BellringerBellringer

1. Write the expression shown below, and explain what it means:

“We all live downstream.”

2. List all the ways you use water in a typical day.

3. List ways you could conserve water without severely altering your lifestyle.

4. Name some reasons people would experience a water "shortage".

Water Use and Water Use and ManagementManagement

Section 11.2Section 11.2

Objectives:1. Identify sources of local drinking

water.2. Explain how water is treated.

3. Identify principal uses of water.4. Describe water conservation

methods.

Global Water Use

3 major uses for water:1. Residential use2. Agricultural use3. Industrial use

Which way(s) do you use water? Would different countries use

water differently?

Global Water Use (cont.)(Fig.5, p.277)

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)

1. Filtration – removes trash and large organisms

2. Coagulation – Alum forms sticky globs that stick to bacteria

3. 2nd filtration4. Chlorination – prevents growth of bacteria5. Aeration – Air forced in to remove unwanted

gases6. 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 water1. Shallow ditches2. 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 Solutions1. Desalination: the process of

removing salt from salt water2. Transporting fresh water

1. In Greece, ships tow large plastic bags full of fresh water to the islands.

2. U.S. is considering towing fresh water from Alaska to California.

3. Why would AK have extra and CA not have enough?

4. Towing icebergs to other locations has long been considered, but not figured out. (What problems would there be?)