So resurrecting an old post here, but...
I never did get pics. The washboarding never did come back on the hive with the water reservoir, though it seemed to be working like a champ. To be fair, the reservoir I built also had vents at the top to help with the added humidity, so there's a lot of confounding variables here. It could just as easily be that the additional ventilation was what helped instead of the water supply. (Either away, they've stayed away from the neighbor's pool.)
I ultimately switched my two nucs to a medium hive body, and then left the three of them alone for the next month. We've been in a serious dearth here in Northern VA, so I checked them last week and this is what I found:
The two new hives (previously nucs) had exactly ZERO honey stores. Not even a drip. They were so dry that even smoking them did nothing but irritate them more. As much as I don't want to, I'm going to have to feed them to get them through the winter.
The hive WITH the water source was still going strong, but also had a very small amount of honey. Only two or three frames worth. Still, the fact that they had any at all I'll assume means the water supply / vents in the hive did something to help them. It certainly didn't seem to hurt.