This study proposes a procedure for the generation of daily discharge data which considers temporal dependence both within short timescales and across different years. The simulation procedure can be applied to individual and multiple sites. It can be used for various applications such as the design of hydropower reservoirs, the assessment of flood risk or the assessment of drought persistence, and the estimation of the risk of multi-year droughts.

Spatio-temporal variability of seasonal snow cover is characterised from 16 years of MODIS data for the Clutha Catchment, New Zealand. No trend was detected in snow-covered area. Spatial modes of variability reveal the role of anomalous winter airflow. The sensitivity of snow cover duration to temperature and precipitation variability is found to vary spatially across the catchment. These findings provide new insight into seasonal snow processes in New Zealand and guidance for modelling efforts.

We tested the performance of the SWAT hydrological model after being transferred from a small Alpine watershed to a greater area. We found that the performance of the model for the greater catchment was satisfactory and the climate change simulations gave insights into the impact of climate change on our site. Assessment tests are important in identifying the strengths and weaknesses of the models when they are applied under extreme conditions different to the ones that were calibrated.

We show that major groundwater resources in the UK exhibit strong multi-year cycles, accounting for up to 40 % of total groundwater level variability. By comparing these cycles with recorded widespread groundwater droughts over the past 60 years, we provide evidence that climatic systems (such as the North Atlantic Oscillation) ultimately drive drought-risk periods in UK groundwater. The recursive nature of these drought-risk periods may lead to improved preparedness for future droughts.

This paper describes the multi-objective calibration approach used to create a consistent dataset of reconstructed daily river flow data for 303 catchments in the UK over 1891–2015. The modelled data perform well when compared to observations, including in the timing and the classification of drought events. This method and data will allow for long-term studies of flow trends and past extreme events that have not been previously possible, enabling water managers to better plan for the future.

The water stored under the surface is very important for defining the amount of water available for human and environmental applications; however, it is still a challenge to obtain such measurements. NASA's GRACE satellites provide information on total terrestrial water storage based on observations of gravity changes. Here, we relate GRACE data to streamflow measurements, providing estimations of the fraction of baseflow and total drainable storage for the Mississippi River basin.

The ecological impact of changes in river flow may be explored through the simulation of ecologically relevant flow indicators. Traditional approaches to model parameterization are not well-suited for this. To this end, this paper considers the ability of a modified covariance approach, applied to five hydrologically diverse catchments. An overall improvement in consistency is observed, whilst timing and rate of change represent the best and worst replicated indicators respectively.

Exchange fluxes between groundwater and surface waters can be quantified using temperature measurements from the upper sediment layers of streams and lakes assuming the thermal properties of sediments. This study quantified the natural variabiilty in sediment thermal conductivity in the vertical direction at the bed of surface waters and showed that fluxes can change by up to +/-75 % depending on using standard literature values or in situ measurements for sediment thermal conductivity.

We adapted and used a spatially distributed eco-hydrological model, EcH₂O-iso, to temporally evaluate the influence of soil freeze–thaw dynamics on evaporation and transpiration fluxes in a northern Swedish catchment. We used multi-criterion calibration over multiple years and found an early-season influence of soil frost on transpiration water ages. This work provides a framework for quantifying the current and future interactions of soil water, evaporation, and transpiration.

The ensemble flood forecasting system can skillfully predict annual maximum floods with a lead time of more than 10 d and has skill in forecasting the snowmelt-related components about 7 d ahead. The accuracy of forecasts for the annual first floods is inferior, with a lead time of only 5 d. The snowmelt-induced surface runoff is the most poorly captured component by the system, and the well-predicted rainfall-related components are the major contributor to good performance.

Urban flooding exposure is generally investigated with the assumption of stationary disasters and disaster-hit bodies during an event, and thus it cannot satisfy the increasingly elaborate modeling and management of urban floods. In this study, a comprehensive method was proposed to simulate dynamic exposure to urban flooding considering human mobility. Several scenarios, including diverse flooding types and various responses of residents to flooding, were considered.

This study presents how the concept of uncertainty quantification can be applied to river engineering problems and how important it is to understand the limitations of numerical models from a probabilistic point of view. We investigated floodplain friction formulations using different uncertainty quantification methods and estimated their contribution in the final results. The analysis of uncertainties is planned to be integrated in future projects and also extended to more complex scenarios.

BARRA is a novel regional reanalysis for Australia. Our research demonstrates that it is able to characterize a rich spatial variation in daily precipitation behaviour. In addition, its ability to represent large rainfalls is valuable for the analysis of extremes. It is a useful complement to existing precipitation datasets for Australia, especially in sparsely gauged regions.

Understanding the projection performance of hydrological models under contrasting climatic conditions supports robust decision making, which highlights the need to adopt time-varying parameters in hydrological modeling to reduce performance degradation. This study improves our understanding of the spatial coherence of time-varying parameters, which will help improve the projection performance under differing climatic conditions.

We developed global maps that concisely quantify the seasonality of stable isotope ratios in precipitation, using data from 653 meteorological stations across all seven continents. We make these gridded global maps publicly available to support diverse stable isotope applications.

This article examines future atmospheric-related phenomena across the interior of western Canada associated with a business-as-usual climate scenario. Changes in large-scale atmospheric circulation and extent of warming vary with season, and these generally lead to increases, especially after mid-century, in factors associated with winter snowstorms, freezing rain, drought, forest fires, as well as atmospheric forcing of spring floods, although not necessarily summer convection.

Boreal forest evapotranspiration and water cycle is modeled at stand and catchment scale using physiological and physical principles, open GIS data and daily weather data. The approach can predict daily evapotranspiration well across Nordic coniferous-dominated stands and successfully reproduces daily streamflow and annual evapotranspiration across boreal headwater catchments in Finland. The model is modular and simple and designed for practical applications over large areas using open data.

A new quasi-3-D model was developed by coupling a soil water balance model with MODFLOW iteratively for regional-scale water flow modeling. The model was tested to be effective and efficient with well-maintained mass balance. A modeling framework was developed to organize the coupling scheme and to handle the pre- and post-processing information. The model is then used to evaluate groundwater recharge in a real-world application, which shows the model practicability in regional-scale problems.