The Thief's Downfall is a waterfall that protects treasures hidden underneath Gringotts Wizarding Bank.
It is one of the many defensive enchantments employed at Gringotts Wizarding Bank. It washes away any concealment or enchantments (including the Imperius Curse) that are being used by the occupants of any mining cart that runs through it, as well as causing the cart to derail and crash, preventing the thieves from progressing any further.
Apparently, it did not wash away the enchantment on Hermione's purse, or the purse would have burst open and spread its contents all over the mining cart.
The Thief's Downfall is a very useful technique for exposing enchantments and Imperiused people. I could imagine shopkeepers installing a smaller version of it in front of their stores. Or putting one in front of the Ministry of Magic offices. Or at the entrance to Hogwarts. Or inside a cave full of dead things in the water. I would pay a goblin good gold to install a small waterfall in front of my business.
I don't recall anything similar to it in the Harry Potter books.
Is there any mention of anything like it?
Please support your answers with quotes from canon sources.