of the permanent part of the Lukanga Swamp which fills a circular depression, and which drains through a channel into the Kafue. The area between the swamp and river is flood plain and when that and surrounding areas are inundated in the rainy season, the combined wetland exceeds 6000 km2. This is the first of the three main wildlife areas of the river, and the least surveyed and protected. Through Kafue National Park The character of the river changes again, as it forms a less meandering dry-season channel with sandy banks and islands. Continuing south-west it enters the Kafue National Park, second largest national park in Africa, where it receives its two largest tributaries, the Lunga and Lufupa rivers, also from the north. The Kafue skirts the south-east edge of the Busanga Plain, one of Africa's premier wildlife areas, known for large herds of cape buffalo, zebra and antelope. In the rainy season the Lufupa floods the plain. Itezhi-Tezhi Gap Like the upper Zambezi, Okavango and Cuando rivers, the Kafue used to flow south all the way to Lake Makgadikgadi and on to the Limpopo River, but the land in that area was uplifted. A rift valley formed running due east of where the Kafue National Park is now, and the Kafue river eroded a channel called the Itezhi-Tezhi Gap through a ridge of hills about 100 m high, flowing eastwards. The Itezhi-Tezhi Dam was built in 1977 at the gap and now forms a reservoir 50 km long and up to 10 km wide. Kafue Flats Further east, the river flows sluggishly across a flat plain called the Kafue Flats (formerly Butwa after the Twa people) and for the third time develops intricate meanders in a maze of swampy channels and lagoons. This time however it also has an immense shallow flood plain which no roads or railways cross, 240 km long and about 50 km wide, flooded to a depth of less than a metre in the rainy season (deeper in some lagoons and permanently swampy areas), and drying out to a clayey black soil in the dry season. The Kafue Flats are the third major wildlife area of the river. Tens of thousands of Kafue Lechwe live on the Kafue Flats and are adapted to wading the flooded areas. This area also has one of the greatest variety and concentrations of birds in the world. The Lochinvar