Contractor, govt agree to fix Isimba Dam defects

The Ugandan government and the China International Water and Electric Corporation (CIWEC), contractors of the Isimba Hydro Power Dam, have shifted their positions and agreed to collaborate on fixing critical defects threatening the facility’s integrity.

This decision follows their agreement to conduct a Physical Model Test (PMT) to address erosion issues in the dam’s spillway. Previously, the government intended to hold the contractor solely responsible for the defects, while CIWEC maintained there were no significant problems.

This change in stance occurred after a joint site visit by Members of Parliament, government officials, the owner’s engineer, and CIWEC’s senior management. In a statement delivered at Parliament yesterday, Mr Herbert Ariko, the chairperson of the House Committee on Natural Resources, confirmed the collaborative agreement.

Key resolutions include immediate meetings between the Ministry of Energy, CIWEC, Uganda Electricity Generation Company, and other stakeholders to plan the spillway rehabilitation process. Earlier committee visits revealed severe erosion in the spillway’s buffer zone, posing a risk of dam collapse and downstream flooding. Experts warned of potential power shortages and risks to thousands of residents. Initially, CIWEC denied significant defects, leading to disagreements.

Now, both parties have agreed to conduct a PMT in China to assess the spillway’s integrity. A team from the Ministry of Energy will witness the tests by March 30. The tests will determine the durability of the spillway materials and identify the causes of degradation. “We are taking a comprehensive approach to ensure that all aspects, from technical solutions to financial safeguards, are addressed.

This dam is critical to Uganda’s power generation, and we cannot afford any further setbacks,” Mr Ariko said. He added: “The PMT is a critical step in identifying the cause of the defects and ensuring that we adopt the right solutions. The results of the 1:20 scale model test will inform us about the root cause of the spillway defects, while the 1:40 model test will determine whether the dam requires an additional spillway to meet discharge capacity requirements.”

The technical team will also assess how to achieve dry conditions for effective spillway repairs, as current underwater inspections yield unclear images. State Minister for Energy Sidronius Okaasai confirmed the collaborative approach, emphasising the urgency of repairs.

“When you look at the demand and supply of electricity in the near future, we are going into the negatives. Losing 183 megawatts from the supply chain would be disastrous,” Mr Okaasai said. The repair costs, estimated at no less than $150 million, will initially be borne by CIWEC. If additional issues arise during the works, the government will provide the funding.

Prof Wanga YongTian, the CIWEC president, acknowledged the defects and agreed to collaborate. “For us, we will continue to take action and work closely with the ministry and all other stakeholders. We will strive to complete all these defect repairs as quickly as possible,” Prof Wanga said. Mr Ariko emphasised that the assessment must conclude by month’s end.

“This is a matter of national interest. We expect all parties to adhere strictly to the agreed timelines so that we can resolve these defects once and for all,” he said, adding that a revised Master Completion Schedule (MCS) must be ready for approval by March 30.

THE DEFECTS

The Uganda Electricity Generation Company Ltd (UEGCL)’s Chief Executive Officer, Mr Harrison Mutikanga, last month told MPs that the dam’s spillway is rapidly eroding, posing a significant threat to its structural integrity.

According to him, the underwater images from the investigations they have done so far using under water cameras, revealed that the spillway’s baffle blocks have eroded, exposing critical reinforcement damage.