Water resource management is pivotal to ensure water security and sustainability. Having such water monitoring resources is challenging, especially in less developed countries that have limited resources. With the advancement in technology and availability of open-access satellite data, there are opportunities to reinforce the abilities of researchers and decision-makers to monitor and identify changes in water resources. This script describes an easy to implement workflow for estimation of surface area of waterbodies using open-access data from Sentinel-2 satellites. The method uses Normalized Difference Water Index (NDWI) for surface water detection that is used to estimate the surface area of the waterbody and analyse changes over a period of time.
Have a look at this paper for details about the workflow and examples.