IT has been billed as an imminent disaster, putting millions of lives at risk.

Now scientists have warned that if work is not completed in time to fix the strategically vital Mosul Dam, floods will destroy other critical infrastructure, swamping entire towns.

While the battle continues to gain control of the Islamic State stronghold of Mosul, engineers and scientists face a desperate race to stop the Mosul Dam — which is just 60km away from Mosul — collapsing in on itself.

Now Italian company TREVI have just 18 months to stop the dam from plunging underground, Al Jazeera reported.

If it were to collapse, up to 11.11 billion cubic-metres of water known as Lake Dahuk, will submerge Mosul, affecting millions of people along the banks of the Tigris River in a major catastrophe, experts have warned.

TREVI is currently carrying out maintenance works on the dam as well as consolidating foundations as part of a $300m contract funded by the World Bank.

However scientists said no matter what maintenance work was carried out it was only delaying the inevitable disaster.

Mosul Dam expert and professor of water resources and environmental engineering at Lulea University in Sweden told Al Jazeera the collapse of the damn was inevitable.

“It is just a matter of time. It will be worse than throwing a nuclear bomb on Iraq,” Prof Ansari said.

The 3.4km dam is the fourth largest in the Middle East but is built on unstable ground with numerous surveys revealing sinkholes as large as 20m wide.

The European Commission Science Centre last April also warned that it would only take a quarter of the dam to collapse to create a flood of catastrophic proportions, affecting up to 7 million people.

Work on repairing the dam has been affected by mismanagement and corruption while vital time was lost when the dam and its surrounds fell under the control of IS in 2014.

Kurdish forces took back control of areas of Makhmur, in northern Iraq from Islamic State (ISIS) militants with the aid of US air strikes in August.

Residents and business owners have slowly returned to the area, but US forces are still targeting IS militants located at the nearby Mosul Dam, a strategically important water source.

In February this year, the US embassy in Iraq released evacuation recommendations it said could help save up to 1.5 million lives at risk from a catastrophic failure of the Mosul Dam, AFP reported.

Concern has grown in recent months over a possible collapse of Iraq’s largest dam, which would unleash a wave that would devastate second city Mosul and flood much of the capital Baghdad.