Sounds good! Esri Wayback, available as a layer in Rapid, seems useful for this because it has imagery taken at various points in the tidal cycle. So my plan was to use imagery taken at (relatively) high tide for the coastline, and imagery taken at (relatively) low tide for the natural= features (wetland, bare rock, sand etc) That will just be based on whenever the picture happened to be taken but better to look at a few points than just one I suppose! Let me know if you know of a better way