Water

1. Water Chapter 11 Environmental Science

2. Water Resources • Section 11.1

3. The Water Cycle • Water Cycle: water molecules circulating between the Earth’s surface and the atmosphere. • It involves condensation, evaporation, transpiration, and precipitation.

4. Global Water Distribution • 71% of the Earth’s surface is covered in water • 97% of that water is salt water in ocean and seas • 77% of the fresh water on Earth is frozen in icecaps and glaciers • Fresh water is a limited resource because there is only about 3% usable freshwater.

5. Surface Water Surface Water: • Is fresh water on Earth’s land surface. • Lakes, streams, rivers, and wetlands. • Water is used for drinking, agriculture, power, and transportation.

6. River Systems vs. Watersheds River Systems Watersheds River are formed by: • Rain and snow draining down from mountains and hills. • Small streams come together to form rivers • A river system is a flowing network of surface water. • Amazon is largest river system. What is a watershed: • The area of land that is drained by a river. • Pollution in a watershed can pollute the river. • Amount of water varies depending on precipitation and melting snow.

7. Groundwater • Ground water: water beneath the Earth’s surface in sediment and rock formations. • Water table is where rock and soil are saturated with water. • Water table varies in wet regions vs. dry regions.

8. Aquifers • Aquifer: an underground formation that contains groundwater. • Consist of rock, sand, and gravel where water can accumulate. • It is an important water source for many cities and for agriculture.

9. Porosity vs. Permeability Porosity : Permeability: • Is the percentage of the total volume of a rock that has spaces or pores. • The more porous a rock, the more water it can hold • The ability of rock or soil to allow water to flow through it. • Example: granite, sandstone, and limestone are permeable but clay is impermeable.

10. The Recharge Zone • Recharge Zone: An area of the Earth’s surface from which water percolates down into an aquifer. Water enters an aquifer through the aquifer’s recharge zone. • Environmentally sensitive because of pollutants. • Size is affected by permeability of the surface above the aquifer. They can be blocked by structures.

11. Wells • Well: a holethat is dug or drilled to reach groundwater. • Are drilled to extend below water table. • Droughts and removing groundwater faster than it is recharged leads to wells drying up.

12. That is all of 11.1 • Time for a reading quiz.

13. Water Use and Management • Section 11.2

14. Global Water Use • Residential (drinking, washing, cooking, toilets) • Industrial (manufacture goods, dispose of waste, and generate power) • Agricultural(most of the fresh water used worldwide is used to irrigate crops)

15. Water Treatment • Water is treated physically and chemically to make it potableor safe to drink • Mercury, arsenic, and lead are removed by adding chlorine. • Pathogens:organisms that cause illness or disease are also removed.

16. Water Management Projects • Aqueducts or huge canalsare used to bring water from mountains to dry areas. • Reservoirs or artificial lakes are used for recreation or drinking water • Dams are structures built across a river to control the river’s flow.

17. Benefits and Consequences of Dams Benefits Consequences • Flood control • Drinking water • Irrigation • Recreation • Industry • Electrical energy • People can be displaced • Entire ecosystems can be destroyed • Farmland below dam becomes less productive • Dam failure can lead to death.

18. Water Conservation • Agriculture: drip irrigation systems • Industry: recycling of cooling water and wastewater • Residential: shorter showers, low-flow toilets/showers, turn water off when brushing teeth, wash full loads, and water lawns sparingly.

19. Solutions for the future • Desalinization: removing salt from salt water. (very expensive) • Transporting water: ships transfer bags of fresh water or towing icebergs. (hard to find efficient way…)

20. That is all for 11.2 • Time for a reading quiz.

21. Water Pollution • Section 11.3

22. Water Pollution • Water pollution: the introduction of chemical, physical, or biological agents into water. • Two causes are industrialization and rapid human population growth.

23. Two Sources of Water Pollution Point-Source Pollution Nonpoint-Source Pollution • Pollution discharged from a single source. • Easier to identify and trace. • Examples: leaking tank or unlined landfill. • Comes from many different sources • Difficult to identify and trace. • Examples: road or agricultural runoff, polluted precipitation, water runoff.

24. Physical Water Pollutants • Pathogens: disease causing organisms • Organic matter: feces, food wastes • Organic chemicals: pesticides, fertilizers, plastics • Inorganic chemicals: acids, bases, salts • Heavy metals: lead, mercury, cadmium, arsenic • Physical agents: heat and suspended solids

25. Wastewater • Wastewater: water that contains waste from homes or industry. • Most wastewater can be treated but some toxic substances require further treatment. • Sewage sludgeis the solid material that remains after treatment • Hard to dispose of so sludge can be used for fertilizer and to make bricks.

26. Artificial Eutrophication • Eutrophicationis when phosphates and nitrates enter the water from sewage and fertilizer runoff. • Can be caused naturally or by humans. • Causes algal blooms that eventually die and causes the water to becomes oxygen depleted.

27. Thermal Pollution • Thermal pollution: when the temperature of a body of water increases. • When power plants use water in their cooling systems and then discharge warm water back into lake or river. • Causes large fish kills and aquatic organisms suffocate.

28. Groundwater Pollution • Groundwater pollution: when polluted surface water percolates down. • Pesticides, fertilizers, and petroleum are groundwater pollutants. • Other sources: leaking underground water tanks, septic tanks, and unlined landfills

29. Cleaning Up Groundwater Pollution • Why it’s a challenging problem: • Aquifers recharge very slowly • Pollution can cling to the materials that make up an aquifer

30. Ocean Pollution • Dumped wastewater and garbage pollute the ocean. • Majority of pollution caused by land activities • Oil spills (37 million gals) • More oil enters from nonpoint sources in cities and towns (200-300 million gals)

31. Water Pollution and Ecosystems • Water pollution: can have immediate effects or lead to biomagnification. • biomagnification:the buildup of pollutants at higher levels as it travels up the food chain.

32. Cleaning up Water Pollution • Clean Water Act (1972): make all surface water fit for fishing/swimming by 1983. • Marine Protection, Research and Sanctuaries Act (1972): to control the dumping of sewage waste/toxic chemicals • Safe Drinking Water Act (1975):to protect groundwater/surface water from pollution • Comprehensive Environmental Response and Compensation and Liability Act (1980): makes owners/operators/customers of hazardous waste responsible for the clean up. • Water Quality Act (1987): support state and local effort to clean polluted runoff. • Oil Pollution Act (1990): protects US waterways from oil pollution.

33. That is all for 11.3 • Time for a reading quiz