/merged similar or identical threads
I did see water texture problems myself after leaving the new Dwarf starter zone for Logar/Howling Mountains. And this was with having water reflection and refraction already disabled (speeds up framerates for me). I have not yet seen ground textures with the checkerboard problem, but they may well be there, or showing up in zones other than HM.
If you try manually repatching, you shouldn't need the first big (1.3GB) patch file. However, if repatching doesn't fix the issue for you, you may have to do a full reinstall. Back up your \Interface\Addons folder before reinstalling, just to make sure.