Mitigating Urban Heat Island Effects via Spatial Planning Integration and Optimization of Urban Green Spaces and Built-up Density in Southeast Sulawesi

Abstract

Rising surface temperatures due to the Urban Heat Island (UHI) phenomenon have become a critical environmental challenge in Kendari and Baubau Cities, Southeast Sulawesi, driven by rapid urbanization, reduced Green Open Space (GOS), and unregulated building density. This study aimed to analyse the dominant factors influencing UHI, evaluate the gaps in spatial planning policies, and develop context-specific mitigation strategies. Using a mixed-method approach combining spatial analysis (NDVI, NDBI, LST), policy document review, and SWOT analysis, the research revealed distinct determinants: in Kendari, vegetation density played a key role in cooling, whereas in Baubau, built-up density was the dominant warming factor. Existing spatial policies were found to be normative and ineffective, with GOS coverage reaching only 11.81% in Kendari and 12.3% in Baubau, poorly distributed, and with weak enforcement of building density regulations. The study concludes that evidence-based, differentiated strategies are essential; Kendari requires the redistribution of GOS and the expansion of functional green space, while Baubau needs strict control of Floor Area Ratio (FAR) and building density. Recommendations include integrating spatial indicators into policy, strengthening legal instruments, and fostering multi-stakeholder collaboration to achieve sustainable, climate-resilient urban development.