Wikki echoes the default conclusion (as with Main Force) that this was much ado about little that did not justify the cost to the RAF:-
Operation Chastise - Wikipedia, the free encyclopedia
Given that the RAF itself has doubts about both that is hardly surprising. The thing I find surprising is that the Germans were allowed to effect repairs unhindered. As Wikki says, a high level follow up raid at the height of the repairs would have sustained the effects of the raid for far longer (anyway, agriculture took until the 50's to recover).
Like Warmtoast I visited the dam, though in the early 60's. I couldn't really make out the repaired section clearly even then. I'm sure if it had been our dam we wouldn't have replicated all the fancy cantilevered archwork at the top (for carrying the roadway?), but reverted to RSJ's etc. Vorsprung durch Technik, no doubt.
I watched the film on TV the other night. Despite all the 'issues' about it disclosed in this Forum, I enjoyed it yet again.
Another portrayal of course was this one:-