Great stuff.

Sorry to appear negative earlier but as it seems to have had a positive effect then I'll stop feeling bad.

As to the canyon... I don't think you need to move it away from the sea but I think the problem is that it appears very deep and then suddenly it is a normal river. For instance, directly south of where the river begins ( meaning the traditional river, not the one assumed to be at the bottom of the canyon ) there is a very long line showing how massive the cliff is there but within a relatively short distance it is then a normal river. I think that line and maybe a few around it need shortening to show the canyon getting shallower. Or at least an abrupt end to the canyon with the river emerging needs somehow showing which will be quite hard to effectively show.