Physiographic and topographic changes in Luvuvhu River Catchment are negatively impacting on the catchment hydrology of the area. A study was carried out to extract and analyze the morphologic and hydrologic properties using GIS techniques. Digital Elevation Modeling hydro-processing procedures were used within an ArcGIS environment where Arc hydro tools were used to extract and show the spatial distribution of the properties. A hydrologically correct Digital Elevation Modeling (DEM) was generated and used to obtain primary and derived terrain elements. The results showed the automated delineation of sub-catchments and the spatial distribution of morphometric and hydrologic properties. The analysis showed how the physiographic changes were impacting on the river regimes and water resources.

Climate change poses a great risk to natural resources and agriculture in the Luvuvhu River Catchment. The catchment has experienced floods resulting from higher than normal rainfall associated with the Intertropical Convergence Zone and cyclones, which have caused enormous damage to property and impacted negatively on fauna and flora and human livelihoods. In order to understand the dynamics involved in the effects of climate change in the catchment, annual maximum flow data was used to evaluate flood frequencies. The distribution models used in the study included the Generalized Extreme Value distributions, the Gumbel Extreme Value type I distribution, the Log-normal distribution and the Log Pearson type III distribution. The extreme value analysis showed that the Log-normal and Log-Pearson type III distributions provided the best fit, which could be used to derive the probability of occurrence of flood events. The results showed a general increase in the frequency of extreme events, accompanied by floods of higher magnitude.