See below.
Rick

ORIGINAL: benpark
I don't see how that's possible. I selected the "8 color" selection on import to the MM, and have added no more than 3 additional. I've gone through in PSD to check with the eyedropper for variations, and don't see anything subtle that I may have missed.
See the attached:
ORIGINAL: benpark
Anyone else seeing corrupted textures? I tried a bunch of different orientations and densities, but keep getting the same thing. This happens with other textures as well. It seems to be this one terrain map selection.
ORIGINAL: benpark
Yep, stock textures. I may have tried a different texture on the terrain base. Maybe that's it. What are the stock texture and settings for the underlying terrain texture?
ORIGINAL: benpark
Rob, have you experimented with using the "lock" tool? You can select the water area pretty precisely and keep the surrounding terrain where you want it.
Rick has a very good description of doing this in his manual, which should be coming down the pike really soon.
ORIGINAL: benpark
Good ideas come from thinking big!
If it's too much of a change for Stridor to make- what about a flat, rectangular model textured as water that we sink below the map to where the river would be? It could be just a bit wider than our average river, and maybe 1/4 the length of a map. These could be used repeatedly to form a complete river, lake etc. for when a problem like the one you have now arise. The main issue with this is that there might be seams where models meet.