Integrated ecohydrological hydrometric and stable water isotope data of a drought-sensitive mixed land use lowland catchment

Data from long-term experimental catchments are the foundation of hydrological sciences and are crucial for benchmarking process understanding, observing trends and natural cycles, and being prerequisites for testing predictive models. Integrated data sets which capture all compartments of our landscapes are particularly important in times of land use and climate change. Here, we present ecohydrological data measured at multiple spatial scales which allow differentiation of "blue"water fluxes (which maintain streamflow generation and groundwater recharge) and "green"water fluxes (which sustain vegetation growth). There are two particular unique aspects to this data set: (a) we measured water stable isotopes in the different landscape compartments (i.e. in precipitation, surface water, soil, groundwater, and plant water), and (b) we conducted this monitoring during the extreme drought of 2018 in central Europe. Stable water isotopes are so useful in hydrology as they provide "fingerprints"of the pathways water took when moving through a catchment. Thus, isotopes allow one to evaluate the dynamic relationships between water storage changes and fluxes, which is fundamental to understanding how catchments respond to hydroclimate perturbations or abrupt land use conversion. Second, as we provide the data until 2020, one can also investigate recovery of water stores and fluxes after extreme droughts. Last but not least, lowland headwaters are often understudied systems despite them providing important ecosystem services such as groundwater and drinking water provision and management for forestry and agriculture. The data are available at 10.18728/igb-fred-826.3 (Dämpfling, 2023).