Abstract
Unmanned aerial vehicle (UAV) photogrammetry has recently become a widespread technique to investigate and monitor the evolution of different types of natural processes. Fluvial geomorphology is one of such fields of application where UAV potentially assumes a key role, since it allows for overcoming the intrinsic limits of satellite and airborne-based optical imagery on one side, and in situ traditional investigations on the other. The main purpose of this paper was to obtain extensive products (digital terrain models (DTMs), orthophotos, and 3D models) in a short time, with low costs and at a high resolution, in order to verify the capability of this technique to analyze the active geomorphic processes on a 12 km long stretch of the French–Italian Roia River at both large and small scales. Two surveys, one year apart from each other, were carried out over the study area and a change detection analysis was performed on the basis of the comparison of the obtained DTMs to point out and characterize both the possible morphologic variations related to fluvial dynamics and modifications in vegetation coverage. The results highlight how the understanding of different fluvial processes may be improved by appropriately exploiting UAV-based products, which can thus represent a low-cost and non-invasive tool to crucially support decisionmakers involved in land management practices.
Highlights
Unmanned aerial vehicles (UAVs), commonly named drones, have recently become widely used to study and monitor several earth surfaces processes
This is true for the use of UAV-acquired imagery, processed with digital photogrammetry technique, that allows for the reconstruction of topographic information and the obtaining of orthophotos, by using light and low-cost optical cameras
Fluvial geomorphology is one of the main fields where aerial imagery has been increasingly used in combination with traditional techniques, since it can have a fundamental role in understanding processes that shape the landscape [1,2]
Summary
Unmanned aerial vehicles (UAVs), commonly named drones, have recently become widely used to study and monitor several earth surfaces processes. Former observations on the behavior of dynamic river channels were performed mainly through detailed withinchannel traditional analysis [3,4], and more recently several studies have highlighted the direct monitoring of channel topography as a useful tool to better comprehend the relationship between river forms and processes for flood protection and river management purposes [5,6,7]. Remote sensing techniques such as UAV photogrammetry have started to be a well-suited alternative to the conventional in situ activities, especially for multitemporal investigations.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
