We describe a novel technique for the precise, quasi-realtime observation of water stable isotopes in gross precipitation and throughfall from tree canopies in parallel. Various processes (e.g. rainfall intensity, evapotranspiration, exchange with ambient vapor) are thereby controlling throughfall intensity and isotopic composition. The achieved temporal resolution now competes with common meteorological measurements thus enabling new ways to employ water stable isotopes in forested catchments. Hide

A new derivation of the equations for one-dimensional open-channel flow in rivers and storm drainage systems has been developed. The new approach solves some long-standing problems of obtaining well-behaved solutions with conservation forms of the equations. This research was motivated by the need for highly-accurate models of large-scale river networks and the storm drainage systems in mega-cities. Such models are difficult to create with existing equation forms. Hide

Description of thermal regimes in flowing waters is key to understanding physical processes and improving bioassessments but has been limited by sparse datasets. Using a large annual temperature dataset from a mountainous area of the western U.S., we explored thermal regimes using principle components analysis. A small number of summary metrics adequately represented most of the variation in this dataset given strong temporal coherence among sites. Hide

Do experts attach the same meaning as laypeople to terms often used in hydrology such as river, flooding and downstream? In this study a survey was completed by 34 experts and 119 laypeople to answer this question. We found that there are some profound differences between experts and laypeople: words like river and river basin turn out to have a thoroughly different interpretation between the two groups. However, when using pictures there is much more agreement between the groups. Hide

The description of pharmaceuticals fate and transport introduced into a watershed is a challenging topic, especially for the possible adverse effects on human health. In addition, an accurate estimation of solute sources and routes is still missing. This study uses a new promising modeling approach to predict pharmaceutical concentrations in rivers. Results show interesting relationship between solute concentrations in waters and touristic fluxes. Hide

We investigate evidence for the effects of anthropogenic warming on groundwater droughts using records of groundwater levels from the UK (1891–2015). We compare measures of groundwater levels with temperature and rainfall and show there has been an increase in groundwater drought months and in the frequency, duration and intensity of groundwater drought events. We infer these changes may be due to increases in evaporation and plant transpiration associated with anthropogenic warming. Hide

Numerical models of wormhole formation in fractured porous media provide basic insights on the evolution of complex conduit systems in karst aquifers. In this work we use a time-propagating reactive flow model to explore the evolution of wormholes in a 2D grid of fractures. We demonstrate physically meaningful mechanisms leading to the formation of individual wormholes and the competition between a set of evolving wormholes. Hide

In order to assess future impacts of climate change on streamflow, climate models are usually coupled with complex rainfall-runoff models. For low flow events, which are little dynamic in space and time, it is hypothesized that predictions can made be using simple statistical relationships with meteorological states. In this study it is assessed whether such relationships exist and if they can be applied in regional climate change impact assessment in the northwestern part of Germany. Hide

This study is an effort for a better understanding and quantification of the water cycle and related processes in the Mediterranean region, by dealing with satellite products and their uncertainties. The aims of the paper are threefold: (1) developing method with hydrological constraint to integrate all the datasets, (2) Giving the full picture of the Mediterranean WC, (3) building an model-independent database that can evaluates the numerous Regional Climate Models (RCMs) for this region. Hide

The potential of rain to cause soil erosion by runoff is called rain erosivity. Rain erosivity is highly variable in space and time even over distances of less than 1 km. Contiguously measured radar rain data depict for the first time this spatio-temporal variation but scaling factors are required to account for differences in spatial and temporal resolution compared to rain gauge data. These scaling factors were obtained from more than two million erosive events. Hide

Seasonal ahead rainfall forecast is very important for water resources management. Classification methods are used to identify the extreme rainfall classes’ dry and wet using climate teleconnections. These models can be used for river basin areal river rainfall forecast, to manage reservoir operation. Forecasts of climate phenomena ElNino Southern Oscillation and Indian Ocean Dipole provide useful information to the Sri Lankan water resources managers through these models. Hide

This paper addresses questions related to the adoption of stochastic methods in hydrogeology, looking at factors such as environmental regulations, financial incentives, higher education, and the collective feedback loop involving these factors. We show that stochastic hydrogeology's blind spot is in focusing on risk while ignoring uncertainty, to the detriment of its potential clients. The imbalance between the treatments of risk and uncertainty is shown to be common to multiple disciplines. Hide

The Kling and Gupta Efficiency (KGE) is a score used in hydrology to evaluate flow simulation compared to observations. In order to force the evaluation on the low-flows, some authors used the log-transformed flow to calculate the KGE. In this technical note, we show that this transformation should be avoided because it produce numerical flaws that lead to difficulties in the score value interpretation. Hide

Simulated climate outputs from GCMs need bias correction before they can be used for any hydro-meteorologic assessment studies. Two different sources of climate projections were tested to quantify the bias in them. Some bias correction methods were evaluated for their effectiveness to reduce bias in projected outputs. Overall, power transformation was best method. The approach was used to create climate database for entire Western Lake Erie Basin, which will be made accessible to public for use. Hide

Floods and droughts cause significant damages and pose risks to lives worldwide. In a climate change context this work identifies hot-spots across Great Britain, i.e. places expected to be impacted by an increase in both floods and droughts. By the 2080s the west coast of England and Wales and northeast Scotland would experience more floods in winter and droughts in autumn, with a higher increase in drought hazard, showing a need for adapting water management policies in light of climate change. Hide

Satellite-based river gauging can be constructed based on remote sensing-derived surface water extent and modelled discharge, and used to estimate river discharges with satellite observations only. This provides opportunities for monitoring river discharge in the absence of a real time hydrological model or gauging stations. Hide

The relationship among glacier melt, groundwater, and streamflow remains highly uncertain, especially in tropical glacierized watersheds in response to climate. We implemented a multi-method approach and found that melt contribution varies considerably and may drive streamflow variability at hourly to multi-year timescales, rather than buffer it, as commonly thought. Some of the melt contribution occurs through groundwater pathways, resulting in longer timescale interactions with streamflow. Hide

We used long time lapse geoelectrical profiles to monitor water infiltration through a landfill cover layer. The obtained electrical resistivity changes are smoothed and reflect both moisture variations, the background resistivity heterogeneity, and temperature and salinity changes due to water infiltration. Interpretation limits were investigated by using synthetic modelling. Using these results to avoid over-interpretation, field observations revealed zones where large infiltration occurs. Hide

A multiplexed pumping system (MPS) for obtaining continuous water quality data at multiple locations was previously reported. The existing design was not practical for sampling water in volume-limited applications such as small mesocosms or porewater sampling. This paper discusses the design and performance of a small-volume MPS and illustrates two applications, showing spatial variability in replicate in-situ mesocosms and short-circuiting in a woodchip bioreactor using porewater sampling. Hide

Many variables, e.g. in hydrology, geology, social sciences, etc., are only observed at a few distinct measurement locations and their actual distribution in the entire space remains unknown. We introduce the new geostatistical interpolation method of Quantile Kriging, providing an improved estimator and associated uncertainty. It can also host variables, which would not fulfill the implict presumptions of the traditional geostatistical interpolation methods. Hide

This work focuses on catchment hydrology understanding in a glaciarized basin of the Andes mountains. Using an approach combining stable water isotopes, ionic chemistry and end member mixing modelling with satellite imagery, meteorological and streamflow data analysis, was possible to discriminate contributions from different water sources in time and space. This is relevant to implement adaptation policies aiming the maintenance of water supply and demand equilibrium in an arid territory. Hide

The hyporheic zone is the area below riverbeds where surface water and groundwater mix together. Hyporheic flow is linked to river processes and functions but research to date has not sufficiently addressed how factors drive hyporheic flow variations. This review critically presents the scale-specific processes and process interactions that control hyporheic flow variation and applies these findings to a case study showing how valley factors affect the expression of flows at the reach scale. Hide

We propose a method for unsupervised classification of the space–time–intensity structure of weather radar images. The resulting classes are interpreted as rain types, i.e. pools of rain fields with homogeneous statistical properties. Such rain types can in turn be used to define stationary periods for further stochastic rainfall modelling. The application of rain typing to real data indicates that non-stationarity can be significant within meteorological seasons, and even within a single storm. Hide

Rainfall data is often not available for the analysis of the water related problems such as floods and droughts. In such cases, researchers and engineers use rainfall generators which can produce synthetic rainfall data. However, most rainfall generators can serve only one specific purpose. In other words, one rainfall generator cannot be applied to analyze both flood and drought. We invented a multi-purpose rainfall generator that can be applied to analyze most water related problems. Hide

The research undertaken for this study have allowed for an accurate direct comparison of indigenous and introduced tree water-use. The measurements of trees growing in the understorey indicate significant water-use in the sub-canopy layer. The results showed that individual tree water-use is largely inter-species specific. The introduced species remain active during the dry winter periods resulting in their cumulative water-use being significantly greater than that of the indigenous species. Hide