There are questions about the Yellow River and the Yangtze River that are asked more often.

1. The loess soil is loose and fine-grained, and once the vegetation is destroyed, soil erosion is extremely serious. Liu Yuxi described it as "Nine curves of the Yellow River and ten thousand miles of sand." Yes, 1.6 billion tons of sediment are dumped every year, 90% of which comes from these gullies on the Loess Plateau. The annual loss of 1.6 billion tons of soil is far more than just dyeing a river a shocking yellow color. It goes down with the water, silting up the lakes, breaking up the hills, raising the riverbed, and sweeping up the plains." Three years, two breaks, a century a major diversion", the mother river finally became "China's worries". The lower reaches of the Yellow River has few tributaries, the upper reaches of the tributaries are not many, but the middle reaches of the Loess Plateau tributaries are particularly developed, branching out, constituting a dense network of waterways. Such as the north of shaanxi wu ding river basin, gully density per square kilometer gully length of 7 kilometers, gully cut erosion is very extensive. Loess itself loose structure, composed of material to chalk-based (accounting for 60% -70%), with the role of cemented limestone and clay particles are not much, but also because of more vertical joints, easy to collapse or washed by the flow of water, limestone is easy to be dissolved and thus make the soil layer occurs in the cave. Generally speaking, the slope of the ground is more than 5 °, and there is no good plant cover, that is, soil erosion occurs. Particularly due to the past under feudal rule, farmers were forced to reclaim steep slopes, or overgrazing in the limited grassland, the result of the destruction of vegetation, resulting in a large number of soil and water loss of serious phenomena. The natural factors in this area can be said to have created the conditions for the development of erosion, while irrational human farming and animal husbandry operations have contributed to the occurrence of erosion. The sand content of the downstream river water thus increased sharply (up to 40%), and according to the average record of Shanzhou for many years, the annual sand loss amounted to 1.38 billion tons, in addition to the river bottom there is a rolling material equivalent to 10%-15% of the amount of sand. Even as in 1933 (the Yellow River flood) sand loss of 3.3 billion tons, such as in 1843 (estimated that the Yellow River occurred once in a thousand years of flooding) sand loss of 5.5 billion tons. Analyze the perennial river sand source: 12% from the Jing, Luo, Wei, 2% from the Fen River, Longmen below the small rivers together accounted for 2%, it can be seen that the Loess Plateau supplies the vast majority of the sand.

2. The Yellow River breaks down, mainly caused by human activities. The destruction of the ecological environment in the Yellow River basin and the irrational exploitation and utilization of water resources are the main reasons for the breakage of the Yellow River.

The Yellow River basin was once a densely forested area in history. But for thousands of years of human activities, the destruction of natural ecology, forests were cut down, grasslands were reclaimed, everywhere is barren mountains, soil erosion, water retention and water conservation capacity is greatly reduced. The rainy season floods and heavy drainage, dry season soil dry spring exhaustion.

People are accustomed to the idea that the river water should be fully utilized, not let it flow to the sea for nothing. It is under the guidance of this idea, a large number of construction of water diversion projects, and do not take into account water conservation, a large number of river water is wasted. The irrational interception and storage of water in many reservoirs in the upper and middle reaches of the river has exacerbated the scarcity of water resources in the lower reaches of the river.

3.

The amount of domestic sewage and garbage is increasing, exceeding the total amount of industrial wastewater and waste residue discharged, and has become the primary factor of pollution of the Han River.In 2004, the total amount of domestic sewage discharged in the Hanzhong basin of the Hanjiang River reached more than 40.91 million tons (accounting for more than twice the amount of industrial emissions), and the amount of COD in the sewage was 16,643.5 tons, and ammonia nitrogen was 1,925.4 tons (accounting for more than four times the amount of industrial emissions). (accounting for more than 4 times the industrial emissions), and more than 500,000 tons of domestic garbage production, becoming the primary factor of water pollution in Hanzhong City. At present, in addition to the urban areas of Hanzhong built 50,000 tons of daily treatment of urban sewage treatment plants and medical waste treatment centers have been built, the garbage disposal site is under construction, the remaining 10 counties and 25 townships along the river are not yet sewage treatment plants and garbage disposal sites.

4. The ecological environment is very poor. 1917 species, the problem of large animals is not very clear.

5. Yellow River carp and Yellow River turtle are specialties

6. It is possible to run ships, but they are small tons, and individual routes. The Yellow River often breaks the flow, the water volume is also small (smaller than the Yangtze River, Pearl River), although it can also be used as inland transportation, but never talk about is the most important in China, the Yangtze River is.

7. Because the source of the Yangtze River is a glacier water flow will not be broken, however, soil erosion will only make the Yangtze River bed rise, will not make the Yangtze River cut off, will only make the Yangtze River water like the Yellow River as turbid.

8. The Yangtze River is the largest river in China, with 35% of the country's water resources. The Yangtze River basin is one of the fastest growing economic regions in China. With the development of Shanghai Pudong, the construction of the Three Gorges Project and the implementation of the South-to-North Water Diversion Project, the water resources of the Yangtze River have become even more important in China's economic construction. Protecting the water resources of the Yangtze River and the ecological environment of the Yangtze River Basin is not only of great significance to the economic and social development of the Yangtze River Basin, but also of great importance to the economic and social development of North China, Beijing and Tianjin and even the whole country. With the rapid development of industry and agriculture in the basin, people's living standards continue to improve, on the one hand, the amount of sewage discharge continues to increase, on the other hand, the higher the requirements of water quality, water pollution in the basin is increasingly prominent, the Yangtze River water quality issues have attracted more and more widespread concern. The Yangtze River basin this year may occur larger floods

According to the meteorological and Yangtze River water conservancy departments and other departments of the latest forecast analysis, this year the Yangtze River basin may occur larger floods. The person in charge of the Yangtze River Flood Control and Drought Relief Command said recently that the flood control situation in the Yangtze River this year is not optimistic and a high degree of vigilance should be maintained.

According to the introduction, the main climatic features affecting the flooding and drought trends in the Yangtze River basin this year is that last August and February this year, respectively, the intensity of the weak "El Ni?o event"; at the end of last year to February this year, the Qinghai-Tibetan Plateau snow, China's high temperatures, the Yangtze River Basin precipitation is too much. According to the main features of the climate and the current climate background, the Hydrological Bureau of the Yangtze River Water Resources Commission of the Ministry of Water Resources has made a comprehensive forecast on the trend of droughts and floods in the Yangtze River basin during the flood season of this year: from May to October, the rainfall in the Yangtze River basin will be generally normal and excessive; from June to August during the main flood season, the rainfall in the upper reaches of the Yangtze River will be basically normal, and it will be excessive in the middle and lower reaches of the Yangtze River, and will be obvious in the middle reaches of the basin near the main stream. more, and concentrated rainfall may occur in some areas of the basin.

The person in charge of the Yangtze River Defense General Administration pointed out that these meteorological and hydrological features are very similar to those of 1998. The Yangtze River has not been basin flooding for many years, last year suffered a rare water level. According to the law of occurrence of large floods, the Yangtze River this year, the possibility of large basin floods is increasing.

9. In 2006, there were almost no albino dolphins left in the Yangtze River, and at the end of 2006, it seemed that scientists from various countries had organized a large-scale expedition to the Yangtze River, which lasted for 39 days and found no sign of the albino dolphins. After the expedition, foreign experts claimed that the baiji was probably the first whale in history to be wiped out by humans.

This is all the information I have in my memory, give me some points! ~~~~~