Sources of Water

Water is a renewable resource. Uses of water include agricultural, industrial, household, recreational and environmental activities. The majority of human uses require fresh water.

Surface water

Surface water is water in a river, lake or fresh water wetland. Surface water is naturally replenished by precipitation and naturally lost through discharge to the oceans, evaporation, evapotranspiration and groundwater recharge. 

☑ Brazil is the country estimated to have the largest supply of fresh water in the world, followed by Russia and Canada

Under river flow

Throughout the course of a river, the total volume of water transported downstream will often be a combination of the visible free water flow together with a substantial contribution flowing through rocks and sediments that underlie the river and its floodplain called the hyporheic zone. For many rivers in large valleys, this unseen component of flow may greatly exceed the visible flow. The hyporheic zone often forms a dynamic interface between surface water and groundwater from aquifers, exchanging flow between rivers and aquifers that may be fully charged or depleted. This is especially significant in karst areas where pot-holes and underground rivers are common.

hyporheic zone:  a region beneath and alongside a stream bed, where there is mixing of shallow groundwater and surface water. 

Groundwater

Groundwater is fresh water located in the subsurface pore space of soil and rocks. It is also water that is flowing within aquifers below the water table. Sometimes it is useful to make a distinction between groundwater that is closely associated with surface water and deep groundwater in an aquifer (sometimes called "fossil water"). The natural input to groundwater is seepage from surface water. The natural outputs from groundwater are springs and seepage to the oceans.

Frozen water

Several schemes have been proposed to make use of icebergs as a water source, however to date this has only been done for research purposes. Glacier runoff is considered to be surface water.

The Himalayas, which are often called "The Roof of the World", contain some of the most extensive and rough high altitude areas on Earth as well as the greatest area of glaciers and permafrost outside of the poles. 

Desalination

Desalination is an artificial process by which saline water (generally sea water) is converted to fresh water. The most common desalination processes are distillation and reverse osmosis. Desalination is currently expensive compared to most alternative sources of water, and only a very small fraction of total human use is satisfied by desalination. It is only economically practical for high-valued uses (such as household and industrial uses) in arid areas. The most extensive use is in the Persian Gulf.

Functions of Water in the Human Body

Water plays an important role in maintaining our health. Nearly all of the major systems in our body depend on water. Do you know why?

The function of water in the human body includes:
☞ Regulates the body temperature.
☞ Moistens tissues such as those in the mouth, eyes and nose
☞ Lubricates joints
☞ Protects body organs and tissues
☞ Prevents constipation
☞ Lessens the burden on the kidneys and liver by flushing out waste products
☞ Helps dissolve minerals and other nutrients to make them accessible to the body
☞ Carries nutrients and oxygen to cells.

Introduction to Water

Water (chemical formula: H₂O) is a transparent fluid which forms the world's streams, lakes, oceans and rain, and is the major constituent of the fluids of organisms. Water is a liquid at standard ambient temperature and pressure, but it often co-exists on Earth with its solid state, ice and gaseous state, steam (water vapor). It also exists as snow, fog, dew and cloud.

Water covers 71% of the Earth's surface. It is vital for all known forms of life.Water on Earth moves continually through the water cycle of evaporation and transpiration (evapotranpiration), condensation, precipitation, and runoff, usually reaching the sea. Evaporation and transpiration contribute to the precipitation over land. Water used in the production of a good or service is known as virtual water.

Safe drinking water is essential to humans and other lifeforms even though it provides no calories or organic nutrients. Access to safe drinking water has improved over the last decades in almost every part of the world, but approximately one billion people still lack access to safe water and over 2.5 billion lack access to adequate sanitation.There is a clear correlation between access to safe water andgross domestic product per capita. However, some observers have estimated that by 2025 more than half of the world population will be facing water-based vulnerability. A report, issued in November 2009, suggests that by 2030, in some developing regions of the world, water demand will exceed supply by 50%. Water plays an important role in the world economy, as it functions as a solvent for a wide variety of chemical substances and facilitates industrial cooling and transportation. 

per capita: for each person; in relation to people taken individually.