**Brief description of the catchment:** The 2.4-ha Ressi catchment is located in the eastern Italian pre-Alps (45°47′11.79″ N; 11°15′54.12″ E). The elevation ranges between 598 and 721 m a.s.l., the average slope is 31° and the main aspect is west. The climate is humid temperate. The bedrock consists of volcanic rocks (rhyolites and dacites of Triassic origin) and the soil is classified as Cambisol. The Ressi catchment is covered by dense forest; the main tree species are beech (*Fagus sylvatica* L.), chestnut (*Castanea sativa* Mill.), maple (*Acer campestre* L.) and hazel (*Corylus avellana* L.). Grassland, sparse trees and a small cultivated area close to the lower eastern divide cover about 11% of the catchment area. ---------- **Data availability and description:** Data are organized in three folders (‘Catchment GIS files’, ‘Hydrometeorological data’ and ‘Tracer data’). The folder ‘Hydrometeorological data’ contains the following subfolders: ‘Air temperature’, 'Depth to water table', ‘Precipitation’, ‘Soil moisture’ and ‘Streamflow’. The folders contain .xlsx files of the collected hydrometeorological (i.e., precipitation, air temperature, streamflow, depth to water table, soil moisture at 0-30 cm depth and at various depths and different sites) and tracer (isotopic) data, shapefiles of the catchment (location of the outlet, instrumentation and polygon of the catchment) and the raster file of the Digital Elevation Model, in the .flt and .hdr format (the .prj file is also included). Currently, the hydrometeorological data sets cover different periods depending on the start of the measurements, whereas the tracer data are available from 12/07/2012 to 30/09/2022. Hydrometeorological and tracer data are provided at the original temporal resolution. The data set is expected to be updated on an annual basis to include the most recent measurements. **Hydrometeorological data file:** - Date and time of the measurements are formatted as dd/mm/yyyy hh:mm. The time zone is UTC+1. - Precipitation data (reported in mm) were collected from the local rain gauge. Data gaps were filled (cells indicated in yellow) by using spatially-interpolated (inverse distance weighting method) precipitation data collected at three rain gauges located 2.3 to 4.8 km away from Ressi, that are operated by the Agency for Environmental Protection of Veneto Region (ARPAV). Temporal resolution of precipitation data collected at the local rain gauge is 5 min in 2012 and 2013, 10 min from 27/01/2014 to 18/05/2018, and 5 min from 18/05/2018. Spatially-interpolated precipitation data are reported at the original 5-min resolution. - Air temperature (reported in °C) was measured at the local weather station, at a 5-min resolution, from 18/05/2018. For the period 01/01/2017-18/05/2018 (cells indicated in yellow), air temperature data were obtained by the analysis of the simple linear regression between the local temperature in Ressi and data (at 15-min resolution) recorded by an ARPAV weather station located at the same elevation of the catchment and 4.8 km away from it. - Soil moisture (reported in %) was collected at 0-30 cm depth at four locations, i.e. in the riparian zone, hillslope toe, middle hillslope and upper hillslope (a probe was removed in 2019 due to the malfunctioning, and replaced with a new sensor on 18/03/2021), with a temporal resolution of 5 min until 27/11/2012, and 10 min afterwards. From 25/05/2017, soil moisture was also measured horizontally at 15, 30 and 45 cm depths in six different locations in the riparian zone and the hillslope (several data gaps are present and were not filled in). - Depth to the water table (reported in m from the ground surface) is available for the riparian piezometer GW 1 (most continuous time series). Temporal resolution of the measurements is 5 min. - Streamflow data, collected at the outlet of the catchment, are reported in l/s. Temporal resolution of the measurements is 5 min. - Missing data are indicated with ‘NA’ (not available), except in the files ‘Ressi_soil_moisture_Decagon_various_depths_May_2017-Nov_2018.xlsx’ and ‘Ressi_soil_moisture_Decagon_various_depths_Dec_2018-Dec_2019.xlsx’, where the cells were left blank. ‘NA’ is also used to fill in the cells when the data temporal resolution is 10 min. **Tracer data file:** - The 'Ressi_isotopic_data_2012-2022.xlsx' file contains six sheets; ‘bulk_precipitation’, 'stream_water', 'groundwater_in_GW 1', 'groundwater_in_GW 4', 'riparian_soil_water' and ‘legend’. The ‘legend’ sheet provides a description of the sampling sites. - Date and time of the measurements are formatted as dd/mm/yyyy hh:mm, as well as reported in in six separated columns ('day', 'month', 'year', 'hour', 'min' and 'sec'). The time zone is UTC+1. - ‘δ2H (‰)’ and ‘δ18O (‰)’ indicate the mean isotopic composition (2H and 18O) based on six injections, whereas ‘Std dev δ2H (‰)’ and ‘Std dev δ18O (‰)’ represent the standard deviations. Isotopic data are expressed as δ notation in unit per mil. All the samples were calibrated with standards relative to the Vienna Standard Mean Ocean Water. - The ‘d-excess’ column reports the deuterium excess data. - For bulk precipitation, start and end of sample collection is indicated for each sample, as well as the corresponding precipitation amount in mm. - For stream water samples, the corresponding streamflow values in m3/s are reported. - Missing data are indicated with ‘NA’ (not available). ---------- **Please cite the next Data Note together with the data set:** Zuecco G., Marchina C., Gelmini Y., Amin A., van Meerveld H.J., Penna D., Borga M., 2021. Ressi experimental catchment: ecohydrological research in the Italian pre-Alps. *Hydrological Processes, 35, e14095*. https://doi.org/10.1002/hyp.14095 ---------- **Related publications:** Brocca L., Massari C., Ciabatta L., Moramarco T., Penna D., Zuecco G., Pianezzola L., Borga M., Matgen P., Martínez-Fernández J., 2015. Rainfall estimation from in situ soil moisture observations at several sites in Europe: an evaluation of the SM2RAIN algorithm. *Journal of Hydrology and Hydromechanics, 63, 201-209*. https://doi.org/10.1515/johh-2015-0016 Gelmini Y., Zuecco G., Zaramella M., Penna D., Borga M., 2022. Hysteresis in streamflow-water table relation provides a new classification system of rainfall-runoff events. *Hydrological Processes, 36, e14685*. https://doi.org/10.1002/hyp.14685 Marchina C., Zuecco G., Chiogna G., Bianchini G., Carturan L., Comiti F., Engel M., Natali C., Borga M., Penna D., 2020. Alternative methods to determine the δ2H-δ18O relationship: An application to different water types. *Journal of Hydrology, 587, 124951*. https://doi.org/10.1016/j.jhydrol.2020.124951 Penna D., van Meerveld H.J., Oliviero O., Zuecco G., Assendelft R.S., Dalla Fontana G., Borga M., 2015. Seasonal changes in runoff generation in a small forested mountain catchment. *Hydrological Processes, 29, 2027-2042*. https://doi.org/10.1002/hyp.10347 Penna D., Oliviero O., Assendelft R., Zuecco G., van Meerveld I., Anfodillo T., Carraro V., Borga M., Dalla Fontana G., 2013. Tracing the water sources of trees and streams: isotopic analysis in a small pre-alpine catchment. *Procedia Environmental Sciences, 19, 106-112*. https://doi.org/10.1016/j.proenv.2013.06.012 Segura C., Penna D., Borga M., Hissler C., Iffly J.F., Klaus J., Latron J., Llorens P., Marchina C., Martínez-Carreras N., Pfister L., Zuecco G., 2023. Comparing hydrological responses across catchments using a new soil water content metric. *Hydrological Processes, 37, e15010*. https://doi.org/10.1002/hyp.15010 Zuecco G., Amin A., Frentress J., Engel M., Marchina C., Anfodillo T., Borga M., Carraro V., Scandellari F., Tagliavini M., Zanotelli D., Comiti F., Penna D., 2022. A comparative study of plant water extraction methods for isotopic analyses: Scholander-type pressure chamber vs. cryogenic vacuum distillation. *Hydrology and Earth System Sciences, 26, 3673–3689*. https://doi.org/10.5194/hess-26-3673-2022 Zuecco G., Penna D., Borga M., van Meerveld H.J., 2016. A versatile index to characterize hysteresis between hydrological variables at the runoff event timescale. *Hydrological Processes, 30, 1449-1466*. https://doi.org/10.1002/hyp.10681 Zuecco G., Penna D., van Meerveld H.J., Hopp L., Dalla Fontana G., Borga M., 2014. Comparison of two different types of throughfall collectors. *Die Bodenkultur, 65 (3-4), 51-56*.