Global Change Research and Monitoring in the Maloti-Drakensberg Mountain System (South Africa-Lesotho)
Byron Gray – South African Earth Observation Network
Byron Gray – University of KwaZulu-Natal
Michele Toucher – South African Earth Observation Network
Alistair Clulow – University of KwaZulu-Natal
Martin Savage – University of KwaZulu-Natal
Two of the main drivers of environmental change are climate change and land use/cover change (LUCC). The hydrological response of a catchment is dependent, inter alia, upon the land cover of the catchment, and is sensitive to changes thereof, as any changes in land cover alter the partitioning of precipitation into various pathways such as infiltration, total evaporation, surface/near-surface runoff or groundwater recharge. Gaining an understanding of how hydrological processes respond to different land cover changes, will aid in improving our understanding of how hydrological processes may respond to future change. The understanding gained is an important step towards improving water resource management in the future, especially in strategic water source areas such as high-altitude mountainous catchments, which are highly sensitive to environmental change. Considered as the water towers of South Africa, the Drakensberg mountains are an important area for generating the water resources for both Gauteng and KwaZulu-Natal. Located within the uKhahlamba Drakensberg Park, are the intensively monitored Cathedral Peak research catchments, with valuable long-term monitoring datasets dating back to the 1950s. Three Cathedral Peak catchments, with diverse land covers, were identified for intensive hydroclimatological monitoring; these are a pristine grassland catchment, a woody encroached catchment and a heavily degraded catchment. The main components of the water balance (rainfall, total evaporation, soil moisture and streamflow), were monitored. The partitioning of the rainfall component into the other three components was compared across the different LUCC conditions. Despite a relatively similar rainfall amount and pattern, the streamflows in the woody encroached catchment are lower than the pristine grassland. Whereas the heavily degraded catchment has a different flow pattern to the other catchments and the relationship with rainfall does not follow the pattern of the pristine catchment. Total evaporation was also higher in the woody encroached and heavily degraded landscapes.