Effects of land use/land cover change on hydrological responses of a watershed in the Central Rift Valley of Ethiopia

Abstract

Abstract The purpose of this study is to evaluate the impacts of LULC changes on the hydrological components of a watershed using multivariate statistics, and hydrological modeling approaches. The study analyzed the LULC distributions, and changes corresponding to the years 2000, 2010, and 2020. The SWAT model was then applied to assess the hydrological impacts of these changes in the studied watershed. Finally, changes in LULC types were correlated with the water balance components using a Partial Least Squares Regression (PLSR) method. The result showed a continuous expansion of barren, built-up, and cropland areas, while forests, shrubs, and grassland decreased by about 67.12, 41, and 36.88%, respectively. The modeling result showed that surface runoff, water yield, and evapotranspiration decreased by 16.1, 2.9, and 9.3%, respectively. In contrast, base flow, soil water storage, and lateral flow of the watershed increased by up to 19.1%, 55.9%, and 150.4%, respectively, due to LULC changes. The PLSR model identified the cropland, forest, and shrub LULC types as the major factors affecting the water resource components. The study results provide useful information for policymakers and planners in the implementation of sustainable water resource planning and management in the context of environmental change.