|ISS007 Earth Sciences and Image Analysis Photographic Highlights|
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ISS007-E-14344 Click the photo number to access all resolutions available and the database record.
|Betsiboka Estuary, Madagascar: The Betsiboka Estuary on the
northwest coast of Madagascar is the mouth of Madagascar’s largest
river and one of the world’s fast-changing coastlines. Nearly a
century of extensive logging of Madagascar’s rainforests and coastal
mangroves has resulted in nearly complete clearing of the land and
fantastic rates of erosion. After every heavy rain, the bright red
soils are washed from the hillsides into the streams and rivers to
the coast. Astronauts describe their view of Madagascar as “bleeding
into the ocean.” One impact of the extensive 20th century erosion is
the filling and clogging of coastal waterways with sediment—a process
that is well illustrated in the Betsiboka estuary. In fact,
ocean-going ships were once able to travel up the Betsiboka estuary,
but must now berth at the coast.
A bad situation is made worse when tropical storms bring severe rainfall, greatly accelerating the rates of erosion. As an illustration, astronauts aboard the International Space Station documented widespread flooding and a massive red sediment plume flowing into the Bestiboka estuary and the ocean in the wake of Tropical Cyclone Gafilo, which hit northern Madagascar on March 7th and 8th, 2004 (top image). A comparative image (bottom) taken in September 2003 shows normal water levels in the estuary.
Despite the heavy coastal flooding in the top image, new coastal developments can be seen. The Mahajanga Aquaculture Development Project, a joint venture between Madagascar and the Japan International Cooperative Agency, strings along the coastal region at the mouth of the estuary (inset images). This project is a shrimp farm and has been developed since 1999. Successive images taken by astronauts show increasing numbers of ponds constructed between 2000 and the present. Coastal aquaculture projects are frequently controversial, pitting the protection and viability of coastal ecosystems (especially rapidly disappearing mangrove environments), against badly needed industry in developing countries.
This service is provided by the International Space Station program and the JSC Astromaterials Research & Exploration Science Directorate.
Recommended Citation: Image Science and Analysis Laboratory, NASA-Johnson Space Center. "The Gateway to Astronaut Photography of Earth." .