you should read the scholar's answer carefully. Mr. Arun have uploaded his published article while answering your previous question.  he worked on Sentinel-1 dataset for Chennai flood. in this article, it is clearly mentioned, how the sentinel-1 images of pre and post event were used to assess the inundation. read that article once and you will get the idea how to use the SAR image. please refer the article.

Cyclone Roanu made its landfall on Eastern coast of Bangladesh 21 may 2016. Innundated coastal area are clearly seen in the post images of Sentinel 1A SAR Datasets. Please find the attached file.

https://scihub.copernicus.eu/dhus/#/home

 I have read the paper. But , some issues are still not clear to me. Which is why I have asked the question in public to see if there are other observation. @ Chetna

Thank you :)

Please make your Question precise, let us know what you are not clear with?

regards..