Uijttewaal Files PDF esurf_6_933_2018.pdf 5.12 MB Close viewer /islandora/object/uuid:86ab202c-7cdc-4fa2-a027-f3a8f1912152/datastream/OBJ/view