Geology

The Okavango Swamp was created by the sinking of the earth's crust, between a series of parallel faults across the Okavango River. It is thought that around 200 million years ago, the Okavango River probably joined the Limpopo River and reached the sea, but the tectonic activity diverted the Okavango River into the Kalahari. The great Makgadikgadi Lake was the original output for the Okavango River, but due to silting and continuous imperceptible uplifting of the land, the lake disappeared, creating the new basin in which the Okavango now stalls and stagnates. The soils of the Okavango Delta are primarily sand, along with the almost 2 million tons of silt that are carried along the river from its headwaters to its ultimate end in the Kalahari Desert. The Okavango river is funneled through parallel faults of the Panhandle as a deep and fast-flowing river before being confronted by another perpendicular fault with a sudden increase in gradient. This slows the water as it spreads into relatively shallow sediment with a fall of only 62 meters over approximately 250 kilometers. Today, during the flood period only 2 to 3% of the annual inflow finds its way into the Thamalakane River, where it is then distributed to the Boteti, towards the Makgadikgadi Pans, the Nhabe, and eventually into Lake Ngami.

The boundaries of the delta are constantly shifting--depending on the degree of flooding in a particular year. In normal flood years, the river carried two million tons of Angolan and Namibian soil--sand, leached nutrients and topsoil--to deposit along the major channels. The soils are then carried off by termites for their nests, or warped and shaped by low-level tectonic activity--these activities alter the landscape of the channel and reshapes the delta.

After a series of earthquakes in 1952-53, the Boro River, which passes directly through the heart of the Okavango Swamp, began flowing for the first time anyone could remember.