10.34622/datarepositorium/TFICCJLauriuchi, Geissielen A.Geissielen A.Lauriuchi0000-0002-5108-5572Institute of Science and Technology of the São Paulo State University "Júlio de Mesquita Filho" (Unesp)Guimarães, CatarinaCatarinaGuimarães0009-0009-4481-9046Department of Biology, Faculty of Sciences, University of PortoPace, GiorgioGiorgioPace0000-0003-4231-5644Centre of Molecular and Environmental Biology (CBMA)/Aquatic Research Network (ARNET) Associate Laboratory, Department of Biology, University of MinhoCaballero, Gabriel R.Gabriel R.Caballero0000-0003-2268-2674Image Processing Laboratory, Universitat de ValènciaSòria-Perpinyà, XavierXavierSòria-Perpinyà0000-0001-8080-5826Image Processing Laboratory, Universitat de ValènciaPompêo, MarceloMarceloPompêo0000-0002-5632-9257Limnology Laboratory, Department of Ecology, Institute of Biosciences (IB), São Paulo University (USP)Delegido, JesúsJesúsDelegido0000-0002-2819-6979Image Processing Laboratory, Universitat de ValènciaAntunes, C. SaraC. SaraAntunes0000-0002-6686-9919Department of Biology, Faculty of Sciences, University of Porto. CIIMAR/CIMAR LA, Interdisciplinary Centre of Marine and Environmental Research, University of PortoRepositório de Dados da Universidade do Minho2026Earth and Environmental Scienceschlorophyll-aSecchi deptheutrophicationoptical water qualityPace, GiorgioGiorgioPaceCentre of Molecular and Environmental Biology (CBMA)/Aquatic Research Network (ARNET) Associate Laboratory, Department of Biology, University of MinhoC. Antunes, SaraSaraC. AntunesDepartment of Biology, Faculty of Sciences, University of Porto. CIIMAR/CIMAR LA, Interdisciplinary Centre of Marine and Environmental Research, University of Porto. CIIMAR/CIMAR LA, Interdisciplinary Centre of Marine and Environmental Research, University of PortoAntunes, Sara C.Sara C.Antunes2026-07-032026-07-17in situ data10.3390/w18131650120902160943046169531483154817162926665357611012776122682307230073540text/plaintext/plaintext/plaintext/plaintext/plaintext/plaintext/plaintext/plaintext/tab-separated-valuestext/tab-separated-valuestext/tab-separated-valuestext/tab-separated-valuestext/tab-separated-valuestext/tab-separated-valuestext/tab-separated-valuestext/tab-separated-values1.0CC BY-NC-SA 4.0This dataset contain data and scripts used in the analyses presented in the manuscript. The files are organised in the same sequence in which they were applied throughout the study, allowing the complete reproduction of the analytical workflow, from the statistical analysis of limnological data to the generation of spatial distribution maps using Sentinel-2 imagery. All statistical analyses were developed and executed using R version 4.5.2.R, version 4.5.2Concerning in situ data, APA/SNIRH monitoring program provided bimonthly measurements collected at the official monitoring stations between 2014 and 2024.Complementarily, the research group conducted seasonal field campaigns in 2023 and 2024, with four sampling surveys per year representing winter, spring, summer, and autumn conditions at the three sampling locations. Sentinel-2 Level-2A (surface reflectance) images were obtained from the Copernicus Browser platform. Image selection followed strict criteria, including a maximum temporal difference of ±3 days relative to in situ sampling dates, cloud cover below 30%, and the absence of visible atmospheric artifacts over the reservoir.This research was funded by national funds through FCT—Fundação para a Ciência e a Tecnologia, I.P., and by the European Commission’s Recovery and Resilience Facility, within the scope of UID/04423/2025 (https://doi.org/10.54499/UID/04423/2025), UID/PRR/04423/2025 (https://doi.org/10.54499/UID/PRR/04423/2025), and LA/P/0101/2020 (https://doi.org/10.544 99/LA/P/0101/2020). This research was also funded by project “2Qua—Water Quality and Quantity, the challenge for the present and future” (ref. COMPETE2030-FEDER-0691700—https://doi.org/10 .54499/2023.17517.ICDT) which is supported by European funds, through COMPETE2030, and by national funds, through the Foundation for Science and Technology (FCT, Portugal). This study also had the support of FCT through the project LA/P/0069/2020 granted to the Associate Laboratory ARNET https://doi.org/10.54499/LA/P/0069/2020) by the “Contrato-Programa” UID/04050/2025 funded by FCT I.P. (https://doi.org/10.54499/UID/04050/2025). This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001.FCThttps://doi.org/10.54499/2023.17517.ICDT