move contents of subfolders in archive mirror for video downloads

Question

I need a script (could of course easily write one , but maybe there's a comfortable one existing) to move away (archive) contents of subfolders of downloads of in may case miro video podcast download software;

The subfolders should be created on another disk in same structure and the contents moved and the source folders emptied but kept so miro could continue store the downloads.

The reason I need it, is I want to keep downloading all the time and need just the (smaller) internal disk running and the terabyte store can be powered off.