The reservoir can hold up to 11.1 cubic kilometers of water and fuel a 1.052 megawatt hydroelectric plant. Hundreds of thousands of people living in the surrounding regions - scene of the conflicts between Iraq and ISIS - depend on the Dam for the water and electricity supply
The project, however, suffered from significant structural limits due to the Tigri’s waters that have opened up flaws on the karstic foundations that have been filled for years with tons of liquid cement.
In order to stop up the dangerous situation and secure the area, in October 2015, the Iraq government launched an international tender, with urgent procedure, for the consolidation and restoration of the Dam function.
In April 2016, the Italian Trevi Spa based in Cesena and specialized in underground engineering and special foundations, won the contract of 273 million euros. The Italian government, to support the work, deployed the task force named "Praesidium", of approximately 450 military personnel, to protect the Dam and personnel involved in work.
The Nautilus’ role
At the end of October 2016, Trevi Spa subcontracted to Nautilus Srl the construction of underwater works for the inspection and restoration of underwater structures that ensure the correct control of the artificial basin’s water level.
For the execution of the work, Nautilus has created a Joint Venture with the company Drafinsub of Genoa, specialized in on-shore and off-shore diving.
To carry out the complex operation, the two companies have transported on the artificial lake of Mosul, with a 35-bin convoy, a floating platform of 30.00 x 18.00 mt, complete with underwater equipment, able to guarantee the diver's operation in the artificial lake, with dives that can reach a depth of -100 mt.
The platform housed a complex of hyperbaric chambers that can hold a 6 sub team that lives and works for 28 days in a hyperbaric controlled environment.
The intervention was planned under the supervision of the Italian military and the USACE Corps of Engineers (USACE) to ensure, in the event of a terrorist attack, the immediate evacuation of divers from the operational area into a special decompression chamber.
The aim of the Italian dive team was to verify and repair the steel bulkheads that allow the opening and closing of the basin drain tunnels when the reservoir exceeds the guard level. Each bulkhead, weighing 80 tons, has been completely lifted out of the water by using a crane with a lifting capacity of 250 tonnes.
Our team performed 328 dives for a total of 285 hours of which 462 minutes of diving in saturation, with injury index 0.
In February 2017, the yard received the visit of Roberta Pinotti, Italian Minister of Defence, who, after visiting the operational area, congratulated for the valuable work of Italian companies.
Our contribution to this project is also reported in the article on "La Repubblica", "Il Sole 24 Ore" of February 3rd, 2017, on "La Stampa" on February 7th, 2017 and on Hydro Review.