1. Chapter 9 Water Resources

2. Fig. 14-3, p. 308 Unconfined Aquifer Recharge Area Precipitation Evaporation and transpirationEvaporation Confined Recharge Area Runoff Flowing artesian well Recharge Unconfined Aquifer Stream Well requiring a pump Infiltration Water table Lake Infiltration Unconfined aquifer Confined aquifer Confining impermeable rock layer Less permeable material such as clay

3. Usable Water is Rare

4.  Comparison of population sizes and shares of the world’s freshwater among the continents. Figure 14-2

5.  We currently use more than half of the world’s reliable runoff of surface water and could be using 70-90% by 2025.  About 70% of the water we withdraw from rivers, lakes, and aquifers is not returned to these sources.  Irrigation is the biggest user of water (70%), followed by industries (20%) and cities and residences (10%).

6.  “It is not until the well runs dry that we know the worth of water” - Ben Franklin  http://www.hippocampus.org/HippoCampus/Earth Science?loadLeftClass=Course&loadLeftId=153&lo adTopicId=10690

7.  Groundwater 100,000 years  Groundwater near surface- 200 years  Lakes – 100 years  Glaciers- 40 years  Water in the soil- 70 days  Rivers- 16 days  Atmosphere- 8days

8.  Aquifers- small spaces found within permeable layers of rock and sediment where water is found.  Unconfined aquifers- an aquifer that is simply porous rock covered by soil.  Confined aquifers- an aquifer surrounded by a layer of impermeable rock or clay. Groundwater

10.  Water table- the uppermost level at which the water in an area fully saturates the rock or soil.  Recharge- the input process of water percolating into an aquifer.  Springs- water from an aquifer that naturally percolates up to the surface. Groundwater

11.  Cone of depression- an area where there is no longer any groundwater. Groundwater

12.  Saltwater intrusion- when the pumping of fresh water out of a well is faster than the recharge. Near coastal areas this can cause salt water to infiltrate the aquifer. Groundwater

13.  Aquifers are naturally recharged by precipitation.  It is a slow process- ground water moves ~ 3 feet/year from higher elevations to lower elevations.  Removing ground water faster than it is replenished disrupts the water cycle. Result- dry streams, lakes, etc.  Provide drinking water to more than 1/4 of world’s population.  Ogallala is the world’s largest aquifer and allowed many parts of the US (arid regions) to become fertile farming areas. Water is being removed 8-10X faster than its natural recharge rate.

15.  Areas of greatest aquifer depletion from groundwater overdraft in the continental U.S. Figure 14-8

16. Supplying More Water Groundwater supplies Consequences: aquifer depletion aquifer subsidence land sinks when water is withdrawn saltwater intrusion Groundwater in the U.S. is being withdrawn at about four times its replacement rate

17.  Sinkholes form when the roof of an underground cavern collapses after being drained of groundwater. Figure 14-10

18. http://www.swfwmd.state.fl.us/hydrology/sinkholes/

19.  Who does the water underground belong to?  Should aquifers be allowed to deplete?  How would you regulate this?  What do you think should be done?

20.  Streams, rivers, ponds, lakes and wetlands. Surface Water

21.  Productivity in a lake:  Oligotrophic- low amounts of nutrients such as phosphorous and nitrogen.  Mesotrophic- a moderate level of productivity  Eutrophic- high levels of productivity Surface Water: Lakes

22.  The world’s largest three rivers are as measured by volume of water  Amazon  Congo  Yangtze  Floodplain: area where the excess water spreads onto land, these areas become nutrient rich fertile plains

23.  Levees- an enlarged bank built up on each side of the river.  Dikes- similar to a levee but built to prevent ocean waters from flooding adjacent land. Altering the Availability of Water

24.  Dams- a barrier that runs across a river or stream to control the flow of water.  Reservoir- the area where water is stored behind the dam. Altering the Availability of Water

25.  Fish ladders- a set of stairs with water flowing over them that have been added to some dams to help migrating fish such as salmon get upstream. Altering the Availability of Water

26. Using Dams and Reservoirs © Brooks/Cole Publishing Company / ITP  800,000 dams currently restrict the world’s rivers.  Positives and negatives for creating these.  Storage of water for human use, but slows downstream flow and disrupts reproductive cycle of many fish. Ex: Salmon difficulty swimming upstream and get caught in turbines.  World Commission on Water in the 21 st Century states that ½ of world’s rivers will dry out because of flow reduction due to building of dams

27. Figure 14-13 How Electricity Works: http://science.howstuffworks.c om/electricity.htm /electricity.htm

28. Pros and Cons of Dams and Reservoirs

29.  Two dams on the Nile River: Aswan High Dam and Aswan Low Dam  Dammed river to protect valley from flooding, provide water and hydroelectric power.  The Aswan High Dam is 3,600 m in length, 980 m wide at the base, 40 m wide at the crest and 111 m tall. It contains 43 million m 3 of material. At maximum, 11,000 m³ of water can pass through the dam every second.  The reservoir, named Lake Nasser, is 550 km long and 35 km at its widest with a surface area of 5,250 km² and holds 132 km³. http://en.wikipedia.org/wiki/Aswan_Dam

30. Aswan High Dam Aerial View

31.  It flooded much of lower Nubia and over 90,000 people were displaced.  Lake Nasser flooded valuable archeological sites.  Silt deposited in the reservoir is lowering the water storage capacity of Lake Nasser  Poor irrigation practices are waterlogging soils and bringing salt to the surface.  Mediterranean fishing declined after the dam was finished because nutrients that used to flow down the Nile to the Mediterranean were trapped behind the dam. http://en.wikipedia.org/wiki/Aswan_Dam

33.  IPC's 17 hydroelectric power plants and it is one of the nation's few investor-owned utilities with a significant hydroelectric generating base. Idaho Power built the majority of its hydroelectric facilities during the 1940s, 1950s and 1960s, culminating with completion of the three-dam Hells Canyon Complex in 1968.hydroelectric power plants  American Falls Dam,Milner Dam,Twin Falls, Shoshone Falls,Clear Lake, Thousand Springs, "Mid-Snakes Project" in Central Idaho on the Snake River consisting of the Upper Salmon Falls power plant and the Lower Salmon Falls, Bliss Dam, "The Malads": Upper Malad and Lower Malad, C. J. Strike Dam, Swan Falls Dam, and Cascade Dam on the Payette River American Falls DamMilner Dam Shoshone FallsBliss Dam C. J. Strike DamSwan Falls Dam  "Hells Canyon Complex": Brownlee Dam power plant at river mile 285.0, Oxbow Dam power plant at river mile 272, and the Hells Canyon Dam

36.  Some dams are being removed for ecological reasons and because they have outlived their usefulness.  In 1998 the U.S. Army Corps of Engineers announced that it would no longer build large dams and diversion projects in the U.S.  The Federal Energy Regulatory Commission has approved the removal of nearly 500 dams.  Removing dams can reestablish ecosystems, but can also re-release toxicants into the environment.

37. The Elwha River flows into the Strait of Juan de Fuca, carrying sediment once trapped behind dams. The gradual release has rebuilt riverbanks and created estuary habitat for Dungeness crabs, clams, and other species.

38.  Are dams a necessary evil?  How do we decide when a river has too many?

39.  Aqueducts- canals or ditches used to carry water from one location to another. Altering the Availability of Water

40. Water transfer – California Water Project The Problem most of the rainfall is in northern California most of the population growth and agriculture is in southern California The Solution water transferred to the south via dams, pumps, and aqueducts The Controversy southern California wants more water for growing cities much of the water transferred is wasted by inefficient irrigation the north needs the water for fisheries and flushing pollutants out of San Francisco Bay © Brooks/Cole Publishing Company / ITP

41.  A massive transfer of water from water-rich northern California to water-poor southern California is controversial. Figure 14-16

42.  California and Nevada are very interested in getting water from elsewhere, should they be able to do this or have to live with the current water they already have?  How would you solve the California crisis?

43.  The Aral Sea was once the world’s fourth largest freshwater lake. Figure 14-17

44.  Diverting water from the Aral Sea and its two feeder rivers mostly for irrigation has created a major ecological, economic, and health disaster.  About 85% of the wetlands have been eliminated and roughly 50% of the local bird and mammal species have disappeared.  Since 1961, the sea’s salinity has tripled and the water has dropped by 22 meters most likely causing 20 of the 24 native fish species to go extinct.

45.  Process of removing salt from salt water to make it suitable for drinking. 2 most common practices are 1. Distillation- heat/evaporates/condenses 2. Reverse osmosis- use of high pressure and thin membrane. Membrane acts like strainer.

46.  Desalination- removing the salt from salt water to obtain fresh water.

47.  Middle Eastern countries produce 60% of world’s desalinated water.  Tampa, Fl has a plant to supplement supplies.  Cons against plants: 1. Process requires a lot of energy- $$$$$ 2. Waste product- where to dump???? -Ocean- increases salinity- effects ecosystems -Land- contaminate groundwater supplies.

48. Agriculture, Industry, and Household Use of Fresh Water 69% for agriculture most does not reach crops (60%–80% wasted) 23% for industry (energy production and various industry) 8% for domestic and municipal use © Brooks/Cole Publishing Company / ITP

49.  Agriculture- the largest user of water around the world. Agriculture

50.  Irrigation techniques-  Furrow irrigation- a trench that is flooded with water.  Flood irrigation- the entire field is flooded with water.  Spray irrigation- an apparatus that sprays water across a field.  Drip irrigation- using a slow dripping hose that is laid on or buried beneath the soil.  Hydroponic agriculture- crops grown in fertilized water and no soil. Agriculture Needs

51. Gravity Flow (efficiency 60% and 80% with surge valves) Water usually comes from an aqueduct system or a nearby river. Drip Irrigation (efficiency 90-95%) Above- or below-ground pipes or tubes deliver water to individual plant roots. Center Pivot (efficiency 80% with low- pressure sprinkler and 90–95% with LEPA sprinkler) Low-Energy Precision Application Water usually pumped from underground and sprayed from mobile boom with sprinklers. Irrigation Techniques Start up cost is expensive, but long term benefits

52. Central Pivot with LEPA System: 90-95% Efficient Central Pivot Without LEPA System: 80% Efficient

53.  Industry- the second largest user of water worldwide. Industry Needs

54.  Households- the third largest user of water worldwide. Household Needs

55. Increasing Water Efficiency increase efficiency of irrigation (~40% is wasted with old techniques- flooding) drip irrigation, central–pivot, computer monitoring use recycled water (Gray water) treat gray water from showers, washing machines for reuse fix leaky pipes water–saving toilets, faucets, and shower heads xeriscaping plant drought–tolerant vegetation in residential communities located in arid and semi–arid areas

57.  Human activities have contributed to flood deaths and damages. Figure 14-23

58.  Rapid population growth  Deforestation  Overgrazing  Unsustainable farming on steep hills  Clearing coastal mangrove forests

59. Fig. 14-24, p. 331 Solutions Reducing Flood Damage PreventionControl Preserve forests on watersheds Strengthen and deepen streams (channelization) Preserve and restore wetlands in floodplains Tax all development on floodplains Build levees or floodwalls along streams Use floodplains primarily for recharging aquifers, sustainable agriculture and forestry, and recreation Build dams

60.  Water ownership- people can have rights to water use, but they do not own the water.  Water conservation- using techniques such as more efficient water fixtures, faucets and washing machines. The Future of Water Availability

61.  We can use water more sustainably by cutting waste, raising water prices, preserving forests and wetlands in water basins, and slowing population growth. Figure 14-25

62.  How would you regulate water?  Do you think the future will have water wars?