malvernmugadzikwa
Sunday Mail Reporter
THE multi-million-dollar Kariba Dam Rehabilitation Project (KDRP) — a critical undertaking meant to extend the life of the dam and ensure stable power supplies in Zimbabwe and Zambia — is now 93 percent complete.
Last week, contractors completed excavation of the dam’s plunge pool, marking a major milestone in the project, which began in 2017.
The ambitious US$294 million project, aimed at reshaping the plunge pool and refurbishing the spillway, promises to extend the dam’s lifespan by 60 years and bolster hydropower generation.
In a statement, the Zambezi River Authority (ZRA) said: “Excavation of the plunge pool, a key milestone in the plunge pool reshaping sub-project of the Kariba Dam Rehabilitation Project, has been successfully completed.
“In total, about 300 100 m³ (about 750 000 tonnes) of rock have been excavated through meticulous drilling and controlled blasting, coupled with the stabilisation of 20 000 m² of slopes using anchors and shotcrete.
“While the excavation works are now 100 percent complete, the overall project is now 93 percent complete.”
The project’s key components include reshaping the plunge pool, an undertaking that involves excavating and reshaping the 80-metre-deep plunge pool at the base of the dam to prevent further erosion and improve water flow.
Refurbishing the spillway, which involves upgrading the spillway gates and control systems, is expected to enhance flood control capabilities and ensure the dam’s safety during heavy rains.
The project also includes institutional strengthening of the ZRA, a component that focuses on equipping the authority with the necessary expertise and resources to effectively manage the dam in the long term.
“As 2023 draws to a close, we commence the final phase of this extraordinary engineering marvel and remain focused on the upcoming challenges related to the strengthening of
the geological fault zone that is located immediately downstream of the dam,” said
ZRA.
“This will be achieved through constructing a reinforced concrete slab that will cover the weak-rock zone to protect it from possible future erosion.
“Upon completion of this concreting work, the plunge pool will be re-watered (refilled with water).”
Refilling of the plunge pool, said the authority, will not affect river levels downstream.
Added ZRA: “The objective of the plunge pool excavation works was to widen and change the shape of the 80m plunge pool, which was created by the immense pressure of the ejected water jets during spilling episodes.
“It is worth noting that the ongoing works are an outstanding engineering feat, with the plunge pool reshaping component particularly taking the trophy for an unprecedented scope of works.
“Upon completion, the KDRP will be recorded in history as the first project of this magnitude ever undertaken with open-pit excavation at the foot of a 60-year-old dam with underground power houses on either banks of the river in full operation.”
It is anticipated that the project will be completed in 2025, when the spillway refurbishment sub-project is finalised.
The Kariba Dam, built in the 1950s, anchors electricity generation for both Zimbabwe and Zambia.
However, years of erosion and wear had threatened its structural integrity and reduced its hydropower output.
Online Reporter