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Posts tagged Sofia River

Mayotte and Sediments from Sofia and Betsiboka Rivers Off Coast of Madagascar – September 21st, 2012

14.7S 46.8E

September 21st, 2012 Category: Image of the day, Rivers

Madagascar – September 16th, 2012

Rivers along the coast of Madagascar release rusty red sediments into the Mozambique Channel. Here, sediments can be seen spilling forth from the Sofia River (center, right) and the Betsiboka River (center, left). The sediments’ distinct red color is due to the red lateritic soils in Madagascar’s central highlands.

Visible by the top edge of the image is Mayotte, an overseas department and region of France consisting of a main island, Grande-Terre (or Mahoré), a smaller island, Petite-Terre (or Pamanzi), and several islets around these two. The archipelago is located in the northern Mozambique Channel in the Indian Ocean, namely between northwestern Madagascar and northeastern Mozambique. Mayotte’s area is 374 square kilometres (144 sq mi) and, with its estimated 194,000 people, is very densely populated (520 /km2 or 1,300 /sq mi).

Rivers Along West Coast of Madagascar

16.6S 44.4E

July 21st, 2010 Category: Lakes, Rivers

Madagascar - July 4th, 2010

Madagascar - July 4th, 2010

Upon opening the full version of this image, the entire western half and coastline of Madagascar can be observed. Several rivermouths can be seen along the shoreline, emptying sediments into the Strait of Mozambique.

Here, most of the sediments are flowing forth from the Sambao River, whose mouth is just below the westernmost point on the island. Following the coastline northwards, the mouths of the Betsiboka River (below) and the Sofia River (above) can also be seen, although these rivers are releasing few sediments at the moment.

Moving southward down the coast, several other rivers appear as light tan lines across the landscape. One of the longest of these  is the Mangoky, whose mouth is situated near a greenish body of water, Lake Ihotry.

Red Sediments from Sofia and Betsiboka Rivers, Madagascar

15.3S 47.0E

May 23rd, 2010 Category: Rivers, Sediments

Madagascar - April 28th, 2010

Madagascar - April 28th, 2010

Madagascar is an island nation in the western Indian Ocean off the southeast coast of Africa. The island is the world’s fourth largest, about 975 mi (1,570 km) long and 355 mi (570 km) wide. It is separated from the African coast by the Mozambique Channel.

Here, rusty red sediments from the Sofia River (above) and the Betsiboka River (below) can be seen spilling into the Mozambique Channel. The sediments’ distinct red color is due to the red lateritic soils in Madagascar’s central highlands.

Central West Coast of Madagascar Flanked by Intense Red Sediments – July 16th, 2009

16.6S 45.0E

July 16th, 2009 Category: Image of the day, Rivers

Madagascar - June 30th, 2009

Madagascar - June 30th, 2009

Coast of upper Melaky Region

Coast of upper Melaky Region

Sofia and Betsiboka Rivers

Sofia and Betsiboka Rivers

The central western coast of Madagascar is flanked by an intense, rusty red outflow of sediments. Most are present along the coast of the Melaky region.

Although such red sediments along the coast are typical for Madagascar, due to its red soils and high erosion rates from deforestation further inland, they are usually also seen further north near the mouths of the Sofia River and the Betsiboka River.

Unusually, in this image (see close-up for better detail), those rivers and their respective bays show a lesser presence of sediments. The Sofia River and bay into which it flows (above) are completely lacking in the characteristic red shade. The Betsiboka River is orange, but is not carrying enough red sediments to completely color the Bombetoka Bay (below).

Erosion from Deforestation Turns Madagascar’s Rivers Red

15.4S 48.0E

June 28th, 2009 Category: Rivers

Madagascar - June 8th, 2009

Madagascar - June 8th, 2009

The Sofia River (above) and the Betsiboka River (below) are red in color due to sediments originating in the central highlands, where red lateritic soils predominate. The Betsiboka River discharges its sediments into the Bombetoka Bay, which then connects to the Mozambique Channel.

The red waters of the river demonstrate soil erosion, one of Madagascar’s greatest environmental problems, caused by deforestation in the central highlands. Such soil erosion is widespread exceding 400 tons/ha per year in some areas.

Soil erosion has also made the Betsiboka Estuary into one of the world’s fast-changing coastlines. The land has been cleared and incredible rates of erosion have occurred due to about 100 years of extensive logging in rainforests and coastal mangroves.

After every heavy rain, exacerbated by tropical cyclones, the bright red soils are washed from the hillsides into the streams and rivers, clogging the coastal waterways with sediment.