It's raining hard, too! Why is waterlogging serious in Guangzhou and not in Shenzhen?

In the first half of the month, the continuous rainfall in South China turned some cities such as Guangzhou into Zeguo. Now, the water has receded, but the serious waterlogging has made the city pay a painful price. It is said that the loss in Guangzhou alone is as high as 1000 billion. Wang Yang, secretary of Guangdong Provincial Party Committee, said: The government is sorry for the people and should apologize. Although natural disasters are unpredictable and called force majeure, it is better to find out the management problems yourself after the disaster than to push the problems to God! In fact, we can also see that this time it rained heavily in Guangdong, Guangzhou was flooded by Jinshan, and Shenzhen was safe and sound. This is not to say that Shenzhen is lucky. In the 1980s and 1990s, Shenzhen was once flooded, and even visiting foreign heads of state were rescued from hotels by boat. As the saying goes, once you fall, you will gain wisdom. Since then, Shenzhen has been studying how to solve the problem of waterlogging. One is to dredge the underground drainage system, and the other is to increase pumping stations to discharge water into natural rivers. These jobs are hard to see on the surface at ordinary times, but they have played a great role at critical moments. In contrast, in many big cities, all articles are written on the ground-many tall buildings have been built, because this can reflect the urban landscape and highlight the achievements of leaders, but what about underground? I can't see it anyway, so why waste more money? As a result, there is a new society on the ground and an old society underground. When the rain, snow and typhoon hit, those invisible things began to get stuck. In fact, there are many reasons for urban waterlogging. For example, in recent years, many cities are reinforced concrete jungles, and the surface hardening is becoming more and more serious. When water falls to the ground, it becomes runoff, and it is completely drained by the pipe network. You may have read Hugo's novel Les Miserables. How did the hero Jean Valjean save the young revolutionary from Paris? He walked out of the sewer. You know, 100 years ago, the diameter of the sewer in Paris was 3 meters, and we have to admire the foresight of the French in the construction of public facilities. And what about our underground drainage facilities? For a long time, I was left with the impression that a worker was struggling to get in for maintenance. If even people can't get in, he just poked the steel bar. Do you think this pipeline can cope with sudden large-scale rainfall? But then again, if you want to prevent heavy rain, it is not cost-effective to increase the caliber of the pipe network indefinitely and deal with a small probability event with excessive investment. What should you do? At this World Expo, the case of Rotterdam, the Netherlands, provided us with a good reference-the whole Netherlands is below sea level, and the probability of waterlogging is very high. Therefore, when people build cities, they reserve many low-lying places in advance, such as building many sinking squares. When it doesn't rain, they can be used as public spaces in the city. When it rains, they will temporarily act as reservoirs to lead water to these places first. The cost is not much, but the effect is good, which reflects the advanced thinking of urban planning. The case of water control in Rotterdam, the Netherlands (Shanghai World Expo 20 10 case) Of course, the advanced planning of the Netherlands is based on its unique geographical location. If many cities want to nip in the bud, I'm afraid they still have to spend their energy on the construction of underground pipe networks that you can't usually see. The function of pipe network is not only to drain water, you can see that in many cities, telephone poles and cobweb-like wires are gradually disappearing. Where have they all gone? They are all "underground"-in order to be safe, intensive and efficient, water, electricity, communication, gas and other pipe networks in modern cities will gather together and put them into an underground pipe network corridor, which we call "the same ditch". I remember when I went to Europe a few years ago, I visited a "ditch" where two trucks could walk side by side. More accurately, this ditch is actually a tunnel, in which lighting is installed, and entrances and exits are reserved at regular intervals, so that maintenance personnel can assemble pipelines at any time for maintenance without digging roads. Full text of Tianjin Tonggou Tunnel crossing Haihe River (Editor: dq 1024)