Chapter 13

WATER WATER RESOURCESRESOURCES

Case Study: Water Case Study: Water Conflicts in the Conflicts in the Middle EastMiddle 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 Water Conflicts in the Middle East the Middle East

(continued)(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 Water’s Importance and Unique PropertiesProperties

-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 PropertiesImportance of Water Properties

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

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

Chemical spills, excess nutrients & acids dissolved in H20 can lead to massive die offs.

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

Properties of WaterWater• Water exists as a

liquid because of the strong hydrogen bonds between water molecules

• 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.

•Water filters out wavelengths of the suns UV radiation that would harm some aquatic organisms

•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 & UseWater 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.

•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 )

Supply, Renewal, and Use of Water Supply, Renewal, and Use of Water ResourcesResources

Reliable runoff- amount of water we can generally count on as a stable source of freshwater from year to year.

Surface WaterSurface Water

Hydrologic Cycle- 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 What is Groundwater?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 soil contain a mixture or air and water

• 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

AquifersAquifers

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 tableJourney through the

Edwards Aquifer video

Groundwater MovementGroundwater MovementGroundwater moves from recharge area

through an aquifer and out a discharge areawell, spring, lake, geyser, artesian well,

steam, oceanNormally moves downhill at only a meter

per year!Some aquifers get little recharge and were

formed thousands of years agoRemoval from these nonrenewable

resources is called water mining.

•Most of the fresh water being used up is to irrigate croplands (70% ) and industries use up 20%, and cities/residences use up only 10%.

• 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)

Where is our water Where is our water going?going?

Cooling towers of power plants

•There are four causes of water There are four causes of water scarcity: scarcity: 1)Drought – prolonged period of low precip., high evapor. rate2)Dry climate3)Desiccation- drying of exposed soil due to deforestation/overgrazing4)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???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 How can we increase our freshwater supplies?freshwater supplies?

1. Dams and reservoirs2. Transporting surface water3. Withdrawing groundwater4. Desalination5. Water conservation6. Better use of natural hydrologic cycle

Using Dams and Reservoirs to Using Dams and Reservoirs to Supply More WaterSupply More WaterAdvantages: Disadvantages:Cheap, constant

electricityReduces downstream

floodingStoring water year-

round for irrigation and cities.

Reservoirs can provide recreational activities

Displaces peopleDisrupts aquatic

ecosystems (i.e. fish migrations/ runoff)

Flooding can destroy surrounding forests and croplands

Large loss of water through evaporation

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 BasinColorado River Basin

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

•Colorado River has so many dams it doesn’t reach the ocean.•Used for hydroelectricity, irrigation (80%) and recreation (whitewater rafting, camping, fishing)

for over 7 states.

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

China’s Three Gorges DamChina’s Three Gorges DamGood News:

•Provide electricity of 18 coal 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

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

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

and reservoir.

Transferring Water from One Place to Transferring Water from One Place to AnotherAnother

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: Case Study: Siberia’s Aral Sea Siberia’s Aral Sea DisasterDisasterAral Sea was once the world’s 4th largest

freshwater lake.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 Aral SeaSea 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: Case Study: The California Water The California Water Transfer ProjectTransfer ProjectThis 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: Case Study: Canada’s James Bay Canada’s James Bay Watershed Transfer ProjectWatershed Transfer ProjectProduce hydroelectric

power for Canada and the United States.

50-year project including over 600 dams that will alter the flow of 19 rivers.

Would flood a boreal forest and tundra

Displace indigenous tribesThe 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 GroundwaterWithdrawing GroundwaterMost 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)

Fig. 13-7, p. 321

TRADE-OFFS

Withdrawing Groundwater

Advantages DisadvantagesUseful for drinking and irrigation

Aquifer depletion from overpumping

Available year-roundSinking of land (subsidence) from overpumping

Exists almost everywhere

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

Case Study: The Shrinking Ogallala Case Study: The Shrinking Ogallala AquiferAquifer

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.

Fig. 13-11, p. 324

SOLUTIONS

Groundwater Depletion

Prevention Control

Waste less water Raise price of water to discourage waste

Subsidize water conservation

Tax water pumped from wells near surface waters

Limit number of wells Set and enforce minimum stream flow levels

Do not grow water-intensive crops in dry areas

Divert surface water in wet years to recharge aquifers

Converting Saltwater to Converting Saltwater to Freshwater Freshwater (15-6 continued)(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 costDeath of marine organismsLarge quantity of brine wastesFuture economics

Ashkelon Plant supplies 15%of Israel’s Householdswater needs-Largest plant in 2005

Seeding Clouds and Towing Icebergs and Seeding Clouds and Towing Icebergs and Big Baggies Big Baggies (15-6 continued)(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

waterLegal disputes over ownership of cloud water.

Reducing Water Waste We waste about two-thirds of the water we use but using water more We waste about two-thirds of the water we use but using water more

efficiently could reduce wastage to about 15%. 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 According to water resource experts the main cause of water waste is that we charge too little for water- 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 efficiencyUse 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 WaterFlooding 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, Rapid population growth, deforestation, overgrazing , unsustainable farming on overgrazing , unsustainable farming on steep and easily erodible mountain slopessteep and easily erodible mountain slopes

Hillside Before and After Deforestation

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

Benefits of FloodplainsHighly productive wetlandsProvide natural flood and erosion controlMaintain high water qualityRecharge groundwaterFertile soilsNearby rivers for transporation use and

recreationFlatlands for urbanization and farming

Dangers of Floodplains and FloodsDeadly and destructiveHuman activities worsen floodsFailing dams and water diversionHurricane Katrina and the Gulf Coast

Removal of coastal wetlands

Before and During a Flood inSt. Louis, Missouri

Case Study: Floodplains of Case Study: Floodplains of BangladeshBangladesh

Dense populationLocated on coastal floodplainModerate floods maintain fertile soilIncrease frequency of large floodsDevelopment in the Himalayan foothillsDestruction of coastal wetlands

In struggle to survive, the poor in Bangladesh have cleared In struggle to survive, the poor in Bangladesh have cleared many of the coastal mangrove forests for fuel woods, many of the coastal mangrove forests for fuel woods, farming, and aquaculture ponds for raising shrimp. This farming, and aquaculture ponds for raising shrimp. This has led to more severe flooding.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