River flow: definition and characteristics

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Water resources are one of the most important resources of the Earth. But they are very limited. After all, although ¾ of the planet's surface is occupied by water, most of it is the s alty oceans. Man needs fresh water.

Its resources are also mostly inaccessible to people, as they are concentrated in the glaciers of the polar and mountainous regions, in swamps, underground. Only a small part of the water is suitable for human use. These are fresh lakes and rivers. And if in the first the water lingers for decades, then in the second it is updated about once every two weeks.

River flow: what does this concept mean?

This term has two main meanings. First, it refers to the entire volume of water flowing into the sea or ocean during the year. This is its difference from the other term "river flow", when the calculation is carried out for a day, hours or seconds.

The second value is the amount of water, dissolved and suspended particles carried by all rivers flowing in a given region: mainland, country, region.

Surface and undergroundriver flow. In the first case, we mean water flowing into the river along the earth's surface. And the underground one is springs and springs gushing under the bed. They also replenish the water supply in the river, and sometimes (during the summer low water or when the surface is ice-bound) they are its only source of food. Together, these two species make up the total river runoff. When they talk about water resources, they mean it.

Factors affecting river flow

This question has already been sufficiently studied. There are two main factors: the terrain and its climatic conditions. In addition to them, a few more additional ones stand out, including human activity.

The main reason for the formation of river flow is the climate. It is the ratio of air temperature and precipitation that determines the evaporation rate in a given area. The formation of rivers is possible only with excessive moisture. If evaporation exceeds the amount of precipitation, there will be no surface runoff.

The nutrition of rivers, their water and ice regime depend on the climate. Atmospheric precipitation provides replenishment of moisture reserves. Low temperatures reduce evaporation, and when the soil freezes, the flow of water from underground sources is reduced.

Relief affects the size of the river's catchment area. It depends on the shape of the earth's surface in which direction and at what speed the moisture will flow. If there are closed depressions in the relief, not rivers, but lakes are formed. The slope of the terrain and the permeability of rocks affect the ratio between flowing into water bodies andpart of the precipitation seeping into the ground.

The importance of rivers for humans

Nile, Indus with Ganges, Tigris and Euphrates, Huang He and Yangtze, Tiber, Dnieper… These rivers became the cradle for different civilizations. Since the birth of mankind, they have served not only as a source of water, but also as channels for penetrating new unexplored lands.

Thanks to river flow, irrigated agriculture is possible, which feeds almost half of the world's population. High water consumption also means rich hydropower potential. River resources are used in industrial production. The production of synthetic fibers and the production of pulp and paper are particularly water-intensive.

River transport is not the fastest, but it is cheap. It is best suited for transporting bulk cargo: timber, ores, oil products, etc.

A lot of water is taken for domestic needs. Finally, rivers are of great recreational importance. These are places of rest, restoration of he alth, a source of inspiration.

The deepest rivers in the world

The largest volume of river flow is in the Amazon. It is almost 7000 km³ per year. And this is not surprising, because the Amazon is full of water all year round due to the fact that its left and right tributaries overflow at different times. In addition, it collects water from an area almost the size of the entire mainland of Australia (over 7000 km^2)!

In second place is the African Congo River with a flow of 1445 km3. located inequatorial belt with daily showers, it never gets shallower.

Next in total river flow resources: Yangtze - the longest in Asia (1080 km³), Orinoco (South America, 914 km^{3), Mississippi (North America, 599 km}3^{). All three spill heavily during the rains and pose a significant threat to the population.}

The 6th and 8th places in this list are the great Siberian rivers - the Yenisei and the Lena (624 and 536 km³ respectively), and between them - the South American Parana (551 km 3^{). Rounding out the top ten is another South American river, the Tocantins (513 km}3^{) and the African Zambezi (504 km}3^).

Water resources of the world

Water is the source of life. Therefore, it is very important to have its reserves. But they are extremely unevenly distributed around the planet.

The provision of countries with river runoff resources is as follows. The top ten countries richest in water are Brazil (8,233 km³), Russia (4.5 thousand km³), the USA (more 3 thousand km^{3), Canada, Indonesia, China, Colombia, Peru, India, Congo.}

Weakly provided territories located in a tropical dry climate: North and South Africa, the countries of the Arabian Peninsula, Australia. There are few rivers in the inland regions of Eurasia, so Mongolia, Kazakhstan, and Central Asian states are among the low-income countries.

If the number of people using this water is taken into account, the figures change somewhat.

River runoff resource availability

Biggest		Smallest
Countries	Security (m3/person)	Countries	Security (m3/person)
French Guiana	609 thousand	Kuwait	Under 7
Iceland	540 thousand	United Arab Emirates	33, 5
Guyana	316K	Qatar	45, 3
Suriname	237 thousand	Bahamas	59, 2
Congo	230 thousand	Oman	91, 6
Papua New Guinea	122 thousand	Saudi Arabia	95, 2
Canada	87k	Libya	95, 3
Russia	32 thousand	Algeria	109, 1

Densely populated countries of Europe with full-flowing rivers are no longer so rich in fresh water: Germany - 1326, France - 3106, Italy - 3052 m³ per capita with an average value for everything world - 25 thousand m^3.

Transboundary runoff and related issues

Many rivers cross the territory of several countries. In this regard, there are difficulties in the joint use of water resources. This problem is especially acute in areas of irrigated agriculture. In them, almost all the water is taken to the fields. And the neighbor downstream may not get anything.

For example, the Amudarya River, which belongs in its upper reachesTajikistan and Afghanistan, and in the middle and lower - Uzbekistan and Turkmenistan, in recent decades does not bring its waters to the Aral Sea. Only with good neighborly relations between neighboring states can its resources be used to the benefit of all.

Egypt receives 100% of its river water from abroad, and reducing the flow of the Nile due to water intake upstream can have an extremely negative impact on the state of the country's agriculture.

In addition, along with water, various pollutants “travel” across the borders of countries: garbage, factory runoff, fertilizers and pesticides washed off the fields. These problems are relevant for the countries lying in the Danube basin.

Rivers of Russia

Our country is rich in large rivers. There are especially many of them in Siberia and the Far East: the Ob, Yenisei, Lena, Amur, Indigirka, Kolyma, etc. And the river flow is the largest in the eastern part of the country. Unfortunately, so far only a small fraction of them have been used. Part goes for household needs, for industrial enterprises.

These rivers have a huge energy potential. Therefore, the largest hydroelectric power plants are built on Siberian rivers. And they are indispensable as transport routes and for timber rafting.

The European part of Russia is also rich in rivers. The largest of them is the Volga, its flow is 243 km3. But 80% of the country's population and economic potential are concentrated here. Therefore, the lack of water resources is sensitive, especially in the southern part. The flow of the Volga and some of its tributaries is regulated by reservoirs; a cascade of hydroelectric power stations has been built on it. The river with its tributaries is the main part of the Unified Deep Water System of Russia.

In the context of the growing worldwide water crisis, Russia is in favorable conditions. The main thing is to prevent pollution of our rivers. Indeed, according to economists, clean water can become a more valuable commodity than oil and other minerals.