A natural wetland
Water resources are sources of water that are useful or potentially useful to humans. Uses of water include agricultural, industrial, household, recreational and environmental activities. Virtually all of these human uses require fresh water. 97% of water on the Earth is salt water, and only 3% is fresh water of which slightly over two thirds is frozen in glaciers and polar ice caps. The remaining unfrozen freshwater is mainly found as groundwater, with only a small fraction present above ground or in the air. Fresh water is a renewable resource, yet the world's supply of clean, fresh water is steadily decreasing. Water demand already exceeds supply in many parts of the world and as the world population continues to rise, so too does the water demand. Awareness of the global importance of preserving water for ecosystem services has only recently emerged as, during the 20th century, more than half the world’s wetlands have been lost along with their valuable environmental services. Biodiversity-rich freshwater ecosystems are currently declining faster than marine or land ecosystems. The framework for allocating water resources to water users (where such a framework exists) is known as water rights. [pic]
A graphical distribution of the locations of water on Earth.
|Contents | |[hide] | |1 Sources of fresh water | |1.1 Surface water | |1.2 Under river flow | |1.3 Ground water | |1.4 Desalination | |1.5 Frozen water | |2 Uses of fresh water | |2.1 Agricultural | |2.2 Industrial | |2.3 Household | |2.4 Recreation | |2.5 Environmental | |3 Water stress | |3.1 Population growth | |3.2 Expansion of business activity | |3.3 Rapid urbanization | |3.4 Climate change | |3.5 Depletion of aquifers | |3.6 Pollution and water protection | |3.7 Water and conflict | |4 World water supply and distribution | |5 Economic considerations | |5.1 Business response | |6 See also | |7 Further reading | |8 Notes | |9 References | |10 External links |
[pic] Sources of fresh water
 Surface water
Main article: Surface water
Lake Chungará and Parinacota volcano in northern Chile
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, and sub-surface seepage. Although the only natural input to any surface water system is...