The region is right on the edge of the Okavango Delta. Why don't you download Google Earth, it's free, and have a look for yourself? You might even enjoy a trip through the Vernuekpan Basin. It's not far away.
Quite simply the writer is a typical charlatan. He makes declarations of facts that just aren’t true like claiming nature doesn’t make straight lines.
Personally I suspect that they are prehistoric Dunes from an arid period in Africa’s distant past. For instance, during the last ice age the Sahara was much greener and the deserts of Africa were further south.
Too many major problems like where did these billions of people go without leaving any trace by their “canals”.
The region is right on the edge of the Okavango Delta. Why don't you download Google Earth, it's free, and have a look for yourself? You might even enjoy a trip through the Vernuekpan Basin. It's not far away.