Browsing by Author "Matiko, Mwita"

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    ,land use and cover changes in Kihansi river catchment and its impact on river flow
    (University of Dar es Salaam, 2006) Matiko, Mwita
    Land-use change includes changes in both land cover and land use. Land –cover change describes differences in the area occupied by cover types for example forest, bushland, agriculture and grassland, through time. Land-use changes have direct impacts water resources. Downstream of Kihansi catchment, there are two major projects: hydropower production and ecological water demand. The kihansi catchment occupies an area of 582.5〖km〗^2. The research endeavored to determine the status of land use and land cover change between 1990 and 2002 and its impacts on the water resources particularly rainfall and river flows. Remote sensing data (Landsat TM5&7) OF 1990 and 2002 and DEM of 90 m resolution were used. IDRISI and ArcView GIS software were used to process the remote sensing data. KIhansi river flow and rainfall (20 years) data were collected and processed. The curve number method was used to link the impact of land use changes and water resources. Findings show that there is significant decrease of forest by 16.104%, 16.355% decrease of bushland with scattered cropland, a 100% decreased in grasses on the flood plain and grassland with scattered cropland increased by 122.256% from 1990 to 2002. The average river flow decreased from 3.41mm/day in 1990 to 2.45mm/day in 2002 while the average rainfall was 3.03mm and 3.80mm respectively. The results from curve number method showed an increase in the surface runoff from 4.58% to 6.92% in 1990 and 2002 respectively. This entails that the increase of surface runoff and decrease of river flows are associated with land use change. Therefore, the catchments should be managed integrally in a holistic manner.