Meteorological ingredients of heavy precipitation and subsequent lake-filling episodes in the northwestern Sahara Hydrology and Earth System Sciences DOI 10.5194/hess-29-1395-2025 17 March 2025 The Sahara was wetter in the past and may become wetter in the future. Lake remnants are evidence of the desert’s wetter past. If the Sahara gets wetter in the future, these lakes may serve as a water resource. However, it is unclear how these lakes get filled and how moisture is carried into the desert and converted into rain in the first place. Therefore, we examine processes currently leading to the filling of a dry lake in the Sahara, which can help assess future water availability. Read more
CH-RUN: a deep-learning-based spatially contiguous runoff reconstruction for Switzerland Hydrology and Earth System Sciences DOI 10.5194/hess-29-1061-2025 27 February 2025 This study reconstructs daily runoff in Switzerland (1962–2023) using a deep-learning model, providing a spatially contiguous dataset on a medium-sized catchment grid. The model outperforms traditional hydrological methods, revealing shifts in Swiss water resources, including more frequent dry years and declining summer runoff. The reconstruction is publicly available. RUN: a deep-learning-based spatially contiguous runoff reconstruction for Switzerland">Read more
Creating a national urban flood dataset for China from news texts (2000–2022) at the county level Hydrology and Earth System Sciences DOI 10.5194/hess-29-767-2025 19 February 2025 We create China’s first open county-level urban flood dataset (2000–2022) using news media data with the help of deep learning. The dataset reflects both natural and societal influences and includes 7595 urban flood events across 2051 counties, covering 46 % of China’s land area. It reveals the predominance of summer floods, an upward trend since 2000, and a decline from southeast to northwest. Notably, some highly developed regions show a decrease, likely due to improved flood management. Read more
Characterizing nonlinear, nonstationary, and heterogeneous hydrologic behavior using ensemble rainfall–runoff analysis (ERRA): proof of concept Hydrology and Earth System Sciences DOI 10.5194/hess-28-4427-2024 11 October 2024 Here, I present a new way to quantify how streamflow responds to rainfall across a range of timescales. This approach can estimate how different rainfall intensities affect streamflow. It can also quantify how runoff response to rainfall varies, depending on how wet the landscape already is before the rain falls. This may help us to understand processes and landscape properties that regulate streamflow and to assess the susceptibility of different landscapes to flooding ERRA): proof of concept">Read more
Large-sample hydrology – a few camels or a whole caravan? Hydrology and Earth System Sciences DOI 10.5194/hess-28-4219-2024 20 September 2024 We show that the differences between the forcing data included in three CAMELS datasets (US, BR, GB) and the forcing data included for the same catchments in the Caravan dataset affect model calibration considerably. The model performance dropped when the data from the Caravan dataset were used instead of the original data. Most of the model performance drop could be attributed to the differences in precipitation data. However, differences were largest for the potential evapotranspiration data. Read more
Young and new water fractions in soil and hillslope waters Hydrology and Earth System Sciences DOI 10.5194/hess-28-4295-2024 20 September 2024 We use a 3-year time series of tracer data of streamflow and soils to show how water moves through the subsurface to become streamflow. Less than 50% of soil water consists of rainfall from the last 3 weeks. Most annual streamflow is older than 3 months, and waters in deep subsurface layers are even older; thus deep layers are not the only source of streamflow. After wet periods more rainfall was found in the subsurface and the stream, suggesting that water moves quicker through wet landscapes. Read more
Mesoscale permeability variations estimated from natural airflows in the decorated Cosquer Cave (southeastern France) Hydrology and Earth System Sciences DOI 10.5194/hess-28-4035-2024 6 September 2024 Conservation of decorated caves is highly dependent on airflows and is correlated with rock formation permeability. We present the first conceptual model of flows around the Paleolithic decorated Cosquer coastal cave (southeastern France), quantify air permeability, and show how its variation affects water levels inside the cave. This study highlights that airflows may change in karst unsaturated zones in response to changes in the water cycle and may thus be affected by climate change. Read more
Merging modelled and reported flood impacts in Europe in a combined flood event catalogue for 1950–2020 Hydrology and Earth System Sciences DOI 10.5194/hess-28-3983-2024 2 September 2024 Long-term trends in flood losses are regulated by multiple factors, including climate variation, population and economic growth, land-use transitions, reservoir construction, and flood risk reduction measures. Here, we reconstruct the factual circumstances in which almost 15 000 potential riverine, coastal and compound floods in Europe occurred between 1950 and 2020. About 10 % of those events are reported to have caused significant socioeconomic impacts. Read more
An increase in the spatial extent of European floods over the last 70 years Hydrology and Earth System Sciences DOI 10.5194/hess-28-3755-2024 23 August 2024 We use grid-based runoff from a hydrological model to identify large spatiotemporally connected flood events in Europe, assess extent trends over the last 70 years, and attribute the trends to different drivers. Our findings reveal a general increase in flood extent, with regional variations driven by diverse factors. The study not only enables a thorough examination of flood events across multiple basins but also highlights the potential challenges arising from changing flood extents. Read more
Hydro-pedotransfer functions: a roadmap for future development Hydrology and Earth System Sciences DOI 10.5194/hess-28-3391-2024 29 July 2024 Pedotransfer functions (PTFs) are used to predict parameters of models describing the hydraulic properties of soils. The appropriateness of these predictions critically relies on the nature of the datasets for training the PTFs and the physical comprehensiveness of the models. This roadmap paper is addressed to PTF developers and users and critically reflects the utility and future of PTFs. To this end, we present a manifesto aiming at a paradigm shift in PTF research. Read more