Carrying Capacity Assessment of the Wai Samal and Wai Eti Watersheds on Seram Island, Maluku Province

Abstract

This study aims to assess the carrying capacity of the Wai Samal and Wai Eti watersheds on Seram Island, Maluku Province, Indonesia, using an integrated multi-criteria approach adapted to small island conditions. A quantitative method was employed using GIS-based land-unit analysis derived from the overlay of topographic, geological, soil, and land-use maps, supported by 31 years of rainfall, hydrological, and socio-economic data. The assessment followed the Indonesian National Watershed Monitoring and Evaluation Framework (Ministerial Regulation No. P.61/Menhut-II/2014), integrating biophysical, hydrological, socio-economic, institutional, water infrastructure, and spatial planning indicators. The results showed that the Wai Samal Watershed achieved a carrying capacity index (DDD) of 78.75 (Good), whereas the Wai Eti Watershed obtained 93.25 (Moderate). The higher carrying capacity of the Wai Samal Watershed was associated with lower critical land extent, lower erosion and flood risk, lower water-use pressure, higher land availability, and stronger institutional performance. In contrast, the Wai Eti Watershed experienced greater environmental and socio-economic pressures, characterized by higher critical land extent, greater land degradation, and less favorable spatial land-use conditions, resulting in lower watershed resilience. These findings demonstrate that the integrated indicator-based assessment provides a scientific basis for identifying watershed-specific management priorities and supports adaptive watershed management and evidence-based spatial planning to enhance long-term sustainability in small island watersheds.