Danu Kerthi as a Hindu theo-ecological practice in conservation of water resources

Background: This study examines Danu Kerthi as a Hindu theo-ecological practice for water resource protection at Lake Batur, Bali. It employed a qualitative approach using a focused ethnographic design conducted from January to March 2026, covering the periods before, during, and after Tumpek Uye. Methods: Data were collected through participant observation, in-depth interviews with 30 informants consisting of customary leaders and community members involved in the tradition, informal conversations, documentation, and a review of scientific publications and policy documents. The data were thematically analyzed across theological, ethical-ecological, and practical dimensions. Findings: The findings demonstrate that Danu Kerthi has been practiced for generations, long before the enactment of Bali Governor Regulation No. 24 of 2020. The tradition shapes the identity of the Batur community as guardians of the lake and centres on the worship of Dewi Danu, locally experienced as Bhatari Batur. The local cosmology reveals a strong feminine dimension in which water is understood both as the source of life and as a manifestation of divine presence. Nevertheless, the study identifies a theo-ecological paradox between the symbolic sacredness of the lake and its material condition. Floating and submerged waste, declining water clarity, odour, nutrient pollution, pressure from floating net cages, agricultural runoff, domestic wastewater, recurrent fish mortality, and invasive species indicate that Lake Batur remains productive but is ecologically degraded and increasingly vulnerable. Conclusion: The study concludes that Danu Kerthi can function as a comprehensive theo-ecological practice only when its niskala dimension is translated into sakala actions, including pollution control, use restrictions based on ecological carrying capacity, stronger customary regulations, regular water-quality monitoring, and ecosystem restoration. Novelty/Originality of this article: Thus, the sacredness of water should not only be ritually affirmed but also demonstrated through the ecological integrity and long-term sustainability of Lake Batur.