Autores: Rabanaque, M. P., Martínez-Fernández, V., Calle, M., Sanchis-Ibor, C., Segura-Beltrán, F., Sánchez-Moya, Y., Benito, G.
Congreso: 10th International Conference on Geomorphology, Coimbra, Portugal.
Fechas: 12–16 Sep 2022
Web: https://www.icg2022.eu/home.html
Resumen: Since the 70s, Mediterranean ephemeral rivers in Spain have been subject to large-scale in-stream gravel mining. In the 90s, this activity ceased to a large extent, although nowadays new controlled in-stream gravel extraction pits have continued. The decreased on gravel mining activity, together with the longitudinal transport of sediment generated by flooding, has allowed these streams to begin to recover their alluvial landforms although their development and continuity is controlled by channel entrenchment and limited by sediment supply. This study aims to quantify the spatial-temporal changes generated along the river in order to characterise the transmission of sediment longitudinally. For this purpose, remote sensing methods offer efficient and powerful techniques. Particularly, a supervised classification with SVM (support vector machine) was carried out annually from 2018 to 2021 in the Rambla de Cervera, an ephemeral stream at the Castelló province in eastern Spain. Orthophotographs from the Institut Cartografic Valencia with a resolution of 0.25 m/pixel and RGBI bands were used for the classification. In this classification, three landforms have been differentiated: bedrock (exposed at riverbed), channel (channel gravels and unvegetated gravel bars) and vegetated gravel bars (gravel bars with vegetation cover). Subsequently, an automatic segmentation along the river corridor was performed every 100 m. Finally, the classification values for each segment were extracted and data analysis was performed.
