The effect of preferential flow on the stability of landslides is studied through numerical simulation of two types of rainfall events on a hypothetical hillslope. A model is developed that consists of two parts. The first part is a model for combined saturated/unsaturated subsurface flow and is used to compute the spatial and temporal water pressure response to rainfall. Preferential flow is simulated with a dual-permeability continuum model consisting of a matrix/preferential flow domain.

The paper presents an integrated approach to monitoring root water uptake and link this information to the plant transpiration measured by sap flow and eddy covariance. The monitoring of soil conditions is achieved using 3-D electrical resistivity tomography. This ensemble of data can be used jointly to model the soil-plant interactions and identify the extent and efficiency of the root zone in front of existing irrigation schemes. A case study is presented regarding an orange orchard in Sicily.

Variability of rainfall in the Nile Basin was found linked to the large-scale atmosphere-ocean interactions. This finding is vital for a number of water management and planning aspects. To give just one example, it may help in obtaining improved quantiles for flood or drought/water scarcity risk management. This is especially important under conditions of (1) questionable data quality, and (2) data scarcity. These conditions are typical of the Nile Basin and inevitably need to be addressed.

This work presents, to our best knowledge, the first pan-European assessment of the future hydro-meteorological hazard based on an ensemble of the new EURO-CORDEX regional climate scenarios. We propose a novel approach, which shows how the change in the frequency of future floods in Europe is likely to have a larger impact on the overall flood hazard as compared to the change in their magnitude. A consistent method is proposed to evaluate the agreement of ensemble projections.

This paper quantitatively analyzed the evolution of human-water relationships in the Heihe River basin over the past 2000 years by reconstructing the catchment water balance. The results provided the basis for investigating the impacts of human societies on hydrological systems. The evolutionary processes of human-water relationships can be divided into four stages: predevelopment, take-off, acceleration, and rebalancing. And the transition of the human-water relationship had no fixed pattern.

This study aimed at reducing structural uncertainty in the conceptual modelling of a semi-arid Andean catchment. A multiple-hypothesis framework was combined with a multi-criteria assessment scheme to characterize both model non-uniqueness and model inadequacy. This led to retaining eight model structures as a representation of the minimum structural uncertainty that could be obtained with this modelling framework.

There is a good agreement between the MODIS snow products and observations from automatic stations and Landsat snow maps in the Pyrenees. The optimal thresholds for which a MODIS pixel is marked as snow-covered are 40mm in water equivalent and 150mm in snow depth. We generate a gap-filled snow cover climatology for the Pyrenees. We compute the mean snow cover duration by elevation and aspect classes. We show anomalous snow patterns in 2012 and consequences on hydropower production.

The English Lowlands is a heavily populated, water-stressed region, which is vulnerable to long droughts typically associated with dry winters. We conduct a long-term (1910-present) quantitative analysis of precipitation, flow and groundwater droughts for the region, and then review potential climatic drivers. No single driver is dominant, but we demonstrate a physical link between La Nina conditions, winter rainfall and long droughts in the region.

Current hydrological change detection methods are subject to a host of limitations. This paper develops a new method, temporally shifting variograms (TSVs), which characterises variability in the river flow regime using several parameters, changes in which can then be attributed to precipitation characteristics. We demonstrate the use of the method through application to 94 UK catchments, showing that periods of extremes as well as more subtle changes can be detected.

This study explores how catchment heterogeneity and variability can be summarized in simplified models, representing the dominant hydrological processes. We apply simple dynamical system approach (Kirchner, 2009) in the Ardèche catchment (south-east France). The simple dynamical system hypothesis works especially well in wet conditions (peaks and recessions are well modelled) and for granite catchments, which are likely to be characterized by shallow subsurface flow.

Changes in climate and land cover are known to warm streams by altering surface heat fluxes. However, the influence of these disturbances on shallow groundwater temperature are not as well understood. In small streams, groundwater discharge may also exert a control on stream temperature, and thus groundwater warming may eventually produce additional stream warming not considered in most existing models. This study investigates these processes and suggests stream temperature model improvements.

The EU Water Framework Directive requires rivers to be of good chemical and ecological quality. Chemical quality is assessed by sampling and analysing the water. Normal sampling regimes might involve taking a sample monthly or weekly. This paper uses high-frequency data from rivers to assess how accurate these regimes are at assessing the true chemical quality. Weekly sampling was more accurate than monthly, but there were still large uncertainties. We suggest ways to improve sampling accuracy.

The 3rd paper in a series dealing with evaporation over indigenous vegetation in an area of South Africa experiencing severe water challenges. The area is a World Heritage site and an important conservation area in which our understanding of the water balance plays a crucial role in system management. We provide the fist estimates of total evaporation from a subtropical peat swamp forest, investigate measurement techniques and provide modelling solutions to estimate long-term evaporation.