Flow generating processes

This chapter starts with an overview of how climatic water deficits affect hydrological processes in different type of catchments. It then continues with a more comprehensive description of drought relevant processes. Two catchments in climatologically contrasting regions are used for illustrative purpose

Human influences

Human activities can cause drought, which was not previously reported (man-induced hydrological drought). Groundwater abstractions for domestic and industrial use are a well-known example of such an environmental chang

Influence of model structure on base flow estimation using BILAN FRIER and HBV-light models

Hydrological models are widely used tools to solve a broad range of hydrological issues. Each model has its own structure defining inter-relationships of hydrological balance components, and comparative differences in the models’ inner structure must be taken into account when discrepancies result from the same data. Results of base flow simulation by three different models BILAN, FRIER and HBV-light were compared based on knowledge of the models’ internal structure. It was proven that the courses of modelled parameters are quite similar, but that the respective values differ. The highest base flow values were simulated by the BILAN model, due to the threshold value of the soil moisture storage incorporated within this model’s structure. The lowest values were obtained by HBV-light model. Simulated base flow values were compared with groundwater heads and minimum monthly discharges. This comparison showed that the base flow values in the Nitra catchment at Nedožery profile simulated by BILAN and FRIER models are closer to the reality than those, simulated by HBV-light model

Human influences

Human activities can cause drought, which was not previously reported (man-induced hydrological drought). Groundwater abstractions for domestic and industrial use are a well-known example of such an environmental chang

Simulation of low flows and drought events in WATCH test basins: impact of climate forcing datasets

The impact of both spatial and temporal resolution on the components of the terrestrial hydrological cycle are investigated using the WATCH forcing dataset (WFD) and the JULES (Joint UK Land Environment Simulator) land surface model. The various spatial resolutions are achieved by degrading the native half degree latitude/longitude resolution WATCH dataset to both one degree and two degrees. The temporal resolutions are created by degrading the native three hourly WATCH forcing dataset to six hourly and using the WATCH interpolator to derive a one hour forcing dataset. There is little difference in the moisture stores of soil water and canopy water in the long term mean from the various resolutions, so the analysis presented is for the changes in evaporation and runoff. The evaporation is further analysed into its various components for the spatial resolution. Results suggest that there is little impact from spatial resolution, but the interpolation method for temporal resolution can have a significant effect on the total mean evaporation/runoff balance