Lake Kariba is now more than 5 metres above the minimum operating level, that is the inlets to the two power stations, and is still rising even before the main floods bring down the main water flows from south-eastern Angola and north-western Zambia.
A latest update from the Zambezi River Authority showed that the water level on Tuesday was 5,26m above the minimum operating level having risen 3,96m since January 19.
The present level means that there are 24,31 billion cubic metres of live storage, that is water above the minimum operating level around three times the 7,48 billion cubic metres this time last year. A billion cubic metres is a cubic kilometre, a cube 1km on a side.
Lake Kariba, the world’s largest reservoir, is a major source of water for power generation, domestic consumption, fisheries and wildlife.
Above normal rains in the present rainfall season have boosted water levels helping the authority to maintain the ration of 30 billion cubic metres of water allocated for power generation operations at Kariba for this year.
“The authority continues to monitor the evolving hydrological situation under the Kariba catchment. This is being undertaken, taking cognisance of the increased rainfall activity, and resulting water levels at Kariba Dam, with the view of making consideration regarding the possibility of revising the water allocation at Kariba Dam,” it said in the latest update.
The rationing was set to ensure that there was a reserve beyond what was discharged through the power stations in case there was another drought. The Zambezi never runs dry, but dry season flows are below what the power stations normally use, hence the need for the rationing,
Lake Kariba is 223km long and stretches 40km across at its widest point.
The authority records daily water levels of the Zambezi River at its 14 gauging stations located across the Kariba catchment to plan reservoir operations at Kariba Dam.