The Kafue River is the longest river lying wholly within Zambia at about long. Its water is used for irrigation and for hydroelectric power. It is the largest tributary of the Zambezi, and of Zambia's principal rivers, it is the most central and the most urban. More than 50% of Zambia's population live in the Kafue River Basin and of these around 65% are urban. It has a mean flow rate of 320 m³/s through its lower half, with high seasonal variations. The river discharges 10 km³ per year into the Zambezi River. Course Sources The Kafue River rises at an elevation of 1350 m on the relatively flat plateau just south the border between Zambia and the Democratic Republic of the Congo 120 km north-west of Chingola in the Copperbelt Province. The source of the Kafue River is in the North-western Province of Zambia. The area is Miombo woodland on the Congo-Zambezi watershed, with many branching dambos lying 10 to 20 m lower than the highest ground, producing a very gently undulating topography. The river starts as a trickle from the marshy dambos (the Munyanshi Swamp is a tributary) and with little slope to speed up river flow, it meanders south-eastwards sluggishly and within 50 km has the character of a mature river. The area receives about 1200 mm of rain in the rainy season, and the river's channel soon reaches 100 m wide with a floodplain of fluvial dambos 1–2 km wide. Through the Copperbelt Before the river reaches the Copperbelt towns, however, it loses its wide floodplain, the channel narrows to 30–40 m and it meanders less, in a shallow valley only 40 m or so lower than the surrounding plateau. It flows close to the Copperbelt towns of Chililabombwe, Chingola and Mufulira, and through the outskirts of Nchanga and Kitwe. The popular picnic spot the Hippo Pool north of Chingola is protected as a national monument. In the Copperbelt, water is taken from the river to irrigate small farms and market gardens. At Kitwe it changes course to the south-west and flows through forest and areas of flat rock over which it floods in the wet season, keeping to a channel about 50 m wide in the dry season. Lukanga Swamp The river again develops intricate meanders and a maze of channels in a swampy floodplain, with oxbow lakes and lagoons. It flows 20 km west