Not actually an entry cos it's not really a water map, but your "river of war" did remind me of this one I did a while back... it's got 4,5,s6,s9,11,s12,12 and mid.
There's water added, but the bases have been re-arranged too... like look at s9/s6. Never played it, but it could be interesting to start in a familiar base but discover the world has moved slightly when you go outside. Its 4-player.
... just a bit of fun