Students get acquainted with this geographical topic in the 8th grade. Inland waters - what is this concept? What sciences study them? And what is the structure of inland waters? All these questions will be answered by our article.
What are inland waters (geography, grade 8)
Water is the most important chemical substance for the existence of all living organisms. In nature, it is represented in three aggregate states: solid (ice), gaseous (vapor in the atmosphere) and liquid (actually water). It all depends on how close the H 2 O molecules are to each other. In the solid phase, they are as tight as possible, but in the gaseous state, the distances between them increase significantly.
The water shell of the Earth, called the hydrosphere in science, includes the oceans, as well as the so-called surface (or internal) waters. These are those hydrological objects that are located inside the continental land (hence the name - internal). These include:
- Rivers.
- Lakes.
- Swamps.
- Underground aquifers.
- Glaciers.
- Artificial water bodies (canals, reservoirs, ponds, etc.).
In international law, inland waters are not only all of the above objects, but also sea bays, bays, ports, and the waters of the seas (but only if they are completely framed by the shores of one state). But in our article we will consider this concept only from the point of view of geographical science.
By the way, in geography, inland waters are studied by several scientific disciplines at once. Let's list them:
- Potamology - studies rivers.
- Limnology - explores the lakes.
- Glaciology - studies glaciers.
- Hydrogeology - studies the composition and patterns of groundwater circulation.
Geography of the planet’s water resources
Inland waters are a zonal category. In other words, their distribution on the earth's surface is not uniform, it depends on the geographical location and climate. Let us briefly consider how the various continents of our planet are provided with surface waters.
Eurasia. The largest continent has tremendous water resources. Eurasia is the mainland of branched river systems, as well as huge lakes in area and depth. Due to its northern position, the vast expanses of the continent are occupied by permafrost and glaciers.
North America ranks second in the world in terms of water availability. There are a lot of deep rivers, glaciers and lakes. True, they are concentrated mainly in the northern part of the mainland.
South America surpasses all other continents of the Earth in terms of river flow. It is here that the largest river system in the world - the Amazon. But large lakes and glaciers in South America are relatively few.
Africa. The formation of the hydrographic network of this continent was significantly affected by the climate. Africa's inland waters are extremely unevenly distributed. So, the northern half of the black continent receives almost no precipitation, so the river network is underdeveloped here. A third of all the rivers of Africa do not bring their waters to the ocean.
Australia is the driest mainland of the planet. It is extremely poor in surface waters. This is due to the dry tropical and subtropical climate, in which most of this continent is located. There are few large rivers and lakes, and there are no glaciers at all (due to the lack of high mountain systems).
Antarctica. About 90% of all fresh water of the Earth is concentrated in the ice of this continent! Do not think that Antarctica is a solid ice shell. There are lakes, and even small rivulets, which, however, come to life only during the short Antarctic summer. On the coast of Antarctica there are even peculiar “glacial swamps”.
Rivers
A river is a natural watercourse that flows in the channel developed by it. This hydrological object is very dependent on climate (the amount of precipitation determines its fullness) and topography (unevenness of the earth's surface determines the direction and nature of its course). As the famous Russian geographer Alexander Voeikov rightly noted, the river is a climate product.
Each river has a source (a place where it begins) and a mouth (a place where it ends). The source most often is an underground spring, stream, glacier or lake. Rivers are fed by atmospheric, underground and (or) glacial waters. At different times of the year, one or another power source may prevail.
The largest rivers of the planet are the Nile, Amazon, Mississippi, Congo, Ob, Yenisei, Lena, Volga.
Lakes and swamps
A lake is a body of water of natural origin that does not have direct communication with the sea or ocean. It is a cup-depression closed in plan (most often rounded), filled with water. By the type of mineralization of water, all lakes are divided into fresh and saline. By origin, tectonic, glacial, floodplain, coastal, dam and volcanic lakes are distinguished.
The largest lake on the planet is the Caspian Sea, and the deepest is Lake Baikal.
A swamp is a piece of land with excess moisture. It is characterized by a specific set of soils and hydrophilic vegetation. Many geographers believe that the swamp is nothing but the final stage of development of the lake. The world's largest areas of wetland are concentrated in the northern regions of Eurasia and North America.
Glaciers
A glacier is called an ice mass of atmospheric origin. Moreover, this mass is not static. All glaciers move under the influence of gravity, albeit at an insignificant speed.
Today, glaciers cover about 11% of the Earth's land. At the same time, they store the main reserves of fresh water on our planet. Glaciologists divide all glaciers into two large groups - cover and mountain (depending on the place of their formation).
Artificial Water Features
Inland waters are not only rivers, lakes, swamps and glaciers, but also objects of anthropogenic origin (that is, created by man). These include reservoirs, canals, stakes and decorative ponds.
A reservoir is an artificial lake. It is formed as a result of the construction of a dam in the riverbed. Reservoirs are created with the aim of accumulating fresh water and its further use in the national economy.
A canal is an artificial river. Most often, it is created either for the purpose of transferring water to a specific area, or for transport. Accordingly, reclamation and shipping channels are distinguished .
Inland waters of Russia (Grade 8): a brief description
In terms of total water resources, Russia is one of the first places in the world. About 2.5 million rivers flow within the country. 47 of them are over 1000 kilometers long. Most of the Russian rivers are flat streams with a smooth flow and small slopes.
In Russia, there are over 2 million lakes. Among them is the largest and deepest body of water on the planet. Most of the lakes are concentrated in Karelia. In this region they make up 20% of the territory.
Rich in Russia and groundwater. Extensive artesian basins - Moscow, Tunguska, West Siberian and others - have been explored and are actively used in a number of regions of the country. Today, groundwater is used to supply 70% of Russian cities.