The four mysteries of Daming Lake have a long history. Wang Xiangchun, a left-wing poet in the late Ming Dynasty, recorded in detail in his book Daming Lake in Yin Qi-"The lake is in the city, but there is nothing in the house. The difference is that the constant rain does not rise, and the long drought does not dry up; As for snakes not appearing and frogs not singing, that's different. " Later, this article was included in Licheng County Records by the Qing people, which should be an earlier written record about the four eccentrics of Huming Lake. This is the well-known "four eccentrics" in Daming Lake, Jinan-frogs don't croak, snakes are hard to find, long droughts don't fall, and long rains don't rise. Snake is not present: the so-called "snake is not present" is because there are many waterfowl in Daming Lake, and it is difficult for snakes to survive in it. Constant rain does not rise: the so-called "constant rain does not rise" is because there are many outlets in Daming Lake. When the water rises, it will naturally flow out. Long drought without waterlogging: the so-called "long drought without waterlogging" is because the bottom of Daming Lake is fine igneous rock, which makes the spring water flowing into the lake unable to be discharged. Frogs don't sing: So far, no one can find a reasonable answer to the mystery of "frogs don't sing" by Daming Lake. There is a beautiful legend about the strange phenomenon that frogs don't cry and snakes don't appear in Daming Lake, but it has been proved to be invented by later generations. During the Qianlong period of the Qing Dynasty, Emperor Qianlong went down to the south of the Yangtze River and passed by Jinan. After visiting Baotu Spring, Qianfo Mountain and other places of interest, he came to the Lixia Pavilion on Daming Lake for a rest at noon. When the real dragon emperor came to Daming Lake, it naturally alarmed all the immortals in Daming Lake, so hundreds of frogs sang in unison, all the snakes gathered together, birds and insects sang over Daming Lake, and all living beings wanted to see the face of the dragon emperor. However, Emperor Qianlong, who was very tired at this time, wanted to have a rest, but the snakes, frogs and birds outside the window were not interested in joining in the fun. So Yan Long was furious, slapped the table, issued an imperial decree and ordered: "Snakes return to the hole, frogs don't sing." When all beings saw the dragon's face was furious, they immediately slipped away in a panic. Since then, Daming Lake has never seen snakes or heard of frogs. Of course, this so-called folk saying is naturally artificial. You know, as early as the Wanli period of the Ming Dynasty, Wang Xiangchun recorded the four eccentrics of Daming Lake. Therefore, this statement was just made up by the Qing people to please the descendants of Qianlong. People who have lived in Jinan for a long time almost know that Daming Lake has "four monsters"-snakes don't come out, frogs don't sing, constant rain doesn't rise, and long drought doesn't dry up.
With the progress of science and technology, the natural ecological mystery of Daming Lake "the snake disappeared and the frog stopped singing" has long been solved. It turns out that "snakes disappear" because there are many waterfowl such as osprey in the lake, which are natural enemies of snakes. Frogs in Jinan never bark. Although the frogs in the city don't croak, once outside the city, frogs croak, which can keep you awake all night. Comparing the two, we can't help wondering. Therefore, over the years, it has become a matter of concern and interest to people. Legend has it that when Emperor Qianlong went down to the south of the Yangtze River and passed by Jinan, he lived by Daming Lake. Because the noise of frogs affected sleep, he ordered the frogs in the city not to bark any more. From then on, until now, the voice of frogs has never been heard in Jinan city. So whenever someone asks Jinan frogs why they don't bark, the old people always take this as an answer. In fact, this is just a legend and has no scientific basis. According to the current scientific explanation, this is because the temperature of spring water gushing from underground in Jinan city is low, and frogs live here, so they can't be in estrus, so they don't bark. When the spring water flows out of the city and meets the ground, the water temperature will rise and frogs will live a normal life here. When they are in heat, they naturally bark. This has nothing to do with Emperor Qianlong who has been to Jinan.
As for Daming Lake, "constant rain does not rise, long drought does not dry up" is closely related to the special geographical environment and natural composition conditions of Daming Lake. Daming Lake is made up of many springs in Jinan. Spring water flows in from the south bank. When it overflows, it can flow out from the North Watergate built on the north bank in the Song Dynasty, flow into the Xiaoqing River, and pour into the Bohai Sea in the east. This excellent dredged river course is not found in many other natural lakes. The bottom of Daming Lake is impervious igneous rock, which makes the spring water flowing into the lake unable to be discharged, resulting in "constant rain does not rise, long drought does not dry up", which keeps the water level of the lake relatively constant all the year round.