Hydrological responses to human-induced land use/land cover changes in the Gidabo River basin, Ethiopia

Land-use/land-cover (LULC) changes in the Gidabo basin, Rift Valley, Ethiopia, have greatly affected the hydrology of the basin. This study integrates hydrological modelling with statistical analysis to evaluate the hydrological response of LULC changes during the period 1988-2018. Using the Soil and Water Assessment Tool (SWAT) and partial least squares regression (PLSR) models, the influences of individual LULC changes on different components of the hydrological cycle are assessed. The results of the Mann-Kendall test showed no significant trends in annual rainfall over the basin at the 95% significance level. Change in LULC resulted in an increase in annual mean surface runoff by 23.6 mm during the period 1988-2018. Meanwhile, the annual mean baseflow, lateral flow, percolation and evapotranspiration (ET) were reduced by 9.1, 4.2, 10.2 and 12.2 mm, respectively. PLSR analysis indicated that cultivated land affected the lateral flow and ET negatively in contrast to agroforestry and grassland, which had a positive influence.