Integrating biophysical and socio-institutional inventories to reduce sedimentation in the Limboto watershed, Indonesia

Abstract

This investigation sought to furnish a comprehensive bio-physical, hydrological, socioeconomic, and institutional inventory of the Limboto Watershed Area (DAS Limboto), specifically to forge a robust foundation for integrated management and the stabilization of Lake Limboto against relentless sedimentation. Operating through a Socio-Environmental Systems (SES) lens, this research masterfully synthesized remote sensing inputs, advanced GIS analytics, and granular social survey data. The empirical distillation reveals that DAS Limboto, sprawling over 89,385 hectares, possesses a characteristically elongated morphology (Rf 0.35; Re 0.46) coupled with a drainage density of 1.84 km/km², signaling an inherent predisposition towards moderate-to-severe surface runoff. Furthermore, the high mean annual precipitation 2.478 mm (with an 25,7 mm/days intensity) significantly amplifies erosion risk, particularly pronounced on slopes >25%. The alarming rate of forest loss (3.1% annually) directly translates into an annual sediment load of 1.2 million m3, catastrophically shallowing the lake to depths under 2.5 meters. Socially, this environmental stress is compounded by 365.000 individuals, a substantial population density of 408 jiwa/km² (supporting lives), and a severely fragmented institutional landscape that exacerbates degradation. These convergent findings compellingly argue for aggressive, cross-sectoral policy integration anchored by the "One Watershed, One Management Plan" directive, necessitating the immediate adoption of "evidence-based watershed management" drawing deeply from fused biophysical and social indicators to fortify conservation effectiveness. Ultimately, this study delivers a critical, empirical model for developing sustainable WSM strategies in Indonesia, positioning its results as the essential calculus for formulating adaptive policies resilient to ongoing climate change and anthropogenic strain.