You have glare on the water. A polarizing filter on your camera can eliminate that problem and create a more transparent look in some areas but with too much water going over the falls, the transparency is going to be limited when using a slower shutterspeed.
As to the little yellow, if you can't easily take it out in a global software colour filter adjustment, then it must have been accurately reproduced from the scene.
did you use auto white balance or meter it? the top picture is really odd and looks unnatural up in the top 1/3rd or so...definitly use a polarizer filter, that will help alot