The Primary Source - Running the Río Marañón
It's not new, but I stumbled upon this video of the Río Marañón that begins in Peru, and it's possible damification. Seems like it's the same struggle we find all over the globe.
Also, that Rio looks sweet! Doubtful the locals would like it commercialized for the touristy gringos, but I'd like to float it some day!
**I have no ties to this video. Just an internet find.