- THE Zambezi River Authority, which manages Kariba Dam and its catchment, says the inland lake has recorded a significant increase in water level as a result of improved inflows, although water for power generation remains generally limited.
Kariba Dam is fed by Zambezi River which starts from northern Zambia and passes through Angola, Namibia, Botswana into Zimbabwe before flushing out to Mozambique into the Indian Ocean.
In a statement, ZRA chief executive Munyaradzi Munodawafa said dam water is now two metres above operating water level.
“The Zambezi River flows monitored at Victoria Falls rose from 349 m3/s at the start of January 2020 to 3,890 m3/s recorded on 27th March 2020. The flows are now 54 percent above the recorded long-term average flow of 2,522 m3/s for this station.
“The lake level rose by 97cm between 1st January 2020 and 27th March 2020. As of 27th March 2020, the recorded lake level at Lake Kariba was 477.64m, signifying 14.86 percent live storage or 9.63 billion cubic meters of usable storage with the lake being just over 2 metres above the Minimum Operating Level (MOL).
“However, this recorded volume of stored usable water is 60 percent lower than that recorded on the same date last year at a lake level of 480.73m with 24.16 BCM or 37.28 percent usable storage with the lake being 5m above the MOL,” said Munodawafa.
Last year, on the same date, the recorded flow was 800 m3/s.
Munodawafa said the increase in the lake levels at Kariba is attributable to the improvement in the inflow from the upper Kariba catchment.
He said during the period October 2019 to Mid-March 2020, the total inflow into the Lake stood at 10.54 BCM when the historical average for this period is no less than 14.39 BCM.
“The below average inflow recorded to date under the 2019/2020 rainfall season accounts for the low water levels that continue to be recorded at Kariba,” he said.
The Zambezi River flows rose from 236 m3/s at the start of January 2020 to a peak of at 5,006 m3/s recorded on 25th February 2020 after which the flows receded, ZRA stated.
The water levels at Kariba are mainly influenced by the inflows into Lake Kariba from the Zambezi River and its tributaries located in the Kariba catchment.
ZRA has 14 gauging stations located within the Kariba catchment including Chavuma and Victoria Falls upstream Munodawafa said ZRA allocated 22 Billion cubic meters to be shared equally between the two power stations at Kariba hence limiting the combined power generation output to an average 550MW for both stations.
“The Authority has maintained this water allocation for the remainder of the 2020 period in the wake of the below average lake inflows under the 2019/2020 rainfall season in an effort to ensure build up the reservoir storage.
The river authority has however said significant water level increase has been recorded upstream at Chavuma Station where on Friday the river flow was at 4,559 m3/s while last year same date it was 732 m3/s.
The current flows at Chavuma are so far the highest in the last twenty years as water level rose by 523 percent better than in 2019, Munodawafa said.
This has seen the Victoria Falls regaining its volumes with the thundering falling water and showers returning.
ZRA authority says it will take four weeks for the flows at Chavuma to reach Victoria Falls owing to the significant influence of the Barotse Flood Plains in Zambia which are now full.
ZRA is a jointly and equally owned organization Zambia and Zimbabwe and is tasked with managing Kariba dam and develop additional water storage infrastructure along the shared river.