Browsing by Author "Ramadhani, Mwalimu"

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    Investigating the effects of land use/cover change on the hydrology of upper Ruvu river basic
    (University of Dar es Salaam, 2008) Ramadhani, Mwalimu
    This research endeavored to determine the effect of land use/cover cover change between 1991 and 2000 and its impacts on the water resources particularly river flows by using hydrological model (SWAT). A case study is upper Ruvu sub catchment, upstream of gauging station 1H10 at Kidunda, which occupies an area of 5,780 km2. Remote sensing data (Land sat images) of 1991 and 2000 and DEM of 90m×90m resolution were used. ILWIS and Arc View GIS software were used to process the remote sensing data. Flow and climatic data were collected and processed. The SWAT model was at first calibrated and validated using the 1995 land use/cover map from IRA. The value of R2 during calibration was 48%. Findings show that there is decrease of forest land by 0.2%, decrease of range bushes land by 0.8%, a 3.6% increase in cultivation land and increased in range grasses by 1.5% from 1991 to 2000. The results from SWAT simulations using different land uses showed an increase in the average annual surface runoff or quick flow from 58.5 mm (34.8%), 60.2mm (36.8%) to 64.1 mm (38.3%) in 1991, 1995 and 2000 respectively. The base flow decreased from 110.4mm (65.3%), 107.2mm (63.2%) to 102.8mm (61.8%) in 1991, 1995 and 2000 respectively. However average annual river flow change from 168.9mm to 166.8mm in 1991 to 2000 respectively is insignificant. This entails that the increase of surface runoff (overland flow) and decrease of base flows are associated with land use change . These results show that the land use condition for 2000 which was used to simulate the flows has shown negative impact on water resources.