Natural rivers are dynamic systems subject to continuous morphological changes due to erosional and depositional processes that constantly reshape riverbanks and channels. Keeping track of these changes is important for understanding how river systems develop and for managing risks related to water and land, especially with the current impacts from human activities and climate change. Increasingly frequent and intense flooding events, combined with human interventions such as dams and defense works, highlight the need for innovative methodologies for detailed monitoring of these changes. This thesis addresses this context by focusing on monitoring bank dynamics in the lower course of the Tagliamento River, specifically in the Ronchis (UD) section. The adopted approach integrates UAV-based multispectral photogrammetry with geomatic change detection techniques. Specifically, drone surveys equipped with high-resolution and multispectral sensors were conducted, combined with multispectral (Sentinel-2) and radar (Sentinel-1) satellite data, producing detailed digital products such as DSMs, orthophotos, and vegetation indices (NDVI and NDWI). The study area, characterized by a meandering channel actively undergoing lateral migration, includes seven monitoring sites selected to represent various erosion and stability conditions. From 2023 to 2025, UAV campaigns and multitemporal analyses of satellite imagery monitored nine flood events, precisely analyzing the river's morphological and vegetation responses. The results clearly show the spatial heterogeneity of river dynamics: some riverbank sections experienced significant erosion with lateral retreats, while others remained essentially stable. Moreover, multispectral analysis highlighted the rapid response of riparian vegetation to flooding events, documenting cycles of erosion followed by recolonization. The integration of high-resolution UAV data with satellite data, characterized by continuous spatial coverage, confirmed the complementary value of these information sources. In conclusion, this study demonstrates the effectiveness and applicability of an integrated multiscale methodology for monitoring river dynamics. The findings provide valuable knowledge and practical tools for more informed and targeted management of hydrogeological and environmental risks, laying the groundwork for further methodological advancements, such as employing even more advanced technologies and artificial intelligence algorithms to automate analysis processes.
I corsi d'acqua naturali sono sistemi dinamici, soggetti a continue trasformazioni morfologiche dovute ai processi erosivi e deposizionali che ne modificano costantemente sponde e alveo. Monitorare queste dinamiche risulta cruciale sia per la comprensione dell’evoluzione ecologica e geomorfologica dei sistemi fluviali, sia per la gestione e mitigazione dei rischi idrogeologici, soprattutto alla luce delle attuali pressioni antropiche e climatiche. Eventi di piena sempre più frequenti e intensi, insieme all’influenza di interventi antropici come dighe e opere di difesa, accentuano la necessità di disporre di metodologie affidabili per il monitoraggio dettagliato di questi cambiamenti. Questa tesi si inserisce in tale contesto e si focalizza sul monitoraggio delle dinamiche spondali del basso corso del fiume Tagliamento, precisamente nel tratto presso Ronchis (UD). L’approccio adottato integra fotogrammetria multispettrale tramite UAV con tecniche di change detection geomatica. In particolare, sono stati condotti rilievi con droni equipaggiati di sensori RGB e multispettrali, combinati con dati satellitari multispettrali (Sentinel-2) e radar (Sentinel-1), ottenendo prodotti digitali dettagliati come DSM, ortofoto e indici di vegetazione (NDVI e NDWI). L’area di studio, caratterizzata da un alveo meandriforme soggetto a migrazione laterale, comprende sette siti di monitoraggio selezionati per rappresentare condizioni diverse di erosione e stabilità. Nel periodo 2023-2025, attraverso campagne UAV e analisi multitemporale delle immagini satellitari, sono stati monitorati nove eventi di piena, analizzando con precisione la risposta morfologica e vegetazionale del fiume. I risultati mostrano chiaramente l’eterogeneità spaziale delle dinamiche fluviali: alcune porzioni delle sponde hanno subito significative erosioni con arretramenti laterali, mentre altre sono rimaste sostanzialmente stabili. Inoltre, l’analisi multispettrale ha permesso di evidenziare la rapida risposta della vegetazione riparia agli eventi di piena, documentando cicli di erosione e successiva ricolonizzazione. L’integrazione dei dati UAV ad alta risoluzione con quelli satellitari, caratterizzati da copertura spaziale continua, ha confermato il valore complementare delle due fonti informative. In conclusione, questo studio dimostra l’efficacia e l’applicabilità di una metodologia integrata multiscala per il monitoraggio delle dinamiche fluviali. I risultati ottenuti forniscono conoscenze utili e strumenti concreti per una gestione più consapevole e mirata del rischio idrogeologico e ambientale, ponendo le basi per ulteriori sviluppi metodologici, come l’impiego di tecnologie ancora più avanzate e algoritmi di intelligenza artificiale per automatizzare il processo di analisi.
MONITORAGGIO DELLE DINAMICHE SPONDALI DEL BASSO TAGLIAMENTO NEL TRATTO DI RONCHIS (UD) MEDIANTE FOTOGRAMMETRIA UAV MULTISPETTRALE E CHANGE DETECTION GEOMATICA
MARTINO, ANDREA
2025
Abstract
Natural rivers are dynamic systems subject to continuous morphological changes due to erosional and depositional processes that constantly reshape riverbanks and channels. Keeping track of these changes is important for understanding how river systems develop and for managing risks related to water and land, especially with the current impacts from human activities and climate change. Increasingly frequent and intense flooding events, combined with human interventions such as dams and defense works, highlight the need for innovative methodologies for detailed monitoring of these changes. This thesis addresses this context by focusing on monitoring bank dynamics in the lower course of the Tagliamento River, specifically in the Ronchis (UD) section. The adopted approach integrates UAV-based multispectral photogrammetry with geomatic change detection techniques. Specifically, drone surveys equipped with high-resolution and multispectral sensors were conducted, combined with multispectral (Sentinel-2) and radar (Sentinel-1) satellite data, producing detailed digital products such as DSMs, orthophotos, and vegetation indices (NDVI and NDWI). The study area, characterized by a meandering channel actively undergoing lateral migration, includes seven monitoring sites selected to represent various erosion and stability conditions. From 2023 to 2025, UAV campaigns and multitemporal analyses of satellite imagery monitored nine flood events, precisely analyzing the river's morphological and vegetation responses. The results clearly show the spatial heterogeneity of river dynamics: some riverbank sections experienced significant erosion with lateral retreats, while others remained essentially stable. Moreover, multispectral analysis highlighted the rapid response of riparian vegetation to flooding events, documenting cycles of erosion followed by recolonization. The integration of high-resolution UAV data with satellite data, characterized by continuous spatial coverage, confirmed the complementary value of these information sources. In conclusion, this study demonstrates the effectiveness and applicability of an integrated multiscale methodology for monitoring river dynamics. The findings provide valuable knowledge and practical tools for more informed and targeted management of hydrogeological and environmental risks, laying the groundwork for further methodological advancements, such as employing even more advanced technologies and artificial intelligence algorithms to automate analysis processes.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.14242/300697
URN:NBN:IT:UNITS-300697