Fresh water

Fresh water or freshwater is all naturally occurring liquid or frozen water containing low concentrations of dissolved salts as well as other total dissolved solids. Although a term specifically excludes seawater as well as brackish water, it does put non-salty mineral-rich waters such(a) as chalybeate springs. Fresh water may encompass frozen together with meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/sleet and graupel, and surface runoffs that score inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as alive as groundwater contained in aquifers, subterranean rivers and lakes. Fresh water is a water resource that is of the almost and immediate usage to humans.

Water is critical to the survival of all living organisms. many organisms can thrive on salt water, but the great majority of higher plants and nearly insects, amphibians, reptiles, mammals and birds need fresh water to survive.

Fresh water is non always potable water, that is, water safe to drink by humans. Much of the earth's fresh water on the surface and groundwater is to a substantial degree unsuitable for human consumption without some treatment. Fresh water can easily become polluted by human activities or due to naturally occurring processes, such as erosion.

Fresh water is a renewable and variable, but finite natural resource. Fresh water is replenished through the process of the water cycle, in which water from seas, lakes, forests, land, rivers and reservoirs evaporates, forms clouds, and returns inland as precipitation. Locally, however, if more fresh water is consumed through human activities than is naturally restored, this may or situation. in reduced fresh water availability or water scarcity from surface and underground direction and can have serious loss to surrounding and associated environments. Water pollution also reduces the availability of fresh water.

Challenges

The add in the world population and the increase in per capita water use puts increasing strains on the finite resources availability of clean fresh water. The response by freshwater ecosystems to a changing climate can be quoted in terms of three interrelated components: water quality, water quantity or volume, and water timing. A modify in one often leads to shifts in the others as well.

Water scarcity closely related to water stress or water crisis is the lack of fresh water resources to meet the requirements water demand. There are two brand of water scarcity: physical or economic water scarcity. Physical water scarcity is where there is not enough water to meet all demands, including that needed for ecosystems to function effectively. Arid areas for example Central and West Asia, and North Africa often suffer from physical water scarcity. On the other hand, economic water scarcity is caused by a lack of investment in infrastructure or engineering to draw water from rivers, aquifers, or other water sources, or insufficient human capacity to satisfy the demand for water. Much of Sub-Saharan Africa has economic water scarcity.: 11 

An important concern for hydrological ecosystems is securing minimum streamflow, especially preserving and restoring instream water allocations. Fresh water is an important natural resource necessary for the survival of all ecosystems.

lakes, rivers, oceans, aquifers, reservoirs and groundwater. Water pollution results when contaminants are delivered into these water bodies. Water pollution can be attributed to one of four sources: sewage discharges, industrial activities, agricultural activities, and urban runoff including stormwater. It can be grouped into surface water pollution either fresh water pollution or marine pollution or groundwater pollution. For example, releasing inadequately treated wastewater into natural waters can lead to degradation of these aquatic ecosystems. Water pollution can also lead to water-borne diseases for people using polluted water for drinking, bathing, washing or irrigation. Water pollution reduces the ability of the body of water to supply the ecosystem services such as drinking water that it would otherwise provide.