(Found) 1960s-70s novel; water levels are rising; character travelling to a "gate" that leads off planet

[Tiggertim]

I would have read this in the 70s or 80s and it was a small, novel sized, paperback typical of the era. The story follows a character who is travelling across another world (I'm sure it's not Earth), trying to reach a gate of some sort that leads off planet as water levels rise everywhere on this world. I can't remember why the water levels were rising but you got the impression it wasn't happening slowly and was displacing everyone. I think it was dark a lot of the time. The charcater may have been riding a horse and carrying something (a weapon perhaps) that was important. I was reading a lot of stuff by Tanith Lee, Fritz Leiber, CJ Cherryh but nothing jumps out when I look at their titles.

 

[Suzecog]

Have you looked at Cherryh’s Morgaine books? They involve gates and although I don’t remember details, it’s so long since I read them, there was a lot of wetness and darkness in them, in particular the second book, Well of Shiuan. In fact that’s all I remember!

 

[Tiggertim]

Have you looked at Cherryh’s Morgaine books? They involve gates and although I don’t remember details, it’s so long since I read them, there was a lot of wetness and darkness in them, in particular the second book, Well of Shiuan. In fact that’s all I remember!

Found: I just read the plot summary of Well of Shiuan and that's definitely it. Thank you very much.