Determining Optimal NDWI and MNDWI Thresholds for Mapping Cape Lowland Freshwater Wetlands within the Cape Town Metropolitan Area Using Remote Sensing and Cloud-Based Analysisb - By Odirile Mamba

This study assesses the use of Sentinel-2 imagery and cloud-based remote sensing on Google Earth Engine to map the extent of Cape Lowland Freshwater Wetlands in Cape Town, a critically endangered ecosystem. By testing NDWI and MNDWI thresholds, it found −0.3 and −0.4 to be optimal for dry and wet seasons respectively, with the best accuracy at 85%. Limited seasonal variation in wetland extent suggests potential ecosystem degradation. The research supports scalable wetland monitoring and contributes to conservation efforts aligned with South Africa’s national inventory goals and the SDGs.