Facts about the International Association of Hydrological Sciences

ABSTRACT

Despite several studies of spatial and temporal variation in water temperature characteristics, few investigations of longer-term water temperature behaviour in Britain rivers have been undertaken. This paper reports the results from a 10-year study of river water temperatures at three monitoring stations on the River Exe, Devon, UK. Data concerning annual statistics, seasonal regime, diurnal variation, duration characteristics and accumulated temperature are analysed and reveal essentially stable water temperature behaviour over the decade 1974–1983. Contrasts between monitoring stations are also evident and reflect the effects of regional and more local controls as well as the influence of hydrological factors. In spite of these differences, water temperature behaviour is largely synchronous across this river system.     

Adaptation of water resources systems to changing society and environment: a statement by the International Association of Hydrological Sciences

ABSTRACT

We explore how to address the challenges of adaptation of water resources systems under changing conditions by supporting flexible, resilient and low-regret solutions, coupled with on-going monitoring and evaluation. This will require improved understanding of the linkages between biophysical and social aspects in order to better anticipate the possible future co-evolution of water systems and society. We also present a call to enhance the dialogue and foster the actions of governments, the international scientific community, research funding agencies and additional stakeholders in order to develop effective solutions to support water resources systems adaptation. Finally, we call the scientific community to a renewed and unified effort to deliver an innovative message to stakeholders. Water science is essential to resolve the water crisis, but the effectiveness of solutions depends, inter alia, on the capability of scientists to deliver a new, coherent and technical vision for the future development of water systems.

EDITOR D. Koutsoyiannis; ASSOCIATE EDITOR not assigned     

Adaptation of water resources systems to changing society and environment: a statement by the International Association of Hydrological Sciences

ABSTRACT

We explore how to address the challenges of adaptation of water resources systems under changing conditions by supporting flexible, resilient and low-regret solutions, coupled with on-going monitoring and evaluation. This will require improved understanding of the linkages between biophysical and social aspects in order to better anticipate the possible future co-evolution of water systems and society. We also present a call to enhance the dialogue and foster the actions of governments, the international scientific community, research funding agencies and additional stakeholders in order to develop effective solutions to support water resources systems adaptation. Finally, we call the scientific community to a renewed and unified effort to deliver an innovative message to stakeholders. Water science is essential to resolve the water crisis, but the effectiveness of solutions depends, inter alia, on the capability of scientists to deliver a new, coherent and technical vision for the future development of water systems.

EDITOR D. Koutsoyiannis; ASSOCIATE EDITOR not assigned     

Hydrological Sciences Journal Contents 2002

Abstract

Flood frequency estimation is crucial in both engineering practice and hydrological research. Regional analysis of flood peak discharges is used for more accurate estimates of flood quantiles in ungauged or poorly gauged catchments. This is based on the identification of homogeneous zones, where the probability distribution of annual maximum peak flows is invariant, except for a scale factor represented by an index flood. The numerous applications of this method have highlighted obtaining accurate estimates of index flood as a critical step, especially in ungauged or poorly gauged sections, where direct estimation by sample mean of annual flood series (AFS) is not possible, or inaccurate. Therein indirect methods have to be used. Most indirect methods are based upon empirical relationships that link index flood to hydrological, climatological and morphological catchment characteristics, developed by means of multi-regression analysis, or simplified lumped representation of rainfall–runoff processes. The limits of these approaches are increasingly evident as the size and spatial variability of the catchment increases. In these cases, the use of a spatially-distributed, physically-based hydrological model, and time continuous simulation of discharge can improve estimation of the index flood. This work presents an application of the FEST-WB model for the reconstruction of 29 years of hourly streamflows for an Alpine snow-fed catchment in northern Italy, to be used for index flood estimation. To extend the length of the simulated discharge time series, meteorological forcings given by daily precipitation and temperature at ground automatic weather stations are disaggregated hourly, and then fed to FEST-WB. The accuracy of the method in estimating index flood depending upon length of the simulated series is discussed, and suggestions for use of the methodology provided.

Editor D. Koutsoyiannis     

Hydrological Sciences Journal Contents 1997

Résumé

Nous examinons ici le phénomène très complexe de l'érosion hydrique de bassins versants. L'approche adoptée consiste d'une part à quantifier l'érosion à plusieurs échelles spatiales, au sens de la méthode Wischmeier, de la simulation de pluies sur 1 et 87 m², de micro-bassins expérimentaux, de retenues collinaires et d'un barrage en exploitation, et d'autre part à rechercher un modèle régressif pouvant expliquer la relation débit solide-débit liquide pour les différentes formes d'érosion. Une zone de marnes du bassin de la Mina en Algérie, productive en sédiments pour un barrage en aval et représentant le cinquième de la surface, a constitué la zone expérimentale. Les résultats montrent que, vu la complexité des facteurs mis enjeu, il est quasiment impossible d'extrapoler à différentes échelles. Le modèle puissance caractérise la relation débit solide-débit liquide, quelle que soit l'échelle spatiale considérée.     

Hydrological Sciences Journal Countents 1994

Abstract

Since eroded sediments are produced from different sources distributed throughout a basin, sediment delivery processes at basin scale have to be modelled by a spatially distributed approach. In this paper a new theoretically based relationship is proposed for evaluating the sediment delivery ratio, SDR_i, of each morphological unit, i, into which a basin is divided. Then, using the sediment balance equation written for the basin outlet, a relationship between the basin sediment delivery ratio, SDR_W and the SDR_i is deduced. This relationship is shown to be independent of the soil erosion model used. Finally, a morphological criterion for estimating a coefficient, β, is proposed.