WaterSection 2 Water Use and Management A shortage of clean, fresh water is one of the world’s most pressing environmental problems. According to the World Health Organization, more than 1 billion people lack access to a clean, reliable source of fresh water.

WaterSection 2 Global Water Use Most used to irrigate crops. of water used – highest percent : North America and Europe. 8% of water used

WaterSection 2 Residential Water Use Large differences in residential water use throughout the world. –United States about 300 L of water a for outside activities –India about 41 L of water a day/person.

WaterSection 2 Water Treatment Most water must first be made potable (suitable for drinking) –Remove heavy metals: mercury, arsenic, and lead, poisonous in low concentrations. –Remove pathogens that result from sewage or animal feces waste

WaterSection 2 Industrial Water Use Most used to cool power plants. –generally clean and can be reused again

WaterSection 2 Agricultural Water Use Acounts for 67 percent of the water used worldwide. –as much as 80 percent of the water used in agriculture evaporates. –Irrigation (method of providing plants with water from sources other than direct precipitation)

WaterSection 2 Water Management Projects People often live in areas where the natural distribution of surface water is inadequate. Water management project goals –bringing in water to a dry area (water diversion) –creating a reservoir for drinking water, or generating electric power, recreation

WaterSection 2 Consequences of projects land behind a dam flooded people are displaced, can be killed by a flood entire ecosystems destroyed fertile sediment builds up behind a dam, land farther down river less productive

WaterSection 2 Water Conservation Industry- recycling of cooling water and wastewater Agriculture- Most loss from evaporation, seepage, and runoff –Solutions: drip irrigation systems Household –Water-saving technology, such as low-flow toilets –Water their lawns at night to reduce evaporation –Xeriscaping, landscape that requires minimal water

WaterSection 2 Solutions for the Future Conservation alone not enough to prevent water shortages Two possible solutions are: Desalination, removing salt from ocean water — some countries in the Middle East Transporting Fresh Water — towing enormous plastic bags full of fresh water — towing icebergs (proposed)

WaterSection 2 Dam: a structure that is built across a river to control a river’s flow. Reservoir : artificial body of water that usually forms behind a dam.