How do anthropogenic activities affect key hydrological indicators in German catchments?

For more than a millenia, human activities have significantly altered various aspects of the hydrological cycle through structural interventions and land-use and land-cover changes. Understanding the magnitude and impacts of these alterations is critical to define a near-natural water cycle. In this study, we clustered more than 1,500 German catchments from the CAMELS-DE dataset into near-natural and non-natural groups based on a comprehensive set of criteria. These criteria regard artificial structures (e.g., dam, reservoir, weir, and others in-stream structures), land-use land-cover characteristics (e.g., fraction of agricultural and artificial lands), and water abstractions (e.g., surface and groundwater abstractions). We then selected a range of hydrological indicators, including actual evapotranspiration, runoff-related metrics, soil moisture, groundwater recharge, and groundwater-level dynamics to evaluate the impact of alterations. Values for these indicators will be derived for both near-natural and non-natural catchment groups using publicly available in situ observations, remote-sensing products, and hydrological modelling approaches. By comparing hydrological indicators across catchment groups while accounting for topographical and geological catchment characteristics, this study aims to improve our understanding of the impacts of human activities on different components of the hydrological cycle to ultimately restore near-natural and resilient conditions.