Zambezi km from the sea the Zambezi receives the drainage of Lake Malawi through the Shire River. On approaching the Indian Ocean, the river splits up into a delta. Each of the four primary distributaries, Kongone, Luabo and Timbwe, is obstructed by a sand bar. A more northerly branch, called the Chinde mouth, has a minimum depth at low water of 2 m at the entrance and 4 m further in, and is the branch used for navigation. 100 km further north is a river called the Quelimane, after the town at its mouth. This stream, which is silting up, receives
Zambezi sourced from the same great internal lake. The Portuguese were also told that the Mozambican Espirito Santo "river" (actually an estuary formed by the Umbeluzi, Matola and Tembe rivers) was sourced from a lake (hence its outlet became known as Delagoa Bay). As a result, several old maps depict the Zambezi and the "Espirito Santo" rivers converging deep in the interior, at the same lake. However, the Bisa-derived etymology is not without dispute. In 1845, W.D. Cooley, examining Pereira's notes, concluded the term "Zambezi" derives not from the Bisa people, but rather from the Bantu term "mbege"/"mbeze" ("fish"), and consequently