Tags to do with coastlines and islands

Looking for advice about the best tags to use for some of the following (if there are any, or what to use if there isn’t)

  1. Mean Low Water - I can’t find a tag for this, and I am aware that MHW should be used for ‘coastline’, but are there any tags that can be used for MLW? I say this because when mapping coastal islands there is often areas of ‘land’ between them that are exposed with the tide and therefore reasonable important for mapping purposes.
  2. Sand Bars
  3. Inlets etc - The ‘bay’ tag seems inappropriate for such things.
  4. Small areas of the sea/ocean that are close (for my purposes) to the shore.