In the file from which I got the data they're called Broad Feng and Qowowuyag. I have no idea which name is more appropriate but I guess I'll stick to having a single source. Thanks for the comment
Good quiz, which could do with more time. The Grande begins with a G not an R! "Rio" is not a part of its name. If it was then all rivers would start with the same letter and this quiz would be rubbish.