General Karim Fatah, commander of a Kurdish peshmerga battalion near the Mosul dam, told ABC News that Kurdish forces have taken control of both ends of the dam. However, fighters from Iraq and Syria (ISIS) still control some positions near the western end of the structure.
The U.S. government is concerned about these developments, causing President Obama to send a letter to Congress. In this letter he authorized airstrikes against ISIS targets at the dam “in the national security and foreign policy interests of the United States.” The letter went on to explain, “The failure of the Mosul Dam could threaten the lives of large numbers of civilians, endanger U.S. personnel and facilities, including the U.S. Embassy in Baghdad, and prevent the Iraqi government from providing critical services to the Iraqi populace.”
The Mosul Dam was built in the 1980s on really terrible ground, requiring constant maintenance to prevent it from collapsing. “Mosul Dam, the largest dam in Iraq, was constructed on a foundation of soluble soils that are continuously dissolving, resulting in the formation of cavities and voids underground that place the dam at risk for failure,” David Petraeus, currently the chairman of KKR’s Global Institute and former commanding general of the U.S. Army, and Ryan Crocker, the former U.S. Ambassador to Iraq, stated in a letter.
The dam requires “extraordinary engineering measures” – which is a lot of grouting operations to fill in the holes and “maintain the structural integrity and operating capability of the dam,” according to a U.S. Army Corps of Engineers report in 2007. The Iraqi government has been able to keep the dam in passing condition by continuously pumping in tons of grout.
“Assuming a worse [sic] case scenario, an instantaneous failure of Mosul Dam filled to its maximum operating level could result in a flood wave over 20 meters [65 feet] deep at the city of Mosul, which would result in a significant loss of life and property,” Petraeus and Crocker’s letter stated.
Last Friday an Iraqi government official said that the lead dam engineer and his steam were still on site. The water level was being kept lower than normal to reduce risk, according to the official.