Fixing the Most Dangerous Dam in the World

Summary by Krater

This video examines the history, engineering challenges, and ongoing mitigation efforts at Mosul Dam in Iraq, explaining why it was once labeled the most dangerous dam in the world due to foundation dissolution in gypsum rock. It concludes that while the extensive multi-year grouting rehabilitation project has significantly improved the dam's structural security, grouting remains a continuous maintenance obligation rather than a permanent fix.

From the video

Answers: Why is Mosul Dam considered the most dangerous dam in the world?

• Mosul Dam foundation geology
• Gypsum dissolution in dam engineering
• Continuous grouting operations
• Badush Dam backup project
• US Army Corps of Engineers dam safety assessments
• Seepage and internal erosion in dams
• Lugeon permeability testing

What it concludes

• Mosul Dam was built on a foundation of soluble gypsum rock, causing continuous dissolution and non-stop underground erosion below the structure.
• Experts concluded that locating a major dam on gypsum foundation rock was fundamentally flawed, making the dam require continuous grouting maintenance.
• Proposals for permanent cutoff solutions, such as an upstream clay blanket or a continuous cutoff wall, were deemed too expensive, technically impractical, or economically unfeasible.
• Initial U.S. Army Corps of Engineers rehabilitation efforts in the 2000s suffered from procurement errors, inadequate contractor training, and equipment that failed to fit inside the narrow grouting gallery.
• The 2016 rehabilitation contract awarded to the Italian company Trevi successfully expanded the foundation grouting program, resulting in 98% of permeability tests meeting the strict standard of under three lugeons.
• Despite being stabilized and winning engineering awards, the grouting program is not a permanent fix, and Mosul Dam remains an ongoing maintenance obligation requiring continuous injection of grout.