Modeling morphodynamic processes in meandering rivers with UAV-based measurements

Accurate surface models are a crucial component of studies of morphodynamic modeling of rivers and river channel evolution. The high flows that rivers have are caused by changes in flood bed or low canal flow, also it changes river channel morphology. Floods that occur during the spring months cause significant geomorphological changes. In addition to this, low flows during the summer also trigger erosion and superficial accumulation in the ongoing process. Using an accurate, high-resolution, seamless surface models of the river channel and floodplain allows to detect morphological changes of the whole river channel more accurately than using traditional methods. This enables a more comprehensive view of the riverbed evolution. Therefore, high-quality topographical data at different scales are required to study fluvial processes and river dynamics. Nowadays, a combination of photogrammetry and Unmanned Aerial Vehicle (UAV) systems is widely used for various applications, especially for 3D surface modelling and large scale mapping. UAV systems offer many advantages in terms of cost and image resolution when compared to terrestrial photogrammetry and satellite remote sensing systems. In the study, aerial imaging was carried out via UAV to produce very high resolution surface models based on Structure from Motion (SfM) technique. Multi-temporal topographic data were produced and morphodynamic processes in the Büyük Menderes River were modeled. Thus, UAV-based a fast and practical way to derive volumetric quantity of lost/gained soil was developed.