I use SRTM 30m images for hidrological studies in general, but now I need more detailed images to use HEC-RAS 5.0 to prepare flood maps. It seems LIDAR is not an option in sub-saharian countries. Is there any better images than SENTINEL2 10m?
May be Sentinel-1 Level-1 SLC SM mode? https://sentinel.esa.int/web/sentinel/user-guides/sentinel-1-sar/resolutions/level-1-single-look-complex
You have tutorials from ESA dealing with the use of Sentinel-1 for flood identification.
A few resources
https://www.youtube.com/watch?v=ux4tx87ux94
https://disasters.nasa.gov/typhoon-damrey-2017/esa-copernicus-sentinel-1-sar-used-flood-detection-maps
http://www.un-spider.org/advisory-support/recommended-practices/recommended-practice-flood-mapping/step-by-step
i agree with the previous answers.
Maybe Landsat 8 also can help you.
I also agree with Paulo's answer, step by step flood mapping practice guide is very well explained.
Many thanks Pabel, Paulo, Luis and Gajanan for your comments and help.
In did Sentinel is a good option.