Canal Transportation (Mobs)
Canal transportation is basically a way to get your mobs from the spawning pads to the killing mechanism.
The canals should always be two blocks wide and two blocks deep. This is to prevent mobs from jumping out and to allow spiders to get in. Not too big as to reduce efficiency of spawning ground for mobs.
In order to get your canals to flow only in one direction, pressure plates or signs should be used. (Ladders can’t be used as mobs collide with them and get stuck). If placed one side of a water source block these will not allow the water to flow past them and do not collide with the mobs as they are pushed beside them.
I will show how to tackle corners and straight lines in the pictures below.