Further damage to Toddbrook Reservoir could see ‘massive flood’

Further damage to a dam which has seen thousands evacuated from their homes over fears it may collapse could lead to "massive flooding", according to an expert.

A wall of a dam at the Toddbrook Reservoir became damaged following flash floods which caused thousands to be evacuated in nearby Whaley Bridge.

An expert from Brunel University in London said the damaged spillway of the dam – designed to release water – could become "fully broken" within hours.

This could lead to "massive flooding" following the heavy rainfall.

Dr Mohammed Heidarzadeh, assistant professor and head of coastal engineering and resilience LAB, said: "Due to heavy rainfall in Whaley Bridge area, the spillway is now broken and a big chunk of its concrete structure is damaged.

"There is a possibility that the spillway could then become fully broken in a few hours.

"If the spillway is fully gone, the embankment dam will be washed away very rapidly, which could cause a massive flood."

He added that a similar situation occurred at the Orovill dam in California in February 2017.

However, as long as the core of the reservoir is not damaged, the wall "should be okay", according to another specialist.

"Within the last few years new valves have been placed in the dam to expedite rapid drawdown in emergencies: presumably, this is happening now," said Professor Roderick Smith, from Imperial College London.

The former chief scientific adviser for the Department for Transport said the reservoir previously had "issues" with an inadequate valve system which has seen been replaced.

Severe flooding in South Yorkshire in 2007 sparked the evacuation of roughly 700 people around Ulley Reservoir, near Rotherham, over fears its walls could burst due to unprecedented rain and apparent "areas of weakness".