Yes, curb stop is the word for the foot valve. I install them at the bottom of the heat tube at the 90 degree fitting coming up. There is a 1/2" square rod coming up along the water line that I can turn with a wrench and it drains back down. A separate municipal style curb stop a few feet away would be easier to turn on and off.

Garvo uses the continuous running style Bohlmann in his buildings but outside with just a few head on it I would go electric. just go with a small bowl size, not a large one. Less water to keep warm and less surface area.