mad_crease: My guess is that little sunken town was supposed to be more then it is now. like 4 houses, a church, and a gas station. Even the little shard thingy talks about the people issues prior to the flooding.
midrand: You think so? I doubt it for the town specifically - seemed quite complete to me for its purpose... Maybe other voyages - yes.
If you swim across, there's a structure that you can't get close to. it turns you back saying you can't go there.
If you cross the dam, and find a way down on the other side, there's a fuming pile across the garbage. The plume of smoke you can see from the dam. As you approach it, you get a msg that says you can't get there YET. So, they either planned it being a DLC or it was closed and just made inaccessible due to the other delays and issues.
That whole area is a garbage pit between 2 dams. It would be enough space to drain the little lake there. There's also a very nice road that leads down to the submerged town.