Jinja, Uganda I URN | As the country enters a season of potentially enhanced rainfall, unresolved defects at Isimba Hydropower Plant have renewed fears about the dam being flooded by excess water.
There is also concern that the contractor has done little to repair a spillway that engineers say cannot safely handle its full design capacity.
Sources revealed that government officials led by Engineer Badru Kiggundu and managers from Uganda Electricity Generation Company Limited (UEGCL) revisited the 183-megawatt plant on Friday to follow up on efforts to have China International Water and Electric Corporation (CIWE) rectify defects at the facility.
Dr. Kiggundu, who leads the presidential Project Steering Committee (PSC) tasked with overseeing the completion, supervision, and remediation of structural defects, including concrete cracks and spillway erosion.
The outcome of Friday’s inspection, including whether the contractor has agreed to a firm schedule for completing the outstanding work, was not immediately available.
It was held behind closed doors for over five hours and could not be disclosed by the source, though he revealed that the parties are still concerned about the continuing erosion at the dam.
Dr. Badiru Kiggundu did not respond when contacted by URN about the said meeting.
The visit comes as the country prepares for increased rainfall and possible flooding during the October-December rainy season.
It also follows repeated warnings by UEGCL engineers that damage to the spillway could compromise the dam’s safety if not adequately addressed.
There is concern that the contractor has not made sufficient progress on the outstanding repairs. The spillway at Isimba cannot safely discharge large volumes of water if river flows increase.
UEGCL has previously reported that the spillway, designed to discharge 4,500 cubic metres of water per second, has been severely affected by concrete erosion, damaged buffer blocks and gaps in the concrete slabs.
When Kamya visited the site
During an inspection by the former Inspector General of Government, Beti Kamya, in 2025, officials said the spillway could discharge less than 40 per cent of its design capacity without causing dangerous vibrations across the structure.
The defects have persisted despite emergency repair attempts following flooding in August 2022.
UEGCL has said subsequent inspections found continued erosion and damage to the spillway’s concrete components.
Kamya and her team had launched an investigation to find out who would be held accountable for the omissions at the dam.
She, however, left office before the findings of the investigation were made public.
In May 2026, UEGCL held further technical meetings with the contractor and engineering experts to review emergency repairs and consider longer-term rehabilitation measures.
The company said underwater inspections had identified additional erosion on the upstream side of the spillway.
The meeting at the dam was attended by the Owner’s Engineer and Prof. Mark Alexander from the University of Cape Town to assess progress on the ongoing emergency spillway repair works and agree on the next course of action.
That meeting, according to sources, discussed the need for the urgent commencement of concrete coring, sampling, and laboratory testing works to establish a comprehensive understanding of the condition of the spillway structure.
The stakeholders also explored a range of sustainable engineering solutions that will guide the long-term rehabilitation and protection of the facility, ensuring its continued safe operation for years to come.
UEGCL Chief Executive Officer, Eng. Dr. Harrison E. Mutikanga reportedly underscored the importance of timely action and the need to execute both the emergency underwater repairs and the emergency spillway channel works.
According to Eng. Dr. Mutikanga noted that underwater inspections had revealed additional erosion on the upstream side of the spillway, highlighting the urgency of implementing the recommended interventions without delay.
At the time, durable, long-term solutions had not been found to ensure the resilience of the plant.
The delays raise questions about how the repairs will be completed while maintaining the dam’s operations and managing the river’s flow.
The spillway is a critical safety component of the dam. It releases water that cannot pass through the turbines, helping to prevent the reservoir from rising to dangerous levels.
UEGCL Chief Executive Officer Harrison Mutikanga has previously warned that the damaged structure could be vulnerable to hydraulic jacking, a process in which water penetrates beneath concrete slabs and exerts pressure that can lift them.
This could trigger backward erosion, potentially extending damage towards the dam’s foundation.
He stated that he personally gets sleepless whenever it rains. “When you have a spillway that is likely not to deal with its flood design capacity, and then you are getting a lot of rain, then you can’t stop worrying,” Mutikanga said during a previous inspection.
UEGCL engineers have in the past explained to Uganda Radio Network that the erosion of buffer blocks and the spillway’s concrete surface had exposed the structure to further damage.
Inspections had established that the defects were continuing to worsen, including gaps between slabs and erosion exposing reinforcement that could corrode.
Nile River flow slows repairs
The engineers also described difficulties carrying out repairs underwater while the River Nile continued to discharge large volumes of water.
Previous underwater repair attempts were suspended as river flows increased, prompting calls for the contractor to consider more comprehensive interventions under safer working conditions.
The government has maintained that CIWE remains responsible for rectifying outstanding defects under the engineering, procurement, construction and commissioning contract.
The government had not issued a completion certificate for the project because outstanding defects remained unresolved.
The government had retained financial safeguards, including a performance guarantee valued at about US$39 million, as well as other guarantees intended to protect its interests.
This was to ensure that the contractor delivered a plant that met the contractual requirements rather than simply obtaining compensation for the defects.
Isimba was commissioned by President Yoweri Museveni on March 21, 2019. The project was financed largely through a loan from China Exim Bank, with a government contribution.
The plant has continued to generate electricity, but its operational performance does not by itself resolve concerns about the spillway’s ability to manage extreme flows.
UEGCL’s Strategic Plan for 2025-2030 identifies Isimba dam failure as a risk being monitored and links the continuing risk to delays in resolving spillway defects by the engineering, procurement and construction contractor.
The defects have also raised questions about the role of Energy Infratech Pvt Limited, the Indian firm contracted to supervise construction at Isimba and Karuma dams.
The firm’s contract was terminated in 2017 following concerns about inadequate technical supervision. A project steering team led by engineer Badru Kiggundu found that the firm had failed to deploy some of the experienced specialists required to supervise construction, including quality-control and geotechnical personnel.
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