Neanderthals keep turning out to have been more capable and smarter than previously thought.
Given the suggested age of 130,000 years old, that would put it around the peak warm before the beginning of the last Ice Age. At that point, sea level would have been similar to ours which means hominids would be living at current altitudes. Certainly if as the ice began to “swallow” the oceans, then “civilization” would have moved closer to the shoreline and now have been drowned. This whole situation tends to confirm my theory (and that of others) that hominids may have reached relatively high levels of development that were then destroyed by the 100,000+ intervals of Ice Ages.
Regarding civilization in the Okavanga Delta region. The evidence is more than tantalizing, it is monstrous. An area between 300 miles and 400 miles square shows repeated patterns of extended “canals” about a mile apart and running for many miles. Some areas look more weathered that others, and what little data I could find suggest that some areas could be tens of thousands of years old. The nearest “civilization” is Great Zimbabwe in Zimbabwe to the east. The link below shows one photo that probably covers 40 or 50 miles width of land (given that the “furrows” are a mile apart. Check out the video, and then click the Google Earth site. I once spent several hours tracing the GE map throughout the region and it was indeed about 400 miles across. I am astonished that National Geographic or other suitable group has not made a significant effort to study this.
http://solarey.net/large-ancient-irrigation-system-found-south-africa/
At this site are a number of areal images of the irrigation mixed in with a lot of other African images.