River Rapids

Connected rivers are a contiguous group of adjacent sites with River in their name, regardless of who controls them, and which contains River Rapids. River Rapids is, by definition, connected to itself, even if it is not connected to any other Rivers.

It is an activated ability that you can choose to activate one time on your turn. You choose a minion that is on a connected river, and push it one step. You can use this to push the minion off of rivers, and you can activate it even if River Rapids is the only 'connected' river.