How are rivers formed?

Rivers usually refer to the water flow that land rivers often or intermittently flow along narrow depressions. Do you want to know the reason why rivers form? The following is what I have compiled about how rivers are formed. I hope you like it!

Rivers are formed because the water in rivers is composed of rainfall, melting water from snow-capped mountains and groundwater. At first, a river may be just a small river formed by snowmelt water, or a spring water gushing from the ground, or a stream where rainwater collects. The more water gathered, the more it began to flow to low-lying areas.

At this time, the water melted by snow water keeps flowing into the river; Some rainwater also falls into the river, while others seep into the soil to form groundwater. Sometimes, groundwater will pass through rocks and soil and slowly seep into rivers. Sometimes, the water in the lake overflows the lake to form a stream and flows into the river. Because rain, snow, groundwater and streams are constantly flowing in, gradually forming a big river and finally flowing into the sea.

1, the internal force of the earth leads to the rupture of the crust, that is, the terrain is divided into high and low, and water may gather in the lowlands and become rivers.

2. External forces, such as wind erosion, cause lowlands.

3. Sufficient supply sources: such as melting water of ice and snow, atmospheric precipitation and groundwater.

The time of emergence should be in the tertiary, because at this time, there were frequent orogenic movements on the earth, and the differences of various high and low landforms appeared on the earth, and then rivers appeared.

Rivers are linear natural waterways where water flows frequently or intermittently on the surface. Rivers in China have many names, the big ones are called Jiang, He, Chuan and Shui, and the small ones are called Jian, Gou and Qu. Tibetan is called Zangbu, and Mongolian is called Guo Le. Every river has its source and entrance. Heyuan refers to the birthplace of rivers, some are springs, some are lakes, swamps or glaciers, and the situation at the source of each river is different. Estuary is the end of the river, that is, the place where the river flows into the ocean, river (such as tributary flows into the main stream), lake or swamp. In arid desert areas, some rivers are consumed by leakage and evaporation along the way and eventually disappear into the desert. This kind of river is called blind tail river.

Except for the source and estuary, each river is divided into upper, middle and lower reaches according to the hydrological and valley topographic characteristics. The upstream gradient is large, the velocity is large, and scouring is the main factor. Most of the rivers are bedrock or gravel. In the middle reaches, the slope and velocity decrease, the discharge increases, and the erosion and siltation are not serious, but the lateral erosion of the river channel has developed, and the river channel is mostly coarse sand. The downstream slope is gentle, the flow rate is small, but the flow rate is large, mainly siltation, mostly shoals or sandbars, and the river channel is mostly fine sand or silt. Usually a big river will be divided into several seas where it enters the sea, forming an estuary delta. Generally, the rivers that flow into the ocean are called outflow rivers, and the basins that supply outflow rivers are called outflow basins. This kind of blind tail river that flows into inland lake or disappears in desert is called inland river, and the basin that supplies inland river is called inland river basin. The outflow basin area of China accounts for 63% of the national area. 76%。 An artificial river channel dug to communicate different rivers, water systems and oceans and develop water traffic is called a canal, also known as a canal. In order to discharge the river flood, the artificially excavated river is called river reduction.

There are more than 65,438+0,500 rivers in China, with a basin area of over 65,438+0,000 square kilometers. The total runoff of China exceeds 2.7 trillion cubic meters, which is equivalent to 5.5% of the global runoff. 8%。 Because most of the major rivers originate from the Qinghai-Tibet Plateau, with a large gap, China is rich in hydraulic resources, with a reserve of 6. 800 million kilowatts, ranking first in the world.

Rivers in China are divided into outflow rivers and inflow rivers. The outflow river that flows into the ocean accounts for about 64% of the total land area of the country. The Yangtze River, Yellow River, Heilongjiang, Pearl River, Liaohe River, Haihe River and Huaihe River flow eastward into the Pacific Ocean; The Yarlung Zangbo River in Tibet flows eastward and southward into the Indian Ocean. It is 504 meters long. The largest canyon in the world, 6 kilometers deep and 6,009 meters? Yarlung Zangbo Grand Canyon; The Irtysh River in Xinjiang flows northward out of China and into the Arctic Ocean. Inland rivers that flow into inland lakes or disappear into deserts and salt flats account for about 36% of the total land area of China. Tarim River in southern Xinjiang is the longest inland river in China, with a total length of 2 179km.

What is the river that flows through the country the most in the world? Danube

It originated at the eastern foot of Heilin Mountain, 679 meters above sea level in southwest Germany, and flowed through nine countries, including Austria, Czech Republic, Slovakia, Hungary, Croatia, the former Yugoslavia, Bulgaria, Romania and Ukraine, and then flowed into the Black Sea from west to east. With a total length of 2,860 kilometers, the Danube is the second longest river in Europe. The Danube meanders like a blue ribbon across Europe.

The longest river in the world? The Nile

The Nile runs through the northeast of the African continent, flows through Burundi, Rwanda, Tanzania, Uganda, Ethiopia, Sudan and Egypt, crosses the largest Sahara desert in the world, and finally empties into the Mediterranean Sea. The basin covers an area of about 3.35 million square kilometers, accounting for one ninth of the African continent, with a total length of 6,650 kilometers and an average annual flow of 3 100 cubic meters per second, making it the longest river in the world.

The river with the largest sediment concentration? Yellow river

The Yellow River originates in Yalazi, the southwest edge of the Yogu Zonglie Basin at the northern foot of Bayan Kara in the Qinghai-Tibet Plateau, meanders through the Loess Plateau and the North China Plain, and finally flows into the Bohai Sea in Kenli County, Shandong Province. With a total length of 5,464 kilometers, 34 important tributaries and a drainage area of 750,000 square kilometers, it is the second longest river in China. The Yellow River is famous for its high sediment concentration. Its sediment concentration ranks first in the world's major rivers. According to calculation, the middle reaches of the Yellow River receive about1.60 billion tons of sand every year. If these sediments are piled into an earth wall with a height of 1 m and a width of 1 m, it can circle the equator of the earth 27 times.

The river with the largest basin area? the Amazon

It is the largest river basin in the world, and the Amazon Plain through which the Amazon River flows is the largest plain in the world. Amazon River is the largest river with the largest flow and the widest basin in the world. Its length is second only to the Nile (about 6400 kilometers) and it is the second largest river in the world. It is estimated that about 20-25% of all water flowing on the earth's surface is in the Amazon River. The estuary is 240 kilometers wide, and the flow in flood season reaches 654.38+0.8 million cubic meters per second, which is 654.38+00 times that of Mississippi River. The displacement is so large that the sea water becomes weak within the range of 160 km from the shore.

The largest inland river in the world? Volga River