Shropshire Star photographer Jamie Ricketts captured the tower, at the reservoir in the hills west of Oswestry, in August and again last week.
The difference between the water levels looking at the bottom of the tower is clear, with recent rain doing little to bring it back up after a persistently hot and dry year so far tested the reserve of water.
In normal times the water level of the lake - which provides drinking water to Liverpool - would be up to the tree line.
Water levels at Lake Vyrnwy have remained extremely low but relatively static since April.
In August the water was low enough for an old village that had been abandoned and submerged so the reservoir could be created to be revealed again.
Llanwddyn was deliberately submerged in the late 1800s after a dam was built to create a reservoir to supply Liverpool with drinking water.
Over the weekend the level at the weir at Llanwddyn measured 0.153 metres.
Natalie Hall, Sustainable Water Manager for Natural Resources Wales said levels were at their lowest - only 43 per cent of storage capacity - since 1995.
She said they were working with the Environment Agency in England to monitor cross-border environmental and water resource impacts.