application of a physically based hydrological model on a semi-arid watershed in northern ghana
abstract
land degradation in semi-arid environments is increasing due to rapid population
growth, poor landuse practices and variable climate conditions. landuse planners
require a better understanding of the impact that proposed changes in landuse practices
have on a watershed’s hydrologic response when implementing policies and programs
designed to decrease the detrimental effects of land degradation. a physically based
hydrological model, r.hydro.casc2d, was used to illustrate the impact changes in
landuse practices have on the hydrologic response of a semi-arid watershed located in
northern ghana. the development of the required model input parameters using
geographical information systems and remote sensing technologies is described. a
sensitivity analysis on selected model inputs was conducted. the models output was
sensitive to all model input parameter tested, such as grid cell size, green and ampt soil
infiltration parameters and manning’s n values. two landuse scenarios were then
developed to illustrate the impact of implementing landuse practices that increase
vegetative ground cover. with increasing vegetative cover, peak discharges decreased
with an associated delayed time to peak discharge. in addition, total runoff volume
decreased as the level of vegetation increased, resulting in total volume of water
infiltrating.
collections
- retrospective theses [1604]