NGAMI, a shallow lake of variable size forming the centre of an inland drainage system in the Bechuanaland (q.v.) Protec torate, South Africa. The lake once extended to a length of 20 m. and a width of io m., but is now little more than an expanse of reeds growing in a soft soil, below which brackish water is found. It is cut by 201° S. and 23° E. Ngami is the lowest point of a large depression in the great plateau of South Africa. The area which drains to it is bounded south by the basin of the Orange, east by the Matabele hills, north by the western affluents of the Zambezi. The greater part of the Ngami water-system lies, how ever, north-west of the lake in the Angola highlands. On the high plateau of Bihe, in the hinterland of Benguella, rise two large rivers, the Okavango and the Kwito, which uniting discharge their waters into Ngami. From the north-east end of Ngami issues the Botletle or Zuga, a stream which runs south-east and drains towards the Makdrikari marsh, from which there is no outlet.
Although Ngami has contracted in size in modern times the Okavango and its tributary the Kwito remain large rivers. The Okavango is known in its upper course as the Kubango. Its most remote source lies in about I2-1° S. and Or E. and its length is over 90o m. It flows first south then south-east and east. In about 18° S. and 20r E. it is joined on the north bank by the Kwito, a large navigable stream rising almost as far north as the Okavango. Its general course is south-east, but between 15° and 17° S. it flows south and even south-west. Below the Kwito con fluence the Okavango, which is also joined by various streams from the south-west, is a rapid stream, generally navigable as far as the Popa falls, in 2 so' E. In the dry season, the water-level
is from 4 to 20 ft. below the banks, but these are overflowed dur ing the rains. At this period, April–June, some of the surplus water finds its way (in about 19° S.) by the Magwekwana to the Kwando or Linyanti (Zambezi system), to which, it is thought, the whole body of water may have once flowed. Below the Mag wekwana outlet the Okavango, now called the Taukhe or Tioghe, turns almost due south, enters a swampy reed-covered plain and is broken into several branches. In this region the effects of desic cation are marked. Through the swamps the river formerly entered Ngami. Through the swamp some of the waters of the Okavango find their way eastward through a channel called Tamalakane to the Zuga or Botletle, the river which formerly flowed out of Ngami. The Botletle, whose bed is about zoo m. in length, loses itself in a system of salt-pans—round or oval basins of varying size sunk to a depth of 3o to 45 ft. in the sand stone, and often bounded by steep banks. The outer pans are dry for a large part of the year, the whole system being filled only at the height of the flood-season in August. The Botletle, which receives in addition the scanty waters of the northern Kalahari, at this season reaches the Makarikari marsh. In 1849 Livingstone found a large shallow lake. In 1896 Lugard and Passarge both found none. (See S. Passarge, Die Kalahari, 1904.)