slowing down the water?

I thought I worked in a desolate area.  But, yesterday, I discovered the Santa Fe Dam Recreational area.  There's a beautiful bike path there, and I plan to spend the next few weeks exploring it.  I'll post photos of the cool things I find. 

I don't really know what this thing is.  I'm pretty sure it's not "the dam."   I don't know what this thing is called.