Land use and land cover change dynamics and its impact on watershed hydrological parameters: the case of Awetu watershed, Ethiopia

Land use land cover (LULC) is the main driver for environmental change. The LULC has a direct or indirect impact on human life and the natural environment. This study aimed to analyze the temporal and spatial land use land cover change (LULCC) over the last 20 years, and evaluate its impact on the hydrological responses using the soil water assessment tool (SWAT) model in the Awetu watershed, Ethiopia. The LULC maps of the years 2001, 2013, and 2020 were derived from satellite images through the supervised classification with a maximum likelihood classifier. The accuracy of classification was checked using the error matrix which provided overall accuracy of 91.4%, 92.1%, and 95.4%, and Kappa coefficient of 87.7%, 89.5%, and 94.2% for 2001, 2013, and 2020 land maps, respectively. The LULCC analysis indicated that from the year 2001-2013, an urban area increased by 35.3%, and agricultural land increased by 13.5%. From 2013 to 2020, urban land increased by 100%. An increase in the agricultural area and urban land uses were mainly at the expense of grassland and forest land which had reduced by 57.1% and 23.7%, respectively, over the last 20 years. The SWAT model was calibrated and validated for streamflow with R-2 and NSE of 0.78 and 0.77 for calibration and 0.76 and 0.73 for validation. Then the model was applied to analyze the impact of LULCC on hydrological components. The study indicated that surface runoff and sediment yield increased while evapotranspiration and groundwater decreased. Analysis of the impact that LULCC has on the watershed can be used as an input into sustainable development and natural resource management. It ensures sustainable water resources for future use.

Automated summary

Land use land cover (LULC) is a significant driver of environmental change, impacting human life and the natural environment. This study analyzed the temporal and spatial changes in LULC over the past 20 years in the Awetu watershed, Ethiopia, and assessed its impact on hydrological responses using the SWAT model. The findings showed an increase in urban and agricultural areas at the expense of grassland and forest land, leading to increased surface runoff and sediment yield, and decreased evapotranspiration and groundwater.