Abstract:
Water is valued resource to be beneficially managed and management of water
resources most often deals with complex systems composed of many interconnected
parts. One of the challenges faced in contemporary water resources management is
land use and land cover changes hence, modeling the hydrology of watersheds is
required for effective watershed management strategy. This study was conducted to
assess land use/cover change of the catchment, land use maps of the study area were
derived from satellite images processed by GIS and ERDAS software for the year
1987, 1997 and 2007. SWAT model was used to simulate stream flow, to determine
the impact of LuLc change on this catchment stream flow. The LuLc change analysis
has shown that there is no significant change for land use such as water body, bare
land and forest land. For bush land, it shows a significant decreasing trend 39.58%,
31.92% and 24.25% for 1987, 1997 and 2007 years respectively. For cultivated land
there is an increasing trend , 10.77%,15.60% and 20.43.The same is true for
settlement showing 6.36%,9.10% and 11.85% for 1987,1997 and 2007 year.
Sensitivity analysis has shown that Gwqmn, Esco, Cn2, Sol_Awc, Ch_K2, Revapmn
are high sensitive parameters. The models were calibrated from 1980 to 1999 and
validated from2000 to 2008. The model performance criteria for calibration showed
that R
2
was found to be 0.742, Nash-Sutcliffe Coeff. 0.76. For the validation period
R
2
was found to be 0.793, Nash-Sutcliffe Coeff. 0.87, which show good performance
of the model. The mean annual surface flow for 2007 land cover was increased by
28% than that of 1987 land cover. Similarly the 1997 land cover mean annual surface
flow was increased by 9% than that 1987 land cover. These land use changes did
result in significant changes in stream flow. This emphasizes the need for assessment
of the impact of land use/land cover on the catchment system and hydrological
parameter. Therefore, it is highly compulsory to launch a good system of both
hydrological and meteorological information systems.
