Click the above link, click on Satellite view, and zoom out. You will see the entire "canal" system, which is very large.
Excellent! That image clearly shows the Okavango Panhandle and the huge delta.
Holy Crap... those structures extend all the way to just north of Etosha National Park. I am boggling here that I never heard of this before.
From that view it would appear that the Okavango Delta is the drainage point from the suspected canal system. Just spitballing but perhaps the system collapsed when the lower end, the Okavango, catastrophically gave way and drained the “farm.”
I have now read the whole article and looked carefully at the map and have some conclusions. The writer has given us a fantastically interesting puzzle. Visually, it is much too regular to not be man made. I think I detect variances in widths in different regions. Some areas are more degraded than others. The water source is definitely the Okavango, and perhaps another river to the east which is much smaller. [I once saw a NOVA film showing how that area changed from wet to dry season, and that too was amazing. Huge increase in amount of water and flooded area.] Lines occur both east and west of Okavango, also north and south. Looking at areas between Okavango and Etosha I see faint hints of square and rectangular patches that look like they might have been delineated property areas. Perhaps concurrent with the use of the canals, or perhaps later land holdings.
The author’s thoughts on age refer to 7,000 years ago, and also 11 to 14 thousand years ago, in other words before and after the disaster that caused the Younger Dryas cooling. [SC, time for that Firestone book.]
In response to a question the author spouts some totally nonscientific thoughts on the age of dinosaurs not being 65 million years old because they are found on the surface. He does not seem to realize that many finds have been made of dinosaurs from cliff faces and road cuts into rocks of great age, and also between volcanic deposits that can be precisely dated. For that matter the Leakey’s found most of their million years old hominid remains on the surface of land where the newer layers had washed/eroded away. So far as his grasp of science is concerned, I am reminded of the saying—even a stopped clock is correct twice a day. Nevertheless, he has brought to our attention a truly exciting and complex puzzle on human civilization and is to be thanked.