Geospatial Based Assessment Of Land Use Land Cover Change Around Lake Dembel, Oromia, Ethiopia

Abstract

This study presents a geospatial-based assessment of Land Use Land Cover (LULC) changes around Lake Dembel, Oromia, Ethiopia, over a 20-year period from 2004 to 2024. The analysis aimed to quantify LULC changes, assess land surface temperature (LST) dynamics, and explore their implications for ecosystem health. Landsat satellite imagery for the years 2004 (Landsat 5 TM), 2014 (Landsat 8 OLI/TIRS), and 2024 (Landsat 8 OLI/TIRS) was used. The Maximum Likelihood Classification (MLC) algorithm was employed for supervised classification, supported by ground truth data and high-resolution Google Earth imagery. Accuracy assessment for the 2024 classification achieved an overall accuracy of 89.5% and a Kappa coefficient of 0.88, indicating strong agreement between classified and actual land cover types.The study revealed significant LULC transformations. Built-up areas expanded from 4.37% in 2004 to 12.68% in 2024, a net increase of 8.31%, driven by rapid urbanization around Batu and nearby settlements. Farmland increased from 12.14% to 15.5%, while vegetation cover sharply declined from 15.87% to 6.24%, equivalent to a loss of approximately 62.89 km². Water body coverage decreased from 67.6% (441.21 km²) to 65.68% (428.11 km²), amounting to a 13.1 km² loss, largely due to sedimentation, agricultural water abstraction, and declining inflow.The environmental consequences were assessed through LST analysis, derived from thermal bands of Landsat data using radiometric and emissivity corrections. The results indicated a consistent increase in LST from 17.2°C in 2004 to 23.1°C in 2024, with an average annual increase of 0.3°C. Spatial correlation analysis showed a strong negative relationship between LST and NDVI (R² = 0.85 to 0.88), confirming that vegetation loss contributed to surface heating. Similarly, a strong positive correlation was observed between LST and NDBI (R² = 0.84 to 0.89), highlighting the heat-retaining effects of expanding built-up areas.The findings serve as a scientific basis for policymakers, planners, and local stakeholders in developing sustainable land and water management interventions within the Rift Valley region.