Despite the fact that about 70% of the earth's surface is covered with water, it is still a very valuable resource. Especially when it comes to quality. What are water resources? What is their structure and world reserves? What water problems are the most acute nowadays? All this will be discussed in the article.
What are water resources?
The geographic shell of the Earth, as you know, consists of five areas: litho-, atmospheric-, bio-, techno- and hydrospheres. What are water resources? This is all the water that is contained in the hydrosphere. It is found in oceans and seas, lakes and rivers, glaciers and reservoirs, in the thickness of the soil and in the air (in the form of water vapor).
About 70% of the earth's surface is covered with water. Only 2.5% of this volume is fresh water, which humanity needs. In absolute terms, this is at least 30 million cubic kilometers, which is thousands of times higher than the needs of world civilization. However, do not forget that the bulk of these reserves are contained in the "ice shells" of the Antarctic, Arctic and Greenland. In addition, the state of water resources available to humans is often unsatisfactory.
The structure of planetary water resources
The planet’s water resources are divided into two classes:
- waters of the oceans;
- sushi water (or surface).
Rivers, lakes, reservoirs and glaciers contain only four percent of the world's water reserves. Moreover, most of them (by volume) are confined specifically to glaciers. And the largest "reservoir" of fresh water on the planet is Antarctica. The Earth's water resources include underground flows, but their quantitative estimates vary greatly in numbers.
Pure fresh water is a most valuable natural resource for humans and any other living organisms. Its protection and rational use is one of the most important tasks of mankind at the present stage.
Water renewal
Features of water resources are the possibility of self-purification and renewal. However, the renewability of water depends on several factors, in particular, on the type of hydrological object.
For example, water in rivers is completely renewed in about two weeks, in a swamp - in five years, and in a lake - in 15-17 years. This process takes the longest time in ice sheets (on average it takes 10 thousand years), and as quickly as possible - in the biosphere. In a living organism, water undergoes a complete renewal cycle in a few hours.
Distribution of water resources by macro-regions and countries
In terms of total water resources in the world, the Asian region leads. It is followed by South America, North America and Europe. The poorest corner of the planet's water reserves is Australia.
However, there is one important nuance. So, if we calculate the volume of water reserves per capita of the mainland or part of the world, then a completely different picture emerges. Australia comes first in this calculation, but Asia comes in last. The thing is that in Asia, the population is growing rapidly. Today it has already reached the milestone of four billion people.
Which countries can not worry about water? The first five countries with the largest fresh water reserves are listed below. It:
- Brazil (6950 km 3 ).
- Russia (4,500 km 3 ).
- Canada (2900 km 3 ).
- China (2800 km 3 ).
- Indonesia (2530 km 3 ).
It is worth noting the uneven distribution of water resources on Earth. So, in the equatorial and temperate climatic zones they are even in abundance. But in the so-called "arid" (tropical and subtropical climate), the population experiences an acute shortage of life-giving moisture.
Water and human
Water is in demand in everyday life, energy, industry, and recreation. The use of this resource may be accompanied by its extraction from a natural source (for example, from a river bed) or pass without it (for example, for the operation of water transport).
The largest consumers of water resources are:
- Agriculture;
- industrial and energy enterprises;
- communal sphere.
The volume of domestic water consumption is constantly growing. According to environmentalists, in large megacities of economically developed countries, one person uses at least 300 liters of fluid daily. This level of consumption may lead to a shortage of this resource in the near future.
Pollution and depletion of world waters
Water pollution is a very acute environmental problem of our time. To date, it has reached catastrophic indicators in some regions of the planet.
Every year, millions of tons of chemicals, oil and oil products, phosphorus compounds, and municipal solid waste enter the World Ocean. The latter form huge floating islands of garbage. The waters of the Persian Gulf, the North and the Caribbean are very polluted with oil. Already about 3% of the surface of the North Atlantic is covered with an oil film, which has a detrimental effect on living organisms of the ocean.
A big problem is also the reduction of the planet’s water resources. However, deterioration in the quality of life-giving moisture is no less dangerous. After all, one cubic meter of untreated sewage can fall into the natural channel of the river and spoil dozens of cubic meters of clean water.
In the developing countries of the world, according to statistics, every third resident suffers from poor-quality drinking water. It serves as the main cause of many diseases of the population of the "arid belt" of Africa and Latin America.
The main types and sources of global water pollution
In ecology, water pollution is understood as the excess of the limit-permissible concentrations of the substances contained in them (harmful chemical compounds). There is also such a thing as depletion of water resources - the deterioration of water quality under the constant influence of anthropogenic activities.
There are three main types of water pollution:
- chemical;
- biological;
- thermal;
- radiation.
Any substance that enters a hydrological object as a result of human activity can act as a pollutant. Moreover, this substance significantly affects the natural quality of water. One of the most dangerous modern pollutants is oil, as well as products from it.
Sources of pollution can be continuous, periodic or seasonal. They can have both anthropogenic and natural origin, be point, linear or areal.
The largest source of pollution is the so-called wastewater. That is, those that are formed as a result of industrial, construction or communal activities of a person. They are usually oversaturated with harmful organic and inorganic substances, heavy metals and microorganisms. Allocate industrial (including mine), municipal, agricultural and other types of wastewater.
Description of water resources in Russia
Russia is one of the countries of the world that does not experience water shortages. The country's modern water resources are 2.5 million rivers and watercourses, about two million lakes and hundreds of thousands of swamps. The territory of Russia is washed by the twelve seas. A huge amount of fresh water is stored in glaciers (mountain and circumpolar).
To improve water supply in the territory of our state, thousands of reservoirs of various sizes have been created. In total, they contain about 800 km 3 of fresh water. These objects not only serve as artificial reservoirs of a valuable natural resource, but also regulate the regime of rivers and prevent floods and floods. Thus, their value is difficult to overestimate.
Among the main problems of water resources in Russia are the following:
- irrational water use;
- deterioration in the quality of drinking water;
- unsatisfactory condition of waterworks and hydraulic structures.
Finally...
What are water resources? This is all the water that is contained in the hydrosphere. The largest reserves of water resources are possessed by countries such as Brazil, Russia, Canada, China, Indonesia and the United States.
In modern realities, the problem of pollution and irrational use of world waters is becoming very urgent, and in some regions it is especially acute. Its solution is impossible without the consolidation of efforts of all countries of the planet and the effective implementation of joint global projects.