A Whaley Bridge resident has said “it’s no surprise” the dam suffered a partial collapse as authorities continue to shore up the fragile structure.
Pictures taken just weeks before the cracks appeared at the Toddbrook Reservoir dam appear to show weeds creeping through the concrete spillway.
The resident, who wished to remain anonymous, said: "The signs have been there for years.
"The slats that have collapsed have had plants growing between them for a long time.
"Now they have collapsed and it's no great surprise. It seems like the dam has just been left to its own devices."
It comes as police warned residents will only have 70 seconds to evacuate if the damaged dam bursts.
Some residents in the Derbyshire town are still refusing to evacuate their homes despite thousands being escorted from the danger zone last week.
Police criticised the belligerent locals and warned there could be “catastrophic” consequences for both them and the emergency services.
Authorities have been frantically working to repair the dam at Toddbrook Reservoir near Whaley Bridge over the past week.
But 31 people, including a “small number” who were initially evacuated but later returned, have remained in 22 properties in the town.
Police said over the weekend that if the dam did burst residents would have not have time to evacuate as the town would be flooded within 70 seconds.
They also described the risk of the 180-year-old dam collapsing as “critical”, with a breach still a “very real threat”.
READ MORE FROM YAHOO UK:
Deputy chief constable Rachel Swann told a residents meeting those who have defied orders to leave are not only putting their own lives at risk, but also those of emergency services staff who may have to look for them if the dam does break.
She said: “We’ve not evacuated this for no reason.
“We’ve evacuated this because there is real prospect the dam could fail and if it fails it is catastrophic. People would die if they were in that evacuation zone.
“So those people who remain in that zone are putting their lives at risk.
“They are also putting the lives of the responders, primarily the police, at risk because we have to keep going in and speaking to them and asking them to leave.”
Water levels at the reservoir have been reduced by more than 3.5 metres and, fortunately for workers at the site, Sunday’s forecast of thunderstorms did not materialise.
The Met Office said there was a risk of some showers overnight into Monday, but these would likely amount to just one or two millimetres of rainfall in the area.
Six rescue boats have been deployed in the region in case the dam bursts.