21/12/2024
LAKE KARIBA IS STILL TWO-THIRDS FULL!
HERE ARE THE FACTS
With the 2024-2025 rainy season having started at last in the Zambezi River Catchment Area, after a period of drought this past year, it seems important to stress, once again, the realities of lake levels in Lake Kariba, which will start to rise as rain inflows arrive in the next few months.
If you look at the Zambezi River Authority's latest (16th December 2024) graphic pictured above, it shows the dam's Live Storage in light blue. This is the water that lies above the dam's hydro-electric turbines in order to ensure that they can operate to produce power. In other words, the light blue is water USABLE for electricity. UNUSABLE water (also known as Dead Storage (shown in dark blue on the graphic) is the water that lies below minimum operating level for the electricity turbines. This is a large amount of water which, although unusable for electricity generation, still remains in the lake for recreational purposes!
In terms of percentages and figures, here are two ways of looking at it.
The dam wall is 128m high. The high water mark is 6m below the top of the wall. So there is 122m of water when the lake is full. The Live Storage or Useable water to produce electricity is 13m below high water. This means the Dead Storage of water below minimum Turbine operating level is 109m. 109m/122m = 89% full using the dam wall as a barometer.
Another way of looking at it is by volume. The Lake holds 181BCM (Billion Cubic Meters) of water when full. If you look at the diagram, the Dead Storage level i.e. below minimum operating level for the turbines, holds 116BCM. Therefore the lake is 116BCM/181BCM = 64% full by volume.
A great analogy for this is that if the level of your swimming pool is below the weir, your pool is not empty. It is rather nearly full, but below the operating level of your pool pump.
Thanks to Mark Lawrence of Cutty Sark in Kariba for this practical explanation. He also advises that the road between Harare and Kariba is in much better condition than it has been for months! So get on up to the Lake and enjoy some sunshine, fishing and relaxation!
