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Archive for Rivers

Colville River Crossing Alaska’s North Slope Borough, USA

70.2N 150.9W

December 29th, 2009 Category: Lakes, Rivers

USA - December 19th, 2009

USA - December 19th, 2009

The landscape of Alaska’s North Slope Borough is dotted by many lakes in this orthorectified image. The borough has a total area of 94,763 square miles (245,436 km²), of which, 88,817 square miles (230,035 km²) of it is land and 5,946 square miles (15,399 km²) of it (6.27%) is water.

Its western coastline is along the Chukchi Sea, while its eastern shores, beyond Point Barrow, are on the Beaufort Sea (visible in the top part of this image). Here, the Colville River can be seen crossing the North Slope and spilling into the Beaufort Sea.

The Colville is a major river of the Arctic Ocean coast of Alaska in the United States, approximately 350 mi (560 km) long. One of the northernmost major rivers in the North America, it drains a remote area of tundra on the north side of the Brooks Range entirely above the Arctic Circle. The river is frozen for more than half the year and floods each spring.

Upon opening the full image, the river can be seen flowing through the foothills on the north side of the Brooks Range, broadening as it receives the inflow of many tributaries that descend from the middle Brooks Range. After flowing across the Arctic plain, it enters the western Beaufort Sea in a broad delta near Nuiqsut, approximately 120 mi (190 km) west of Prudhoe Bay.

Vegetation Index North and South of Zambezi River, Mozambique

17.8S 35.3E

December 29th, 2009 Category: Climate Change, Rivers

Mozambique - December 17th, 2009

Mozambique - December 17th, 2009

Mozambique is divided into two topographical regions by the Zambezi River, visible running through the center of the full version of this FAPAR image, taken midway through the country’s wet season.

To the north of the Zambezi River, the narrow coastline moves inland to hills and low plateaus, and further west to rugged highlands, which include the Niassa highlands, Namuli or Shire highlands, Angonia highlands, Tete highlands and the Makonde plateau, covered with miombo woodlands.

To the south of the Zambezi River, the lowlands are broader with the Mashonaland plateau and Lebomo mountains located in the deep south. Green and red areas, indicating high photosynthetic activity, are visible both north and south of the river. Yellow areas indicate lower activity.

The Islands of Viti Levu and Ovalau, Fiji – December 29th, 2009

18.1S 178.4E

December 29th, 2009 Category: Image of the day, Rivers

Fiji - December 19th, 2009

Fiji - December 19th, 2009

This orthorectified image focuses on the island of Viti Levu, the largest island in the Republic of Fiji. Viti Levu is the site of the nation’s capital, Suva, visible on a peninsula near the Rewa River.

The island is home to 70% of the population (about 600,000) and is the hub of the entire Fijian archipelago. It measures 146 kilometers long and 106 kilometers wide and has an area of 10,389 square kilometers.

Geologists believe that Viti Levu has been submerged a number of times, and has been covered by lava and other volcanic materials. Earthquakes and volcanic eruptions account for the somewhat rugged terrain of the island, which is divided into roughly equal halves by a north-south mountain range. The centre of the island includes the nation’s highest peak Mount Tomanivi (otherwise Mt. Victoria) rising to 1,324 meters.

Several other islands can be seen near Viti Levu, the largest of which is Ovalau, the sixth largest island in Fiji’s Lomaiviti archipelago. Situated 60 km north east from the national capital Suva and 20 km off the east coast of Viti Levu, the island is about 13 kilometers long and 10 kilometers wide. It covers a total area of 102.3 square kilometers and has a population of around 9,000, approximately half the Lomaiviti population.

Ovalau is characterized by its rugged topography, with little flat land apart from the Lovoni Valley in the centre of the island. The island is an eroded volcanic crater with a narrow belt of flat to udulating country between the encircling lagoon and the steep crater sides. The highest peaks are Nadelaiovalau, with an altitude of 625 meters, in the east, and Tomuna, 526 meters, in the south.

Sobradinho Reservoir in Northern Bahia State, Brazil

December 28th, 2009 Category: Lakes, Rivers

Brazil - November 15th, 2009

Brazil - November 15th, 2009

Sobradinho Lake is located in the northern part of the Brazilian state of Bahia. Created by the Sobradinho Dam, it is the largest reservoir in Brazil in terms of surface area.

The dam was built in the hydrologic basin of the São Francisco River at a distance of 748 km from its source and 1,912 km from its estuary on the Atlantic coast. The power generation was started on 31 November 1979.

The reservoir covers an area of 4,225 km2 with mean depth of 8.6 m and a maximum depth of 30 m. At the maximum elevation of 392.5 m above sea level, the reservoir accumulates 34.1×109 m3 of water with a regulated discharge rate of 1,060 m3 sec-1.

The geological formation of the region consists of very ancient rocks of the Brazilian shield, igneous or highly metamorphosed and dating back to the Precambrian era. The soils are predominantly latosol, quartz sand and lithosol.

The climate is semi-arid, characterized by very high evaporation rate. Mean annual rainfall ranges between 400 mm and 800 mm and mean annual temperature of 26-27deg C is affected by the water body of the reservoir.

The prevailing vegetation consists of caranauba (a type of palm tree), hypoxerophilous and hyperxerophilous shrubs of medium height, and low shrubs. When the water level becomes low, wet areas around the reservoir are cultivated.

Reservoir on Narmada River, India – December 28th, 2009

23.2N 77.4E

December 28th, 2009 Category: Image of the day, Lakes, Rivers

India - December 9th, 2009
India – December 9th, 2009

The Narmada River in central India is the fifth largest river in the Indian subcontinent. It forms the traditional boundary between North India and South India and flows westwards over a length of 1,312 km (815.2 mi) before draining into the Arabian Sea. It is one of only three major rivers in pensinsular India that runs from east to west. It is also the only river in India that flows in a rift valley flowing west between the Satpura and Vindhya ranges.

In this orthorectified image, the Narmada can be seen connected to a large reservoir that is part of the Indira Sagar Project, a multipurpose key Project of Madhya Pradesh on the Narmada River at Narmadanagar in the Khandwa District of Madhya Pradesh. The construction of main dam started in 1992. Total catchment area at the dam site is 61642 km2.