Thesis (MA (Geography and Environmental Studies))--University of Stellenbosch, 2009. / Agricultural production has become vital to the Sandveld, of which Verlorenvlei is a part, in terms of both economic growth and food security. It is well documented as an area under threat of severe natural resource depletion if it is not well managed with sustainability in mind. Agricultural production, other human-driven development and the survival of the local ecosystems compete for the limited water resources. This study uses the SWAT hydrological model to simulate the transport of water through the catchment area. ArcSWAT, a third-party software extension to ArcGIS, is used as an interface between ArcGIS and the SWAT model. Spatial data (DEM, soil and landuse) is used in the preprocessing phase and fed into the SWAT model through the interface. Daily climate data were sourced and prepared according to the SWAT model’s input requirements. Considerable effort was required to fill temporal and spatial gaps in available climate data, and to infer certain unmeasured climate variables from other measurements (e.g. infer solar radiation from daylight hours, time of the year and latitude). The SWAT hydrological model was then run. The model results compared favourably to measured flow data. The study recommends building on from this first step using the SWAT hydrological model to simulate future land use scenarios for the catchment area.