Reasons for the formation of North China Plain
Question 2: How was the North China Plain formed? The formation of the North China Plain can be traced back to the Yanshan Movement more than1.300 million years ago. At that time, there was a strong crustal movement in the northern region, forming the majestic Taihang Mountain. During the Himalayan movement 30 million years ago, Taihang Mountain rose again and the eastern region continued to sink. Over time, a large fan-shaped alluvial plain has formed in the eastern part of the foothills. Because the Yellow River, Haihe River, Luanhe River and other water systems carry a lot of sediment every year, they scour and accumulate in the low-lying areas in the east from west to east, which makes the area of ancient alluvial fans expand eastward and finally forms a vast North China Plain.
Question 3: How was the North China Plain formed? It is mainly alluvial from the Yellow River, Haihe River and Huaihe River, including alluvial fans at the foot of the mountain, central plains and coastal bottom plains.
Question 4: The formation of North China Plain, also known as Huanghuaihai Plain.
It is formed by the impact of the Yellow River, Huaihe River and Haihe River with the upstream sediment.
See the third volume of junior high school geography published by People's Education Press.
general situation
China's second largest plain. Located in the lower reaches of the Yellow River. It starts from Taihang Mountain and Western Henan Mountain in the west, reaches the Yellow Sea, Bohai Sea and Shandong Hill in the east, starts from Yanshan Mountain in the north, reaches Tongbai Mountain and Dabie Mountain in the southwest, reaches northern Jiangsu and Anhui in the southeast, and is connected with the plain in the middle and lower reaches of the Yangtze River. It extends to seven provinces and cities including Beijing, Tianjin, Hebei, Shandong, Henan, Anhui and Jiangsu. It covers an area of about 300,000 square kilometers. Mainly from the Yellow River, Huaihe River, Haihe River, Luanhe River alluvial, so it is also called Huanghuaihai Plain. The lower reaches of the Yellow River naturally cross the middle and are divided into two parts: the Huanghuai Plain in the south and the Haihe Plain in the north. Over the past century, the Yellow River has reclaimed 2300 square kilometers of land here. The plain continues to extend to the ocean, the fastest being the Yellow River Delta, with an average of 2-3 kilometers per year. The terrain is low and flat, mostly below 50 meters above sea level, and the eastern coastal plain is below 10 meters above sea level. Slightly inclined from west to east. It mainly belongs to Cenozoic giant depression with a sedimentary thickness of about1500 ~ 5000m. There are many low-lying areas and lakes and swamps on the plain. Concentrated in the northern part of the Yellow River alluvial fan between Baoding and Dagu, Tianjin. The contact area between the eastern edge of alluvial fan and Shandong hills has poor drainage and high groundwater level, which is easily threatened by floods and forms saline-alkali land. 1949, it was reformed and managed. It belongs to a warm temperate continental climate with obvious changes in four seasons. The Huaihe river basin in the south is in a transitional area to the subtropical zone, and the temperature and precipitation are higher than those in the north. The average annual temperature in the plain is 8 ~ 15℃, and it is cold and dry in winter. The average temperature in Leng Yue (65438+1October) is 0 ~-6℃, the average temperature in the hottest month in summer (July) is 28℃, and the average annual precipitation is 600 ~ 800 mm; The frost-free period is 6 ~ 8 months; There is plenty of sunshine, and the average sunshine hours in most years are 2300 ~ 2800 hours. Most crops are planted three times a year, and two times a year in the south. The soil is deep and fertile. The main food crops are wheat, rice, corn, sorghum, millet and sweet potato, and the cash crops are mainly cotton, peanuts, sesame seeds, soybeans and tobacco. Rich in mineral resources, such as coal, oil and iron ore, China's famous Dagang Oilfield and Shengli Oilfield. The eastern coasts of Bohai Sea and Yellow Sea are flat and suitable for drying sea salt. There are famous Luchang salt area and Subei salt area, and there are also important saline-alkali industrial bases. North China Plain is the cradle of ancient culture in China, with many ancient cities, such as Beijing (Hebei), Handan, Kaifeng, Shangqiu and Huaiyang.
water resource
The per capita water resources in North China Plain is only 335 cubic meters/year, which is less than the national 1/6. Surface water is unevenly distributed in time and space, and groundwater has become an important pillar of sustainable economic and social development in North China Plain. At present, groundwater exploitation in Beijing, Shijiazhuang, Xingtai, Handan, Baoding, Hengshui, Langfang and Tangshan has accounted for more than 70% of the total water supply.
Investigation shows that the natural resources of groundwater in North China Plain is 22.74 billion cubic meters/year. The exploitable resources of shallow groundwater are16.83 billion cubic meters per year, and the exploitable resources of deep groundwater are 2.42 billion cubic meters per year.
In 2000, the groundwater exploitation in North China Plain was 265.438+0.2 billion cubic meters. Among them, the exploitation of shallow groundwater is 65.438+07.84 billion cubic meters, accounting for 84.2% of the total exploitation. The exploitation of deep groundwater is 3.36 billion cubic meters, accounting for 15.8% of the total exploitation.
The exploitation and utilization degree of shallow groundwater in North China Plain is 106%, and that of deep groundwater is 139%. Due to the unreasonable mining layout, the head of deep groundwater is declining, and the head range of deep groundwater below sea level in the whole region has reached 76,732 square kilometers, accounting for 55% of the total area of plain area.
In order to ensure the safety of water supply in major cities in Beijing, Tianjin and Hebei before the South-to-North Water Transfer Project was put into use, 23 underground water sources for emergency water supply were delineated on the basis of investigation and evaluation, with an emergency water supply potential of 65.438+0 billion cubic meters per year.
Question 5: Why is the North China Plain called the most complete plain? North China Plain is the second largest plain in China. Located in the lower reaches of the Yellow River. It starts from Taihang Mountain and Western Henan Mountain in the west, reaches the Yellow Sea, Bohai Sea and Shandong Hill in the east, starts from Yanshan Mountain in the north, reaches Tongbai Mountain and Dabie Mountain in the southwest, reaches northern Jiangsu and Anhui in the southeast, and is connected with the plain in the middle and lower reaches of the Yangtze River. It extends to Beijing, Tianjin, Hebei, Shandong, Henan, Anhui and Jiangsu provinces. The area is about 3 1 10,000 square kilometers. The North China Plain has a warm temperate monsoon climate with obvious changes in four seasons. The Huaihe river basin in the south is in a transitional area to the subtropical zone, and the temperature and precipitation are higher than those in the north. The average annual temperature in the plain is 8 ~ 15℃, and it is cold and dry in winter. Most crops are harvested three times a year and twice a year in the south. Mainly from the Yellow River, Huaihe River, Haihe River, Luanhe River alluvial, so it is also called Huanghuaihai Plain. The lower reaches of the Yellow River naturally cross the middle and are divided into two parts: the Huanghuai Plain in the south and the Haihe Plain in the north. Over the past century, the Yellow River has reclaimed 2300 square kilometers of land here. The plain continues to extend to the ocean, with the Yellow River Delta as the fastest, averaging 2-3 kilometers per year. The terrain is low and flat, mostly below 50 meters above sea level, and the eastern coastal plain is below 10 meters above sea level. Slightly inclined from west to east. It mainly belongs to Cenozoic giant depression with a sedimentary thickness of about1500 ~ 5000m. There are many low-lying areas and lakes and swamps on the plain. Concentrated in the northern part of the Yellow River alluvial fan between Baoding and Dagu, Tianjin. Because the Yellow River carries a lot of sediment, the riverbed is silted year by year, and the riverbed in the lower reaches is 3-4 meters higher than the ground on both banks, and in some places it is 10 meter higher. However, the neglect of management of the Yellow River in past dynasties led to the frequent overflow, flooding and diversion of the Yellow River. The diversion and migration of the lower Yellow River also affected the drainage of Haihe River and Huaihe River, resulting in the formation of many shallow depressions of different sizes in the North China Plain, which aggravated the threat of floods. Low and flat depressions are also easy to salinize the soil. 1949, it was reformed and managed. Since 1949, the levee in the lower reaches of the Yellow River 1800 km has been maintained and repaired every year, ensuring the safe flood discharge of the Yellow River for more than 30 years. It also reclaimed silt on both sides of the Yellow River, improved saline-alkali land and diverted water for irrigation. The Huaihe River and Haihe River have also been treated on a large scale.
Question 6: Explain the reasons for the formation of the North China Plain from the hydrological characteristics. The hydrological characteristics of rivers in Northeast China are as follows: 1. There are two flood seasons in a year. The first flood season is spring flood caused by melting snow in spring and winter (some are ice flood, that is, rivers freeze in winter and the temperature gets warmer in spring), and the second flood season is summer flood caused by rainfall brought by monsoon climate; 2. Ice age; 3. The sediment concentration is small, and the upstream water and soil conservation is good; 4. There is little water in the river!
The ice age has a long flood season (spring flood and summer flood, spring flood is the melting water of winter snow, and the latter is caused by summer monsoon precipitation). Note: It must be meltwater, not a glacier. Glacier meltwater is only found in the northwest of China. The amount of water is small, and the sediment concentration is relatively small!