Water movement through unsaturated soils generates streaming potential (SP). Reliability of SP for the determination of soil properties is investigated. First, influence of hydraulic and geophysical soil parameters on the SP signals is assessed using global sensitivity analysis. Then, a Bayesian approach is used to assess the identifiability of the parameters from SP data. The results of a synthetic drainage column experiment show that all parameters can be reasonably estimated from SP signals.

Montane snowpacks are extremely complex to represent and usually require assimilating remote sensing images at very fine spatial resolutions, which is computationally expensive. Adapting the grid size of the terrain to its complexity was shown to cut runtime and storage needs by half while preserving the accuracy of ~ 100 m snow estimates. This novel approach will facilitate the large-scale implementation of high-resolution remote sensing data assimilation over snow-dominated montane ranges.

Media play a key role in the communication between scientists and the general public. However, the interaction between scientists and journalists is not always straightforward. In this opinion paper, we present insights from hydrologists and journalists into the benefits, aftermath and potential pitfalls of science–media interaction. We aim to encourage scientists to participate in the diverse and evolving media landscape, and we call on the scientific community to support scientists who do so.

The skill of an experimental streamflow forecast system in the Ahlergaarde catchment, Denmark, is analyzed. Inputs to generate the forecasts are taken from the ECMWF System 4 seasonal forecasting system and an ensemble of observations (ESP). Reduction of biases is achieved by processing the meteorological and/or streamflow forecasts. In general, this is not sufficient to ensure a higher level of accuracy than the ESP, indicating a modest added value of a seasonal meteorological system.

To extract water from soils for isotopic analysis, cryogenic water extraction is the most widely used removal technique. This work presents results from a worldwide laboratory intercomparison test of cryogenic extraction systems. Our results showed large differences in retrieved isotopic signatures among participating laboratories linked to interactions between soil type and properties, system setup, extraction efficiency, extraction system leaks, and each lab’s internal accuracy.

We present a Lagrangian model for non-uniform soil water dynamics. It handles 2-D diffusion (based on a spatial random walk and implicit pore space redistribution) and 1-D advection in representative macropores (as film flow with dynamic interaction with the soil matrix). The interplay between the domains is calculated based on an energy-balance approach which does not require any additional parameterisation. Model tests give insight into the evolution of the non-uniform infiltration patterns.

In this study we explore the role of spatially distributed information on hydrological modeling. For that, we develop and test an approach which draws upon information theory and thermodynamic reasoning. We show that the proposed set of methods provide a powerful framework for understanding and diagnosing how and when process organization and functional similarity of hydrological systems emerge in time and, hence, when which landscape characteristic is important in a model application.

Existing satellite products are often insufficient for use in small-scale (< 10 km) hydrological and meteorological studies. We propose a new approach based on the cumulative distribution of frequency to downscale satellite precipitation products with geostationary (GEO) data. This paper uses CMORPH and FY2-E GEO data to examine the approach in six different climate regions. The downscaled precipitation performed better for convective systems.

The influence of long-term changes in canopy structure on rainfall interception loss was studied in a 55-year old forest. Interception loss was similar at the same site (38 %), when the forest was 29 years old. In the past, the forest was denser and had a higher storage capacity, but the evaporation rates were lower. We emphasize the importance of quantifying downward sensible heat flux and heat release from canopy biomass in tall forest in order to improve the quantification of evaporation.

Many glacial lakes in the Himalayas are held in place by natural sediment dams, which are prone to collapse, causing a glacial lake outburst flood (GLOF). This study models a GLOF as a process chain, in which an avalanche enters the lake, creates a large wave that erodes the sediment dam, and produces a flood downstream. Results indicate that Imja Tsho presents little hazard for the next 30 years, but the model is replicable and should be used at other lakes that may present greater hazard.

Facing a growing number of climate models, many selection methods were proposed to select subsets in the field of climate simulation, but the transferability of their performances to hydrological impacts remains doubtful. We investigate the transferability of climate simulation uncertainty to hydrological impacts using two selection methods, and conclude that envelope-based selection of about 10 climate simulations based on properly chosen climate variables is suggested for impact studies.

The goal of the paper was to develop a method to identify the length and severity of flood events for (re)insurance and risk management usage. We took publically available nationwide discharge data from the USGS to apply our method to. We were able to define a peak and a threshold for each individual site, which served as the basis of our method. The hope was that the method would help replace the current standard hours clause and hopefully improve how flood insurance is covered internationally.

In a warmer climate, it is expected that precipitation intensities will increase and form a considerable risk of high-impact precipitation extremes. We investigate how observed extreme precipitation events would look like if they took place in a future warmer climate. This study applies three methods to transform a historic extreme precipitation event in the Netherlands to a similar event in a future warmer climate, thus compiling a future weather scenario.

The paper proposed an approach to develop a decision support tool to evaluate impacts of land use change and best management practices (BMPs) on water quantity and quality for large ungauged watersheds. It was developed based on statistical equations derived from Soil and Water Assessment Tool (SWAT) simulations in a small experimental watershed. The decision support tool reproduced annual stream discharge and sediment and nutrient loadings for another watershed fairly well.

This paper investigates potential impacts of climate change on mountainous karst systems. Our study highlights the fast groundwater dynamics in mountainous karst catchments, which make them highly vulnerable to future changing-climate conditions. Additionally, this work presents a novel holistic modeling approach, which can be transferred to similar karst systems for studying the impact of climate change on local karst water resources.

Gravity monitoring at the surface and in situ (in caves) has been conducted in a karst hydro-system in the south of France (Larzac plateau). Subsurface water storage is evidenced with a spatial variability probably associated with lithology differences and confirmed by MRS measurements. Gravity allows transient water storage to be estimated on the seasonal scale.

We explored how the fraction of streamflow younger than ca. 3 months (F_yw) varies with landscape characteristics and climatic forcing, using an extensive isotope data set from 22 Swiss catchments. Overall, F_yw tends to be larger when catchments are wet and discharge is correspondingly higher, indicating an increase in the proportional contribution of faster flow paths at higher flows. We quantify this discharge sensitivity of F_yw and relate it to the dominant streamflow-generating mechanisms.

This work improves river discharge estimation by taking advantages of observation and model simulations. The new estimation takes into account both gauged and un-gauged rivers, and it compensates model systematic errors and missing processes (e.g., human water usage). This improved estimation is important not only for water resources management and ecosystem health over continent but also for ocean dynamics and salinity.

We present a model for water and sediment transport in a small catchment. For the water balance, we use a simple hydrological model that can explain the observed sudden increase in river flow between storm events. This model drives a hydraulic model of the river, which is needed to determine erosion and sedimentation in the river. Sediments are mainly generated in urban areas as the topography of the catchment is smooth. During storm events, erosion and deposition in the river becomes relevant.

Saturated hydraulic conductivity (K_sat) is an important soil parameter that highly depends on soil's particle size distribution (PSD). The nature of this dependency is explored in this work in two ways, (1) by using the information entropy as a heterogeneity parameter of the PSD and (2) by using descriptions of PSD in forms of textural triplets, different than the usual description in terms of the triplet of sand, silt, and clay contents.

A new generation of global climate models with resolutions between 50 and 10 km is becoming available. Here, we assess how well one such model simulates European precipitation. We find clear improvements in the mean precipitation pattern, and importantly also for extreme daily precipitation over 30 major European river basins. Despite remaining limitations, new high-resolution global models hold great promise for improved climate predictions of European precipitation at impact-relevant scales.

Existing analytical solutions associated with groundwater recharge are only applicable to the studies of saturated flow in aquifers. This paper develops an analytical solution for 3-D unsaturated–saturated flow due to localized recharge into an unconfined aquifer. The effects of unsaturated flow on the recharge process are analyzed. The present solution agrees well with a finite-difference solution. The solution’s predictions also match well with observed data obtained by a field experiment.

We estimated water ages in the upper critical zone with a soil physical model (SWIS) and found that the age of water stored in the soil, as well as of water leaving the soil via evaporation, transpiration, or recharge, was younger the higher soil water storage (inverse storage effect). Travel times of transpiration and evaporation were different. We conceptualized the subsurface into fast and slow flow domains and the water was usually half as young in the fast as in the slow flow domain.

The Arctic has warmed and vegetation has expanded; however, impacts on hydrology are poorly understood. This study used observed meteorology from the last 56 years and changes in vegetation to simulate the water cycle of an Arctic headwater basin. Several changes were found: decreased snow cover duration, deeper permafrost and earlier peak flows. Most changes are from climate change; however, vegetation impacts blowing snow, partially compensating the impact of climate change on streamflow.

Significant evaporative losses from local water reservoirs in arid regions exacerbate water shortages during dry spells. We propose a systematic approach for modeling energy balance and fluxes from covered water bodies using self-assembling floating elements, considering cover properties and local conditions. The study will provide a scientific and generalized basis for designing and implementing this important water conservation strategy to assist with its adaptation in various arid regions.

We used the PERSiST model to explore the role of riparian evapotranspiration (ET) in regulating streamflow in Mediterranean regions. Riparian ET was essential for understanding streamflow dynamics, especially in summer. Moreover, climate change simulations showed that the contribution of riparian ET to annual water budgets will increase in the future. We must include riparian zones in hydrological models in order to establish proper management strategies in water-limited regions.

Considering effective precipitation (P_e), the Budyko framework was extended to the annual water balance analysis. To reflect the mismatch between water supply (precipitation, P) and energy (potential evapotranspiration, E₀), a climate seasonality and asynchrony index (SAI) were proposed in terms of both phase and amplitude mismatch between P and E₀.

In this study, we adjust a simple hydrological model to several observational datasets, including satellite observations of the land's total water storage. We apply the model to northern latitudes and find that the dominating factor of changes in the total water storage depends on both the spatial and temporal scale of analysis. While snow dominates seasonal variations, liquid water determines year-to-year variations, yet with increasing contribution of snow when averaging over larger regions.

The dual nitrate isotope technique is one of the most commonly used approaches to study the origin and fate of N introduced in aquifers. In this study, we first demonstrate a large attenuation of groundwater N at a former industrial site, especially at the interface between surface and groundwater. We also provide evidence for a switch in the oxygen isotopic signature of groundwater due to this extensive N attenuation. This could be used to better quantify N attenuation processes in aquifers.

To simulate the water balance of, e.g., a forest plot, it is important to estimate the maximum volume of water available to plants. This depends on soil properties and the average depth of roots. Rooting depth has proven challenging to estimate. Here, we applied a model assuming that plants dimension their roots to optimize their carbon budget. We compared its results with values obtained by calibrating a dynamic water balance model. In most cases, there is good agreement between both methods.