Inflows into Kariba and Victoria Falls rise to a 13-year-high

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The Zambezi River Authority says water inflows into the upstream of Kariba and Victoria Falls have risen to levels last seen in 2006-7 season.

However, ZRA warns that electricity generation from Lake Kariba remains depressed as the Kariba dam wall’s water levels are yet to rise significantly.

Flows at Victoria Falls have increased by 25 percent, averaging 831 m3/s from the 663 m3/s flowrate recorded on February 7, 2020.

This comes as Lake Kariba levels increased in the past weeks and hydrological simulations have estimated that the levels will reach their peak in June this year at 478 metres, which will be about three metres above the minimum operating levels for power generation.

ZRA Chief Executive Engineer Munyaradzi Munodawafa said figures point to a marked improvement in inflows at Victoria Falls at the end of March.

He said indications are that the Barotse Flood Plains are filling up and expected to peak in March.

The flood plains, which are estimated to store 8,6 billion cubic metres of water, draw much of the flows that would have been recorded at Chavuma.

With them filling up, the resultant increased run-off is consequential to Victoria Falls and Lake Kariba, but ZRA has ruled out an immediate review of water allocations for power generation.

“A notable increase in the Zambezi River flows was recorded at the Chavuma Gauging Station, increasing by as much as 3 159 m3/s between the 7th and 21st February 2020, an indication of intense run-off from the rainfall received in the area around the Zambezi headwaters.”

“The flows recorded at Chavuma have continued to rise, trending above the long term average by 208 percent when you compare the current flows recorded on 21st February, 2020 of 4 621m3/s with the long-term average flow of 1 500m3/s.

“Further, the Chavuma flow recorded on 21st February, 2020 of 4 621m3/s is also the highest flow observed in the month of February since 2006-07 when a flow of 4 065m3/s was recorded on 14th February 2007,” he said.

Mr Munodawafa said Lake Kariba was affected by low inflows between October 2019 and January 2020.

ZRA has put a cap of 22 billion cubic metres of water for power generation, about 12 billion cubic metres less than the 34 billion cubic metres allocated last year.

This translates to an average production of rate of 550MW shared equally between to riparian states.

“It is worth noting, however, that despite the increase in rainfall activities in the Kariba catchment area, there has been no significant rise in the Kariba Lake levels. Therefore, generation capacity remains constrained.”