Notes 11-2

11.2 Water Use and Management

What is one of the worlds’ most pressing environmental problems?

A shortage of clean, fresh water

According to the World Health Organization how many people lack access to a clean, reliable source of water?

1 billion

Global Water Use

What are the three major uses of water?

Residential, agricultural, industrial

What is most water used worldwide for?

Irrigate crops

What affects how people use water?

Availability of fresh water, population sizes, economic conditions

How do Asia and Europe use water differently in agriculture?

Agriculture is 80% of use in Asia = only 38% use in Europe

What % of the water is used for industry in the world?

19

What is about 8% of the water used worldwide for?

Household activities such as drinking and washing

Residential Water Use

How much water does the average person in the US use every day?

300 L (80 gallons)

What activities inside the house is water used for?

Drinking, cooking, washing, toilet flushing

What activities outside the house is water used for?

Watering lawns, washing cars

Water Treatment

What is potable water?

Water that is safe to drink

What elements are removed from treated water?

Mercury, arsenic, lead

What is a pathogen and give examples?

Organisms that cause illness or disease.  Bacteria, viruses, protozoa, and parasitic worms are examples

What is the only continent that uses more water for industry than agriculture?

Europe

What is the second leading use of daily water in the US?

Toilet flushing

In a treatment plant what is added to water to form sticky blobs?

Alum

What are the sticky blobs called and what is their purpose?

Flocs, bacteria and other impurities cling to flocs, and settle to bottom of tank

Why is chlorine added to water?

Prevent bacteria from growing in the water

Why is air forced through the water as it is treated?

Release unwanted gases, reducing odor and improving taste

Why may fluoride be added?

Prevent tooth decay

What can be added to soften hard water?

Sodium compounds or lime

Industrial Water Use

What 5 major industrial uses of water were classified?

Manufacture goods, dispose of waste, generate power, produce computer chips and semiconductors, cool power plants

How much water is needed to manufacture a car?

500,000 Liters

What is most water in industry used for?

Cool power plants

Agricultural Water Use

How much water does it take to produce one of corn and what is that equal to?

300 L (80 gallons), average person in US use per day

What % of water use in agricultural use worldwide?

67%

What happens to 80% of water used in agriculture?

Evaporates and never reaches plant roots

Irrigation

Why is irrigation used?

Rainfall is inadequate

What is irrigation?

Method of providing plants with water from sources other than direct precipitation

How is cotton irrigated?

Shallow, water filled ditches

What is the most common irrigation method in the US?

Overhead sprinklers

What is wrong with this method of irrigation (US)?

Inefficient – nearly half the water evaporates

Water Management Projects

What is an aqueduct?

Huge canals that brought water from mountains to the dry areas of Spain and France

What were examples of water management projects?

Dams, water diversion canals

What were some goals of water management projects?

Bringing water to make dry area inhabitable, creating a reservoir for recreation or drinking water, generating electric power

Water Diversion Projects

Explain what happens to the Colorado River from its beginning until it flows into the Gulf of Mexico?

Begins as glacial stream in Rocky Mountains and grows larger as flows south – it is divided to meet needs of seven western states and so much is diverted that it often runs dry before it reaches Gulf of California

Dams and Reservoirs

What is a dam?

Structure built across a river to control the river’s flow

What is a reservoir?

An artificial lake that forms behind a dam

What six things can reservoirs be used for?

Flood control, drinking water, irrigation, recreation, industry, generate electrical energy

What produce electricity from water and how much of the world’s electricity comes from this?

Hydroelectric dams that use flowing water to turn turbines to generate electricity– 20%

How do dams affect land behind them?

People displaced (50 million worldwide), entire ecosystems destroyed

How does a dam affect areas below them?

Fertile sediment is stopped from enriching soil downstream

Why would dam failure be a problem?

People living downstream can be killed

Where are most large dam constructions occurring?

Developing countries such as Brazil, India, and China

Water Conservation

Why does water become more expensive as it becomes depleted?

Wells must be dug deeper, water must be piped greater distances, polluted water must be cleaned up before it can be used

Water Conservation in Agriculture

Where does most water loss come from in agriculture?

Evaporation, seepage, and runoff

How does drip irrigation work and what is the advantage?

Deliver small amount of water directly to plants roots by using perforated tubing, water is released to plants as needed and at a controlled rate – loses very little water to evaporation, seepage, or runoff

Water Conservation in Industry

What is the most widely used way of conserving water in industry?

Recycling of cooling water and wastewater

Water Conservation at Home

What is one-third of water used in US household used for?

Landscaping

What two technologies can be used in the household to save water?

Low-flow toilets and shower heads

When do people water lawns to conserve water?

Night

What is xeriscaping?

Designing a landscape that requires minimal water use

Solutions for the Future

What were two possible solutions to prevent water shortages?

Desalination and transporting fresh water

Desalination

What is desalination?

Process of removing salt from salt water

Where are many of these plants and what is the drawback?

Drier parts of the world, such as Middle East, consumes a lot of energy and is expensive

Transporting Water

What are some scientists proposing to get water from Alaska to California?

Fill huge bags with water from Alaskan rives and tow down coast to California

Where is 76% of the earth’s water?

Frozen in icecaps

What is the other way people have considered getting freshwater and what is the drawback?

Towing icebergs to communities that lack water, no efficient way to tow icebergs