I. Introduction to the Yellow River
Located in the north of China, the Yellow River is one of the longest rivers in the world and the second longest river in China. The yellow of the Yellow River is actually sediment. The ancient book says: "The Yellow River fights water, and mud ranks seventh."
90% of the sediment of the Yellow River comes from the Loess Plateau, where the soil is loose and easy to erode and disperse. Whenever it is washed by heavy rain, it will lose a lot of soil and water and flow into the Yellow River. The river basin is long in winter and short in summer, with large temperature difference between winter and summer and obvious seasonal temperature change. There is little precipitation in the basin, mainly dry land agriculture, which is dry in winter and spring, and the precipitation in summer and autumn is concentrated in July and August.
Second, the geological impact of the Yellow River
The gestation, birth and development of the Yellow River are controlled by geological processes in geological history. The tectonic movements caused by crustal changes are external forces, and the erosion, transportation and accumulation generated by itself under hydrogeological conditions are internal forces. In the historical process of becoming a river, it keeps moving forward and keeps pace with the times.
Soil erosion in the Loess Plateau and sediment deposition in the lower reaches of the Yellow River began in prehistoric geological times, and have been increasingly influenced by human activities since then. According to various studies, the ancient Yellow River has three stages of development: the early Pleistocene from Tertiary to Quaternary is the gestation period of the ancient Yellow River.
Three. Yellow river runoff
The Yellow River belongs to the Pacific water system. The main stream is mostly arc-shaped, which is called "Jiuqu Yellow River". The actual flow of the river is 2.64 times of the straight line distance from the source to the estuary. There are many tributaries of the Yellow River, from Maquguo in Heyuan to the estuary, which flows directly into the Yellow River along the way. There are 220 tributaries with a drainage area of 100 square kilometers, which constitutes the Yellow River water system.
There are 76 tributaries with an area greater than 1 1,000 square kilometers, with a basin area of 580,000 square kilometers, accounting for 77% of the total catchment area of rivers; 1 tributary of more than square kilometers 1 1, with a drainage area of 370,000 square kilometers, accounting for 50% of the total water area of rivers. The larger tributary is the main body of the Yellow River Basin.
Fourthly, the geomorphological features of the Yellow River.
The Yellow River basin starts from Bayan Kara in the west, reaches Yinshan Mountain in the north, Qinling Mountain in the south and Bohai Sea in the east. The inland potential in the basin is high in the west and low in the east, and the height difference is very large, forming three steps with high in the west and low in the east.