APPLICATION OF THE SOIL WATER ASSESSMENT TOOL (SWAT) USING REMOTE SENSED DATA ON THE KABOMPO RIVER BASIN, ZAMBIA

Abstract

A river basin-scale hydrological model of the Kabompo river basin located in the north-west of Zambia was developed using remote sensed data to address key water resources management problems of water allocation to agriculture and ecosystems, effects of land-cover change on the flow regime and potential impacts from mine tailing dams. Because of paucity of observed data in the Kabompo basin, the model primarily depended on remote sensing datasets for calibration and validation. Methodology included the use of a semi-distributed; ArcGIS based Soil Water Assessment Tool (SWAT) software for hydrological modeling. The Kabompo basin was discretized into 177 sub-basins with a total of 1004 hydrological response units. Remote sensing data sets that included weather data, drainage network and slopes, landuse/ land cover and soils were used to create a database for the sub basins using ArcGIS. The simulated flow from the SWAT model was calibrated with ESA ERS-2 and ENVISAT radar altimetry river stage data. The model’s results showed good correlation with observed data giving a Nash Sutcliffe coefficient of 0.87 and an R² value of 0.93, after calibration. The simulation results obtained from the model can be used in a number of water resources management activities like water rights, water allocation, and flood warning. It’s also able to simulate long term data of a wider area including inaccessible locations which makes it to be more convenient than conventional hydrological techniques. Hence it is concluded that remote sensing is a useful tool for hydrological modeling in the generation of hydrological data where it is lacking or in ungauged and inaccessible areas. Its wide use in a country like Zambia would greatly improve water resources management.