Sentinel-2 open data processing and morphodynamic modelling: an integrated approach to model sediment supply effects on rivers, estuarine and coastal areas
Bianca Federici, Lorenza Apicella, Monica De Martino
Morphodynamics aims to predict the evolution of the topography of rivers, estuaries, and coastal regions under different environmental forcings. Understanding the stability of such systems is a fundamental issue which may help the management of these areas in terms of flood control, erosion prevention, and habitat restoration.
Although the study of morphodynamics has made great progress over the decades, even from a theoretical point of view, models need data to be tested and eventually used in machine learning algorithms. From this point of view, remote sensing is a powerful tool that provides data and a way to monitor changes in these systems over time.
The processing of open images from Sentinel-2 (https://sentinel.esa.int/web/sentinel/missions/sentinel-2) satellite can support the study of the morphodynamic evolution of river, estuaries, and coastal environments. By collecting multispectral images and using appropriate algorithms, the water depth of riverbed and seafloor can be derived, the emerged and submerged areas can be classified automatically into types of bedrocks or vegetation. In addition, satellite images can be used to derive parameters, such as channel width, the evolution of which over time indicates erosion or deposition processes, and water turbidity, which can be an indicator of suspended sediment transport. Hence, data collected through image analysis provides a useful tool for morphodynamic modelling.
We propose combining remote sensing and morphodynamic modelling for a comprehensive river system assessment. This integrated approach can provide an accurate understanding of river morphology, hydrodynamics, and sediment dynamics, supporting informed decision-making for sustainable river management. In this paper, a preliminary application of this novel approach to a case of the Roia river in Liguria is presented. The Sentinel-2 multispectral optical images are processed and integrated with in-situ measurements to create a dataset for the morphodynamic model. In particular, the Satellite Derived Bathymetry is computed to estimate the depth variations along the river course, and the image classification is performed mapping different types of riverbed features such as vegetation, water turbidity, and sedimentation (Apicella et al. 2023, Apicella et al. 2022). Such a dataset is first used to test the capacity of some existing theoretical morphodynamic models (Seminara et a al. 2012, Ragno et al.,2021) to predict the equilibrium topography of the inlet reach of the Roia river. As a second step, the stability and evolution of the system under different scenarios of river discharges and sea forcing will be investigated.
The work is carried on within the Robotics and AI for Socio-economic Empowerment – RAISE (https://www.raiseliguria.it/) project funded by the “Piano Nazionale di Ripresa e Resilienza” - PNRR (https://www.mise.gov.it/it/pnrr), aiming to create a sustainable and resilient ecosystem that supports economic development, social well-being, and environmental conservation. An application activity focuses on the hydrographic, coastal and marine environment, which are key drivers of the local economy. In this context, one of the outcomes will be the risk assessment system and vulnerability of coastal areas (deltas, river mouths and lagoons) to climate change.
Acknowledgments
This work was carried out within the framework of the project "RAISE - Robotics and AI for Socioeconomic Empowerment” and has been supported by European Union – NextGenerationEU.
References
Apicella, L.; De Martino, M.; Ferrando, I.; Quarati, A.; Federici, B. Deriving Coastal Shallow Bathymetry from Sentinel 2-, Aircraft- and UAV-Derived Orthophotos: A Case Study in Ligurian Marinas. J. Mar. Sci. Eng. 2023, 11, 671. https://doi.org/10.3390/jmse11030671
Apicella, L.; De Martino, M.; Quarati, A. Copernicus User Uptake: From Data to Applications. ISPRS Int. J. Geo-Inf. 2022, 11, 121. https://doi.org/10.3390/ijgi11020121
Ragno, N.; Tambroni, N.; Bolla Pittaluga, M. When and where do free bars in estuaries and tidal channels form? Journal of Geophysical Research: Earth Surface 2021, 126, e2021JF006196. https://doi.org/10.1029/2021JF006196
Seminara, G.; Bolla Pittaluga, M.; Tambroni, N. Morphodynamic equilibrium of tidal channels. In W. Rodi, & M. Uhlmann (Eds.), Environmental fluid mechanics: Memorial volume in honour of Prof. Gerhard H. Jirka 2012, pp. 153– 174. CRC Press. https://doi.org/10.1201/b12283