Why do the city s rivers dry up?

From the source, most of the rivers in the north originate from the Loess Plateau and the Taihang Mountains, and the basic ability to store water in these areas has disappeared due to serious forest damage. As a result, the humidity is low, precipitation is low, and the groundwater is particularly low to recharge the river water. So, the source of the water has been cut off.

From the geographical point of view of the river flow, the river basin in the north is densely populated with cities. Severe consumption. This is mainly industrial water.

It can be said that agricultural water use, although it is a part, but the problem must not be attributed to agriculture, whether from the reality or from the historical point of view, agricultural water use is basically fixed, can it be said that the current agricultural water will be more than in ancient times? This makes no sense: now that water is used frugally in agriculture, with the application of high technology, water consumption is even less; In addition, so much land has been used (for construction), and the total agricultural land is less, how can it be able to consume more water than the original vast agricultural land?

It is the problem of water waste, which has little to do with the statement of drying up, because the total amount of water is reduced, which will contain a certain amount of waste. If you look at it according to the law of conservation of precipitation and evaporation, even if you waste it, you will be evaporated. Eventually raindrops form and fall back.

But in general, there is a natural need for water waste, because the natural cycle of evaporation and rainfall is too long. Here, let's talk about the natural cycle of water, which is your third question, where does the water go? The natural cycle is a cycle on a large scale, and it is also a national and even global cycle.

So, if you look at the amount of water in the country, the total amount is basically constant. The south is flooded, and the north is basically drought! Or vice versa; Your question about why the amount of water in the north is not conserved is because the water cycle is very large, and it has broken through the small range of the north, and a wider space is needed.

The problem is that there is too little rainfall in the north, especially in the middle and upper reaches of rivers;

Water pollution. In the same way, although the total amount of water vapor (nationwide) has not been reduced, the current amount of water in the region (north) has been reduced. One of the important direct causes of the drying up of the river:

The geographical distribution of precipitation is uneven. This is probably the main reason why the rivers in the north are drying up.

There should be a direct cause of the changeable weather, the earth has entered a warm period of evaporation, coupled with man-made natural destruction, agriculture is water, but if the water resources are not properly used, the natural cycle can not be guaranteed, the flood irrigation of large water is the surface water can not seep down, direct evaporation, water vapor will be lost, groundwater is only a small part of the flow into the ocean, a lot of scattered in the ground, can not be used by human beings, is only one of the reasons why the river dries up.

Wherever a city is internationally famous, there is always a famous river that accompanies it. In Europe, the Danube, an international river, gives birth to urban agglomerations on both banks; In China, the Huangpu River and the East China Sea nourished and gave birth to Shanghai, making it rapidly rise from a small fishing village to an international metropolis. The world-famous metropolis of Paris is inextricably linked to water.

The Seine River flows through the middle of the city of Paris, dividing Paris into north and south, and it strung the whole of Paris like a beautiful necklace. The Seine is home to many of the cultural landscapes of Paris, as well as many of the best of France, through the ages. It is difficult for anyone to imagine what Paris would be like without the beautiful Seine.

Without the Huangpu River and Suzhou Creek, Shanghai would not be the Shanghai it is today.

Most of the world's major cities are built on the waterfront. In general, most of the middle and lower reaches of rivers are areas with concentrated cities and relatively developed economies. In the lower reaches of China's seven major rivers, the population is dense, the cities are concentrated, and the economy is developed, with 1 2 percent of the population, 1 3 percent of the arable land and 70 percent of the country's industrial and agricultural output value. The delta, formed by sediment deposits at the mouth of the river, is the economic center

For example, the Yangtze River Delta is located in the core of the Shanghai Economic Zone, and the Pearl River Delta in the Shenzhen, Guangzhou and Zhuhai economic zones in southern China. According to **, at the beginning of this century, the total number of cities of various sizes in the country will exceed 1,000, most of which are distributed in the Yangtze River, the Yellow River and other seven major water systems and coastal areas, and their birth and development are closely related to the river system. The amount of water in a river is determined by both recharge and depletion.

For most rivers, the main recharge is atmospheric precipitation. The main losses are evaporation, infiltration, human water diversion and utilization along the way.

When the amount of water recharged is less than the amount lost, the river slowly dries up.

This year's drought in the southwest has caused many rivers to dry up, which is caused by prolonged lack of rain, coupled with a lot of evaporation and human water use.

Under normal circumstances, rivers will not dry up even if there is no life, such as the Dead Sea, if a river has no water**, and during this time, the amount of precipitation is much less than the amount of evaporation (regardless of the topography), then the river will dry up after a period of time. If a river like the Yangtze River and the Yellow River is a river that uses glacial meltwater, then you can assume that the temperature is low enough not to freeze downstream, then there is no water source, and the river will still flow into the sea, then it will dry up. In addition, if the lake and river water ** is precipitation and underground runoff, the front one can be as long as the temperature is high but the precipitation is low (evaporation" precipitation, and the wind here blows the precipitation clouds to other places), and the back runoff water must be added to the geographical reasons, which may be the excessive intake of water in the city or the change of topographic structure caused by the underground runoff can not supply water, so it will dry up.

1. Rivers will decline because the replenishment of groundwater cannot keep up with the rate of consumption. For example, there is a significant decrease in rainfall, the diversion of rivers, and the overexploitation of human beings.

2. The decline of rivers is also caused by geological changes. Such as the elevation of the terrain and the subsidence of the underground river.

3. The relationship between the river water and the groundwater around the river is to supplement each other, once the river is diverted, the groundwater can not be replenished from the river when it is reduced, and the phenomenon of returning to the limb under the groundwater level will occur in this celebration.

1. Rivers will decline because the replenishment of groundwater cannot keep up with the rate of consumption. For example, Mori said that rainfall has decreased significantly, rivers have been diverted, and human beings have overexploited and used them.

2. The decline of the river is also caused by geological changes. Such as the elevation of the terrain and the subsidence of the underground river.

3. The river water and the groundwater around the river are complementary to each other, once the river is diverted, the groundwater can not be replenished from the river water when the groundwater is reduced, and the groundwater level will decline.

Rivers are more appropriate to use "dry".

A dry river means that there is no water in a river to see the bottom of.

The "dryness" in the title has the following explanation.

Plants and trees are senile or lose their vitality due to lack of nutrients and water: Trees |Seedlings. Lack of fat or moisture and **dryness: lips .

It is more likely that the grass and trees lose moisture, or the soil is dry and cracked.

And "dry" refers to the river or ancient wells that are dry, and you can shout to see the bottom of the river. Although the meaning is the same, the emphasis is different.

Dry up to make a sentence: 1. The heat has dried up this lake.

2. The Yellow River is starting to dry up.

3. During the drought, all the lakes and water wells dried up.

Many older friends living in the countryside may have noticed such a phenomenon, that is, when I was a child, there were many rivers before and after the village, and there was water in the river, which was very clear and clean, and there were all kinds of fish and shrimp in it, and many friends also had the experience of swimming and catching fish in the river, I did a lot of such things when I was a child, and many memories were inseparable from the small rivers before and after the village, but now those rivers are basically dried up, even if there is water, it is occasionally a little, and there is no more in a short time. What's going on?

<> actually speaking, the reasons are not complicated, mainly due to three factors. First of all, the emergence of a large number of reservoirs has led to the interception of many rivers, and many sluice gates have been built on many rivers, so it can be said that the flow of river water is completely controlled. We all know that rivers are formed by rainfall, melting water and underground springs, and the characteristics of water flowing to lower places encourage water to converge into small streams and rivers, and then into larger rivers, but reservoirs and river gates can store water in the rivers, so there is no water to flow in the rivers downstream of the reservoirs and gates.

Another reason is the decline of groundwater, which is more obvious in the northern region, due to the general drought and lack of water in the northern region, so a lot of industrial and agricultural water needs to pump a large amount of groundwater, resulting in the repeated decline of groundwater level, and the decline of groundwater needs to be supplemented by surface water, especially shallow groundwater, the lack of this type of groundwater will make the water in the surface river infiltrate into the ground at an accelerated pace, resulting in the water in the surface river drying up quickly.

<> the third reason is that the agricultural water is too strong, the previous rural water conservancy conditions are not very good, many farmlands can not be watered, and there are not many equipment that can be watered, but now almost every household in the countryside has a machine and a water pump for watering, when the farmland is relatively dry, as long as you see the water coming from the river, you will set up a machine to water the field, so that the water in the river will be drained soon, so even if the water is put down in the reservoir or river, the water in the river cannot be stored in the place where it is convenient for irrigation.

<> in such a realistic state, it is difficult to see the former Qingshui River flowing around the village, and now it is in the tide of rural urbanization reform, a large number of rural people have moved to the town, and the original rural scenery will also usher in changes, but the rural environment also needs to be managed in an orderly and reasonable manner, with good management and environmental protection, the rural scenery will be more beautiful than before.

1.The first is the large number of reservoirs that have created the situation of damming many rivers. Many river gates have also been built.

It can be said that the flow of the river water is fully controlled. We all know that rivers are formed by rainfall, melting ice, and groundwater. The incoming water accumulates in the creek and then joins the large river.

However, river reservoirs and sluice gates can accumulate water in the river, so there is no water in the river downstream of the reservoir and sluice gates.

2.Another reason is the reduction of groundwater, which is more pronounced in the northern regions。Due to the widespread drought and water scarcity in the northern region, many industries and agriculture require large amounts of pumping, which has led to a continuous decline in the water table.

Groundwater requires surface water, and in addition, especially in shallow groundwater, the loss of groundwater accelerates the infiltration of water from surface rivers to the surface, which causes the water in surface rivers to dry up quickly.

3.The third reason is that there is too much water for agriculture. In the past, the conditions for protecting water in rural areas were not very good.

Much of the farmland is unirrigated and there is not much equipment for irrigation. But now almost all rural houses have irrigation machines and water pumps. When the farmland is relatively dry, as soon as a river is seen, a machine is used to irrigate the field so that the water in the river drains quickly, even if it is deposited in a reservoir.

As a result, even if the water is drained from a reservoir or river, the river water cannot be stored in a convenient place for irrigation.

Given this reality, it is difficult to see the ancient Qingshui River that surrounds the village, which is now in the process of rural urbanization, with a large rural population being transferred to the city and the ancient ecological rural landscape. Of course, this will bring about some changes, but the rural environment also needs to be managed in an orderly and rational manner. With good management and environmental protection, the rural landscape will be even more beautiful than before.

Because it has something to do with global warming, and the environmental pollution in rural areas is also more serious.

With normal convection, the river flows south and the clouds fly north. The clouds turned into rain and fell, and they became rivers.

Abnormal convection, the river flows south, the clouds fly north, and before the clouds fly to the north, the pollutants pull the clouds down. As the days go by, the water runs out.

This is because farmers overexploit arable land and then irrigate it with water from rivers.

The water reservoirs used to irrigate the fields in the countryside are becoming less and less water, or even drying up, and the farmers living in the mountains can only rely on the weather for food, and if it rains, there will be a harvest, and if it does not rain, there will be no one to water the fields, resulting in no harvest.

In fact, for this phenomenon, there are many predisposing factors.

I think it's because the number of rivers in the countryside is decreasing.