PEMETAAN KERAPATAN VEGETASI MENGGUNAKAN GOOGLE EARTH ENGINE DI DAERAH ALIRAN SUNGAI (DAS) WATUTELA PROVINSI SULAWESI TENGAH

Abstract

The Watutela Watershed plays an important role as a regulator of the hydrological system and ecosystem stability in Palu City and its surrounding areas. A reduction in vegetation cover within the watershed directly affects river water quality and the sustainability of the local environment. To support effective monitoring of vegetation changes, satellite-based remote sensing technology offers a practical solution. This study aims to map the spatial variation of vegetation density in the Watutela Watershed, Central Sulawesi Province. A remote sensing approach was employed using the Google Earth Engine (GEE) platform and ArcGIS 10.8, with vegetation density quantified using the Normalized Difference Vegetation Index (NDVI) algorithm. The results demonstrate considerable variability in vegetation density, ranging from non-vegetated and very sparse to dense vegetation classes. The watershed is predominantly characterized by dense vegetation, covering approximately 462.65 ha (49.64%), followed by very dense vegetation 367.49 ha (39.43%). These dominant classes are concentrated in the central and eastern regions, while moderately dense 101.96 ha (10.94%) and sparse vegetation 53.03 ha (5.69%) are more common in the western part of the watershed. The presence of low and sparse vegetation density indicates that land development for settlements has occurred in the downstream area of the watershed, and potentially increasing watershed vulnerability; therefore, adaptive watershed management planning should be emphasized. The classification results were also validated, yielding an accuracy of 85.7%, indicating that the NDVI classification method using Sentinel-2A imagery on the Google Earth Engine (GEE) platform is highly effective for mapping vegetation density in the Watutela Watershed.