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Archive for Lakes

Western Australia, from Temperate to Desert Climate Zones

December 30th, 2009 Category: Lakes

Australia - November 30th, 2009

Australia - November 30th, 2009

The southern part of Western Australia has a temperate climate, particularly in the southwest coastal area, whose mostly tan-colored landscape can be observed in the lower left quadrant. The darker green patches are areas of forests and mountain ranges, including the Stirling Range National Park and the Peak Charles National Park. The latter is easily identifiable as a dark green area shaped like a perfect square.

Moving to the northeast, the landscape changes to the red semi-arid or desert area of the central part of the state. Many salt lakes appear as white streaks across the red earth of this region, including the intermittent Lake Barlee, shaped like the letter “M”. Lake Barlee is more than 100 km wide from west to east, and about 80 km wide from north to south. It usually fills only once every ten years, after which the water generally remains present for less than a year.

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.

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.

Jordan River Flowing into the Dead Sea

31.5N 35.5E

December 27th, 2009 Category: Lakes, Rivers

Dead Sea - December 19th, 2009

Dead Sea - December 19th, 2009

The Jordan River is a 251 kilometre (156 mile) long river in Southwest Asia which flows vertically through the center of this image, into the Dead Sea. The last section, between the Sea of Galilee and the Dead Sea, has the least gradient. Thus, the river begins to meander before it enters the Dead Sea, which is about 400 metres below sea level and has no outlet. Two major tributaries enter from the east during this last phase: the Yarmouk River and Jabbok River.

In 1964, Israel began operating a dam that diverts water from the Sea of Galilee, a major Jordan River water provider, to the National Water Carrier. Also in 1964, Jordan constructed a channel that diverted water from the Yarmouk River. Syria has also built reservoirs that catch the Yarmouk’s waters. Environmentalists blame Israel, Jordan and Syria for extensive damage to the Jordan River ecosystem.

In modern times, the waters are 70% to 90% used for human purposes and the flow is much reduced. Because of this and the high evaporation rate of the Dead Sea, the sea is shrinking. All the shallow waters of the southern end of the sea have been drained in modern times and are now salt flats.

In 2007, Friends of the Earth Middle East named the Jordan River as one of the world’s 100 most endangered ecological sites, due in part to lack of cooperation between Israel and the neighboring Arab states.