ENVIRONMENTAL SCIENCE CHAPTER 11 WATER 11 1 Water

ENVIRONMENTAL SCIENCE CHAPTER 11 WATER

11 -1 Water Resources Objectives • Describe the distribution of Earth’s water resources. • Explain why fresh water is one of Earth’s limited resources. • Describe the distribution of Earth’s surface water. • Describe the relationship between groundwater and surface water in a watershed.

1. Where does the water we drink today originate from? • It has been around since water first formed on Earth billions of years ago

2. What are two types of water found on Earth? • Freshwater • Saltwater

3. Is water a renewable or nonrenewable resource? • It is renewable because it is circulated in the water cycle and is essential for life • We can live for more than a month without food, but only a few days without water.

4. What is the water cycle? • The process of water moving through the Earth’s atmosphere, lithosphere, and hydrosphere via condensation, evaporation, and precipitation.

5. What percentage of the Earth’s surface is water? • Approximately 71% • However: – 97% of Earth’s water is salt water (in oceans and seas) – 3% is freshwater – 77% of freshwater is frozen in polar icecaps so only a small portion is available for us to use – 22% is groundwater – 1% is other water (lakes, rivers, soil moisture, atmosphere)

Global Water Distribution

6. Where does the water we require for our everyday needs come from? • surface water • groundwater

7. What is surface water? • Freshwater that is above ground in lakes, ponds, rivers and streams • The distribution of surface water has played a vital role in the development of human societies.

8. What type of areas generally depend on surface water for their water supplies? • Large cities • Surface waters provide water for drinking, growing crops and food such as fish, power for industry, and transportation (boat).

9. Where does the water in a river come from? • Streams form as water from falling rain and melting snow drains from mountains, hills, plateaus, and plains. • As streams flow downhill, they combine with other streams and form rivers.

10. What is a river system? • A flowing network of • rivers and streams (tributaries) draining a river basin. The Amazon River system is the largest river system in the world as it drains an area of land that is nearly the size of Europe.

11. What is a watershed? • The entire area of land • that is drained by a river The amount of water that enters a watershed varies throughout the year.

Watersheds of the World

12. What is the longest river in the US? • Mississippi River

12. How can a river become a source of controversy? • People/countries have conflicts over water rights • EX: farmers, Arizona/California, Turkey/Syria/Iraq, Georgia/Florida/Alabama

13. What is groundwater? • Water that seeps • • down through the rocks and soil and is stored underground The water table is the upper limit of the saturated zone. The water table is not level but has peaks and valleys.

14. What is an aquifer? • Underground rock • formations that store water They are usually made of rocks, sand, and gravel with a lot of air spaces in which water can accumulate

15. What is porosity? • The percentage of the total volume of a rock or sediment that consists of open spaces. • Water in an aquifer is stored in the pore spaces and flows from one pore space to another. • The more porous a rock is, the more water it can hold.

16. What is permeability? • The ability of a rock or sediment to let fluids pass through its open spaces or pores. • Materials such as gravel that allow the flow of water are permeable. • Materials such as clay or granite that stop the flow or water are impermeable. • The most productive aquifers usually form in permeable materials, such as sandstone, limestone, or layers of sand gravel.

Percolation and Permeability

17. What is a recharge zone? • The area of land from which the groundwater originates • To reach an aquifer, surface water must travel down through permeable layers of soil and rock. If the aquifer is covered by impermeable materials, the water cannot reach the aquifer. • Recharge zones are environmentally sensitive areas because any pollution in the recharge zone can also enter the

Recharge Zone

Recharge Zone • The size of an aquifer’s recharge zone is affected by the permeability of the surface above the aquifer. • Structures such as buildings and parking lots can act as impermeable layers and reduce the amount of water entering an aquifer. • Communities should carefully manage recharge zones because surface water can take a very long time to refill an aquifer, even tens of thousands of years.

18. How do people who depend on groundwater for their water supplies get this water? • Drill a well and pump it to the surface (sometimes groundwater it so close to the surface that is forms a spring) • Humans have dug wells to reach groundwater for thousands of years. • We dig wells because groundwater may be a more reliable source of water than surface water and because it is filtered as it travels underground.

19. What causes a well to dry up? • The water table may fall below the bottom of the well during a drought and cause it to dry up. • The height of the water table changes seasonally, so when initially drilled, wells are drilled to extend below the water table. • If a well dries up, it may have to be drilled deeper.

20. What is the problem with using groundwater? • We are using it faster • than it is being replaced See Case Study on the Ogallala Aquifer p. 292

11 -2 Water Use and Management “Everyone Lives Downstream”

Objectives • Identify patterns of global water use. • Explain how water is treated so that it can be used for drinking. • Identify how water is used in homes, in industry, and in agriculture. • Describe how dams and water diversion projects are used to manage freshwater resources. • Identify five ways that water can be conserved.

1. Water use and management: • When a water supply is polluted or overused, everyone living downstream can be affected. • A shortage of clean freshwater is one of the world’s most pressing environmental problems. • According to the World Health Organization (WHO), more than 1 billion people lack access to a clean, reliable source of freshwater.

2. What are three major uses of freshwater? • Residential • Agricultural • Industrial

3. What is the biggest use of freshwater worldwide? • Agricultural – to irrigate crops • Freshwater use varies from country to country because of the availability of freshwater, population sizes, and economic conditions. • Industry accounts for appx. 19% of the water used in the world, with the highest percent occurring in North America and Europe. About 8% of water is used by households.

Freshwater Use In Bleckley Co.

4. How does residential water use compare throughout the world? • There is a lot of difference worldwide. • The average person in the US uses about 300 L of water a day. But in India, the average person used only 41 L per day. • In the US, only about half of the residential water use if for activities inside the home, such as drinking and cooking. The remainder is used for things outside the home such as watering lawns.

Residential Water Use

5. What is potable water? • Water suitable for drinking. • Water is often treated to make it potable. • Water treatment removes elements such as mercury, arsenic, and lead, which are poisonous to humans even in low concentrations. • These elements are found in polluted water, but they can also occur naturally in groundwater. • Fish Consumption Advisories in Georgia

6. What are pathogens? • Viruses, microorganisms, or other disease causing organisms. • They can be found in water contaminated by sewage or animal feces, but can be removed with water treatment. • Can cause cholera, hepatitis, typhoid in people who drink water polluted with pathogens • Water can be tested for pathogens

7. What are some common methods of water treatment? • Physical and chemical treatment of the water.

8. How does industry use water? • Industry accounts for 19% of water use worldwide • Water is used to manufacture goods, dispose of wastes, and generate power.

9. Industrial Water Use • Most of the water that is used in industry is used to cool power plants. • The water that is returned is usually warmer than the source, but is generally clean and can be used again.

10. How does agriculture use water? • Irrigation • Agriculture accounts for 67% of the water used worldwide. • Plants require a lot of water to grow and as much as 80% of the water used in agriculture evaporates.

11. What is irrigation? • A method of providing plants with water from sources other than direct precipitation. • Irrigation techniques: – shallow, water filled ditches – Overhead sprinklers

Irrigation Methods

12. How are freshwater resources being managed? • Dams and Reservoirs • Water Diversion Projects • Water Conservation

13. Why do freshwater resources need to be managed? • Some people prefer to live in areas with inadequate water supplies. • Sometimes water needs to be managed to make a dry area habitable, to create electric power, to create a reservoir for drinking water, for flood control, recreation, and industry.

14. What is water diversion? • Changing the natural pathway of water. • Canals are often dug for this purpose. • Some rivers that have been diverted to provide water for dry areas: – Owens River in California (supplies water to LA) – Colorado River is diverted to meet the needs of seven states

Colorado River Basin:

15. What is a dam? • A structure built across a river or stream to control its flow.

16. What is a reservoir? • An artificial lake that • forms behind a dam The reservoir can be used for flood control, drinking water, irrigation, recreation, and industry

17. What is a hydroelectric dam? • A dam that uses the power of flowing water to turn a turbine that generates electrical energy. • Appx. 20% of the worlds electrical energy is generated this way.

18. What are some negative effects of dam building? • When the land behind the dam is flooded, people are displaced and entire ecosystems are destroyed. • Fertile sediment builds up behind a dam instead of enriching the land farther down the river, and farmland below may be less productive. • Dam failure can be a problem. If a dam bursts, the people living along the river may be killed.

19. Why does water become more expensive as water sources become depleted? • Wells have to be dug deeper • Water must be piped greater distances • Polluted water must be cleaned up before it can be used.

20. What is water conservation? • Saving water • It is one way we can help ensure that everyone will have enough water at a reasonable price.

21. Water Conservation in Agriculture • Most water loss in agriculture comes from evaporation, seepage, and runoff. • Drip irrigation systems help conserve water used in agriculture.

22. Water Conservation in Industry: • It has become common for industries to recycle cooling water and wastewater. Instead of discharging used water into a nearby river, businesses often recycle it and use it again.

23. Water Conservation at Home: • People can conserve water by changing a few everyday habits and by using only the water they need. • Water saving technology (low-flow toilets) can help reduce household water use. • Water lawn at night (reduced evaporation) • Use xeriscaping

Water Conservation at Home: p. 302

24. What are some solutions, other than water conservation, for water shortages in the future? • Desalination • Transporting Freshwater

25. What is desalination? • Process of removing the salt • • from salt water Some countries in drier parts of the world, such as the Middle East, have built desalination plants to provide freshwater. Most desalination plants heat salt water and collect the freshwater that evaporates Process is very expensive

26. Transporting water: • In some areas where freshwater resources are not adequate, water can be transported from other regions. • EX: ships regularly travel from the mainland to the Greek Islands towing enormous plastic bags full of freshwater. The freshwater is pumped from the ship onto the islands.

Transporting water: • Transporting water in bags is also being considered in the US, where almost half of the available freshwater is in Alaska. • Because 76% of Earth’s freshwater is frozen in icecaps, icebergs are another potential freshwater source. • People have considered towing icebergs to communities that lack freshwater. An efficient way to do this has not been found.

11 -3 Water Pollution

Objectives: • Compare point-source pollution and nonpoint-source pollution. • Classify water pollutants by five types. • Explain why groundwater pollution is difficult to clean. • Describe the major sources of ocean pollution, and explain the effects of pollution of ecosystems. • Describe six major laws designed to improve water quality in the US.

1. What is water pollution? • The introduction of chemical, physical, or biological material into water that degrades the quality of the water and affects the organisms that drink it and live in it

2. What are 2 causes of water pollution? • Industrialization • Rapid Human population growth **Both of these produce waste products that cannot be disposed of as fast as they are produced

3. Water pollution: • Developed countries have made progress cleaning up polluted water, but some water is still dangerously polluted. • Developing countries have a bigger water pollution problem because often the only water available for drinking is polluted with sewage and agriculture runoff, which can spread waterborne diseases.

4. What are the two types of sources of water pollution? • Point pollution • Nonpoint pollution

5. What is point pollution? • Pollution that is discharged from a single source, such as a factory, a wastewater treatment plant, or an oil tanker • It can often be identified and traced to a source, but enforcing cleanup is sometimes difficult.

6. What is nonpoint pollution? • Pollution that comes from many sources rather than from a single specific site • May reach bodies of water by way of streets and sewers • It comes from anywhere (homes, lawns, farms, highways, etc. ) • It is hard to regulate and control because it enters bodies of water in many different ways • Controlling it depends on public awareness of the effects of activities such as spraying lawn chemicals.

Principal Water Pollutants

7. What is wastewater? • Water that contains wastes from homes or industry.

8. What is done with wastewater? • Drain → Sewage Pipes → Wastewater Treatment Plant → River/Lake OR • Goes through an oxidation pond where microorganisms break down the harmful bacteria before being returned to a lake/river (**these can no longer be built)

9. Treating Wastewater: • Most of the wastewater from homes contains biodegradable material that can be broken down by microorganisms. • EX: wastewater from toilets and kitchen sinks contain animal and plant wastes, paper, and soap, all of which are biodegradable. • Some household and industrial water and some storm-water runoff contains toxic substances that cannot be removed by the standard treatment.

10. What is sewage sludge? • The solid materials leftover after wastewater goes through the treatment plant • May contain dangerous concentrations of toxic substance (hazardous waste). This is often incinerated and the ash buried in a secure landfill. • Can be expensive to dispose of.

Sewage sludge: • Communities are looking for ways to use this sludge (EX: fertilizer, bricks, zoo doo pets)

11. What is artificial eutrophication? • A process that increases the amount of nutrients in a body of water through human activities, such as waste disposal and land drainage. • When lakes and slow-moving streams contain an abundance of nutrients, they become eutrophic. • Eutrophication occurs naturally when organic matter builds up in water then starts to decay.

Artificial eutrophication: • During decomposition, the oxygen level decreases, which is bad for the organisms that live in the water. • Eventually plants take root in the nutrient rich soil and the body of water becomes a swamp or marsh. • This process is accelerated when inorganic plant nutrients, such as phosphorus and nitrogen, enter the water from sewage and fertilizer runoff.

Artificial eutrophication: • The excess phosphorus can cause algae to grow out of control and form an algal bloom. • As the algae die and decompose, most of the dissolved oxygen is used and fish and other organisms suffocate in the oxygendepleted water.

Algal Bloom

12. What can be done to stop artificial eutrophication from occurring? • Ban phosphate detergents or limit the amount of phosphates in them • Control runoff of fertilizers/animal sewage

13. What is thermal pollution? • A temperature increase in the water that is caused by human activity and has harmful effects on water quality and organisms living in the water. • Can occur when power plants and industries use water in their cooling systems and then discharge the warm water into a lake or river.

Thermal Pollution: • Hot water holds less dissolved oxygen than cold water. • Can cause fish kills due to the decrease in oxygen.

14. What causes groundwater pollution? • Pollutants usually enter groundwater when polluted surface water percolates down from the surface. • Any pollution of the surface water in an area can affect the groundwater. • Pesticides, chemical fertilizers and petroleum products are common groundwater pollutants. • Other sources of groundwater pollution include: septic tanks, unlined landfills, and industrial wastewater lagoons.

Groundwater pollution: • Leaking underground storage tanks are another major source of groundwater pollution. • Modern storage tanks are contained in concrete and have many other features to prevent and detect leaks.

Groundwater pollution:

15. Why is groundwater pollution hard to clean up? • Because it recharges so slowly. • Pollution can cling to the materials that make up an aquifer so even if all the water in the aquifer were pumped out and replaced with clean water, the groundwater could still be polluted.

16. Where does ocean pollution come from? • It may be dumped directly into the ocean (ships can legally dump wastewater and garbage in some parts of the ocean) • 85% comes from activities on land near the coast (includes pollutants such as oil, toxic wastes, medical wastes) • Sensitive coastal ecosystems, such as coral reefs, are the most affected by pollution.

17. Oil Spills: • Accidental oil spills from oil tankers are a small source of oil pollution in oceans. • Most of the oil in the ocean comes from nonpoint sources in cities and towns • Limiting these nonpoint sources would help keep oil out of the ocean. The best way to do this is to educate people about it.

Major oil spills

18. What is biomagnification? • The buildup of pollutants at higher levels on the food chain. • This occurs with pollutants that do not decompose quickly. • Biomagnification has alarming consequences for organisms at the top of the food chain and is one reason why US states limit the amount of fish consumption from certain bodies of water.

Biomagnification • EX: DDT

19. Cleaning up water pollution: • The Clean Water Act of 1972 was designed to “restore and maintain the chemical, physical, and biological integrity of the nation’s waters. • The goal of making all surface water clean enough for fishing and swimming by 1983 was never achieved, but much progress has been made since the act was passed.

Cleaning Up Water Pollution: • The percentage of lakes that are fit for swimming has increased by 30% and many states have passed stricter waterquality standards. • The Clean Water Act opened the door for other water-quality legislation. • EX: Marine Protection Research and Sanctuaries Act of 1972 strengthened the laws against ocean dumping.

20. Who owns the oceans? • Law of the Sea Treaty – states that the laws of a • • coastal nation extend 12 nautical miles from its coastline (this is a nation’s territorial sea) (US did not sign this treaty) The exclusive economic zone extends 200 nautical miles from land a nation has control over economic activity, environmental preservation, and research in this area International Seabed Authority – controls the rest of the world’s oceans