The Straining Tower - where the water leaves the lake to start its journey to Liverpool - isn't purely decorative. It has an inlet pipe in sections, so the water can be taken from as close to the surface as possible whatever the level of the lake, and it has three enormous strainers, now superseded by modern water treatment works elsewhere.
This is part of the engine that operates the inlet and the strainers. It's totally green - the power comes from a stored rainwater system on the hill above!