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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.

Sediments from the São Francisco River Enter Sobradinho Lake

9.9S 42.1W

December 14th, 2009 Category: Lakes, Rivers

Brazil - November 28th, 2009

Brazil - November 28th, 2009

The São Francisco River empties tan sediments into Sobradinho Lake in the Brazilian state of Bahia. The sediments gradually diffuse into the lake, such that the waters near the inflow appear tan and those near the outflow appear dark green.

The lake itself is one of the largest artificial reservoirs in the world, with an area of 4,214 square kilometres (1,627 sq mi). The Sobradinho Dam, one of four hydroelectric plants built along the São Francisco River, has a storage capacity of 34.1 billion m3 of water.

Sobradinho Reservoir on the São Francisco River, Brazil

9.6S 41.5W

November 29th, 2009 Category: Lakes, Rivers

Brazil - November 15th, 2009

Brazil - November 15th, 2009

Sobradinho Lake is one of the largest artificial reservoirs in the world, with an area of 4,214 square kilometres (1,627 sq mi). It lies along the São Francisco River, in the Brazilian state of Bahia.

The Sobradinho Dam, built in 1977 and one of four hydroelectric plants along the course of the river, has storage capacity of 34.1 billion m3 of water.

The lower end of the reservoir appears tan in color, as it is filled with sediments where the São Francisco River spills into it. The color appears more greenish where the river exits after flowing through the dam.

São Francisco River Flowing into Sobradinho Reservoir, Brazil

9.4S 40.8W

September 23rd, 2009 Category: Lakes, Rivers

Brazil - September 3rd, 2009

Brazil - September 3rd, 2009

The artificial lake known as the Sobradinho Reservoir, created by the dam of the same name, in the Brazilian state of Bahia, can be seen at the top center. The São Francisco River flows vertically from south to north through the middle of the image, into the lake.

The river, which both the reservoir’s primary inflow and outflow, empties golden sediments into the southern reaches of the lake. As these mix with the waters of the 320 km long and (on average) 8.6m deep reservoir, the water color changes from golden to green to dark blue.

Agriculture Near Sobradinho Lake, Brazil – May 19th, 2009

May 19th, 2009 Category: Image of the day, Lakes, Rivers

Sobradinho Lake, Brazil - May 11th, 2009

Sobradinho Lake, Brazil - May 11th, 2009

Sobradinho Lake lies in the São Francisco River Basin, in one of the most arid regions in Northeastern Brazil, within a land stretch categorized as the Lower-middle São Francisco, in the state of Pernambuco.

The dam, in its full capacity, consists of a lake of approximately 4,214 km2; 280 km in length, the width of which varies from 5 to 50 km, according to the Smithsonian Astrophysical Observatory. The dam storage capacity is that of 34.1 billion m3 of water.

Here, the lake appears  strikingly bright yellow-green due to sediments from the São Francisco River.

Being situated in a semi-arid region, the dam brought about significant development to local irrigated agriculture. Many fields can be seen east of the river in the full image.

The Caatinga ecosystem (xeric shrubland and thorn forest) has also, for that matter, undergone considerable changes. Stastical analysis of data collected before and after the filling of the lake showed that the dam has brought about considerable changes to regional meteorology, particularly concerning atmospheric humidity and wind speed.