How USACE and other personnel handled underwater work at Mosul Dam

0
1134

Performing underwater work at a dam and hydroelectric facility is challenging enough. Imagine the added complexity of performing this work in a war zone. This article brings that situation to life.

This barge provided a base of operations for diving work at Mosul Dam (in the background), while also serving as a platform for the team’s saturation system Raffaella.

 

International Hydro Content-HRW.

Each day started as would any day at dive stations around the world: The team arrived at the job site, equipment and clearances were checked, a safety meeting was held, and work began.

However, for the Drafinsub-Nautilus Joint Venture (DNJV) dive team that was working at Mosul Dam in the Ninawa Governorate of Iraq, most days also included: watching war planes, helicopters and drones buzz overhead, as well as seeing rockets being launched from nearby hills, hearing distant explosions and seeing billowing black smoke framing battles raging between Iraqi-led forces and the Islamic State (ISIS) in nearby Mosul City.

“The daily reminder of war, the sights and sounds of nearby battles, certainly grabbed our attention. We can see, smell and hear war just about every day,” said Drafinsub Diving Project Manager Marco Vacchieri. “It’s hard not to notice when you have helicopters flying near our dive station with their gunners test firing 50-caliber machine guns into the lake. There were a couple of times when we all
hit the deck and ducked for cover.”

Nearly coinciding with efforts by the coalition military (which includes the Iraq army and Kurdish, Sunni and Shia militia) to expel ISIS from this Kurdish-administered region of northern Iraq, planning for DNJV’s mission at Mosul Dam began in December 2015. The underwater work, including sonar and video surveys, started in September 2016. Full-time diving was executed from January 2017 through July 2017, a time that paralleled the push by Iraqi and Kurdish forces to complete its purge of ISIS fighters from Mosul City.

Background on Mosul Dam

Mosul Dam, which was formally named Saddam Dam after Iraq’s deposed President Saddam Hussein, is the largest dam in Iraq in terms of both its impoundment (at 11 billion cubic meters of water) and power production (3,420 GWh annually). The dam is 371 feet high and nearly 2 miles long. The earth and concrete dam with a five-gate spillway provides flood control for the upper Tigris River, irrigation water and hydroelectric power through a 750-MW powerhouse that is equipped with four Francis turbine-generator units.

The dam also serves as a constant reminder of the area’s violence and volatility, showing battle scars from fire-fights between U.S. forces and Hussein’s expelled government, as well as from combat between ISIS, Kurdish and Iraqi forces.

Now an international community of engineers, scientists and government officials believe the dam’s most critical battle is being fought as Iraq’s government, with its consortium of nations and contractors, battles to repair and save what has often been called “the most dangerous dam in the world.”

Commissioned in 1986, geologically Mosul Dam sits on a karst foundation of soluble rocks such as limestone, dolomite and gypsum. What concerns the international community most is that according to a 2007 U.S. government report produced by USACE and the Special Inspector General for Iraqi Reconstruction (SIGIR), about 1.5 million people in the downriver cities of Mosul, Tikrit, Samarra and Baghdad would be imperiled if the dam failed. Additionally, according to that same U.S. report, if the dam collapsed, failure models predict that within hours of the breach, Mosul City could be swamped by up to 70 ft of water.

Although Iraqi efforts to stabilize the dam’s foundation had been ongoing since the 1980s, several incidents — including worker deaths and the appearance of downstream sinkholes and seepage — led Iraq’s government to concede that international help was needed. The government signed a renewable 18-month contract in February 2016 with Trevi Group of Cesena, Italy, for a reported $296 million to keep Mosul Dam from collapsing.

Besides drilling and injecting grout to strengthen Mosul Dam’s geologic foundation, Trevi’s contract also called for:

• An underwater inspection to evaluate structural integrity of the bottom outlet bulkhead guide slots and sills, bulkhead dogging beams, lifting eyes and underwater storage slots; and

• Repairs and rehabilitation of the facility’s massive bottom outlet structure, which houses two 2,500-ft-long and 40-ft-high bypass tunnels, associated bulkheads, gates, and mechanical and electronic controls, as well as the downstream plunge pool.

Drafinsub-Nautilus project manager Marco Vacchieri and USACE dive safety officer Rick Benoit deploy into the lake via a man-basket from the work barge.

Drafinsub-Nautilus project manager Marco Vacchieri and USACE dive safety officer Rick Benoit deploy into the lake via a man-basket from the work barge.

Performing the work

During 19 months of planning and execution, the Mosul Dam Bottom Outlet Rehabilitation Project was a collaborative effort between four Italian-based companies: Drafinsub of Genoa and its Venetian joint-venture partner Nautilus, Seli Overseas of Rome and prime contractor Trevi.

Additionally, these contractors worked with the U.S. Army Corps of Engineers (USACE), which served as project engineer, as well as Mosul Dam stakeholders the Ministry of Water Resources (MWR), Ministry of Electricity (MOE) and Iraq’s national government owner of the facility.

For all in-water operations, the Mosul Dam Task Force used USACE lone personnel specially trained in saturation diving, deep diving and underwater construction inspection techniques. These personnel were Todd Manny of USACE’s Portland District and Rick Benoit of the Transatlantic Division – Afghanistan. They provided both remote and on-site submittal review and oversight of diving, clearance/lock-out tag-out, safety and quality assurance.

“There were many kinds of challenging aspects to this job; one of the biggest challenges for me was the size of this project and working with so many different entities,”
said Drafinsub’s Vacchieri, who holds degrees in naval architecture and marine engineering, as well as a master’s degree in nautical engineering from the University of Genova. “But most importantly, this project was being watched by three, if not four, governments: Iraqi, Italian, American as well as the Kurds. And because of the urgency and critical need for repairs, it was like the whole world was watching our progress as we worked with a war going on around us.”

Drafinsub Chief Executive Officer Gianluca Passeri echoed these sentiments, saying that a “special” aspect of the Mosul Dam Project has been the professionalism and positive relationships between contractors, project managers and government officials. “For this mission, I cannot say enough how well everyone worked together,” said Passeri, whose family-owned firm opened in 1977 as a small, shallow-water dive company. “It was the professionalism of Trevi, Seli, USACE and my team that made this mission’s success possible and allowed us to work safely in a very dangerous area such as Mosul.”

DNJV completed its assigned work on schedule in July 2017, while Trevi’s planned drilling and grouting efforts atop the dam and within its gallery section are ongoing. USACE also executed additional work, engaging the U.S. Army’s 569th Engineering Dive Detachment of Ft. Eustis, Va., U.S., during July and August 2017 to provide follow-up underwater plunge pool and powerhouse inspections.

Along with an extensive mobilization and de-mobilization, the DNJV team was required to provide:

• Multi-beam sonar profiles and remotely operated vehicle (ROV) video surveys of the dam’s forebay and its downstream plunge pool

• Inspection and repair, removal and installation of four 70-ton bulkheads measuring 40 ft by 20 ft

• Installation of four 10-ton mooring blocks and location and positional buoy systems.

During operations, DNJV worked 12-hour days, seven days per week aboard a 110-ft-90-ft flexi-float barge, which also served as a platform for the team’s saturation system Raffaella. Most diving in this northern Iraqi reservoir was accomplished using surface-supplied air with Kirby Morgan 37s. About 10 dives were executed using a two-person diving bell when depths approached 200 ft. All dives, which took place in the shadow of Turkey’s snowcapped Mardin Mountain Range, required high-altitude adjustments.

The DNJV team, which rotated its dive team roster of 25 people about every 45 days, included Christian and Muslim personnel from Italy, Egypt, Romania, Turkey, Iraq, Kurdistan and the U.S., each speaking either their native language or English with varying degrees of fluency. Adding to the mission’s social complexity were the various dive and work regulations DNJV needed to follow — including those of USACE (EM 385), the International Marine Contractor’s Association, and the Royal Institution of Naval Architects — as well as Italian labor laws and applicable on-site contractor safe practice manuals.

However, unlike other jobs experienced by the crew, work was completed under the constant watch of nearly 500 Italian soldiers (Esercito Italiano) sitting behind 50-caliber machine guns mounted atop Iveco Defense Vehicles. Briefly controlled by ISIS in July 2014, Mosul Dam is located in Iraq’s autonomous region of Kurdistan and is also protected by AK-47-carrying Kurdish Peshmerger security forces.

Trevi celebrated its one-year work anniversary at Mosul Dam on Aug. 11, 2017. During this time, Trevi has drilled about 100 km worth of grouting holes, with the total number of grouting holes drilled in excess of 200. Trevi has injected 6,000 tons of grout.

Conclusion

Despite the challenges of living and working in a war zone, blending a multi-cultural team and operating according to sometimes unfamiliar regulations, the DNJV team executed its mission without accident or incident for 11 months. In total, the team accumulated 3,492 work hours supporting 328 dives and 293 hours of diving.

“This was the most challenging aspect of our job; maintaining personnel safety for all of our people,” said Passeri, whose 40-year-old company specializes in deep-water and saturation diving for oil and gas companies. “This was also one of the more satisfying aspects of our job; the team’s excellence and professionalism allowing us to work in a very dangerous environment without any accidents.”

In addition to daily reminders of noises and sights produced by the bloody urban war being fought 30 miles south in Mosul City, dive team members also battled temperatures up to 120 degrees Fahrenheit, poisonous vipers, insects and austere living conditions. Daily, dive team members passed through multiple sand-bagged check points that were guarded by Kurdish and Italian soldiers, traveling 4 miles round-trip by bus between Lake Dahuk and their base camp, where they lived behind a ring of 20-foot-high concrete T-walls below armed guard towers and strings of barbed wire.

And although there was no “official” opportunity to be “outside the wire” except when working, some dive team members clandestinely traveled into the barren, dust-choked hills surrounding Mosul Dam, bringing food, water and children’s toys to displaced families and refugees escaping the fight in Mosul City.

“It all was extremely interesting work but humbling work in a very strange environment surrounded by war and soldiers with guns to protect us from ISIS. In the beginning, it was quite unsettling and uncomfortable,” said Vacchieri, a 33-year-old father of three. “But, like anything else, after a while you get used to where you are. Most importantly, being here made going home to my family, to Genoa, which by the way is the most beautiful city in the world, very, very special.”

Rick Benoit served as the U.S. Army Corps of Engineers’ Mosul Dam Task Force Dive Safety Officer in Iraq, overseeing dive operations from November 2016 thru June 2017. A commercial diver, dive supervisor and instructor, Benoit, who has also deployed to Afghanistan with USACE, currently works for the North Atlantic Division.

Original Source