Abstract:
Land use and land cover changes in Kulfo River watershed experiences a lot of human
disturbances due to agricultural expansion, and increasing urban demand for charcoal, fuel wood
and timber; resulting in forest and land degradation. This in turn altered the hydrologic responses
of the catchment. This study was conducted to assess the hydrological response of land use/cover
change on Kulfo River flows. In this study SWAT model was selected as it applies distributed
hydrologic model where various spatial parameters could be used and runoff is simulated at
required scale. Spatial data (land use, DEM and soil) and meteorological data were obtained
from USGS Satellite image, Ministries of Water Resources, Irrigation and Energy, National
Meteorology agency respectively. SWAT model was used to simulate stream-flow for land
use/land cover for the year 1985, 1995 and 2005 to determine the impact of land use/cover
change on Kulfo stream flow. Land use maps of 1985, 1995 and 2005 were derived from satellite
images processed using ERDAS Imagine 9.1 software. The model is calibrated and validated
using historical flow data. Land cover change analysis has shown an increment in the
proportional of the Agricultural land from 11.9% to 14.39%, Bare land from 25.8% to 14.14%,
Forest from 16% to 12.43%. Water body, remain stable, however, Shrub land increased from
29.28% to 36.82% in between 1985 to 2005. Sensitivity analysis has shown that the curve
number is the most sensitive parameter that affects the hydrology of the watershed. The models
were calibrated using flow data from the 1989 to 2001 and validate from 2002 to 2008. The R
2
and Nash- Sutcliffe Efficient (NSE) value for the watershed were 0.78 and 0.93 for calibration
and 0.80 and 0.78 for the validation respectively. It has been concluded that LULC highly
affected the runoff process in the watershed.
