The lake “falling from the sky”

“Clear Spring” emerges in the desert

  In August 2014, a group of shepherds in Tunisia, a North African country, were driving their sheep through the desert belt of Gafsa Province. Gafsa is located in the central part of Tunisia. The climate is a tropical desert climate. During the year, the temperature can reach 40°C. Even in the coldest time, the temperature will be above 20°C and the average annual precipitation is less than 150 mm. .
  The hot summer sun made the shepherds sweat profusely, and the long journey for several hours made them exhausted. However, after passing through this desert zone, you will soon reach the savanna area, where the soil is fertile and there are grasslands suitable for grazing cattle and sheep. However, at this moment, an unexpected situation happened. Not far away, a big blue lake glowing with heat unexpectedly appeared.
  At first, the shepherds thought they had hallucinations. After walking for a few hours in the hot summer, all they saw were the “mirages” that often appeared in the desert. However, when they got closer and closer to the lake, they found that it was not the case. The hot and humid steam rushed towards their faces, and when they reached the lake, they could really hold up the water in the lake with their hands. This is the real lake!
  The news that a lake suddenly appeared in the desert caused a sensation in the local area. Later, experts who rushed over measured the lake. The measurement results showed that the area of ​​the lake reached 10,000 square meters, with an average depth of 10-18 meters, and the lake water was very clear.
  Not only Tunisia has lakes that “fall from the sky”, such lakes have also appeared in another part of Africa. Enugu State is a city in southern Nigeria, a western African country. On November 11, 2014, local herders heard a huge explosion. When they were curious to check what happened, they found that there was a huge explosion. In the low-lying area, water began to gush out, and the amount of water continued to increase, eventually forming a lake with a diameter of 170 meters.
  However, there has never been any lake in this area. Where does the water come from?
  Local people in Tunisia and Nigeria think this is a supernatural phenomenon. In Nigeria, the locals even believe that the lake water can cure diseases, and there are many stories about the lake water curing diseases. For example, a widely circulated version of the story is that a paralyzed person can walk on the ground after bathing in the water. People in poor areas of Nigeria, and even people in neighboring countries such as Ghana, Togo, and the Republic of Benin believe in these stories. Every day, people from all over the world will rush to the lake to bathe in the lake water, or drink the lake water, and even the vegetation around the lake water is picked to make tea that is said to have the effect of curing diseases.
Rainwater gathers?

  How do scientists explain these magical lakes?
  One of the guesses is that rainwater is formed on the surface. In Tunisia, where the lake is located in the Gafsa region, the terrain is a sun-backed valley. Those with ten rich wilderness survival experience will know that when you are looking for a life-saving water source in the vast desert area, in addition to looking for green plants and digging for water sources where they grow, another way to smoke is to find a sun-backed canyon. . One reason for looking for the Backyang Canyon is that once it rains, the terrain of the canyon is conducive to storing precious water, and the other is because it is not directly exposed to sunlight, the water here is also easy to retain. The lakes in Tunisia are sparsely populated. Perhaps after a few rains, rainwater slowly gathered here to form this seemingly sudden lake.
  The lakes in Nigeria can be better explained. Nigeria is located on the west coast of the Gulf of Guinea. It has a savanna climate with high temperature and rain all year round. Enugu State, located in southern Nigeria, not far from the Gulf of Guinea, has more rainfall. November happens to be the rainy season in Enugu State. The lake topography formed in Enugu State is also a basin.
  However, this explanation seems reasonable, but it is still questioned. Although Nigeria’s lakes can be formed by heavy rainstorms overnight, August is one of the hottest and driest periods in Tunisia. The precipitation is scarce, and the average annual precipitation there is only 150 mm. It can be seen that 10,000 square meters is not It can fill up in a few days of rain. How did that big lake form?
Earthquake caused the underground aquifer to break?

  Some other scientists put forward another guess based on what people described as “the sound of an explosion was heard when the Nigerian lake was formed”. Maybe it was a small-scale earthquake in these places, which caused impermeable rock formations to break and groundwater to flow along the cracks To low-lying desert areas.
  Although the desert area looks particularly dry, it gives the impression of being extremely hot. However, in some desert areas, groundwater reserves are very abundant. For example, the edge of the Guerbantonggut Desert in the Junggar Basin of China is buried with abundant groundwater. Tunisia and Nigeria are both coastal countries, and groundwater reserves should be very abundant. If the earthquake touches the reservoir at this time, it is likely that the people will see the “suddenly appearing” lake.
  This explanation is more reasonable than the previous explanation. However, now, scientists have not found relevant water reservoirs in these places.
More like a curse

  It is precisely because scientists have not yet given a clear explanation. In these two countries, people believe that this is a blessing from the gods. However, unlike the thinking of these people, these lakes may be more like a “curse.” The color of the desert lakes in Tunisia has just begun to see a deep blue in the south, turning into a potentially toxic green. The Nigerian lakes are already turbid and full of pathogenic bacteria.
  However, the reason for the deterioration of the water quality of these lakes is not mysterious. The deterioration of the water quality of the lakes in Nigeria is caused by thousands of believers bathing in the lake water and excreting them on the shore. It has become a breeding ground for mosquitoes, which may be possible at any time. An outbreak of dysentery. And some infectious diseases may also spread among believers, and are brought to remote places by those who come from very remote places, causing pathogens to spread in the wilderness far away from the city.
  The desert lakes in Tunisia turn green because there is no other water source to replenish them, and a lot of algae grow in the lakes. The Gafsa area where it is located is rich in phosphate, which is radioactive and may have contaminated water and can cause cancer. However, the people here still ignore official warnings and come here for swimming, diving and boating.
  Therefore, unless science gives a reasonable explanation for this mysterious phenomenon, superstition and ignorance will still prevail in these areas. What caused the sudden emergence of lakes in the desert can only wait for scientists to conduct more in-depth investigations