The Yellow River is cut off.

The frequent seasonal interruption of the Yellow River began in the early 1970s. Relevant data show that the runoff of the Yellow River into the sea has gradually decreased since 1970s: 57.5 billion cubic meters in 1960s, 365.438+0.3 billion cubic meters in 1970s, 28.4 billion cubic meters in 1980s and 65.438+0.87 billion cubic meters in the mid-1990s. In just a few decades, the total runoff of the Yellow River into the sea has dropped by more than half. At the same time, the lower reaches of the Yellow River have been cut off for many times. Especially after entering the 1990s, the phenomenon of broken files became more serious.

Statistics of Lijin Cut-off of the Yellow River

Annual cut-off date

199 1 16

1992 83

1993 60

1994 74

1995 122

1996 136

1997 226

1998 142

1999 42

This situation changed in 2000 and did not stop in 2000. On the contrary, by September 2003, the middle and upper reaches of the Yellow River had repeatedly rained and the water potential rose. No.28 dam of Caiji control diversion project in Lankao section of Henan Province was torn and broken, causing great property and economic losses. However, the phenomenon that the Yellow River is cut off is still worthy of our analysis and discussion.

Second, the Yellow River cut-off reason analysis

1. Natural causes of the Yellow River cut off

In recent years, the decrease of precipitation in the Yellow River basin is the main natural reason for the interruption of the Yellow River, and precipitation is directly affected by climate change. Generally speaking, the natural reasons for the interruption of the Yellow River mainly include the following points:

(1) Variation of solar radiation. Solar radiation is the energy of the earth's climate, so the change of solar radiation output will inevitably lead to the change of the earth's climate. According to observation, since 1970s, the amount of solar radiation has been increasing, the temperature of the earth has been rising, and evaporation has been strengthened, which has made the Yellow River basin and even the northern and northwestern regions in China more arid.

2 sunspots. According to the observation and analysis, it is found that there is a certain correlation between the monsoon climate in Southeast Asia and the sunspot 1 1 annual cycle. Generally speaking, near the sunspot extreme year, the monsoon component in the surface atmospheric circulation in China is greater than the planetary wind component. In the mid-1990s, it was between the two extreme years of sunspots, so the monsoon force in China was weaker than in previous years, especially in the Loess Plateau and North China, which made monsoon precipitation and rain belts wander in the middle and lower reaches of the Yangtze River, resulting in a significant drought in North China (for example, 1997 Yellow River was the most severely cut off).

③ Interglacial period. According to archaeological analysis, the climate on the earth changes alternately between cold, warm, dry and wet, and the change cycle is different. Between the great ice ages, there was a warmer interglacial period. During the Quaternary Great Glaciation, it was divided into several sub-glacial periods and sub-interglacial periods. Today, the world is in the Quaternary interglacial period, with the temperature rising year by year and the precipitation decreasing year by year, especially in the Yellow River basin, where the climate is dry. The average precipitation in the basin above Huayuankou in the south of the Yellow River decreased 1990 ~ 1995.

④ Changes of atmospheric transparency. The surface climate is influenced by solar radiation. Solar radiation is not only affected by the change of the sun itself, but also by the transparency of the atmosphere. Volcanic activity has the greatest influence on atmospheric transparency. Dust emitted by volcanic eruption can strongly reflect and scatter solar radiation, but it has little effect on long-wave radiation emitted from the ground. According to calculation, the ability of volcanic dust to scatter solar radiation is 30 times greater than that of ground long-wave radiation, and the role of dust in reflecting solar radiation is much stronger than that of atmospheric molecules. According to the measurement results, in the years with more volcanic activity, the solar radiation reaching the ground is correspondingly less. 19 12 from the 1990s, there was relatively little volcanic activity in the northern hemisphere, and the atmospheric turbidity was reduced, so it could absorb more solar radiation. So the temperature rises, forming a warm period, evaporation intensifies, and the climate becomes dry.

⑤ Watershed conditions. Most of the Yellow River basin belongs to arid and semi-arid continental climate zone. The average annual precipitation is 476 mm, and the distribution of precipitation is uneven during the year. About 60% of the precipitation is concentrated from June to September. Runoff is mainly supplied by precipitation, so it is unevenly distributed and varies greatly during the year. The natural river runoff is 65.8 billion cubic meters, and the measured annual runoff is 43 1 100 million cubic meters. The ratio of the maximum annual runoff to the minimum annual runoff in the main stream is 2 ~ 3. Rainfall is not abundant and water resources are insufficient. After entering the warm period, evaporation is strengthened, precipitation is reduced, drought is aggravated, and the relationship between supply and demand of water resources is more tense. Finally, the phenomenon that the Yellow River was cut off appeared.

6. Downstream replenishment. The lower reaches of the Yellow River flows through the North China Plain, with wide and flat riverbed, slow water flow and large sediment deposition. It is a world-famous above-ground river, so that this section of the Yellow River not only can't get water supply from the underground aquifers on both sides of the river, but needs to recharge the underground aquifers with river water infiltration. The drier it is, the more serious it will be.

⑦ Upper and middle reaches supply. The runoff of the Yellow River mainly comes from surface runoff and underground runoff, supplemented by precipitation in the upper and middle reaches. The decrease of precipitation in the basin directly reduces the water supply of runoff.

2. Man-made reasons for the interruption of the Yellow River.

Unreasonable utilization of water resources and human destruction of the environment are also one of the main reasons for the interruption of the Yellow River.

① Low forest coverage and serious soil erosion. In history, the deterioration of vegetation has a great influence on the interruption of the Yellow River. In the Loess Plateau, the original dense forest was destroyed by man after the Tang and Song Dynasties. Until today, the forest coverage rate of the Yellow River Basin is still far below the national average, and its ecological destruction trend is far from being fundamentally curbed or even developed. The amount of soil erosion is amazing, which makes the land's water storage and water conservation performance very poor. The deterioration of ecological environment and the disappearance of forests are the historical reasons for the coexistence of floods and the interruption of the Yellow River.

With the rapid development of population and economy, water consumption has increased dramatically. Since the 1950s, the population of the Yellow River Basin has surged, the scale of human production and life has expanded without restraint, and the water consumption has shown a sharp upward trend. In 1950s, the irrigated farmland in the lower Yellow River irrigation area was 6.5438+0.4 million hectares. In 1990s, the irrigated area rose to 5 million hectares, and the industrial production water consumption also increased several times. In the early 1950s, the annual average water consumption in the Yellow River water supply area was 65.438+0.22 billion cubic meters, and reached 30 billion cubic meters in the early 1990s, while the annual average precipitation decreased. Compared with the 1950s, the inflow of water from the lower reaches of the Yellow River decreased by 2.45 billion cubic meters in the non-flood season in the 1990s, and the water consumption increased by 810.50 billion cubic meters in the same period. The contradiction between supply and demand of water resources is sharp, and the supply of water resources in the Yellow River is far less than the demand, so it is inevitable to cut off water.

③ The management of water resources is not harmonious. In the dry season or dry season, all areas along the Yellow River only consider their own interests, and draw water, store water, compete for water and grab water one after another. Water resources management is chaotic, water distribution is unreasonable, and the contradiction of water shortage is more prominent. This aggravated the degree of water shortage downstream.

④ The water fee is low, the agricultural irrigation method is primitive, and the waste of water resources is amazing. The Yellow River flows through the important agricultural production areas in northern China, and agricultural irrigation water accounts for more than 90% of the total water consumption of the whole river. In Huang Qu, the water fee per cubic meter is only 3.6 cents, which is far lower than the production cost of water supply. Such a low water price naturally cannot arouse people's awareness of water conservation. At present, there are 5 million hectares of irrigated land in the Yellow River Basin, and the original irrigation methods such as flood irrigation and series irrigation are still the main ones. In some irrigation areas, the average annual total water consumption per hectare is as high as 60 cubic meters. Extensive agricultural production mode makes the effective utilization rate of water resources in the Yellow River less than 40%, and the waste of water resources is amazing.

⑤ The water pollution is serious and the water quality is poor. With the rapid increase of population and economic development, the degree of water pollution in the Yellow River basin is increasing year by year, and the water quality is obviously declining, which not only affects human health, but also reduces the development and utilization rate of water resources in the Yellow River, and the contradiction of "water shortage" is more acute.

⑥ Greenhouse effect. The greenhouse effect produced by greenhouse gases such as carbon dioxide has accelerated the temperature rise, increased evaporation, decreased precipitation and intensified drought.

⑦ Marine desertification. At present, about 654.38+0.8 billion tons of oil are transported to consumption places by sea every year. Due to improper transportation or tanker accidents, about 6.5438+0.8 million tons of oil flows into the ocean every year. In addition, waste oil produced in industrial processes is discharged into the sea. It is estimated that the amount of oil injected into the ocean every year is 2 million tons ~150,000 tons, and some of it forms an oil film floating on the sea surface to inhibit seawater evaporation. Reduce the amount of water involved in water vapor transportation. At the same time, it reduces the transformation of latent heat on the sea surface, reduces the role of the ocean in regulating climate, and produces the "marine desertification effect". Especially since the 1970s, it has become more and more obvious in China's offshore waters, which directly affects China's climate and precipitation and reduces China's precipitation.

⑧ Artificial heat release. With the development of industry and transportation, the energy consumption in the world is increasing rapidly. In 2000 alone, the global energy consumption was equivalent to the energy released by burning 38 billion tons of coal, which enhanced the dryness of the atmosphere and reduced the precipitation on land to some extent.

Pet-name ruby coastal city climate interception. Due to the urban heat island effect, the temperature difference between urban and suburban areas is caused, thus forming local thermal circulation, which is more obvious when the pressure gradient is small in a large range. There is a strong updraft in the city during the day. In this way, because there are a lot of condensation nuclei and updraft in the urban area, the precipitation is more than that in the suburbs, which can generally increase by 5% ~ 10%. In recent years, the process of urbanization in eastern China is particularly fast, with large-scale urban development and many cities. Many urban agglomerations have an obvious "interception" effect on the water vapor entering the mainland, which makes it produce precipitation locally, reduces the amount of water entering the inland (such as the middle and upper reaches of the Yellow River) and reduces the precipitation in the main recharge areas of the Yellow River.

Third, the impact of the Yellow River cut off.

1. Harm of Yellow River cut-off to coastal natural ecological environment

The cut-off of the Yellow River will cause the river channel to shrink, and a large amount of sediment originally imported into the ocean can only be deposited in coastal areas, thus raising the river bed, which is not conducive to flood discharge in flood season and is easy to induce greater flood disasters. The sudden increase of sediment in the dry river makes it possible for the river to evolve into a huge sand belt. Over time, the tragedy of the Yellow River's old course filled with wind and sand may reappear, and the coastal land lacks water protection, and the possibility of land desertification and desertification increases. After the seasonal cut-off of the Yellow River, the Yellow River Delta region lacks sufficient sediment deposition and water input, the groundwater level drops, seawater immersion accelerates soil salinization, and the biodiversity advantage will be lost. In a word, the interruption of the Yellow River makes the natural ecological environment in the lower reaches of the Yellow River tend to deteriorate, the ecological balance is out of balance, and the soil fertility declines, which is not conducive to human survival and development.

2. The impact of the Yellow River interruption on human activities along the coast.

Due to the interruption of the Yellow River, the industrial and agricultural losses in the lower reaches of the Yellow River from 1.972 to 1.996 totaled about 26.8 billion yuan, with an average annual loss of 654.38+0.4 billion yuan. Drought-affected farmland is 5 million hectares, reducing grain by 654.38 billion tons. The interruption of the Yellow River has seriously disrupted the lives of people along the coast, with Shandong exceeding 1 100 million yuan. The seasonal cut-off of the Yellow River reduces the water source in the downstream area, but the industrial sewage and domestic wastewater discharged into the Yellow River increase year by year, the self-purification ability of the Yellow River weakens, and the groundwater quality deteriorates, threatening people's health. The seasonal interruption of the Yellow River has greatly restricted the healthy development of social economy in North China.

Fourth, the countermeasures of the Yellow River cut off.

1. Plant trees and grass, green the earth, improve local climate, plant trees and grass, expand vegetation coverage, develop ecological economy, combine resource development with soil and water conservation, conserve water and soil, prevent soil erosion, improve local climate, reduce flood disasters, increase soil fertility and increase underground runoff.

2. Controlling population and improving population quality The Yellow River Basin should pay attention to effectively controlling population growth, and at the same time urge citizens to consciously protect the environment and water resources, use water rationally and save water.

3. Unified planning, coordinated development, unified management of the Yellow River water resources, overall planning of the Yellow River water resources utilization and scheduling scheme, adjust measures to local conditions, give full play to the role of large-scale water conservancy projects, and retain floods to regulate runoff.

4. Increase water resource use fees, promote water conservation and implement a system of paid use of water resources, collect water resource use fees according to law, and appropriately raise water prices, so as to stimulate people's water use concepts, awaken water-saving awareness, and avoid or reduce water waste.

5. Adjust the agricultural structure of the basin, reduce water consumption, vigorously cultivate and popularize drought-tolerant crops in the basin, and reduce irrigation water consumption.

6. Scientific farming and implementation of new technologies of water-saving irrigation Pipe irrigation, sprinkler irrigation, drip irrigation and infiltration irrigation are internationally recognized new technologies of water-saving irrigation, and the water consumption per hectare of water-saving irrigation is only 1/5 of that of traditional irrigation. The Yellow River basin has a vast area of cultivated land, and traditional irrigation methods are common. The new technology of water-saving irrigation has a broad market and great water-saving potential. This should be promoted not only in the middle and lower reaches of the Yellow River, but also in Ningxia Plain and Hetao Plain, which are big water users of the Yellow River.

7. Strengthening sewage purification and improving the reuse rate of water resources is an important means of industrial water saving. Efforts should be made to improve the purification and treatment of polluted water bodies, improve the reuse rate of industrial water as much as possible, and save water.

8. The South-to-North Water Transfer Project, the South-to-North Water Transfer Project, and the diversion of water from the Yangtze River to the Yellow River are important measures to solve the water shortage in the Yellow River basin.

9. Update industrial and transportation equipment and design new equipment to absorb and store heat, so that the heat energy released in transportation and industry can be reused. Reduce man-made heat release and reduce the drying of air on land.

10. Reduce the oil slick on the ocean surface. Take effective measures to recover waste oil, transport oil reasonably, and reduce oil from entering the sea. The "ocean oil absorber" aims to "clean up" the oil slick on the ocean surface regularly to reduce the phenomenon of marine desertification.

1 1. Reduce carbon dioxide emissions, popularize the use of clean energy such as solar energy and geothermal energy, reduce carbon dioxide emissions, slow down the "greenhouse effect" and reduce air dryness.