Impact of Land use change on Tikurwuha river, Ethiopia

The Specific objective of this study is to asses impact of land use change on Tikur Wuha River located at Awassa Lake catchment. Hydrologic model, HEC-HMS model was used to asses¿ impact of land use change. Orthorectified Landsat MSS, TM and ETM+ images covering the study area was classified by supervised image classification using maximum likelihood classifier (MLC). The sample set for the classification was created using the combination of bands 7, 4, 2 (for Landsat TM and ETM+ images of year 1986 and 2000, 2005,) and bands 4, 2,1 (for Landsat MSS image of year 1973). Result of image classification showed 28.77% reduction in forest cover, 3.6% reduction in lake cover, 23.49% increase in agricultural land, 3.6% increase in swamp and 5.3% increase in grassland within the span of 32 years from 1973 to 2005. Hydrologic impact assessment indicated that with the land-cover changes that have occurred, there is a change on the catchment runoff. This study reveals that watersheds run off was lower by 5.79 % in period 1973, 0.27% in 1986 compared to period of 2005 as reference.