The research study on testing the capability of HYPE model to simulate streamflow, nitrogen and phosphorus was motivated by the inclusion of in-stream processes of transport and dynamics of nutrients in the routing functions of the model. Results indicate that high streamflow events were represented well, with a general over-simulation of low flows. These findings are consistent with observations of spatial and seasonal distribution of nutrients in the catchment.

Catchment response can be influenced by man’s activities as well as natural forces like climate, and understanding how stream flow is affected by such activities is important in a changing world, particularly in developing countries. Data for the Bani River in Africa show a steady decrease in the groundwater component of stream flow. This paper shows that the decrease appears to be driven by increased water use in the catchment, and has resulted in the river ceasing to flow in the dry season.

The 3rd paper in a series dealing with evaporation over indigenous vegetation in an area of South Africa experiencing severe water challenges. The area is a World Heritage site and an important conservation area in which our understanding of the water balance plays a crucial role in system management. We provide the fist estimates of total evaporation from a subtropical peat swamp forest, investigate measurement techniques and provide modelling solutions to estimate long-term evaporation.

We studied long-term daily records of rainfall and streamflow of the Incomati River basin in southern Africa. We used statistical analysis and the Indicators of Hydrologic Alteration tool to describe the spatial and temporal variability flow regime. We found significant declining trends in October flows, and low flow indicators; however, no significant trend was found in rainfall. Land use and flow regulation are larger drivers of temporal changes in streamflow than climatic forces in the basin.