Follow the Water from Brook to Ocean (Let's-Read-and-Find-Out Science 2) 

This book not only teaches kids about the various types of water bodies - brook, stream, river, ocean but also takes them on a trip - in a canoe and other things and all the animals that you will find on these trips.
As a kid when I visited a dam, I was overwhelmed and scared by the amount of water. With examples of grand Canyon, Colorado and snowy mountains, there are some discussion points for further questions.