So i'm in the Forgotten Vale, and in the area where there are waterfalls surrounded by ice, my game continues to freeze, only in this area. Do i need to re-download my Dawnguard DLC? And if i do that, will my save files still be at the Forgotten Vale when i start playing again? Thanks

I don't know if uninstalling will fix your problem but it won't effect your saves.

If you have a USB transfer your saves and try a clean install, then try playing without transfering your saves back, if it works try with your saves, if it starts again when you transfer your saves they are corrupted/faulty/etc.