Ngounie River

Ngounié
The Ngounié River flows through southwest-central Gabon, flowing through Mouila
Country	Gabon
Basin features
Main source	Chaillu Mountains, Republic of the Congo
River mouth	Lambaréné, Gabon
Basin size	33,100 km2 (12,800 sq mi)
Physical characteristics
Length	680 km (420 mi)

The Ngounié River (also Ngunyé) is a river flowing through southwest-central Gabon. It is the last and second most important tributary of the Ogooué River, the first being the Ivindo River. It initially flows down from the Chaillu Mountains, along the border with Congo, and then turns northwest, flowing through the towns of Fougamou, Sindara and Mouila before flowing into the Ogooué.

The river name, Ngounié, is a French rewording of "Ngugni", which was originally used by Vili language speakers in the Samba Falls/Imperatrice Falls area in the mid-1800s to call the northern border of their district, "Nsina-Ngugni". When Robert Bruce Napoleon Walker and Paul Du Chaillu arrived in the area, they wrote down "Ngouyai" or "Ngunyé". The Gisir and Punu language speakers of Gabon know the river as "Durembu-du-Manga", while the Apindji, Eviya and Tsogo speakers know it as Otembo-a-Manga. The Kele speakers know it as "Melembye-a-Manga". The first part of these names means "body of water" in the given languages, and "manga" refers to dwarf palm trees which grow along its bank.

The Ngounié River, with a basin area of about 33,100 square kilometres (12,800 sq mi), is the second largest tributary of the Ogooué River. It rises in the Chaillu Mountains. For 60 kilometres (37 mi), the river has a south and then west flow, and forms a border with Congo. At the Polo River confluence, it changes direction, heading northwest, before passing through three waterfalls. It then establishes a floodplain within a 220 kilometres (140 mi) valley between the Moukande Mountains and the Massif due Chaillu. After meandering for more than 400 kilometres (250 mi) on the valley floor, it joins the Ogooué prior to Lambaréné. Development in the floodplain occurs mostly in the areas between Lebamba and Mouila, and again from the Fougamou area to the Ogooué at Lambarene. Conservatively, the estimated valley flood land area is approximately 150,000 hectares (370,000 acres). The left bank is characterized by sandy clay soils.