pour-off

[keitra]

What does pour-off mean? and drainage?in the following.
a twelve-foot pour-off into the drainage itself.

[Quizmonster]

A pour-off is the channel or 'passageway' through which water at a high level flows down to some lower level. Drainage is the system by which water - generally waste-water from bathrooms etc - is taken away to wherever it has to go, either naturally or by man-made pipes etc.

So, "a 12-foot pour-off into the drainage itself" might refer to a length of pipe leading to a sewer, for example, or to a slope in a garden leading to a ditch which carries the water away.