DOES SAYING THAT A RIVER IS A PERSON GIVE THE RIVER THE ABILITY TO MAKE DECISIONS?

In the last few weeks at least two rivers have been granted legal “personhood,” one in New Zealand and one in India.  I’m as big on environmental protections as anyone, but I have a few questions:
What, exactly, does it mean when a river is granted personhood?  Does the river have the same legal rights as a person?  How does that work?
Since a river can’t assert its rights, who gets to do that?  
If the river receives compensation for an injury to its rights, who gets to decide what to do with it, and who gets to handle the money?   
Of course I’m sure that the people who are given the authority to exercise these rights of personhood on behalf of the river will do it only with the best of intentions, and will never substitute their own interests for those of the river, right?
Which leads to my final question: how do the people exercising the river’s rights on its behalf know what the river wants?  Or is it a matter of the people deciding what’s best for the river?  Who oversees those decisions?
Just asking.