|
The Swakop River (Khoekhoe: ''Tsoaxaub'') is a major river in the western part of Namibia, reaching the sea at the southern edge of the city of Swakopmund (German for ''Mouth of the Swakop''). The Swakop is an ephemeral river, its run-off is roughly 40 million cubic metres per annum. The Swakop River, along with its main tributary Khan, is one of the largest temporary water-bearing rivers in the dry western part of Namibia. It is 460 km long and has a 30,100 km ² large catchment area. In Swakopmund, it flows into the South Atlantic. The name comes from the Khoekhoe languages of the Nama and Damara ''Tsoa-xaub''. ''Tsoa'' means ‘excrement opening’ or ‘anus‘ while ''xaub'' stands for the ‘contents of excrement.’ This name derives from the observation that the flow of large amounts of brownish sludge in the rain with it and discharges into the Atlantic Ocean. The area around the river mouth and the surrounding dunes are also known for rich bird life and some unusual plant species (like the Welwitschia) that use the regular fog drifting in from the sea to sustain themselves in the absence of other moisture. Groundwater levels in the area have also dropped about 0.3 m further due to the presence of two big dams built on the Swakop River.〔 Notwithstanding the river’s irregular flow, some agriculture is undertaken in the Swakop River valley, thus the region is well known for its fresh produce, especially tomatoes, asparagus and olives. There are some fears of salt and uranium (possibly natural, possibly from the Rössing uranium mine) endangering this farming industry.〔''(Uranium in groundwater 'not serious': Roessing )'' - The Namibian, Friday 24 June 2005〕〔(【引用サイトリンク】title=''Rössing in the Erongo Region'' )〕 ==Hydrology== The Swakop drains a catchment area of 30,100 km² extending from the mouth into the Atlantic Ocean at Swakopmund over Otjimbingwe and in the east to about 50 km from Okahandja, and in the south to Khomas Highlands outside Windhoek. The highest point of the watershed is located at 2480 m. Annual rainfall varies from 0 mm in the lower reaches up to 475 mm in the eastern Khomas Highlands. 39% of the catchment area experiences rainfall that exceeds 300 mm per year, and up to 80% of the catchment experiences annual rainfall above 100 mm. The Von Bach Dam near Okahandja and Swakoppoort Dam west of Gross Barmen in the upper reaches of the Swakop are of great importance for the water supply of Central Namibia. Like all rivers, the Swakop also has a number of major sources and major wetlands in the lower reaches. Existing groundwater, however, is often salty due to soil salinity. On the lower reaches of the river, flooding has become ever more increasing, due to increased land use of the Swakop gallery forests. This contributes to a stronger and more rapid runoff and increased erosion of the Swakop Marshlands. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Swakop River」の詳細全文を読む スポンサード リンク
|