Bathymetric Structure from Motion: Change Detection and Technical Improvements

Quantifying the rates of geomorphic change is critical for a range of applications within river science and management, including monitoring the evolution of river restoration and assessing the impacts of flow modifications and engineering structures on habitat availability. The tools available for monitoring small river systems at high spatial resolutions are growing with the adoption/availability of airborne/terrestrial laser scanning data and Structure from Motion (SfM)-based
photogrammetry. Monitoring the bathymetry of these smaller stream systems is still limited to traditional survey techniques and these methods do not provide
spatially continuous data and can overlook important changes at a range of spatial scales. Recently, we have advanced our capabilities for spatially continuous
surveying of fluvial geomorphology at finer spatial scales using unmanned aerial systems (UAS) and SfM photogrammetry. In this research, we highlight several methodological improvements for the bathymetric SfM process and assess the potential for refraction corrected SfM data to be used for change detection in the lowland
River Teme in Herefordshire, UK.