[1.1 BUG] I can build a pier even though I am not near any rivers

No. Using mods?

Also there are misplaced river terrain tiles in some stamps. You may have one of those near your city. Even though it doesn't look like a river it counts as one.

This is common with a few stamps. Especially on with a mountain and a river next to it.

Mouseover the terrain, even though it looks like plains it might be a river.

Good catch guys!  I'm not using any mods.  It's one bad tile in the stamp.  I'll update the OP too.

 http://www.mediafire.com/?yt4kgzaorkckd38

I've seen this sort of thing pretty regularly in my last few games.  Rivers that aren't rivers.  Plains that are rivers.  Hills that look like plains.  It's pretty annoying.

I had a problem as well, if you making a map, those rivers tool can be painful to use, not even delete button can removed river on map even it's not show a river but a land...very annying in map maker...