Chapter 13 WATER RESOURCES

Case Study: Water Conflicts in the Middle East

•Most of the water in the middle east comes from three shared river basins: the Nile,

Jordan, and Tigris-Euphrates.

•Most likely in the future, these water short countries are going to face conflicts over access to water resources.

•The water from the

Nile River is used by three countries: Ethiopia, Sudan, and Egypt

. Since Ethiopia’s population is rapidly increasing, they plan to divert more water from the Nile, along with Sudan.

•The

Jordan basin

is the

most water short region

and has competition

between Jordan, Syria,

Palestine, and Israel. Syria plans to build dams and withdraw more water from the Jordan River, decreasing the downstream water supply for Jordan and Israel; where Israel threatens to destroy the dam.

Water Conflicts in the Middle East (continued)

•Turkey is in control of the

Tigris Euphrates river,

controlling how much water flows down stream

to Iraq and Syria

before it empty’s into the Persian Gulf.

•Turkey is building dams, and if these dams are complete, it will reduce the flow of water downstream to Syria ad Iraq by 35%.

Water’s Importance and Unique Properties

-Keeps us alive -Moderates climate -Sculpts the land -Removes and dilutes wastes and pollutants

71% of the Earth’s surface is water

Importance of Water Properties

Running water can quickly erode topsoil rendering farmland infertile and streams contaminated.

Lack of access to clean water supplies can quickly lead to dehydration and death.

Chemical spills, excess nutrients & acids dissolved in H 2 0 can lead to massive die offs.

Michael D. Lee Ph.D. Geography and Environmental Studies

Properties of

Water

• Water exists as a liquid because of the strong

hydrogen bonds

between water molecules • Water filters out wavelengths of the suns UV radiation that would harm some aquatic organisms • Water moves easily-from one physical state to another, and from one place to another.

• Water slowly absorbs and releases large quantities of energy.

• Water is a superior solvent.

• Makes up all living things.

• Attractive forces between the molecules of liquid water cause its surface to contract and to adhere to and coat a solid.

• Water expands when it freezes.

Water Supply & Use

The Story of Drinking Water Online Game

(Quiz yourself!)

 Comparison of population sizes and shares of the world’s freshwater among the continents.

Supply, Renewal, and Use of Water Resources

•

Only a small amount of water is fresh

water (0.01%) that is continuously recycled through the hydrologic cycle.

• 97.4% of the world water is salty ocean water .

•

Surface runoff

is the water that evaporates/transpires back into the atmosphere and does not infiltrate the ground.

•

Watershed (Drainage Basin)

- is the region at which surface water drains into another body of water (lakes, streams, wetlands, and reservoirs ) Reliable runoff amount of water we can generally count on as a stable source of freshwater from year to year.

Surface Water

Hydrologic Cycle-

Know how water moves through from land and atmosphere!

• Powered by solar energy and

gravity

• Evaporation and precipitation • Continuous recycling of water • Runoff • Infiltration • Evaporation • Temporary storage as snow and ice • Temporary storage in lakes • Temporary storage in plants (transpiration) and animals • Chemical reactions with rocks and minerals • Volcanism also causes melting of snow caps and mudflows as melted water mixes with ash • Source of additional water? volcanism (steam)

What is Groundwater?



Ground water

is one of the most important sources of water on earth it contains more water than any other source of fresh water.

It’s the precipitation that infiltrates and percolates through the voids in soil and rock.

•

Zone of aeration-

Close to the surface; pores of mixture or air and water soil contain a •

Zone of saturation

- lower layers of soil where spaces between particles are completely filled with water.

•

Water table

- located at the top of the zone of saturation; top of zone levels rises in wet weather and falls in dry.

•

Porosity/Permeability

Groundwater

Groundwater Animation

Aquifers

 Porous, water-saturated layers of sand, gravel or bedrock through which groundwater flows; like a flowing “river under the ground”  Area of land that supplies water to aquifer is called the

recharge area

 Natural recharge is when water percolates downward, but sometimes

lateral recharge

occurs   Confined aquifers- bounded above and below by less permeable bedrock; confined by pressure Unconfined aquifers- contains the water table Journey through the Edwards Aquifer video

Groundwater Movement

 Groundwater moves from recharge area through an aquifer and out a discharge area 

well, spring, lake, geyser, artesian well, steam, ocean

 Normally moves downhill at only a meter per

year!

 Some aquifers get little recharge and were formed thousands of years ago  Removal from these nonrenewable resources is called

water mining.

Where is our water going?

• Most of the fresh water being used up is to

irrigate croplands (70% )

and

industries

use up 20%, and

cities/residences

up only 10%.

use • Some parts of the U.S such as the eastern states get plenty of irrigation, while western states are very dry, while other states have contaminated aquifers.

• This problem may cause “water wars” in the future because developing urban areas are in need of water. (ie.

California/Arizona and Middle East)

Cooling towers of power plants

Too little Water

•

There are four causes of water scarcity:

1)Drought – prolonged period of low precip., high evapor. rate

2)Dry climate

3)Desiccation- drying of exposed soil due to deforestation/overgrazing 4)water stress – increasing #’s of people relying on limited runoff • The volumes of some of the worlds lakes and rivers have shrunk drastically because mostly because of human

withdrawals of water for irrigation and for industry.

• About 1/6 of the percent of people on this earth do not have enough access to fresh water, and it is believed that will continue to increase.

Global Water Shortage We can increase water supplies by building dams, bringing in water from elsewhere withdrawing groundwater, converting saltwater to freshwater and importing food.

Who owns water???

• There is major controversy of whether

water supplies should be owned and managed by governments or by private corporations.

• Governments hiring private companies to manage water resources must set standards and maintain strict oversight of such contracts.

The movie F.L.O.W. – For the Love of Water

How can we increase our freshwater supplies?

1.

2.

3.

4.

5.

6.

Dams and reservoirs Transporting surface water Withdrawing groundwater Desalination Water conservation Better use of natural hydrologic cycle

Using Dams and Reservoirs to Supply More Water

Advantages:

  Cheap, constant electricity Reduces downstream flooding   Storing water year-round for irrigation and cities.

Reservoirs can provide recreational activities

Disadvantages:

  Displaces people Disrupts aquatic ecosystems (i.e. fish migrations/ runoff )   Large loss of water through evaporation  Flooding can destroy surrounding forests and croplands Reservoirs behind dams collect increased levels of silt and slow water flow.

Map of decommissioned dams

(click yellow dot for Kissimmee River Dam – removal part of CERP)

•Colorado River has so many dams it doesn’t reach the ocean.

•Used for hydroelectricity, irrigation (80%)

Colorado River Basin

and recreation

(whitewater rafting, camping, fishing)

for over 7 states.

Lake Mead at Hoover Dam, October, 2007. According to Scripps researchers, Lake Mead could be dry by 2021 if climate changes as expected and future water usage is not curtailed. Photo courtesy of Dr. Ken Dewey, Applied Climate Sciences Group, University of Nebraska, Lincoln

The Flow of the Colorado River Measured at Its Mouth Has Dropped Sharply

Good News:

•Provide electricity of 18 coal

China’s Three Gorges Dam

burning plants and reduce China’s dependence on coal •Larger ships can enter interior = less in transportation costs •Reduce greenhouse gas emissions •Improve air quality

Once completed (2013), it will be the world’s largest dam and reservoir.

Bad News:

• 1.9 M people being relocated •Build over a seismic fault •Flooding potential •High costs

Transferring Water from One Place to Another



Moving water from water-rich areas to water-poor

through tunnels, aqueducts, and underground pipe can be helpful and harmful.  Case Studies showcasing this include the Aral Sea, the California Water Project, and

Canada’s James Bay

Watershed.

Case Study: Siberia’s Aral Sea Disaster

 Aral Sea was once the world’s 4 th lake.

largest freshwater  Since 1960, enormous amounts of irrigation water have been diverted from the inland Aral Sea and its two feeder rivers, resulting in a large-scale water transfer project for irrigation of cotton and rice cropland.

 This large-scale water diversion project, coupled with

droughts and high evaporation rates in this area’s

hot and dry climate, has caused a ecological, economic and health disaster.

Aral Sea

 Led to 85% loss of wetlands  loss of major birds and mammals in the area  Salt concentrations increase  decrease in fish pops. and spreading of salt to croplands and glaciers  Increase in salt, dust and toxic contaminants in Aral Sea watershed has led to health problems.

*In 1999, UN and World Bank stepped in and spent $600M to purify drinking water and upgrade irrigation and drainage systems.

Case Study: The California Water Transfer Project

 This project uses a maze of giant dams, pumps, and aqueducts to transport water from water-rich northern California to southern California’s heavily populated arid and semi-arid agricultural regions.  It could degrade the Sacramento River, threaten fisheries, and reduce flushing action that helps clean San Francisco Bay of pollutants.

    

Case Study: Canada’s James Bay Watershed

Produce hydroelectric power for Canada and the United States.

Transfer Project

50-year project including over 600 dams that will alter the flow of 19 rivers. Would flood a boreal forest and tundra Displace indigenous tribes The second phase of the project was postponed indefinitely because the first phase produced more power than could be sold, as well as increase opposition to the project by environmentalist and indigenous tribes.

Withdrawing Groundwater

 Most aquifers are renewable sources unless the water

is removed faster than it is replenished or becomes contaminated.

 Aquifers provide drinking water for about one-fourth of the world’s population.

 In U.S., groundwater is being withdrawn at 4x’s its replacement rate.

 Bad news: the water tables are falling in many areas of the world as the rate of pumping out water exceeds the rate of natural recharge from precipitation. (mostly

for crop irrigation)

Aquifer Depletion from Groundwater Overdraft in the United States

Other Effects of Groundwater Overpumping

 Groundwater overpumping can cause land to sink, and contaminate freshwater aquifers near coastal areas with saltwater.

(Saltwater Intrusion)

TRADE-OFFS Withdrawing Groundwater Advantages Useful for drinking and irrigation Disadvantages Aquifer depletion from overpumping Available year-round Exists almost everywhere Sinking of land (subsidence) from overpumping Aquifers polluted for decades or centuries Renewable if not overpumped or contaminated Saltwater intrusion into drinking water supplies near coastal areas No evaporation losses Reduced water flows into surface waters Cheaper to extract than most surface waters Increased cost and contamination from deeper wells Fig. 13-7, p. 321

Case Study: The Shrinking Ogallala Aquifer

 Pumping water from the world’s largest aquifer has greatly increased food production, but over pumping is a serious problem in some areas.  Transformed the most arid areas of the midwest, into the most productive agricultural regions in the United States.

Ogallala Aquifer

Can Deep Aquifers Supply More Water?

 Scientists are evaluating huge, deep aquifers as a source of water.

 Two major concerns about tapping water from these deep aquifers:  We know little about the geological and ecological impacts of pumping from deep aquifers.

 No international water treaties govern the rights to and ownership of water underlies several countries.

SOLUTIONS

Groundwater Depletion Prevention Waste less water Subsidize water conservation Limit number of wells Do not grow water intensive crops in dry areas Control Raise price of water to discourage waste Tax water pumped from wells near surface waters Set and enforce minimum stream flow levels Divert surface water in wet years to recharge aquifers Fig. 13-11, p. 324

Converting Saltwater to Freshwater

(15-6 continued)

 Removing saltwater from seawater will probably not be done widely because of high costs and what to do with the resulting salt.

 Ways to

desalinate seawater include:



Distillation-

heat saltwater until it evaporates, leaves behind salts, and collect freshwater in cooler condensation chamber.



Reverse osmosis-

pumping saltwater at high pressure through a thin membrane that forces fresh water through, but traps salt solutes.

 15,000 desalination plants in 125 countries

Reverse Osmosis

Major Problems with Desalination

 High cost  Death of marine organisms  Large quantity of brine wastes  Future economics

Ashkelon Plant supplies 15% of Israel’s Households water needs Largest plant in 2005

Seeding Clouds and Towing Icebergs and Big Baggies

(15-6 continued)

 Seeding clouds with tiny particles of chemicals to increase rainfall, or towing icebergs or huge bags filled with freshwater to dry coastal areas, probably will not provide significant amounts of fresh water in the future. 

Bad News:

 Cloud seeding does not work very well in very dry areas where rain is needed most, because there are few clouds.

  There is no compelling scientific evidence that it works.

Introduces large amounts of chemicals to soil and water  Legal disputes over ownership of cloud water.

Reducing Water Waste

 We waste about two-thirds of the water we use but using water more efficiently could reduce wastage to about 15%.   Worldwide – 65-70% freshwater loss  Evaporation, leaks Education of benefits of water conservation  According to water resource experts the main cause of water waste is that we charge too little for water Regulating water prices, decrease government subsidies for supply water and increase subsidies for water waste reduction    Improve irrigation efficiency Improve collection efficiency Use less in homes and businesses

Major Irrigation Systems

Gravity Flow: efficiency 60% and 80% with surge valves. Water usually comes from an aqueduct system or a nearby river.

Drip Irrigation: MOST EFFICIENT!

Center Pivot: efficiency 80% with low pressure sprinkler and 90-95% with LEPA sprinkler. Water usually pumped from underground and sprayed from sprinklers.

Too Much Water

 Flooding is caused by increased precipitation and human impacts on earth.

 Used to occur every 50 years but now come about every 4 years Rapid population growth, deforestation, overgrazing , unsustainable farming on steep and easily erodible mountain slopes

Hillside Before and After Deforestation

Floodplain- when a stream overflows and spills over into surrounding land area

Benefits of Floodplains

 Highly productive wetlands  Provide natural flood and erosion control  Maintain high water quality  Recharge groundwater  Fertile soils  Nearby rivers for transporation use and recreation  Flatlands for urbanization and farming

Dangers of Floodplains and Floods

 Deadly and destructive  Human activities worsen floods  Failing dams and water diversion  Hurricane Katrina and the Gulf Coast  Removal of coastal wetlands

Before and During a Flood in St. Louis, Missouri

Case Study: Floodplains of Bangladesh

 Dense population  Located on coastal floodplain  Moderate floods maintain fertile soil  Increase frequency of large floods  Development in the Himalayan foothills  Destruction of coastal wetlands In struggle to survive, the poor in Bangladesh have cleared many of the coastal mangrove forests for fuel woods, farming, and aquaculture ponds for raising shrimp. This has led to more severe flooding.

How Can We Use Water More Sustainably?

Take the home water audit quiz online to see how much water YOU use! Due Tues. 2/8