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Accueil du site → Master → Royaume Uni → Factors influencing runoff generation, and estimates of runoff in a semi-arid area, S. E. Spain

University of Leeds (2011)

Factors influencing runoff generation, and estimates of runoff in a semi-arid area, S. E. Spain

Dalen, E. N

Titre : Factors influencing runoff generation, and estimates of runoff in a semi-arid area, S. E. Spain

Auteur : Dalen, E. N

Université de soutenance : University of Leeds

Grade : M.Phil. 2011

Résumé
The aim of this work was to test and evaluate the concept of Hydrologically Similar Surfaces (HYSS), which provide a categorisation of catchment response to rainfall and which can be used to improve the limited understanding of surface runoff generation from semi-arid catchments. The HYSS concept was tested with particular reference to medium-scale (100-200 km2) catchments in S E Spain. Field campaigns for this project focussed on intensive infiltration measurements within two catchments, Rambla Nogalte and Rambla de Torrealvilla in the provinces of Murcia and Almeria. These infiltration data were analysed within the framework of the Green-Ampt infiltration equation. The methodology adopted was to classify the study catchments into HYSS, which are defined as areas with similar 1-D (vertical) partitioning of net rainfall between infiltration and surface runoff. Similar areas were identified from physical characteristics of lithology, cultivation and soils, taken from field survey, DEM and RS images, as a basis for stratifying infiltration measurements. In successive field campaigns, areas were lumped together to minimise variability within each HYSS and maximise the variability between HYSS. The HYSS were then used as the basis for further measurements of infiltration rates to refine the categorisation. The visual physical characteristics of the final HYSS were then used to map HYSS across the area of Rambla Nogalte, and each of the final five HYSS had a statistical distribution of infiltration rate parameters associated with it. This evaluation of the HYSS concept demonstrated that, for these catchments, a small number of statistically different HYSS provided the best representation of the catchments response to rainfall. The high variability of the infiltration rates within each HYSS clearly indicated that the dataset did not statistically support the finer set of HYSS categorisation that was initially hypothesised on the basis of field-based and remotely sensed characteristics

Accès au document : Proquest Dissertations & Theses

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