I made these rivers by making a gimp file with spray painted terrain, opened it up in Wilbur and made rivers in it, then brought it back to Gimp. Once in Gimp I made a copy of the Wilbur terrain and threshed it (thresholded isn't a word it seems) to get the shape of my lake and major rivers. I then bumped a new white layer with the Wilbur terrain and threshed that as well. This second endeavor is to get the river tributaries that were left out by the lake and river shape, however this didn't automatically turn out as nicely so I had to white out random speckles, join water pathways that seemed like they should be joined, and fill in large water pathways which were so wide that they left blank space in their midst. Lastly I had to set the tributary layer to darken only before merging it with the lake shape layer.
Anyway, the reason for my post is just what my title says. Are these good rivers? Are there any problems with them?