 This study evaluated the performance of the newly available Sentinel-2A multispectral instrument, MSI, imagery for mapping water bodies. The study used the Normalized Difference Water Index, NDWI, at 10 M resolution to sharpen the 20 MSWIR bands. The results showed that the proposed NDWI-based MNDWI image has better separability and is more effective for both classification level and boundary level final water maps than traditional approaches. This article was authored by Shu Qingyang, Shen Chenjiao, Shu Binqin, and others.