This makes a nice followup to yesterday's post on wired tomatoes: a floating dairy (in the Netherlands, of course).
The idea here is "circular farming", where manure from the dairy cows is captured and used to grow vegetables. But the key thing seems to be the availability of open (water) space in an urban area.
Count me skeptical: one reason is my memory of the flooding the Netherlands suffered back in the 1950's. The water won't always be calm, and cows like humans can panic.