Isimba Dam Faces Flooding Fears as Rainy Season Approaches Amidst Unresolved Defects

As Uganda braces for increased rainfall, the Isimba Hydropower Plant is once again at the center of concerns regarding potential flooding due to unresolved structural defects. The primary worry revolves around the dam’s spillway, which engineers have warned cannot safely handle its full design capacity.

Government officials and representatives from the Uganda Electricity Generation Company Limited (UEGCL) recently visited the 183-megawatt facility to assess the progress of repairs being undertaken by the contractor, China International Water and Electric Corporation (CIWE). The inspection followed previous warnings from UEGCL engineers about the compromised state of the spillway, which has been affected by concrete erosion, damaged buffer blocks, and gaps in its slabs.

During a 2025 inspection, it was noted that the spillway could only discharge less than 40% of its intended capacity without risking dangerous vibrations. These issues have persisted despite emergency repair attempts following flooding in August 2022. UEGCL has reported ongoing erosion and damage, raising questions about the contractor’s commitment to rectifying the defects.

The spillway is a crucial component for dam safety, designed to release excess water and prevent reservoir levels from becoming dangerously high. UEGCL’s CEO, Harrison Mutikanga, has previously voiced his anxieties, stating that a spillway unable to manage its design flood capacity poses a significant risk during heavy rainfall. The continuous erosion and exposed reinforcement raise fears of backward erosion that could impact the dam’s foundation.

Repairs have been complicated by the need to work underwater while the Nile River continues to discharge significant volumes of water. The government has maintained that CIWE is contractually obligated to fix the remaining defects and has withheld the project’s completion certificate, along with financial safeguards, to ensure the contractor fulfills its obligations. The Isimba dam, financed partly by a loan from China Exim Bank, was commissioned in March 2019, but operational performance does not negate the ongoing safety concerns linked to the spillway’s condition.