Notwane River

Notwane River
Notwane River
	Kalahari
Mouth	Pala Camp
• location	Limpopo River, South Africa/Botswana border
• coordinates	23°44′56″S 26°57′37″E / 23.74889°S 26.96028°E
• elevation	847 m (2,779 ft)
Basin size	18,053 km2 (6,970 sq mi)

The Notwane River (or Ngotwane River) is a river in southeastern Botswana. Certain sections of its course form the international boundary with South Africa. Its mouth is at the head of the Limpopo River. It has a catchment area of 18,053 square kilometers.

Course

The Notwane rises about 11 kilometres (6.8 mi) south of Ramotswa, and runs along the border in a northeast direction to enter the Limpopo at the same longitude as Mahalapye.^[1] The Notwane has its source in the

sandveld, at the eastern fringes of the Kalahari Desert. It flows roughly northeastwards past the most densely populated area of Botswana, passing east of Lobatse, between the city of Gaborone and Tlokweng village and then through Mochudi village. Finally it joins the left bank of the Limpopo River at the border with South Africa, just 6 km short of the confluence of the Limpopo with the Matlabas River.^[2]

The Notwane basin is drained by the Notwane itself and its tributaries the Taung, Segoditshane, Metsimotlhabe, Metsemaswaane and Nywane.^[1] Its main tributaries are the

flash floods.^[3]

History

The banks of the Notwane River have been occupied since the middle Stone Age. The first modern settlement was

Tlokwa in the late 1880s, near the site of the modern capital.^[4] The city of Gaborone, an expansion of the earlier settlement, was developed on the Notwane River in the 1960s in part due to proximity to the railway, in part due to availability of water provided by the river.^[5]

Dams

The Gaborone Dam, which supplies water to the city of Gaborone, has a capacity of 144,000,000 cubic metres (5.1×10⁹ cu ft). Further upstream, the Ngotwane Dam in Lehurutshe, South Africa has a capacity of 18,000,000 cubic metres (640,000,000 cu ft). In the Gaborone dam catchment area there are many other dams, mostly very small, with only the Nnywane Dam near Lobatse being used for domestic water supply. Following a 1992 study on their impact on downstream water resources, a moratorium was placed on construction of small dams in the catchment area.^[6]

Fauna and Flora

Whilst the flow of the Notwane is ephemeral; biodiversity is the highest immediately upstream of the Gaborone Dam, north of the confluence with the Taung river. The riverbed in this area generally retains small pools of water, even during prolonged dry periods.

The

African sharptooth catfish, locally known as barbel, are the most common fish species in these waters. The river also supports smaller populations of bream, tilapia and introduced carp

.

Birdlife proliferates as one gets nearer to the Gaborone Dam, this includes a number of heron and kingfisher species. African fish eagle are seen regularly, along with reed cormorant and african darter. Verreaux's eagle-owl do occur in the area and yellow-billed kite are common summer visitors. Southern yellow-billed hornbill, southern red-billed hornbill and natal spurfowl are often seen in the surrounding woodland.