The topic of thesis deals with a hydrological model SWAT used for impact assessment of landscape structure on surface water pollution in Krivoklatsko protected area. For this purpose using ArcSWAT in the ArcGIS environment there were built hydrological models of three watersheds of various landscape structure located in the area of interest. The measured data of nitrate were used for these models. Concentration of nitrates in the surface waters were simulated by using these models in the period from 2003 until mid-2014. The statistical evaluation of the models including actual landscape structure did not show satisfactory match of the simulated values with the measured values. Due to the uncertainties of the model, including insufficient quantity of measured nitrates, it was not possible to expect exact results. After validation of basic models, it was important to create new models that would include various scenarios of landscape structure organization. New versions represented changes in the use of land classified as arable land in pasture or mixed forests, in the area around the stream to 250 m and 500 m. Modelling of the impact of individual scenarios on the structure of the landscape structure on nitrate concentrations there was displayed a positive effect of grassing and afforestation of...

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.