Kariba Dam

The Kariba dam creates Lake Kariba,  one of the largest artificial reservoirs in the world that straddles the border between Zambia and Zimbabwe. The reservoir is an important resource for agriculture and fisheries; it is also a key source of hydroelectric power for the region with a storage capacity of 185 billion cubic meters of water.

Water first began to fill the reservoir in 1958, following the damming of the Zambezi River at the end of the colonial period. It was built to accelerate economic growth and ended up becoming central to the independent African states. With an installed capacity of 1,626 megawatts, today, Kariba provides the bulk of electricity consumed in both Zambia and Zimbabwe.

When the dam first was built the population of Zimbabwe was about 3.5 million and the population of Zambia was around 3 million. Today Zimbabwe has a population of 16 million and Zambia a population of 19.5 million. While Zimbabwe has been one of Africa’s agricultural powerhouses, Zambia has become urbanized and is a big global supplier of copper and cobalt that require energy-intensive production but are also crucial for battery manufacture and copper wire essential for power storage and energy transitions around the world.

For over a half-century, the lake level has seen ups and downs due to variations in water use and climate patterns. NASA now tells us that Lake levels plummet during El Niño years, when reduced rainfall upstream lessens the flow of rivers feeding Lake Kariba. Since 2000, El Niño events have been observed in 2002–03, 2004–05, 2006–07, 2009–10, 2014–16, and 2018–19. Nonetheless, the Lake has not been full since 2011. Lake Kariba is so low that Zimbabwe had to ration electricity because the hydropower from lake Kariba is Zimbabwe’s main electricity source. In truth, there are only a few hours a day when there is power. The drying up of the Kariba reservoir has devastating consequences not only for electricity generation but also for regional water supply.

 Zambia has managed their share of water resources better than Zimbabwe, so they still have a little bit of water available for power generation and public supply. Zimbabwe has suffered public sector corruption and mismanagement at the local and central government levels have exacerbated the problem. This appears to be a result of overuse and mismanagement of a slowly dwindling supply of water. You can’t simply point your finger at climate change. The river water flow is highly variable with weather and may be decreasing. However, the water use for power generation, urban populations, mining and agriculture has exploded. It is not and never was an unlimited resource. What once supplied the needs for 6.5 million people has failed to supply 35 million people. Hardly surprising.

                      

from NASA