Mosul Dam is built on soils that constantly break down.
A report released on Oct. 30 by the Special Inspector General for Iraq Reconstruction lambastes U.S. Dept. of State reconstruction officials and the U.S. Army Corps of Engineers’ Gulf Regional Division’s performance in the planning and administering of contracts to stabilize Mosul Dam, about 50 km northwest of Mosul.
The report faults the projects’ scale, organization, administration and oversight and says that at the time of the inspectors’ visits in September, about $19.4 million worth of equipment and materials had been paid for and delivered that “currently do not provide benefits” to the Iraqi Ministry of Water Resources.
The 3.2-km-long, 113-meter-tall, earth-filled dam was completed in 1984, impounding 12.5 billion cu m of water in the Tigris River Valley. Its four turbines have a rated capacity of 750 MW and make a significant contribution to the country’s power supply, but dam experts worldwide have worried about the dam’s vulnerability to catastrophic failure since the 2003 invasion, and before.
The dam is built on soluble soils that erode constantly, creating voids requiring continuous grouting. A system of three grout-mixing plants with a total capacity of 47 cu m/hr pumps material through a system of pipes in a gallery in the base of the dam and into its foundation. Seepage has been observed ever since the reservoir was filled, but a series of sinkholes, particularly one near the base of the dam in early 2005, convinced engineers that the condition was worsening. Beginning in 2005, the U.S. funded a short-term program to enhance the grouting system, issuing 21 contracts worth $27 million. A joint venture of CH2M Hill and Parsons Corp. provided program management services.
The SIGIR report questions the scale of the system’s enhancement, which in 45 hours can produce as much grout as the dam has ever consumed in a single year. It strongly faults the decision by the U.S. Embassy’s Iraq Transition Assistance Office to treat all 21 contracts as procurement contracts, therefore not requiring design drawings and construction oversight, when it says some of them clearly needed them. The report faults the Corps for overlooking critical details in planning and bid evaluation and for relying on the Iraqi Ministry of Water Resources personnel for quality assurance.
In responses from ITAO and the Corps, about the only thing widely agreed upon is that the “post-delivery support plan” to rescue the project and deliver the intended benefits deserves strong support, which they all pledge to provide.