Spatial and Temporal Influence of the Kebena River Corridor on Vegetation, Land Surface Temperature, and Built-Up Intensity in Addis Ababa, Ethiopia (2015–2026)

Urban river corridors play an important role in reducing urban heat and supporting vegetation, yet their environmental influence is still poorly understood in rapidly growing African cities. This study examined the spatial and temporal relationship between vegetation cover (NDVI), land surface temperature (LST), and built-up intensity (NDBI) along the Kebena River corridor in Addis Ababa, Ethiopia, using Landsat 8 and 9 imagery from 2015, 2018, 2022, and 2026. A buffer-based approach (0–250 m, 250–500 m, and 500–1000 m) was applied to evaluate how these indicators change with distance from the river. The results reveal a clear environmental gradient. The 0–250 m zone consistently showed higher vegetation cover, lower surface temperature, and lower built-up intensity compared with the outer zones. Pearson correlation analysis indicated a significant negative relationship between NDVI and LST (r = −0.49 to −0.64) and a strong negative relationship between NDVI and NDBI (r = −0.83 to −0.90), while NDBI and LST were positively correlated (r = 0.51 to 0.67). Regression analysis further showed that a 0.1 increase in NDVI reduced LST by approximately 2.7–3.9 °C. The river corridor continued to provide measurable cooling benefits, notwithstanding a slight reduction in vegetation cover over the study period. The lower built-up intensity near the river in 2026 is consistent with the timing and recorded activities of the recent Kebena River rehabilitation programme. These results indicate that conservation and restoration of urban river corridors can improve ecological resilience, mitigate the effects of urban heat and support the sustainability of green infrastructure in rapidly urbanising cities. This study offers evidence to guide conservation planning and long-term management of urban riparian ecosystems in Addis Ababa and other cities facing similar environmental pressures.