How does Lake Valor get back to normal?

Question

Team Galactic set off a bomb at Lake Valor, and after I caught Giratina, it was back to normal! How did this happen? BTW this is on Platinum.

Answer 1

They would have set it all back to the way it was.
I don't know if you noticed, but the time you were in the Distortion World is actaully a long time and being that time goes faster in the Distortion World you would come back to find the world ahead of when you left it.

Distortion World doesn't go by the normal worlds time.
Besides why would they leave a perfect lake like that? They would actually have put a lot of efforts into replacing it.

Hope this answers your question :)

Answer 2

Something gamefreak desided Maybe Shaymin put it back to normal or when you caught giratina It made it better or team galactic put it back together while you were in the distortion world as time goes faster then average. Therefor, giving enough time to rebuild the lake. This is impossible if you didn't catch giratina.