Whenever I load in a world it crashes after exploring a bit. I've attached the crash log below.

latest.log

This issue has gone stale due to it having no activity for 60 days. Is this still a problem?

That's strange. Logs seem to suggest there are no biomes for the type river of which there should be at least two (in vanilla). My best guess is another mod you have is (for some reason) removing these from the biome dictionary.