im trying to make the waterfall model from "landing at white falls" a little bigger (wider) so it wont look bad with my river. is there a way to do this or am gonna have to do it in photoshop... which i do not want to do
To be honest you're better off editing your river so it will either fit two waterfalls, or become narrower as it nears the fall. One option is to create a pool at the top and bottom, as waterfalls will sometimes do this in real-life, so widen your river a bit then narrow it to fit.
There is a really hackish way that could workusing the original model, but I would suggest editing your river as it is the easier and less problem-prone solution.