Water Resources

Chapter 13YOUR Responsibility: READ ALL OF CHAPTER 13!

Composition of Seawater

• Average salinity of seawater = 35ppt

• 35ppt = saltwater• 35-0.5 = brackish• Below 0.5 = freshwater

Where does our water come from?

Seawater 96.5%

Most freshwater is locked up as ice

Antarctica

Know these terms…• Salinity & ppt• Reservoir• Hydrogen bond• Polarity of a water molecule• Melting/freezing points of water (°C & °F)• Heat capacity• Vaporize• Sublimate• Universal solvent• Wetlands• Drainage Basin / Watershed

QUESTIONS ON ANY TERMS????QUESTIONS ON ANY TERMS????

U.S. Water Budget(excluding Alaska and Hawaii)

15.9 trillion L precipitation

per day

After evaporation…

~5.3 trillion liters are left per day

But this never gets used

Leaving only this for us to use

AQUITARD

Groundwater and Zone of Saturation

Aquifers Hold GROUNDWATER

Aquifers and Wells

Can wells go “dry”? YES!!!YES!!!

Subsidencedue to aquifer depletion

from porous rock~San Joaquin Valley, CA~

In addition to subsidence, aquifer depletion can

cause sinkholes & saltwater intrusion…

SinkholesMay 9, 1981: Winter Park,

Florida

•Collapse occurred when carbonate bedrock had dissolved to the point that it could no longer support the weight of the overlying soil and sediment. •The city stabilized and sealed the sinkhole, converting it into a 350-foot-wide urban lake.

•1 house•5 Porsches at a luxury car dealership•½ of an Olympic-sized swimming pool.

Sinkholes don’t just come from overpumping groundwater…

• This sinkhole is 300 ft in diameter, and 18 feet deep.

• Formed from salt mining.

• Note the person in the lower left corner for size reference.

• Formed from oil drilling.

U.S. Water Consumption(as a % of the renewable supply)

West & Southwest

have the biggest

problem!!

Average consumption =

44% of their renewable

water

National average

elsewhere=

4%

Most critical in 3 places:

S. Arizona

California

The High Plains

Remember, this can cause:

Subsidence

Sinkholes

Saltwater intrusion

Natural Capital Degradation: Aquifer Depletion

Ogallala Aquifer

This aerial view shows the density of center pivot sprinklers being used in areas of Kansas. Each circular field includes more than

100 acres. (Kansas State University photo)

• Largest groundwater deposit in the world.– Covers 6% of U.S. land– Produces >15% of our wheat, corn, sorghum, and cotton– Produces ~40% of our livestock– Requires ~30% of U.S. irrigation water.

• Some areas are drawing water 40x faster than nature replaces it

• Some farmers are leaving because their farms are failing in dry spells.

• Some are trying dry-land farming, but it’s no cure!• Solutions:

• water conservation, more efficient irrigation.

Saltwater Intrusion• What’s going on here?• Ever noticed this at the

beach?• Man… that shower was

salty!! (and the tap water, too!!!)

• So… what is this caused by again?– Aquifer depletion!

• And what else is caused by this???– Sinkholes!

Salinization of Irrigated Soil

• Irrigation water soaks through the soil area where the plant roots grow, adding to the existing water.

• The additional irrigation water causes the underground water-table to rise, bringing salt to the surface.

• When the irrigated area dries & the underground water table recedes, salt is left on the surface soil.

• Each time the area is irrigated this salinity process is repeated.

Salinization of Irrigated Soil

Extra water flows through the soil, mixing w/ salt underground, and bringing it to the surface.

This is in Australia – occurred not from irrigation, but from lack of water-loving plants.

Irrigation salinization is basically the same concept, and the ground would look just like this.

Trade-Offs: Withdrawing Groundwater, Advantages and Disadvantages

Advantages• Useful for drinking water

and irrigation• Available year-round• Exists almost anywhere• Renewable if not

overpumped or contaminated

• No evaporation losses• Cheaper to extract than

most surface waters

Disadvantages• Aquifer depletion• Sinking of land• Aquifers polluted for

decades or centuries• Saltwater intrusion• Reduced water flows into

surface waters• Increased cost and

contamination from deeper wells

Fig. 13-11, p. 324

SOLUTIONS

Groundwater Depletion

Prevention ControlWaste 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

Overuse of Water:Mono Lake, CA

• Inflow = rivers Outflow = evaporation only– Over time, salinity will naturally ____________.

• Problem: much water diverted to Los Angeles– Water level dropped ~46 ft– Salinity increased drastically

• Affected brine shrimp, alkali flies, and their predators

– Dust storms increased

• Solutions:– Water diversion stopped in 1989.– Los Angeles is now funding reclaimed water projects to

replace the water that used to come from Mono Lake.

INCREASE

How do WE use water?68.3% of the world’s water usage is for…

AGRICULTURE/IRRIGATION

21.3% is for…Industry

8.6% is for…Domestic and municipal use

Do you know what

“ARID” means??

How does development change the natural flow of water?

Removing vegetation?How does losing forests affect wetlands?

Xeriscaping• “zeer-i-scape”• Greek word: xeros (“dry”)• Refers to a landscape which will thrive in a semi-arid climate.

Principles:• Use space

effectively• Improve soil• Limit size of turf • Use good

irrigation• Mulch (to retain

water)• Choose plants

that are well-suited to the growing conditions

What is a Watershed?watershed drainage basin animation

NORTH CAROLINA WATERSHEDS

(drainage basins)

Flood Plains & Levees

• Developing in flood plains causes great economic loss.

• What can we do to help this??

• Build smaller levees farther apart…

• Less expensive to build…

• Improves habitat in the flood plain.

Mississippi Watershed Floods (1993)

• What happened?– 50 deaths– Property damage = $12B– 70,000 people left

homeless– 8.7 M acres farmland lost

• Environmental Impacts– Pesticides & agricultural

chemicals washed into Gulf of Mexico

– Zebra mussels carried to new waters (AP EXAM ‘10)

Exacerbating factors:

(2) Building on flood plains

(3) Constructing levees

(1) Draining wetlands

Levee Breach

MISSISSIPPI RIVER

NEW ORLEANS

SOLUTIONSReducing Flood Damage

PreventionPrevention ControlControl

Preserve forests on watersheds

Straighten and deepen streams (channelization)Preserve and restore

wetlands in floodplains

Tax development on floodplains

Build levees or floodwalls along streams

Use floodplains primarily for recharging aquifers, sustainable agriculture and forestry

Build dams

US WATER NEEDS &

PROBLEMS

Average annual precipitation (centimeters)

41–81 More than 122

Less than 41 81–122

Wat

er H

ots

po

ts in

17

Wes

tern

U.S

. Sta

tes

Colorado Colorado River BasinRiver BasinProvides water for LOTS of people in LOTS of different

places

Upper Colorado(CO, UT, WY)

Lower Colorado (CA, NV, AZ, NM)

Mexico

COLORADO PROBLEM:

2,300 km through 7 U.S. states

14 Dams and reservoirs

Located in a desert area within the rain shadow of the Rocky

Mountains

Water supplied mostly from snowmelt of the Rocky

Mountains

Colorado River Basin

• 1922: Colorado River Compact: Allotted water usage for upper & lower regions

• Problem: – Upper Region used less (fewer people), giving

more to the Lower Region, who grew accustomed to overusing the water.

– Now, more development in the Upper Region is causing strain, and Mexico gets little water which is often saltier than the ocean.

• Solution: – desalting plant in AZ to help Mexico

Desalination

Distillation Reverse OsmosisUses less energy (better technology)

-Disposal of the salt is a problem…

-Big industry in N. Africa & Middle East

Water Diversion in Southern California

• Lots of aqueducts to divert the water.

• $$$$$$$$

• Diverting the river causes severe damage

California Aqueduct

Ancient Aqueduct (Arles, France)

Water Management

• River Management:– Flow through multiple jurisdictions, so common

agreements must be made.• Groundwater Management:

– More complicated…– Extent of local groundwater supplies is unknown.– Includes:

• Permits for drilling wells• Limiting the # of wells in an area• Restricting the amount of water that may be pumped from each

well.

• Consumers rarely pay for the entire cost of H2O (transport, storage, treatment)– Taxes pay for it!– Raise the price = more efficient use

DON’T write this – just think!

Too Little Water!

• Overdrawing Surface Waters

– 30% of water from rivers & lakes can be withdrawn without greatly affecting the natural ecosystem.

– If we withdraw more……• Wetlands dry up

– What organisms are affected most by this?

• Estuaries become saltier– How does this affect productivity?

The point of water management is…..• … to provide a sustainable supply of high-

quality water!

• Water supplies are obtained by– building dams– diverting water– removing salt from seawater

or salty groundwater

DAMSDAMSAdvantages and

Disadvantages of Large Dams and Reservoirs

GOOD Things About Dams:• Ensure year-round supply of water• Generate electricity• Flood control for areas downstream

• They let water out slowly to minimize impact

• Recreation BAD Things About Dams:• Heavy sediment deposition upstream

• Little sediment gets past the dam (sediment fills <50 yrs)

• Downstream riverbed is deeply cut (poor habitat)

How a Dam Works…

Hoover Dam

Periodic Flooding of Dams• Sometimes, damming a river is detrimental

to wildlife & the rest of the ecosystem.

• Periodic Flooding can help with this by…– Rebuilds beaches & sandbars– Kills exotic vegetation that has come in– Partly restores fish spawning habitats

Diablo Dam

Sometimes, you just gotta tear it down…

• If it adversely affects fish populations, sometimes it’s best to tear it down.

• That’s a lot of money out the door…

Safety Problems:Baldwin Hills Dam

Aerial View of Glen Canyon Dam Colorado River

The Ataturk Dam Project in Eastern Turkey

Provides water for irrigation in an arid land

The Flow of the Colorado River Measured at Its Mouth

Columbia RiverColumbia River

Biggest problem here:

Salmon PopulationSalmon Population

– Dams impeded salmon migrations …overfished in the Pacific anyway

– Logging near their habitat caused • sediment pollution• increase in water temperature

Columbia River Solutions• Fish Ladder installation

– Doesn’t help much: don’t get through easily (dumb fish!)

• Hatcheries built to replenish the stock– But they’re not genetically compatible with the wild fish

• Barges transport some of the fish– But they don’t “learn” where to go that way… like fishy

cheating.

• Generators periodically shut off so they don’t get mashed by the turbine blades– But we lose electricity at these times!

• Extra water released to help them get downstream faster– But that water is economically “wasted”

• no electricity or irrigation water from it!

Grand Coulee Dam (Columbia River)

Oh no, Harry!!

We can’t get upstream to make the fish of

tomorrow!!!

DAM!!

Fish Ladder(Bonneville Dam, Columbia River, Oregon)

Hurray!!!

A Fish Ladder!!!

Missouri RiverMissouri River• Longest River in the US• Drains 1/6 of the country.• It’s been diverted &

altered in many ways• Big Fight: Farmers vs. Environmentalists!

– Farmers: if we restore the natural flow of the river, I lose my irrigation water!

– Environmentalists: if we don’t restore the natural flow, most of our fish will be gone!

Water ConservationWater Conservation~Reducing Agricultural Water Waste~

• Microirrigation (drip or trickle irrigation) reduces water use by 40-60%• Use lasers to level fields

• Reduce water consumption.

• Challenge: sophisticated irrigation is $$$$$$$– It’s expensive for

AMERICANS – imagine if you were a subsistence farmer in CHINA or INDIA!!

Fig. 13-20, p. 335

Stepped Art

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)

Water usually pumped from underground and sprayed from mobile boom with sprinklers.

Solutions: Reducing Irrigation Water Waste

Peruvian Fog-Catcher Nets

Water Conservation~Reducing Water Waste in Industry~

• In the US, five industries use 90% of the industrially used H2O

• Recycle it! – Reduces water use & therefore reduces

water treatment costs.

• Stricter pollution control laws help as well.

Water Conservation~Reducing Municipal Water Waste~

• Use Gray Water (next slide)

• Wastewater reuse– Treated & used for purposes like irrigation

– Israel is GREAT at this!• Many of the pollutants are from treated sewage, which actually

benefits crops!

• Other conservation methods:– Consumer education

– Water-saving household fixtures (or fixing leaks!)

– Economic incentives to save water• Install a water meter: if I pay attention, I’ll conserve more!• $ rebates for installing water-saving devices• Make it more expensive!

Recycling Water

• “Gray Water” …already been used in sinks, showers, washing machines, and dishwashers.

• Can be used when clean water is not required (flushing toilets, washing the car, sprinkling the lawn)

Water Conservation

• One of the biggest incentives to reduce water usage:

$$$$$$Make them pay more!

Water Conservation~Reducing Water Waste at Home~

What can we do @ home / school / work?

Residential water use in 3 highly developed countries

Global Water

Problems

We Need to Use Water More Sustainably

“The frog does not drink up the pond

in which it lives”

Blue Revolution –

efforts to help

developing

countries to

stave off water

insecurity

Natural Capital Degradation: Stress on the World’s Major River Basins

Global Water Random Facts!!• Worldwide, the amount of fresh water is adequate to meet

human needs– But this doesn’t consider population distributions!

• Many people travel far to get their water– Tends to perpetuate poverty

• WHO estimate:» 1.4B: no safe drinking water» 2.9B: no satisfactory means of domestic

wastewater and fecal waste disposal» 80% human illnesses result from insufficient

water supplies and poor water quality caused by lack of sanitation.

• US AID (Agency for International Development)– one of many that helps solve these global problems

Quick Discussion:In what ways does population growth affect water problems?

Drinking Water: sometimes must be rationed!Drinking Water: sometimes must be rationed!

Drought issues are MUCH worse when Drought issues are MUCH worse when population is so high.population is so high.

Conflict increases.Conflict increases.

Poverty increases.Poverty increases.

Food availability decreases (less irrigation)… Food availability decreases (less irrigation)… may lead to famine!may lead to famine!

Rhine River Basin

• Shared by:– Switzerland, Germany, France, Luxembourg, & the

Netherlands

• Traditionally:– Switzerland, Germany, and France used the water

industrially, then discharged the polluted water back into the river.

– The Dutch had to clean it up before they could drink it!

• Led to the ICPR (International Commission for Protection of the Rhine River) which formally recognized that international cooperation is essential

Aral Sea1976 (between Uzbekistan & Kazakhstan) 1997

• Same problem as Mono Lake!!– Which was……..?????

• Inflow = rivers Outflow = evaporation only!!

• Rivers were diverted for irrigation– By 1980s, >95% of the Aral Sea’s inflow was

diverted!– Total volume dropped by 80%– ALL 24 native fish species are gone.– Disease increasing (TB, anemia, resp. illnesses)

• Virtually no chance of being refilled.

Aral Sea1976 (between Uzbekistan & Kazakhstan) 1997

• Plans to save the Aral Sea ended with the breakup of the Soviet Union (1991).– Responsibility shifted to:

• Uzbekistan, Kazakstan, Kyrgyzstan, Turkmenistan, & Tajikistan

– They do have a joint fund “to prevent the complete disappearance of the Aral Sea”

– World Bank & UNEP are also helping

• Another BIG problem…– Soviets buried hundreds of tons of anthrax bacterial

endospores on an island in the Aral Sea… which may still be alive

– The US has been asked to help clean it up, but it may be prohibitively expensive.

JORDAN RIVERSupplies Israel, Jordan, the

West Bank, & Gaza Strip• Huge population increases• Greater agricultural &

economic needs• Need more effective irrigation

NILE RIVERSupplies 10 nations

• Upriver countries like Ethiopia & Sudan are using more and more water

• This could imperil Egypt’s water supply

Lake Chad

Watch what happens to the lake… this is due to severe drought and

water diversion for irrigation

Lake Chad

Lake Chad

Lake Chad

Lake Chad

China’s Three Gorges Dam• World’s largest hydroelectric dam system

• 2 km long across the Yangtze River

• PROS– Electricity-producing potential is huge– Holds back the River floodwaters– Allows cargo-carrying ships

• CONS– Displaces about 5.4 million people– Built over a seismic fault– Rotting plant and animal matter (from flooding of

floodplains is producing CH4 (Methane)• Worse than CO2 emissions

– Will the Yangtze River become a sewer?

Three Gorges Dam - China

http://news.cnet.com/2300-13840_3-6219797.html

World’ s largest dam

Displaced 1.2 millionPeople from homes

Rotting vegetationProduces methane

Erosion and landslides

Hydroelectric power Reduces need for coal

Case Studymiddle east water conflicts video