Comment on essd-2025-538

Abstract. We present a 225-year (1799–2024) homogenized daily water level series for the Vistula River in Warsaw, comprising 82,453 observations. The construction of this consistent dataset required adjustments for changes in gauge location, shifts in gauge zero, differences in historical measurement units, and calendar discrepancies between the Julian and Gregorian systems. A small number of missing observations were reconstructed using stage–stage relationships established between overlapping periods of observation at the Warsaw gauge and parallel measurements from downstream stations along the Vistula. The resulting dataset offers a robust foundation for long-term hydrological, climatic, and socio-environmental research. The dataset is openly available at Zenodo repository: https://doi.org/10.5281/zenodo.16919654 (Sobechowicz et al., 2025).