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Bellringer. Write the expression shown below, and explain what it means: “We all live downstream.” List all the ways you use water in a typical day. List ways you could conserve water without severely altering your lifestyle. Name some reasons people would experience a water "shortage".
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Bellringer • Write the expression shown below, and explain what it means: “We all live downstream.” • List all the ways you use water in a typical day. • List ways you could conserve water without severely altering your lifestyle. • Name some reasons people would experience a water "shortage".
Water Use and ManagementSection 11.2 Objectives: Identify sources of local drinking water. Explain how water is treated. Identify principal uses of water. Describe water conservation methods.
Global Water Use • 3 major uses for water: • Residential use • Agricultural use • Industrial use • Which way(s) do you use water? • Would different countries use water differently?
1. Residential Water Use • In the U.S., each person uses about 300 L (80 gal) a day; in India, 41 L a day. • How do you think we use it? • Table 1, p.277
1. Residential Water Use (cont.) • Water treatment • Potable: safe to drink • Removes poisons and pathogens: organisms that cause disease or illness • Drinking-water treatment steps (p.276) • Filtration – removes trash and large organisms • Coagulation – Alum forms sticky globs that stick to bacteria • 2nd filtration • Chlorination – prevents growth of bacteria • Aeration – Air forced in to remove unwanted gases • Additives – fluoride, water softeners
2. Industrial Water Use • 19% of water used worldwide • Most is used to cool power plants. • Pull water from surface sources, run it through pipes in a cooling tower, and pump it back to its source. • How would this cool the power plant? • How would this affect the temperature of the water in the pipes? • How would this affect the surface water source?
3. Agricultural Water Use • 67% of water used worldwide! • Irrigation: providing plants with water • Shallow ditches • Overhead sprinklers – most lost to evaporation
Water Management Projects • Water diversion projects – diverting water to areas that need it (EX: canals) • Dams and Reservoirs • Dams: structures built across rivers to control water flow • Reservoirs: artificial lakes formed behind dams
Water Management Projects, continued….. What would be some advantages to building dams and reservoirs? Pros: Water can be used for drinking water, irrigation, electrical energy, flood control, recreation What would be some disadvantages to building dams and reservoirs? Cons: floods upstream, lack of sediments downstream (less fertile land), dam failure
Water Conservation • Why conserve water? • In agriculture • Most loss is due to evaporation, runoff, and seepage • Drip irrigation systems deliver small amounts of water directly to the roots through perforated tubes (Think soaker hose)
Water Conservation (cont.) • In industry - recycling cooling water and wastewater • At home • Can one person make a difference? • Table 2, p.282
Other Solutions • Desalination: the process of removing salt from salt water • Transporting fresh water • In Greece, ships tow large plastic bags full of fresh water to the islands. • U.S. is considering towing fresh water from Alaska to California. • Why would AK have extra and CA not have enough? • Towing icebergs to other locations has long been considered, but not figured out. (What problems would there be?)