Enhancing Active channel Delineation in Alluvial Rivers using Monthly Aggregation of Sentinel-2 Imagery

Enhancing Active channel Delineation in Alluvial Rivers using Monthly Aggregation of Sentinel-2 Imagery | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 30 June 2025 V1 Latest version Share on Enhancing Active channel Delineation in Alluvial Rivers using Monthly Aggregation of Sentinel-2 Imagery Authors : Elisa Bozzolan 0000-0001-5353-8099 [email protected] , Elisa Matteligh , Andrea Brenna , Martina Cecchetto , Nicola Surian 0000-0002-8436-3196 , Simone Bizzi 0000-0002-0588-826X , and Patrice Carbonneau Authors Info & Affiliations https://doi.org/10.22541/au.175131223.38074417/v1 Published Earth and Space Science Version of record Peer review timeline 369 views 303 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract In aerial and satellite imagery, the active channel of an alluvial river encompasses water channels and exposed sediment bars, delineating areas of geomorphic activity over a defined time window. While increasing satellite data availability enables monthly active channels delineations, multi-year analyses often rely on synthetic composites (e.g., annual medians) to reduce computational costs and intra-annual variability. The potential of monthly information to improve active channels delineation accuracy and geomorphic interpretation remains largely unexplored. In this work, we delineated yearly active channels for the Po River (Italy) by aggregating monthly Sentinel-2 (S2) classifications based on pixel-level occurrence frequencies for river and sediment classes, derived from a pre-trained global Fully Convolutional Neural Network applicable across river morphologies. Monthly variations in water and sediment classifications reveal both model classification biases and geomorphic dynamics. Results show that: 1) Monthly-aggregated information can enhance the accuracy of annual active channel delineations once the model classification biases are known; 2) In dynamic reaches, monthly active channel areas can vary substantially due to intra-annual sediment bar dynamics; these variations are masked in delineations based on single high-resolution orthophotos or on synthetic S2 annual medians. In contrast, active channel delineations on less dynamic reaches show minimal differences across methods. These findings highlight how different temporal aggregation should be considered for active channel delineations across different river morphologies, with dynamic rivers more dependent on high-revisit frequency data. Supplementary Material File (1037927_0_merged_1750684761.pdf) Download 2.55 MB File (bozzolan_et_al_2025_main_text.docx) Download 8.46 MB File (bozzolan_et_al_2025_supplementary material.docx) Download 2.49 MB Information & Authors Information Version history V1 Version 1 30 June 2025 Peer review timeline Published Earth and Space Science Version of Record 14 Jan 2026 Published Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords environmental sciences fluvial geomorphology geography monthly information remote sensing river active channel sentinel-2 Authors Affiliations Elisa Bozzolan 0000-0001-5353-8099 [email protected] University of Padua, Department of Geosciences View all articles by this author Elisa Matteligh University of Padua, Department of Geosciences View all articles by this author Andrea Brenna Earth Science Department Ardito Desio View all articles by this author Martina Cecchetto University of Padua, Department of Geosciences View all articles by this author Nicola Surian 0000-0002-8436-3196 University of Padova View all articles by this author Simone Bizzi 0000-0002-0588-826X University of Padova View all articles by this author Patrice Carbonneau Durham University View all articles by this author Metrics & Citations Metrics Article Usage 369 views 303 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Elisa Bozzolan, Elisa Matteligh, Andrea Brenna, et al. Enhancing Active channel Delineation in Alluvial Rivers using Monthly Aggregation of Sentinel-2 Imagery. Authorea . 30 June 2025. DOI: https://doi.org/10.22541/au.175131223.38074417/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . Format Please select one from the list RIS (ProCite, Reference Manager) EndNote BibTex Medlars RefWorks Direct import Tips for downloading citations document.getElementById('citMgrHelpLink').addEventListener('click', function() { popupHelp(this.href); return false; }); $(".js__slcInclude").on("change", function(e){ if ($(this).val() == 'refworks') $('#direct').prop("checked", false); $('#direct').prop("disabled", ($(this).val() == 'refworks')); }); Cited by Elisa Bozzolan, Elisa Matteligh, Andrea Brenna, Martina Cecchetto, Nicola Surian, Patrice Carbonneau, Simone Bizzi, Enhancing Active Channel Delineation in Alluvial Rivers Using Monthly Aggregation of Sentinel‐2 Imagery, Earth and Space Science, 13 , 1, (2026). https://doi.org/10.1029/2025EA004642 Crossref Loading... View Options View options PDF View PDF Figures Tables Media Share Share Share article link Copy Link Copied! Copying failed. 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