What's the noun for drainages? Here's the word you're looking for.
drain
A conduit allowing liquid to flow out of an otherwise contained volume.
(chiefly Britain) An access point or conduit for rainwater that drains directly downstream in a (drainage) basin without going through sewers or water treatment in order to prevent or belay floods.
Something consuming resources and providing nothing in return.
A slightly elevated and inclined surface, designed so that wet objects can be placed on that surface, and water on those objects can drip or drain away.