Floods of the Okavango finally arrived in Maun early this week. The water is currently flowing slowly through the Thamalakane River to the enjoyment of Maun residents. The Thamalakane river flows through a line of fault called the Thamalakane Fault that runs from the north to the south of Maun. Apparently, there are three prominent fault lines that resulted in the formation of the Okavango Delta.
These are the Gumare Fault in the north and the Thamalamakane Fault in the south and the Kunyere Fault. The formation of the Gumare fault caused a reduction in the elevation of the land, thus causing the water of the Okavango River to spread out over a much larger area of land and forming the now characteristic fan-shaped inland delta of the Okavango.
The Gumare fault separates the Panhandle from the alluvial fan of the Okavango Delta. The Kunyere and Thamalakane faults determines the flow of water in the Delta south-eastwards slowly and spreading into a fan. These two faults are fundamental in confining Delta’s alluvial fan. To the south end of the Delta are the Kunyere and Thamalakane faults.
The Thamalakane Fault marks the Thamalakane River which forms the most southerly extent of the Okavango Delta. Here the Thamalakane River collects the meagre outflow from the Okavango’s Delta and diverts it southwest along the fault line, and ultimately into Lake Ngami and the Boteti. Maun therefore sits in the narrow space between the Kunyere and Thamalakane faults.
Most of the Okavango Delta lies between the northeast-southwest trending normal faults (Gumare and Thamalakane faults) of the asymmetric Okavango Rift, which is commonly interpreted as a southwestern branch of the East-African Rift System. The Thamalakane River derives its flood water from the Boro River. More than 95% of the Okavango’s water evaporates before it reaches the Thamalakane River in Maun. The Thamalakane River deposits its flood water to the Boteti River, which flows through a break in the fault to Lake Xau and eventually the Makgadikgadi Pans. Thamalakane River also drains its flood water into Nhabe River which thus flows into Lake Ngami.
The Okavango Delta is the second largest inland delta in the world after the central Niger delta. It is one of the very few major interior delta systems that do not flow into a sea or ocean but drains inland into the Kalahari sands. The Okavango Delta is thus a large, flat wetland which covers thousands of square kilometers of the Kalahari Desert.
One of the unique characteristics of the annual flooding from the Okavango River Delta is that it occurs during the dry season hence flooding of the Thamalakane River this week (this is in exception of floods which occurs during the rainy season which is generally lower than the second flood that occurs in the dry season).
The case of the Okavango Delta and the water to be flowing in the Thamalakane River during the dry season is an exceptional example of the interaction between climatic, hydrological, and biological processes. While residents of Maun are excited about the arrival of the flood in the Thamalakane River, it is equally critical to advice people to be careful when enjoying the flood since it brings with it dangerous creatures which might be a danger to human life. In addition, conservation of the water is essential hence littering and poor waste disposal methods in recreation sites along the river should equally be avoided.