I have Macro question, and have enquired and discussed this topic with numerous people. My background is more in Economics and Finance, and read a very interesting article if I am not mistaken 10-15 years ago in the Farmers weekly of a WITS (Witwatersrand University Johannesburg) Geography professor who did a study in +-1905. Much of the article had to do with energy and the amount of energy used for cloud formation and movement from the Coast into the central parts of Southern Africa. Energy at the time I assume was a "buzz topic" as Electricity was in its early stage.

The Professor had, among others, identified a location on the Zambezi River where the Zambezi and Chobe rivers meet +-40km upriver from the Victoria Falls, I assume close to the newly built Kazungula Bridge?

In essence the suggestion was that by the construction a 14 meter high, controllable weir, in times of flooding the river would be able to flow along the ancient route, filling Lake Liambezi, and pushing back to Maun and back via the Boteti river ultimately filling the Makgadikgadi pans. This would also mitigate he flooding downstream in Mozambique.

Building a 14m high Weir 1km wide using human and animal labour was an immense challenge 120 years ago. With modern earthmoving equipment such a task would be like building a "big farm dam" today!

My question and thinking - this would refill the MASSIVE "evaporation pans" as they were centuries ago, which would in turn raise the rainfall in especially the winter months in much of the Northern Cape, and especially Botswana moving over to Limpopo province, and ultimately raise the Average Rainfall throughout the entire Southern Africa. The thinking is that Lake Malawi and some of the lakes further north have large cloud formations late afternoons?

I assume in the 1900's many studies were done on energy rather than Water supply, with a considerably lower world populations at that time and sufficient water per capita. Thus the building of the Cahora Basa dam and Lake Kariba for Hydro Electricity

Today Climate change and its consequences are some of the biggest challenges facing Humanity, with water scarcity being the big factor in Sub-Sahara Africa.

By Ultimately raising the Rainfall in the entire Southern Africa, through the managed and controlled filling and utilization of the Natural 30 000 - 60 000 square km of evaporation pans more regularly, will this not lower the extreme temperatures (day and night temperatures due to water absorbing much of the daytime heat and releasing it during the night) and drought patterns Southern Africa has experienced, and by all predictions are bound to worsen and could become more extreme? In effect, creating a second Okavango Delta, but considerably bigger - large parts of Chobe.

A study of such a magnitude will need large amounts of research in multidisciplinary sciences, from Archaeology to Agriculture to Economics, and a much broader field of expertise - the biggest being Politics!

Could such a mammoth project not be but one small answer to a much bigger Climate Change challenge facing the Earth? (and ultimately send a bit of rain to my little piece of land in the Waterberg in the long dry winter months when we receive those dry West Winds - and fires become a serious hazard - simply by adding a bit of moisture from the vast pans Botswana are so blessed with!)

My mind has been going in circles as to the feasibility of such a mammoth, yet so cheap and easily implementable idea?

Any ideas?

  • $\begingroup$ Sorry, it is the Chobe Rivier running through the Caprivi Delta. $\endgroup$ Jun 13, 2022 at 20:26
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    $\begingroup$ You likely overestimate the atmospheric affect of such a redirection... the Salton Sea for example in California, US, an accidental rerouting of the Colorado River 100 years ago, and Lake Meade (a reservoir created by damming) add up to be a fair fraction of your area, yet there hasn't been grand new rainfalls (and each took prolonged storage of the majority of the Colorado River to fill initially). I believe the answer to problems tend not to be so simple... few realize the scale of the atmosphere (or Earth)... it took a century of worldwide pollution to alter Earth's temperature a degree $\endgroup$ Jun 14, 2022 at 6:10
  • $\begingroup$ The pans were permanently full many centuries ago as have been found by archaeological sites. The entire "bushveld coal complex" a few hundred kilometres to the east had large swathes of forests, with "desert creep" encroaching with each passing decade. The deepest parts of the pans should be close to 20m, thus the waters should be very warm. The altitude at 900m above sea level should also assist in precipitation? All questions I do not have expertise in? $\endgroup$ Jun 14, 2022 at 14:39
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    $\begingroup$ Correlation does not imply causation. Or better put... the basins were full and the area forested probably BOTH because the regional/global weather pattern was different, the (in the grand scheme of things) small traps more probably weren't the cause of the difference. Small alterations in weather are possible, but hard to predict where/how much... and would more likely take geologic timescales for any positive feedbacks to amplify enough to bring real notable change. My thinking at least :-) $\endgroup$ Jun 14, 2022 at 17:21
  • $\begingroup$ (As you mentioned it in a comment to an answer, here is the input you got on the same question on WorldBuilding SE, so everyone can use it as well) Generally on SE we request you try to avoid posting the same question in multiple places, and if told its off topic and belongs somewhere else, it can be flagged to be transferred to the proper site. But understand you are new to the site, so just a heads up) :-) $\endgroup$ Jun 15, 2022 at 18:38

1 Answer 1


We agree that additional evaporation enhances energy transport from the surface to the atmosphere and intensifies the hydrological cycle and cloud formation, and that some of the most serious climate change issues such as:

  • Rapidly expanding deserts with forest and species extinction
  • Accelerated rising sea level and earth temperature
  • In many places sinking groundwater levels, drainage of the regions and continents -Periods of drought with temperature records and heavy rain events with flooding …are all linked to the presence or absence of water !

You can read here what a slightly modified concept for reducing sea level rise through water and rain retention and for cooling the Earth's temperature through additional cloud albedo could look like: https://climate-protecion-hardware.webnode.page/english/

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    $\begingroup$ Are you associated with that website? You've used that text and link in several answers and that can start to look a bit spammy. $\endgroup$
    – Deditos
    Jun 15, 2022 at 8:15
  • $\begingroup$ Sorry, I posted the same question on an incorrect "fictional" StackExchange website - was only informed afterwards that my question was a "real world" question, and not "fictional- would be better placed on the "real world" exchange. Embarrassed from my side. Got some brilliant answers none the less, even though it was on the Fictional exchange- supper impressed!! $\endgroup$ Jun 15, 2022 at 14:49
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    $\begingroup$ @CharlYazbek Don't worry, my comment was about this answer rather than your question. $\endgroup$
    – Deditos
    Jun 16, 2022 at 8:02

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