Modified Normalized Difference Water Index (MNDWI)
"The Modified Normalized Difference Water Index (MNDWI) uses green and SWIR bands for the enhancement of open water features. It also diminishes built-up area features that are often correlated with open water in other indices.
MNDWI = (Green - SWIR) / (Green + SWIR)
Green = pixel values from the green band
SWIR = pixel values from the short-wave infrared band
Reference: Xu, H. "Modification of Normalised Difference Water Index (NDWI) to Enhance Open Water Features in Remotely Sensed Imagery." International Journal of Remote Sensing 27, No. 14 (2006): 3025-3033." (ESRI, 2018)