Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Identification of relationships between catchment-scale hydrologic response and landscape attributes

Auteur : Post, David Andrew

Université de soutenance : Australian National University

Grade : Doctor of Philosophy (1996)

Résumé partiel
The derivation of relationships between catchment-scale hydrologic response and landscape attributes allows the hydrologic response of an ungauged catchment to be predicted from its climate. Previous studies have generally made predictions for specific aspects of hydro logic response, such as flood frequencies or low flow statistics. The use of a rainfall-runoff model in the present study allows a prediction to be made of the daily streamflow of an ungauged catchment. Appropriate relationships also allow predictions to be made of the hydrologic impact of altering the vegetation cover through forestryrelated activities, for example. Previous studies have used a control catchment approach to provide estimates of the change in water yield on an annual basis, or a rainfall-runoff model to provide monthly estimates. The rainfall-runoff model used in the present study allows a prediction to be made of the change in daily streamflow due to fores try treatments. One case study examined in this thesis was concerned with deriving relationships between landscape attributes and turbidity for tributaries of the Murray River. Relationships were derived between landscape attributes and the turbidity of 6 tributaries and 61 subcatchments of the Murray River between Hume Reservoir and Swan Hill. The mean and 90th percentile of turbidity were found to be related to the percentage of the catchment under agriculture. These relationships appeared to be due to both an increase in the volume and rate of recession of surface runoff. The relationships were observed over a range of spatial scales, ranging from 100 to 15 000 km2. In the second case study, a lumped conceptual, rainfall-runoff model, IHACRES, was applied at a daily timestep to define the hydrologic response of 16 small (less than 1 km2 catchments in the Maroondah region of Victoria, Australia. Daily modelled streamflow was defined by 7 hydrologic response characteristics, and relationships were derived between : + The quickflow recession of streamflow and catchment drainage density. + The slowflow recession of streamflow and slope of the catchment lid. + The volumetric throughput of slowflow and percent runoff of the catchment. The maximum volume of the conceptual water store and the catchment vegetation . The peak of the unit hydro graph and catchment area . + The temperature modulation factor on the rate of catchment water loss, and the catchment gradient. + The parameter governing the rate of catchment water loss and the maximum volume of the conceptual water store.

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