There wasn't anything left of the cavern, but there was barely any damage to the forest around it. The walls and ceiling collapsed on the underground space and were all piled up inside the hole. The only effect it had on the village was that the spring was buried. Not that it mattered, since the oblivion water would be gone regardless.
Thanks to the Grail's energy being isolated, the communications with Chaldea were restored.

- Chaldea Case Files: Caged Girls