We present an analysis of meteorological conditions and melt for Universidad Glacier in central Chile. This glacier is characterized by high melt rates over the ablation season, representing a mean contribution of between 10 and 13 % of the total runoff observed in the upper Tinguiririca Basin during the November 2009 to March 2010 period. Few studies have quantified the glacier melt contribution to river runoff in Chile, and this work represents a new precedent for the Andes.

Reliable estimation of hydrological soil moisture state is of critical importance in operational hydrology to improve the flood prediction and hydrological cycle description. This paper attempts for the first time to build a soil moisture product directly applicable to hydrology using multiple data sources retrieved from remote sensing and land surface modelling. The result shows a significant improvement of the soil moisture state accuracy; the method can be easily applied in other catchments.

An estuary is where fresh water rivers meet the salty open sea. This mixture of salty fresh water leads to a varying water quality. There a model works well showing how far the salty water can travel, with an empirical parameter that needs to be calibrated every time. This paper provides a possible solution for this parameter to make the model predictive. Also, the model was improved by considering 2-D exchange flow. This new model was supported by observations in 18 estuaries around the world.

The analogue method aims at forecasting precipitation by means of a statistical relationship with meteorological variables at a large scale, such as the general atmospheric circulation. A moving time window has been introduced here in order to allow finding better analogue situations at different hours of the day. This change resulted in a better analogy of the atmospheric circulation, with improved prediction skills, and even to a greater extent for days with heavy precipitation.

Models are tools for understanding how watersheds function and may respond to land cover and climate change. Before we can use models towards these purposes, we need to ensure that a model adequately represents watershed-wide observations. In this paper, we propose a new way to evaluate whether model simulations match observations, using a variety of information sources. We show how this information can reduce uncertainty in inputs to models, reducing uncertainty in hydrologic predictions.

The paper provides an easy-to-use implementation of the UNCODE framework, which allows one to estimate the design flood value by directly accounting for sample uncertainty. Other than a design tool, this methodology is also a practical way to quantify the value of data in the design process.

Soil moisture and evapotranspiration (ET) are important to flood forecasting. An energy balance scheme based on the representative temperature (RET) was developed and coupled to the original mass balance scheme of the Xin'anjiang model. Validation against both runoff and land surface temperature confirmed the accuracy and applicability of the improved model (XAJ-EB). RET serves as a new constraint to the model and can be used for model calibration and validation.

Leaf transpiration and energy exchange are coupled processes at the small scale that have strong effects on the water cycle and climate at the large scale. In this technical note, we present a novel experimental set-up that enables detailed study of these coupled processes in the laboratory under controlled conditions. Results document the abilities of the experimental set-up to confirm or challenge our understanding of these processes.

The study analysed the quality and partitioning of a 15-year surface energy dataset from Skukuza flux tower. The yearly mean energy balance ratio (EBR) was 0.93, with the dry season having the lowest ratio. Night ratio was lower than daytime, with analysis showing an increase in EBR with increase in friction velocity, which is also linked to time of day. The energy partitioning showed that sensible heat flux is the dominant portion in the dry season, and latent heat flux during the wet season.

Since groundwater is the linkage between climate changes and fresh submarine groundwater discharge, the variations of and relationships among monthly groundwater table, rainfall, snowfall, and climate change events from 1985 to 2015 were analyzed by wavelet coherence to discuss the implications for climate changes. The results show the increase in precipitation and the groundwater table, indicating that fresh submarine groundwater discharge flux may increase under climate change.

The diversity in hydrologic models has led to controversy surrounding the “correct” approach to hydrologic modeling. In this paper we revisit key modeling challenges on requirements to (1) define suitable model equations, (2) define adequate model parameters, and (3) cope with limitations in computing power. We outline the historical modeling challenges, summarize modeling advances that address these challenges, and define outstanding research needs.

The paper aims to investigate current and tide correlation in a basin named Mar Piccolo, located in the inner part of the Ionian Sea. It is considered highly vulnerable, being exposed to urban and industrial discharges as well as to intense naval traffic. A continuous monitoring action of the principal hydrodynamic parameters could be a useful managing tool, considering that the diffusion and dispersions of polluting tracers is strictly connected to currents, tide, and waves propagation.

In 2009, the "planetary boundaries" were introduced. They consist of nine global control variables and corresponding "thresholds which, if crossed, could generate unacceptable environmental change". The idea has been very successful, but also controversial. This paper picks up the debate with regard to the boundary on "global freshwater use": it argues that such a boundary is based on mere speculation, and that any exercise of assigning actual numbers is arbitrary, premature, and misleading.

Regional hydro-climatic variables are modulated by large-scale, reoccurring climate oscillations. In this article, the authors provide both statistical and physical evidence of how Taiwan’s summertime streamflow is strongly correlated with specific teleconnection patterns dominating cyclonic activity in the western North Pacific. However, such correlation can be strengthened or weakened by notable climate regime shifts, illustrating the pitfall of empirical seasonal forecasting.

The physically based Cold Regions Hydrological Model (CRHM) was utilized to simulate runoff in the La Salle River, located in the northern Great Plains with flat topography, clay soils, and surface drainage. Snow sublimation and transport as well as infiltration to frozen soils were identified as critical in defining snowmelt. Challenges in representing infiltration into frozen but dry clay soils and flow routing under both dry and flooded conditions indicate the need for further study.

In the current study, we have developed a method to obtain marginal cost curves (MCCs) for WF reduction in crop production. The method is innovative by employing a model that combines soil water balance accounting and a crop growth model and assessing costs and WF reduction for all combinations of irrigation techniques, irrigation strategies and mulching practices. While this approach has been used in the field of constructing MCCs for carbon footprint reduction, this has never been done before.

Precipitation measurements were combined from eight separate precipitation testbeds to create multi-site transfer functions for the correction of unshielded and single-Alter-shielded precipitation gauge measurements. Site-specific errors and more universally applicable corrections were created from these WMO-SPICE measurements. The importance and magnitude of such wind speed corrections were demonstrated.

This paper indicates that precipitation data derived from GPM-IMERG correspond more closely to TMPA V7 than TMPA RT datasets, but both GPM-IMERG and TMPA V7 precipitation data tend to overestimate, in comparison to observed rainfall (by 11.1 % and 15.7 %, respectively). Statistical analysis indicates that GPM-IMERG is as useful as TMPA V7 or TMPA RT datasets for estimating observed streamflows in Andean–Amazonian regions (Ucayali Basin, southern regions of the Amazon Basin of Peru and Ecuador).

Land surface models bear substantial biases. To reduce model biases, we apply a simple but efficient bias correction method to a land surface model. We first derive a relationship between observations and model simulations, and apply this relationship in the application period. While the bias correction method improves model-based estimates without improving the model physical parameterization, results do provide guidance for physically based model development effort.

In this study, we developed new tools for identifying potential hydrologic connectivity between wetlands and stream networks, which can better inform regulatory decisions and enhance the ability to better manage wetlands under various planning scenarios. The resulting flow network delineated potential flow paths connecting wetland depressions to each other or to the river network on scales finer than those available through the National Hydrography Dataset.

Reproduction of past floods requires information on discharge and flood extent, commonly unavailable or uncertain during extreme events. We explored the possibility of reproducing an extreme flood disaster using rainfall and post-event hydrometric information by combining a rainfall-runoff and hydraulic modelling tool within an uncertainty analysis framework. Considering the uncertainty in post–event data, it was possible to reasonably reproduce the extreme event.

The history of the co-evolution of the coupled human–groundwater system in Cangzhou (a region with the most serious depression cone in the North China Plain) is analyzed with a particular focus on how the groundwater crisis unfolded and how people attempted to settle the crisis. The evolution of the system was substantially impacted by two droughts. Further restoration of groundwater environment could be anticipated, but the occurrence of drought still remains an undetermined external forcing.

This paper aims to improve the understanding of transport processes in karst aquifers, which remains a great challenge due to its complex nature. A framework is proposed to identify and quantify the spatio-temporal variability of lateral exchanges along a karst conduit network during flood events, for both flow and solute transport. An inverse problem approach is used on discharge and water mineralization data sets and gives new insights into the hydrogeological behavior of such complex systems.

The paper aims to propose a conceptual framework that supports nuanced understanding and analytical assessment of resilience in socio-hydrological contexts. We identify three framings of resilience for different human–water couplings, which have distinct application fields and are used for different water management challenges. To assess and improve socio-hydrological resilience in each type, we introduce a resilience canvas as a heuristic tool to design bespoke management strategies.

The western US relies heavily on irrigation water which is allocated following local water rights. We develop and test a novel model that explicitly integrates water rights into a conceptual hydrologic model to spatially allocate irrigation water. The model well captures the timing and magnitude of irrigation water allocation in our study area and is applicable to semi-arid regions with similar water right regulations. The results could inform future water policies and management decisions.

Assuming that floods are driven by both short- (meteorological forcing) and long-term perturbations (higher-than-usual moisture), we propose a technique for updating a season in advance the flood frequency distribution. Its application in the Po and Danube rivers helped to reduce the uncertainty in the estimation of floods and thus constitutes a promising tool for real-time management of flood risk mitigation. This study is the result of the stay of the first author at the University of Bologna.

In this synthesis of hydrologic scaling and similarity, we assert that it is time for hydrology to embrace a fourth paradigm of data-intensive science. Advances in information-based hydrologic science, coupled with an explosion of hydrologic data and advances in parameter estimation and modeling, have laid the foundation for a data-driven framework for scrutinizing hydrological hypotheses. We call upon the community to develop a focused effort towards a fourth paradigm for hydrology.

This paper addresses the evaluation of extreme floods in western/central Europe in terms of different index variants. The comparison of extreme floods' rankings is presented, as well as the main characteristics of temporal and spatial distributions of flood extremes. The results will be used for the assessment of related meteorological conditions. A comparison of major floods with precipitation and circulation extremes will be useful for a better understanding of the causes of extensive floods.

This study investigates the temporal dynamics and response velocities of lateral preferential flow at the hillslope. The results are compared to catchment response behavior to infer the large-scale implications of the observed processes. A large portion of mobile water flows through preferential flow paths in the structured soils, causing an immediate discharge response. The study presents a methodological approach to cover the spatial and temporal domain of these highly heterogeneous processes.

Rapid subsurface flow in structured soils facilitates fast vertical and lateral redistribution of event water. We present its in situ exploration through local measurements and irrigation experiments. Special emphasis is given to a coherent combination of hydrological and geophysical methods. The study highlights that form and function operate as conjugated pairs. Dynamic imaging through time-lapse GPR was key to observing both and to identifying hydrologically relevant structures.

Large-scale hydrological variability can affect society in profound ways; floods and droughts, for example, often cause major damage and hardship. A recent gathering of hydrologists at a symposium to honor the career of Professor Eric Wood motivates the present survey of recent research on this variability. The surveyed literature and the illustrative examples provided in the paper show that research into hydrological variability continues to be strong, vibrant, and multifaceted.

Fruits take up soil water as they grow, and thus the fruit water is related to the rain or irrigation the crop receives. We used a novel sampling system to measure the stable isotopes of H and O in the fruit water to determine its geographic origin by comparing it to maps of isotopes in rain. We used this approach to teach an audience of science students and teachers about water cycle concepts and how humans may modify the water cycle through agriculture and irrigation water diversions.

Nitrate–nitrogen is a groundwater contaminant worldwide that originates commonly from agricultural fertilization. In this work, we built a computer model which follows the fate of nitrogen from land surface to deep (~100 m) and distant (~km) groundwater wells. The model succeeded estimating total groundwater nitrate, yet failed to point-estimate contaminated wells, extra assumptions fixed it. This enabled prediction of future groundwater–nitrate which revealed the need to reduce fertilization.

The accurate reduction of hydrologic model input data is an impediment towards understanding input uncertainty and model structural errors. This paper compares the ability of two transforms to reduce rainfall input data. The resultant transforms are compressed to varying extents and reconstructed before being evaluated with standard simulation performance summary metrics and descriptive statistics. It is concluded the discrete wavelet transform is most capable of preserving rainfall time series.

We sampled the isotopic composition in the top 20 cm at four different sites in the Scottish Highlands at 5 cm intervals over 1 year. The relationship between the soil water isotopic fractionation and evapotranspiration showed a hysteresis pattern due to a lag response to onset and offset of the evaporative losses. The isotope data revealed that vegetation had a significant influence on the soil evaporation with evaporation being double from soils beneath Scots pine compared to heather.

In the last decades, new instruments were developed to measure rainfall and hydrological processes at high resolution. Weather radars are used, for example, to measure how rainfall varies in space and time. At the same time, new models were proposed to reproduce and predict hydrological response, in order to prevent flooding in urban areas. This paper presents a review of our current knowledge of rainfall and hydrological processes in urban areas, focusing on their variability in time and space.

We examine the opportunities and challenges that technological advances in Earth observation will present to the hydrological community. From advanced space-based sensors to unmanned aerial vehicles and ground-based distributed networks, these emergent systems are set to revolutionize our understanding and interpretation of hydrological and related processes.

Water supply forecasts are critical to support water resources operations and planning. The skill of such forecasts depends on our knowledge of (i) future meteorological conditions and (ii) the amount of water stored in a basin. We address this problem by testing several approaches that make use of these sources of predictability, either separately or in a combined fashion. The main goal is to understand the marginal benefits of both information and methodological complexity in forecast skill.