Allied troops and ISIS are set to battle for a collapsing dam that would spew nearly 600 times the water of the River Thames onto Mosul if it breaches.

Engineers from an Italian company have been tasked with fixing the Mosul Dam's foundations to stop more than 11 trillion litres of water (11.11billion cubic metres) from flooding Mosul.

Experts are warning their work could be in vain, and should the catastrophe happen, it is estimated 1.5million people could be killed by the floods in an impact described as 'worse than a nuclear bomb'.

Waves of up to 45ft would be unleashed if the dam breaks, and the equivalent to 4.4million Olympic size swimming pools would flood the surrounding areas amid a constant threat from Islamic State terrorists fleeing the Iraqi city.

An aerial shot of the Mosul Dam showing the 11billion litres of water it is holding at bay

Experts have stated that waves of up to 45ft would be unleashed if the dam breaks

A bottom outlet for the Mosul Dam controls the water flow, but the foundations are crumbling

This satellite image of the Mosul Dam from February 11, 2007 was coupled with an audit report stating nine years ago it was risk of collapse

The Mosul Dam on the Tigris River, around 50 km north of the Iraqi city of Mosul, which would be flooded catastrophically should the structure collapse

E ngineers from Italian firm TREVI have 18 months to solidify the dam, which is located 60km north of Mosul.

But professor of water resources and environmental engineering at Lulea University in Sweden has said the structure is doomed regardless of who has control of it.

'No matter how much grouting and maintenance the company will do, it may expand the life span of the dam, but it is just going to delay the disaster.

'It is just a matter of time. It will be worse than throwing a nuclear bomb on Iraq,' he told Al Jazeera.

The Mosul Dam is holding back the equivalent to 585 times the water in the River Thames at any one time

11billion litres would flood Mosul if the dam were to collapse - the equivalent to one and a half Loch Ness'

Meanwhile, some 250 miles away, a battle for another Middle Eastern dam is imminent.

Kurdish troops are now just three miles from the Euphrates Dam in Syria, which is under Islamic State control.

Talal Sillo of the Syria Democratic Forces said the fighters, with the support of US, French and British special forces, have driven IS from dozens of villages and farms in recent days and now have the strategic dam in their sites.

Unlike Mosul Dam, the structure near Raqqa is nowhere near as treacherous as the its Iraqi counterpart.

Mosul Dam collapsing would be seen as a 'humanitarian catastrophe of epic proportions' and could kill 1.5million people, a US ambassador warned earlier this year.

Governments were urged in March to move quickly to prevent a breach of Iraq's largest dam, which would unleash a wave as high as 45ft, devastating Mosul and flooding much of the capital Baghdad.

After hosting a meeting with Iraq's UN Ambassador Mohamed Ali Alhakim to hear briefings on the potential disaster, US Ambassador Samantha Power called on all UN member states to take immediate steps.

'It is crucial that all UN member states quickly get informed about the magnitude of the problem and the importance of readiness to prevent a humanitarian catastrophe of epic proportions,' said Power.

If the dam, pictured here, were to breach, waves of up to 45ft would hit the surrounding areas

Italian engineers are desperately trying to fix the Mosul Dam and have been given 18 months to do so

The ambassador described briefings by technical experts, engineers and representatives from UN aid and development agencies as 'chilling.'

The dam in northern Iraq was built on an unstable foundation that continuously erodes, and a lapse in required maintenance after the Islamic State jihadist group briefly seized it in 2014 weakened the already flawed structure.

'In the event of a breach, there is the potential in some places for a flood wave up to 14 meters high that could sweep up everything in its path, including people, cars, unexploded ordnance, waste and other hazardous material, further endangering massive population centres that lie in the flood path,' said Power in a statement released by the US mission.

After six months of planning, the Italian company were given the $300million contract which is funded by World Bank to attempt to save the lives of those living near the Tigris river.

The dam in northern Iraq was built on an unstable foundation that continuously erodes, and a lapse in required maintenance after ISIS briefly seized it in 2014 weakened the already flawed structure

Kurdish Peshmegra forces guard the dam, which is in an area close to land controlled by ISIS fighters

The engineers are guarded in the war-torn city by 500 soldiers from Italian and Kurdish Peshmerga forces, according to Al Jazeera.

They are tasked with injecting cement mix into the foundations in a process called grouting.

A European Commission's Science Centre study published last year stated seven million Iraqis could be affected by floods from the dam.