Waters tank/watershed/ water catchment area is a simple term used to mean an area of land where one all water flows into a single stream, river or water body. Nyungwe National Park one of the largest protected mountain rain forests in Africa. It extends to the Kibira National Park in Burundi and besides being a protected mountain rain forest that accommodates a big number of animals and plants, people depend on this forest when it comes to water.
Nyungwe national park is known as the water tank of Rwanda because 70% of the water people use in Rwanda is from Nyungwe national park because it is the furthest source of the Nile and the mother of Africa’s two largest rivers. These are Congo River which flows towards the west of Nyungwe National Park and River Nile which is fed by the rivers that flow towards the East of the Nyungwe National Park.
Nyungwe national park has many rivers and streams that are the source of a big river and Lakes after they unite forming the Water tank of Rwanda.
Rivers that flow from Nyungwe national park to westward empty into Lake Kivu which is one of the African Great Lakes. Lake Kivu lies on the border of Rwanda and DRC in the western part of Rwanda. Lake Kivu forms the River known as River Rusizi which flows southward and pours into Lake Tanganyika. Lake Kivu was named the eighteenth deepest Lake in the world with its maximum depth of 480m. Although the Lake is shared between Rwanda and DRC, 58 percent lies in DRC. Lake Kivu is approximately 50km wide and 90km long.
Nyungwe national park is the source of Rwanda’s major river (hence the water tank area) i.e. Nyabarongo River and it is Rwanda’s longest River. Nyabarongo River forms from the merge of the Two Rivers which are Mbirurume and Mwogo rivers and they both flow from Nyungwe national park in the Southwest of Rwanda. And the two rivers are the true source of the River Nile, and the Nyabarongo river acts as the boundary of the western province and Southern province. The river will merge with the other River from the North of the country which is Mukungwa River, then it flows towards the east of the country. It then takes about 12km and starts flowing Southeast of the country for the rest of its journey. The River Nyabarongo it is also the boundary that separates of Kigali city and the Southern province. On the other side, the Nyabarongo River is the boundary of Kigali city and Eastern province, between Kigali and the Eastern province where the two Rivers that are Nyabarongo and Akanyaru Rivers merge. From this merge, the River Akagera is formed and then the Akagera River empties into Lake Rweru from Eastern province of Bugesera district which then separates Burundi from Rwanda. The Akagera River continues and empty into Lake Victoria and form River Nile.
So its clearly understandable that Nyungwe national park is a water tank/watershed of Africa, in accordance with the sources of great rivers of Africa such as River Nile. And the rivers from Nyungwe that empty into the Great Lakes of Africa i.e. from Lake Kivu, Rusizi River to Tanganyika Lake and Congo River. Also from Nyabarongo River, Akagera River, Lake Rweru to Victoria Lake and River Nile.
If you take a look at the valleys around Nyabarongo and Akagera River, you will get to understand how the lives of the people around depend on those rivers. From their daily activities such as agriculture, for example, the wetlands of sugar cane plantation between Kigali city and Bugesera district in Eastern province, cattle rearing and all sorts of land cultivation. But also people around those rivers get water for daily use like cooking, drinking, and washing form the Rivers.
When you visit Nyungwe national park, you pass via countless streams and waterfalls especially the big one in a park known as Kamiranzovu waterfall where you will get to see why Nyungwe called Water tank of Rwanda.