<![CDATA[River basin protection in South Bali faces increasing pressures from development, urbanization, and tourism activities that threaten the sustainability of river ecosystems. Although Indonesia has established a legal framework through the 1945 Constitution of the Republic of Indonesia, Law Number 17 of 2019 concerning Water Resources, environmental protection regulations, and spatial planning law, river basin protection remains constrained by regulatory fragmentation, overlapping authority, and inconsistent spatial utilization. This study aims to analyze the legal construction of river basin protection from the perspectives of water resources, environmental, and spatial planning law; identify normative disharmony and implementation challenges in South Bali; and formulate a legal harmonization model based on an ecosystem-based governance approach. This study employs normative legal research using statutory, conceptual, and analytical approaches. The results indicate that these legal regimes provide a strong normative foundation but continue to operate sectorally, limiting optimal river protection. The proposed harmonization model emphasizes the integration of legal norms, river basin-based spatial planning, strengthened institutional coordination, effective oversight mechanisms, and meaningful public participation. An ecosystem-based approach is essential to balance economic development, legal certainty, and ecological sustainability in river areas, particularly amid the growing development pressures in South Bali.]]>
