Kariba floodgates partially opened

The Zambezi River Authority (ZRA) has begun commissioning tests on the newly rehabilitated sluice gates at Kariba Dam, marking a critical phase in the near-completion of a major rehabilitation project that began in 2019.

Last Friday, ZRA engineers conducted a controlled release of water from one of the dam's floodgates, known as Sluice No. 2, allowing water to plunge briefly for approximately four minutes into the reshaped plunge pool below the dam wall. The tests are part of a rigorous quality assurance process to ensure the structural integrity and functionality of the refurbished gate.

According to ZRA planning officer Engineer Munesushe Mudzi, the test involved releasing around 1,500 cubic metres of water  -  the equivalent of what is used in three seconds of power generation by one turbine.

"Today, we were commissioning Sluice No. 2 that we have been working on since 2019. The tests are part of the quality checks that we do," Eng Mudzi explained. "We used 1,500 cubic metres of water, and in terms of power generation, this is similar to three seconds of turbines turning."

The plunge pool reshaping was a key component of the overall project, aimed at mitigating the risk of scouring at the dam's base, which had developed due to decades of high-pressure water flow during floodgate openings. The commissioning test focused on evaluating not only the gate's mechanical performance but also the watertightness of the stop beams that control water discharge.

"The stop beams have to be tight when closed to ensure that no water passes through," Eng Mudzi added, noting that the results of the test were promising.

The Kariba Dam rehabilitation project is being jointly funded by the European Union, the World Bank, the African Development Bank, and the Zambezi River Authority. It comprises two key components: the reshaping of the plunge pool and the refurbishment of the spillway gates  -  both aimed at ensuring the long-term safety and operational efficiency of one of southern Africa's most important hydropower facilities.

Kariba Dam, which straddles the border between Zimbabwe and Zambia, is a vital source of hydroelectric power for both countries. Its safety and reliability are crucial to the region's energy security.

With commissioning tests now underway, ZRA officials are optimistic that the decades-old structure will continue to operate safely and effectively for generations to come. The full rehabilitation project is expected to be completed later this year.