Troops from the Light Dragoons load up sandbags as part of their efforts to help shore up Whaley Bridge Dam (Picture: MOD).
More than 40 soldiers from the Light Dragoons are helping block a critical sluice gate with sandbags to prevent more water entering the damaged dam in Derbyshire.
The Catterick-based troops are working with Environment Agency engineers to secure Whaley Bridge dam, which is feared to be at risk of collapse. Wing Commander John Coles said:
"While it is not a very glamorous task, it is actually critical and potentially the piece of this which is going to endure for about a year... To allow them to repair the dam from within."
Troops have also joined police officers visiting residents in nearby Marple, issuing flood advice as forecasters predict thunderstorms which could bring more unwanted rainfall.
An RAF Chinook helicopter is also due to be back in action this evening.
Dozens more homes have been evacuated in Whaley Bridge ahead of expected bad weather
Forecasters warned of the potential for up to 40mm of rain to fall in just an hour or two on Sunday afternoon.
While residents had been allowed to return to their homes for brief periods this weekend to collect essential items, police said no-one would be allowed to return on Sunday ahead of expected heavy rainfall.
A Met Office yellow weather warning is in place for much of northern England and the Midlands, including the area around the reservoir.