Experiences from the use of Unmanned Aerial Vehicles (UAV) for River Bathymetry Modelling in Norway

: Peggy Zinke, Claude Flener

Publisher: Norsk Vannforening

: 2013

Vann

: 3

: 48

: 3

: 351

: 360

: 10

: 0042-2592

Knowledge of underwater morphology provides essential input to hydrodynamic model applica- tions as part of studies of habitats and the effects of hydropower regulation in rivers. Traditional manual or vessel-based bathymetry surveys are time-consuming and sometimes dangerous or impossible to implement in rivers with strong currents. Remote sensing techniques based on low altitude airborne colour photography may represent an alternative.
This paper describes a pilot study carried out in the river Surna, a gravel-bed river in Mid- Norway, to test the use of Unmanned Aerial Vehicles (UAV) for river bathymetry modelling based on optical remote sensing. Optical bathy- metric modelling relies on the relationship bet- ween water depth and radiance values captured in an aerial image. Lyzenga’s (1981) deep water correction method was used in conjunction with shallow-water calibration. Modelling requires some field-measured depth values for calibra- tion. The method was applied by acquiring aerial photographs along two approximately 1-kilometre river reaches, using a Microdrone flying at heights ranging between 70 and 135 metres.
The pilot study showed that the application of UAV-based optical remote sensing methods has great potential for bathymetric surveys in fluvial settings, provided that the survey is carefully prepared and performed under favourable weather conditions.