However, taken to the sea by rivers. 1.
However, sea water is not suitable for consumption in drinking or irrigating, because it contains sodium chloride and magnesium sulphate (to make potable it requires expensive treatment). These salts and many other substances are taken to the sea by rivers.
1. Glacial ice:
On Earth, 99% of glacial ice is contained within vast ice sheets in the Polar Regions, but glaciers may be found in mountain ranges of every continent except Australia. In the tropics, glaciers occur only on high mountains. Glacial ice is the largest reservoir of freshwater on Earth. Many glaciers store water during one season and release it later as melt-water, a water source that is especially important for plants, animals and human uses when other sources may be scant.
2. Lakes: Lakes are formed by geo:
3. Streams and Rivers:
A stream is a body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a river (a large natural stream), creek, brook (A stream smaller than a creek, especially one that is fed by a spring or seep; A brook is characterised by its shallowness and its bed being composed primarily of rocks), branch (also known as tributory, beck, burn, creek, gill (occasionally ghyll), kill, lick, rill, river, syke, bayou, rivulet, stream age, wash, run or runnel. Streams are important as conduits in the water cycle, instruments in groundwater recharge, and corridors for fish and wildlife migration.
The biological habitat in the immediate vicinity of a stream is called a riparian zone. Given the status of the ongoing Holocene extinction, streams play an important corridor role in connecting fragmented habitats and thus in conserving biodiversity.
A wetland is classified by the plant species that live in it. What types of plants grow depend on how fast the water in the wetland flows. Some wetlands are like a swiftly flowing river, while others are like a thick sponge. The world’s major wetlands are located in southern Africa, North America, central South America, and Asia.
The largest wetlands in the world are the bogs of the Siberian lowlands in Russia. They cover 600,000 km. That’s three times the size of Great Britain. All the world’s wetlands, even the large Siberian bogs, are endangered environments.
Wetlands are found in almost every region of the world and are considered the most biologically diverse of all ecosystems. They provide habitat for a great number of water and land species. They are also an important environment to many migratory bird species. Types of wetlands include swamps, bogs, marshes and estuaries.
Groundwater is water that comes from the ground. Where does groundwater come from? Groundwater comes from rain, snow, sleet, and hail that soaks into the ground. The water moves down into the ground because of gravity, passing between particles of soil, sand, gravel, or rock until it reaches a depth where the ground is filled, or saturated, with water.
Access to freshwater resources has always been a major issue for particular regions and countries. However, in the twenty-first century humanity will experience a serious shortage of freshwater on a global scale. Current world total renewable water resources are estimated at 310 km/year (310 billion litres.
Total renewable water resources provides the total water available to a country but does not include water resource totals that have been reserved for upstream or downstream countries through international agreements. Renewable water means water continuously renewed within reasonable time spans by the hydrological cycle, such as that in streams, reservoirs, or aquafiers that refill from precipitation, run-off, or groundwater recharge. Total Renewable Water Resources per capita by for the whole world is 24,650,000 litres).
According to Food and Agriculture Organisation, ten countries with largest total renewable water resources include Brazil, Russian Federation, Canada, Indonesia, Colombia, United States, Peru, India, Democratic Republic of Congo, and Venezuela.
Countries like China, India, Middle-east, and majority of African nations will face a surge in demand for fresh water. Even the developed countries (except Australia, Canada, Norway, Switzerland, and Austria) will have to deal with fresh water issues during most of 21st century.
China, the fastest growing economy and population is ranked 88 in the rankings of exploited water resources. Within countries there is uneven territorial distribution, thus limiting the development only to fresh water available ones.
However, during this century cross-border trade in fresh water is going to be a big business. It also provides an opportunity of establishing large desalination projects throughout the world. The country that controls the source of another country’s freshwater resources that originates from abroad, particularly a neighbouring country. The countries do so by diverting freshwater by creating an artificial reservoir (or number of reservoirs).
Recently, it came to knowledge of India that China is constructing many dams over River Brahmaputra and it may block India’s fresh water supply to its north-eastern regions. To avoid conflicts, the Nile Basin Initiative is good agreement, since it passes through Uganda, Congo, Ethiopia, Eritrea, Zaire, Kenya, Tanzania, Rwanda, and Burundi.