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

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. HIGHLIGHTS SWAT was calibrated and validated under varying LULC information.; Water balance components were correlated with multi-date LULC changes.; Substantial increases in cropland and built-up area, while a decrease in shrubs and forests in the area.; The declines in surface runoff and total water yield were reflected agricultural intensification, and vegetation removal.;

Keywords

• hydrological response
• lulc changes
• plsr model
• swat model