|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
WONDERS OF NATURE
Lake Chad. Nature miracle
To the south of the sultry deserts of North Africa, almost in the center of the "black continent", at the junction of the borders of four countries lies the "Sea of the Sahara" - the huge Lake Chad.
Chad is located not only at the point where the borders of different states converge, but also on a peculiar border of natural zones: to the north of it lies the greatest desert of the Earth - the Sahara, and to the south - the savannas of Sudan rustling with tall grasses. It is from the south that the largest of the rivers that feed it, the Shari, flows into the lake. However, except for those that arise in the summer, during the rainy season, temporary rivers and streams, Chad has only two tributaries. The lake in the heart of Africa asked many riddles to scientists. Some of them remain unanswered to this day. True, representatives of European science did not have much time to unravel the mysteries of Chad. Indeed, until the XNUMXth century, not a single European set foot on the shores of this reservoir, although it was known from the notes of Arab travelers Ibn Battuta and Leo the African that there was a "sea" in the depths of the Sahara. It was not until 1823 that the Scotsman Clapperton, with his companions Denham and Audney, traveled from the Mediterranean to Lake Chad for the first time. The British expedition discovered an endless expanse of water stretched among the sands, which they could not even map. But when the German scientist and traveler Heinrich Barth visited the coast of Chad thirty years later, he saw only a heavily overgrown swampy reservoir with rare spots of a free water surface. Twenty years later, in 1871, the level of the lake began to rise again, and on the northern outskirts of its outflow, the waters sank and destroyed the city of Ngagmi, which had stood for centuries. Such fluctuations in the level and area of the lake occur every twenty to thirty years and are associated with changes in the amount of precipitation in the upper reaches of the Shari River. During periods of heavy rainfall, the depth of Chad increases by three to five meters, and the territory covered by its waters increases two and a half times, reaching twenty-six thousand square kilometers. The lake then occupies the twelfth place in the world, surpassing such large reservoirs as Balkhash and Lake Ladoga. And then there comes a time when precipitation becomes less and the level of the lake drops again for several years. The size of Chad also changes throughout the year. The summer rainy season in the equatorial zone replenishes the Shari and its tributaries. A full-flowing river fills the lake to the highest levels by autumn. And in May - during the period of the lowest level of the lake - Chad loses three-quarters of its water and dries up before our eyes, exposing tens of kilometers of a viscous, muddy bottom. After all, the average depth of Chad is only two meters, and the greatest is four meters. The second mystery of Chad is its weak salinity. Usually in drainless lakes located in deserts and semi-deserts, the water is salty. And this is understandable: the dissolved salts brought by the rivers, albeit in small quantities, accumulate in them, and the water constantly evaporates. But in Chad, the water is almost fresh, both animals and people drink it freely. What's the matter? Scientists have proposed several versions about this strange anomaly. Chemists said that the salts were somehow cemented and precipitated; biologists believed that they were absorbed by aquatic vegetation. However, only geographers managed to unravel the true reason for the low salinity of Chad. It turns out that nine hundred kilometers northeast of the lake is the vast Bodele depression, the bottom of which is eighty meters below the water level in Chad. The dry bed of the Bahr-el-Ghazal River (in Arabic - "River of Gazelles") stretched to this basin from the lake. But this river is only at first glance dried up. In the thickness of sand deposits, under the bed of the Bahr el Ghazal, there is a constant outflow of water from Chad towards the Bodele depression. It is enough to dig sand at the bottom of a "dry" river, as groundwater will appear in the formed hole. This property of Bahr el-Ghazal is often used by nomads when they need to get water for drinking or water their cattle. And very rarely, once every hundred years or even less often, the water level in Lake Chad rises so much that surface runoff appears in the dry riverbed. Arab chronicles say that at the end of the XNUMXth century, Bahr el-Ghazal was so full of water that people floated on it on pirogues. Thus, Chad is not a drainless lake in the full sense of the word, and its low salinity is quite understandable. Naturally, both the coast and the waters of the vast, almost fresh reservoir in this hot region attract a huge number of the most diverse animals and birds. The fauna of Chad and its environs is especially rich in summer and autumn, when the savannahs on the southern and southeastern shores of the lake, filled with rain, are covered with lush vegetation. Dense thickets of Sudanese grass at this time are so high that they hide the horseman's head. Green acacias and baobabs rise above the grass cover. Herds of zebras and antelopes, giraffes and ostriches, buffaloes and wild warthogs graze in the savannah. Elephants and rhinos are not uncommon here. The herds of ungulates are followed by lions and hyenas. And in the lake itself, especially near the islands of the east coast, there are many hippos, sometimes found in herds of forty or fifty heads. In the coastal mud, with only their nostrils sticking out, crocodiles guard their prey. A rare species of aquatic mammals also lives in Chad: a close relative of the sea cow - a huge four-meter manatee. How this giant, an inhabitant of sea waters, got into a fresh water reservoir located in the middle of the African continent is another mystery of the lake. And the most beautiful and graceful creature of Chad is the water antelope living in the coastal reed beds. This tiny, hare-sized, ungulate struck the zoologists who discovered it by the fact that, in addition to water greenery, it also feeds on ... fish. Moreover, the water antelope itself skillfully catches it in shallow water. Unfortunately, the future fate of the unique lake is alarming. Deforestation on the banks of the Shari River and its tributaries, as well as the construction of irrigation canals, have led to the fact that the main water artery that feeds the lake carries less and less water into it. In addition, during the flood, Shari washes sand and clay from the exposed shores and carries them into Lake Chad. In the XNUMXth century, the level of the reservoir never rose to the height noted in past centuries. With each decade, the area of the reservoir decreases, and even its floods are far from the previous violent floods. Scientists are talking about the possible imminent "death" of Lake Chad. If this happens, the consequences of such an environmental catastrophe will be severe. Water will disappear in wells in a vast area northeast of Chad, where groundwater is fed from the lake. More than a quarter of a million inhabitants of the Republic of Chad are at risk of death or forced displacement. The desert will also spread to the west, taking over the populated areas of Nigeria and Cameroon. Naturally, the unique fauna of Chad will also disappear. However, there is a project, and by no means fantastic, but confirmed by calculations and allowing not only to save Lake Chad, but also to radically transform the nature of the Sahara over a large area. For this, it is planned to use the waters of the most full-flowing river in the world after the Amazon - the Congo, which flows into the Atlantic Ocean. In a narrow gorge near the Livingston waterfalls, it is easy to create a dam, above which a giant reservoir is formed - the "Congo Sea". The largest tributary of the Congo - the river Ubangi, approaching the headwaters almost close to the tributaries of the Shari, will flow from the "sea of the Congo" in the opposite direction and through the channel will connect with the Chad basin. In fifty years the area of the lake will grow almost a hundred times! Another inland sea is being formed - the "Sea of Chad", the size of half the Mediterranean Sea! From this giant reservoir to the north, to the Mediterranean, an artificial river, the New Nile, will flow. Millions of hectares of cotton and wheat fields, plantations of date palms and orange groves, irrigated by the fertile waters of the "Sea of Chad", will appear along its shores. There will be, in fact, a huge man-made oasis - the second Egypt, where it will be possible to collect three crops a year. About a million more hectares will become suitable for agriculture on the shores of Chad itself. And this will not be violence against nature, but only its return to its former state. It has long been proven that the Sahara, eight to ten thousand years ago, was not a desert at all, and its current appearance is largely the result of unreasonable human activity. Once upon a time there were hippos, elephants, giraffes and crocodiles, full-flowing rivers flowed here, there were crowded cities and fertile oases. This was told by the rock paintings of ancient people preserved on the Ahaggar plateau, in the center of the Sahara, and the results of archaeologists' excavations also speak of this. And the XNUMXst century may become a time when the technological achievements of mankind will bring back to life a drying up unique lake and feed a large part of the inhabitants of the poorest and most hungry continent on Earth. Author: B.Wagner
▪ Karadag
Artificial leather for touch emulation
15.04.2024 Petgugu Global cat litter
15.04.2024 The attractiveness of caring men
14.04.2024
▪ Organic LEDs are getting cheaper ▪ Huawei FreeBuds Pro 2+ headphones with thermometer and heart rate monitor ▪ Li-ion solid electrolyte transistor ▪ The lightest paint ever developed
▪ section of the site Videotechnique. Article selection ▪ White Crow article. Popular expression ▪ article What is ammonia? Detailed answer ▪ Article Monitoring the pulse and respiration. Health care ▪ article Drawn Signal Generator. Encyclopedia of radio electronics and electrical engineering ▪ article Postcard-boomerang. Focus Secret
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
We recommend interesting articles Section 
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page