Thesis (MA (Geography and Environmental Studies))--University of Stellenbosch, 2005. / River basins have long been attracting human settlement and development, promising water and fertile lands (Newson 1992). The Bot River Catchment on the southern coast of South Africa is no exception. However, much of the development in this catchment has not been controlled and its land and water resources are being abused. This is affecting the water quality and quantity of the river system and estuary at an alarming rate. In this thesis, the ‘reference’ land cover in the Bot River Catchment is recreated. This term is used to describe “the hydrological state of the catchment as it was when completely covered in natural vegetation, thus before it was impacted by humans” (Jacobs & Bruwer 2002:12). A rainfall-runoff model is employed to investigate the effects of various land covers on the catchment’s runoff quantity, by comparing the simulation results of the catchment’s reference and current state. The results of the model point to a large reduction in runoff since the reference state of the catchment. As the rainfall-runoff model applied did not allow for modelling of the annual agriculture that dominates the catchment, the runoff reduction was attributed to the smaller areas of perennial agriculture, forestry and alien vegetation infestation. The simulation results confirmed the threat of current land use practices on the environmental integrity of the Bot River Catchment. A transition to agricultural practices that are more suited to the climate is suggested and the eradication of alien vegetation should be seen as a priority. Most importantly, a holistic approach should be taken towards the management of the Bot River Catchment. The altered hydrodynamic regime of the Bot River Estuary is symptomatic of misuse of the entire catchment. As ongoing demographic and land use pressures create a new generation of water management problems (Department of Water Affairs & Forestry 1993), a deeper understanding of the relationships between the different components in the Bot River Catchment becomes increasingly urgent.

Cape Town, South Africa, falls within a winter rainfall region, making it difficult to assess the feasibility of rain- and stormwater harvesting. The reason for this is because the region’s high water demand period coincides with the low rainfall summer season, thereby limiting the availability of this alternative water resource when most needed. During this study, rainwater harvesting for toilet flushing purposes, collected from roof surfaces, was practically assessed by means of inserted flow meters at a pilot study site in Kommetjie, Cape Town. The combined and single system roof- and land surface runoff yields and savings of commercial buildings within the Kommetjie business area, were also theoretically assessed by making use of a mathematical roof- and land surface runoff model specifically developed during this study. The statistical testing of the hypotheses statements relating to the pre- and post-harvesting savings at the pilot study building, compared against the average actual municipal water usage, were performed. Hypotheses testing were also performed in order to compare the theoretical rain- and stormwater runoff yields for the commercial business area against the average actual municipal water consumption. The conclusions drawn from this study indicated that valuable potable water, as well as related financial savings, can be achieved within a winter rainfall region, thereby making rain- and stormwater harvesting a feasible option for commercial businesses in Cape Town. / Environmental Sciences / M.Sc. (Environmental Management)

Cape Town, South Africa, falls within a winter rainfall region, making it difficult to assess the feasibility of rain- and stormwater harvesting. The reason for this is because the region’s high water demand period coincides with the low rainfall summer season, thereby limiting the availability of this alternative water resource when most needed. During this study, rainwater harvesting for toilet flushing purposes, collected from roof surfaces, was practically assessed by means of inserted flow meters at a pilot study site in Kommetjie, Cape Town. The combined and single system roof- and land surface runoff yields and savings of commercial buildings within the Kommetjie business area, were also theoretically assessed by making use of a mathematical roof- and land surface runoff model specifically developed during this study. The statistical testing of the hypotheses statements relating to the pre- and post-harvesting savings at the pilot study building, compared against the average actual municipal water usage, were performed. Hypotheses testing were also performed in order to compare the theoretical rain- and stormwater runoff yields for the commercial business area against the average actual municipal water consumption. The conclusions drawn from this study indicated that valuable potable water, as well as related financial savings, can be achieved within a winter rainfall region, thereby making rain- and stormwater harvesting a feasible option for commercial businesses in Cape Town. / Environmental Sciences / M.Sc. (Environmental Management)