Chapter 980 is very tricky

Shan Liangkun's problem is also a concern for everyone, the situation of over-exploitation of groundwater, so that the underground is emptied, is not only a problem in Shimen City, and the scope is not limited to Gongtian Province, but a problem that is widespread in most parts of the country. If this problem cannot be satisfactorily resolved, then the subsidence accident in Shimen City may spread to the whole country.

Liu Shiqing is also very worried about this problem, as early as the beginning of the establishment of Yinhe Industry, because of the large-scale production of strong drinks, the problem of water resources, once attracted Liu Shiqing's attention, and he also had a little understanding of the exploitation of groundwater in Wuling City. Wuling City is definitely a city with over-exploitation of groundwater, and the groundwater in some places has basically been emptied, that is to say, there is a possibility of sudden subsidence.

Liu Shiqing's family, most of the assets are all in Wuling City, if Wuling City accidentally falls, and it happens to happen to his family, company, or factory, Liu Shiqing has no way to accept it, he doesn't care about property loss, he is afraid that people will have problems.

"Theoretically speaking, the cause of the subsidence is that the groundwater is overexploited, and it is easy to draw a conclusion from the source to find a solution, that is, to realize the backfilling of groundwater." Specifically, it is possible to solve the root cause of the subsidence accident by pouring clean and unpolluted fresh water from the surface back into the ground to restore it to its original state. ”

Shan Liangkun said: "Since this method can be solved, let's backfill." ”

The former director shook his head, "Vice Prime Minister Shan, things are not so simple. First of all, the distribution of groundwater in the ground, not a small pond as we imagined, the amount of it extracted is calculated in 10,000 tons. Let's take an example, if you join a family of three and you need three tons of water every month, you need 36 tons of water a year. 100 households of three need to use 360 tons of water, 10,000 households is 360,000 tons, if you count industrial water, agricultural water, and then count the first well to the present, how many years have passed? Let's figure out what kind of number it is. ”

Shan Liangkun, Ye Songren and others gasped, if according to the former director of the Geological Bureau, it is not tens of thousands of tons, but tens of millions of tons, or even billions of tons. Where can you find such a large amount of water? I am afraid that if all the water of the Yellow River is brought over, it will take a long time to replenish the over-extracted groundwater in a city in Shimen City.

Guo Qianrong asked: "Old director, when it rains and snows every year, can't rain and snow water penetrate into the ground to replenish the aquifer?" And the water of rivers and lakes can also replenish the aquifer to a certain extent? ”

The former director of the Geological Bureau sighed, "Here's the problem. Rainwater, snow water, and water from rivers and lakes can indeed replenish part of the water into the aquifer by means of guò infiltration. But the amount of this supplement is limited, not to say how much rain and snow falls from God, and finally can penetrate into the ground, what can really penetrate into the aquifer is only a small part, most of the rain and snow water, either evaporated, returned to the atmosphere, formed clouds, waiting to be the water source for the next rain and snowfall, or it is gathered into rivers and lakes, along the big rivers, rolling east, and flowing into the sea.

Let's talk about rivers and lakes, let's not talk about the flow into the sea, just talk about the water in the river, these years, the government departments have invested a lot of money to rectify the river, one of the most common practices is to use large stones to reinforce the bottom of the river and both sides, and also use cement to smear the gaps between the big stones, although this practice strengthens the river, but also reduces the flow of the river, the infiltration effect on groundwater, before the reinforcement, the infiltration value is said to be one hundred, then after the reinforcement, This value may only be a dozen or even a few points.

This problem also exists in the infiltration of rain and snow. Nowadays, urbanization is intensifying, even in the countryside, people are also pursuing the comfort and hygiene of life, rural courtyards with concrete pouring, paving masonry, etc., a large number of asphalt roads, concrete roads are built, in the city, there is almost no trace of dirt floor, like the use of modern means to build roads and cities, the contribution to rain, snow water infiltration into the ground, is almost zero. You can calculate how many roads have been built and how much the city has expanded, and how much groundwater cannot seep back into the ground because of these deposits.

In fact, one of the most intuitive phenomena of groundwater overexploitation is that when we dig wells now, the depth of the well is getting deeper and deeper, and it may only take a few meters before, and even in some places, just take a shovel and dig a few times, you can dig a well out, and you can get groundwater, but now, this phenomenon is basically extinct in our north, and if we want to use groundwater, we have to drill deep wells. Tens of meters, even hundreds of meters, hundreds of meters deep, in this way, it is possible to extract groundwater. But the water at this depth is the water that nature accumulated thousands of years ago, even tens of thousands of years ago, hundreds of thousands of years ago, and we have now taken this water away, so that our children and grandchildren will no longer have groundwater to drink. ”

The words of the former director of the Geological Bureau made everyone silent, and everyone here did not know what he said, but it is one thing to know, and it is another thing to know how to do it. Overexploitation of groundwater is not a new topic, and the phenomenon of wells and machine wells getting deeper and deeper is also known to Shan Liangkun, Ye Songren and others, and they also understand what it means to do so. But what can you do if you don't dig a well, if you don't dig deeper? Without water, people will have problems with even the most basic livelihoods, let alone get rid of poverty and become well-off.

Over-exploitation of groundwater is also a last resort, after all, in many places, in addition to extracting groundwater, there is no other way to find water, it may be that there is no corresponding technology, or there may be no local water source other than groundwater. And even if there is technology and water, the dependence on groundwater is still existing.

A very typical example, Yanjing. Yanjing has a permanent population of 16,700 million, and the foreign and floating population, almost 100 million, these people eat, drink and Lazar, as well as the dependence on water for industrial and agricultural production formed around them, has strictly exceeded the amount of water resources that Yanjing itself has, in addition to using a variety of channels including groundwater extraction to raise water sources, Gongtian Province also needs to mobilize a large number of fresh water resources every year to support Yanjing, for this reason, Gongtian Province is close to Yanjing Some counties and cities, Originally, many places were planted with rice, but they were forced to switch to crops such as corn and wheat, which do not require so much water.

This means that if people's lives are to improve, and if the country wants to pursue the growth of GDP and increase national strength, then it is impossible to stop the exploitation of groundwater. As a result, over-exploitation of groundwater will become more and more common, and there will be more and more overhanging areas underground, which may collapse one day in the future.

The former director of the Geological Bureau continued: "Backfilling groundwater is the best way to solve the phenomenon of subsidence, but there are two problems that must be solved by using this method: first, where does a large amount of backfilled fresh water come from, and it is definitely not possible to use seawater. If seawater is used, all the freshwater resources in the ground will be polluted, at least salty, and if the seawater is polluted, then the groundwater will also be polluted. If the groundwater is polluted, then the land above the groundwater may no longer be suitable for growing crops, flowers and trees, and in order to avoid these situations, it is best to backfill it with fresh water, preferably pure fresh water.

Second, how to solve the technical problem of backfilling? If you want to use rain and snow to infiltrate this way, this way is too slow, tens of thousands of times slower than the speed of a snail, and the operability of this method is too poor and unrealistic. In addition, pouring fresh water directly into the well, this method is also difficult to solve the problem, the problem is that the speed of infiltration is too slow, after all, the vast majority of groundwater is not stored in the form of rivers and lakes, but in the form of underground aquifers, so that the water wants to return to the underground aquifer, it is not as simple as flowing into rivers and lakes.

By the way, there is another problem, that is, how to monitor, how much groundwater backfill, there must be a more accurate number, at least it is about the same, more, it is good to say, if it is less, the amount of fresh water backfilled is not enough, there is no way to restore the support role of fù on the surface land, and when the time comes, the backfill will be in vain.

Okay, chiefs, I'm done with that, what to do next, what to do, I will ask the leaders to instruct. ”

No one spoke in the conference room, and what the former director of the Geological Bureau said was all about the ins and outs of the subsidence phenomenon and the solutions, and they were also very clear. But it is precisely because he said it too clearly and too clearly, Shan Liangkun, Ye Songren and others found that the phenomenon of subsidence seems simple, but it is very tricky and difficult to solve this problem.

It's difficult, it's hard to get to the sky.

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