water resources chapter 13. what would you do exercise in the future of the middle east many...

Water Resources

Chapter 13

What would you do

Exercise in the future of the Middle east

Many analysts list the 3 most serious environmental problems the world faces• Climate change• Biodiversity loss• Emerging water shortages

Core Case Study: Water Conflicts in the Middle East: A Preview of the Future

Water shortages in the Middle East: hydrological poverty

Nile River

Jordan Basin

Tigris and Euphrates Rivers

Peacefully solving the problems

Three Major River Basins in the Middle East

13-1 Will We Have Enough Usable Water?

Concept 13-1A We are using available freshwater unsustainably by wasting it, polluting it, and charging too little for this irreplaceable natural resource.

Concept 13-1B One of every six people does not have sufficient access to clean water, and this situation will almost certainly get worse.

Freshwater Is an Irreplaceable Resource That We Are Managing Poorly (1)

Why is water so important?

Earth as a watery world: 71%

Freshwater availability: 0.024%

Poorly managed resource

Hydrologic cycle

Water pollution

Freshwater Is an Irreplaceable Resource That We Are Managing Poorly (2)

Access to water is • A global health issue• An economic issue• A women’s and children’s issue• A national and global security issue

Girl Carrying Well Water over Dried Out Earth during a Severe Drought in India

Most of the Earth’s Freshwater Is Not Available to Us

Hydrologic cycle • Movement of water in the seas, land, and air• Driven by solar energy and gravity

People divided into• Water haves• Water have-nots

Natural Capital: Groundwater System: Unconfined and Confined Aquifer

Fig. 13-3, p. 316

Unconfined Aquifer Recharge Area

Precipitation Evaporation and transpiration Evaporation

Confined Recharge Area Runoff

Flowing artesian well

Well requiring a pump Stream

InfiltrationWater table Lake

InfiltrationUnconfined aquiferLess permeable

material such as clay

Confined aquiferConfining impermeable rock layer

We Get Freshwater from Groundwater and Surface Water (1)

Ground water

Zone of saturation

Water table

Aquifers• Natural recharge • Lateral recharge

We Get Freshwater from Groundwater and Surface Water (2)

Surface Water• Surface runoff• Watershed (drainage) basin• Reliable runoff• 1/3 of total

We Use a Large and Growing Portion of the World’s Reliable Runoff

2/3 of the surface runoff: lost by seasonal floods

1/3 runoff usable • Domestic: 10%• Agriculture: 70%• Industrial use: 20%

Fred Pearce, author of When the Rivers Run Dry

Case Study: Freshwater Resources in the United States

More than enough renewable freshwater, unevenly distributed (east vs west)

Effect of• Floods• Pollution• Drought

2007: U.S. Geological Survey projection • Water hotspots

Average Annual Precipitation and Major Rivers, Water-Deficit Regions in U.S.

Fig. 13-4a, p. 317

Fig. 13-4a, p. 317

Average annual precipitation (centimeters)

41–81 More than 122

Less than 41 81–122

Fig. 13-4b, p. 317

Fig. 13-4b, p. 317

Shortage

Acute shortage

Adequate supply

Metropolitan regions with population greater than 1 million

Water Hotspots in 17 Western U.S. States

Fig. 13-5, p. 318

Substantial conflict potential

Highly likely conflict potential

Unmet rural water needs

Moderate conflict potential

Washington

Oregon

MontanaNorth Dakota

Idaho South DakotaWyoming

Nevada NebraskaUtah

ColoradoKansas

CaliforniaOklahoma

New Mexico

Texas

Arizona

Water Shortages Will Grow (1)

Dry climate

Drought

Too many people using a normal supply of water

Water Shortages Will Grow (2)

Wasteful use of water

China and urbanization (2/3rds faced water shortages in 2006)

Hydrological poverty

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

Fig. 13-6, p. 319

Europe Asia

North America

Africa

South America Australia

Stress

High None

Long-Term Severe Drought Is Increasing

Causes• Extended period of below-normal rainfall• Diminished groundwater

Harmful environmental effects• Dries out soils• Reduces stream flows• Decreases tree growth and biomass• Lowers net primary productivity and crop yields• Shift in biomes

In Water-Short Areas Farmers and Cities Compete for Water Resources

2007: National Academy of Science study• Increased corn production in the U.S. to make

ethanol as an alternative fuel• Decreasing water supplies• Aquifer depletion• Increase in pollution of streams and aquifers

Who Should Own and Manage Freshwater Resources? (1)

Most water resources• Owned by governments• Managed as publicly owned resources

Veolia and Suez: French companies• Buy and manage water resources • Successful outcomes in many areas (china)

Who Should Own and Manage Freshwater Resources? (2)

Bechtel Corporation• Poor water management in Bolivia

A subsidiary of Bechtel Corporation• Poor water management in Ecuador

Potential problems with full privatization of water resources• Financial incentive to sell water; not conserve it• Poor will still be left out

Who should own the water resources?

How can more water be produced?

In America

85% of Americans get their water from publically owned utilities

Within 10 years the 2 European companies aim to control 70% of the water supply in the US

Assignment:

Where do you get your water from?

If a company, which one?

If your family receives a water bill, ask to see it.

Record the following:• Amount of water used (in gallons)• Period of time recorded amount was used

(months)• Cost in dollars for that water

Pros and Cons for privately owned water companies

Pro: • Companies have money and expertise to

manage these resources better (more efficiently) than the government

Con: • Companies motive is money, which may dictate

their customer service• Cost of reacquiring water resources is high• Incentive is to sell water not conserve it• Poor will be left out

Exit Questions

1) How can some areas that receive a moderate amount of rainfall still suffer from water shortages?

2) Between farmers and city dwellers, which group should have greater access to water in water-short areas?

3) How might the scarcity of water in the Middle east affect nations that are dependent on oil from the Middle East?

What can we do to guarantee our water security?

Possible choices for sources of water

Extract more Groundwater

Build More Dams

Transfer water from one place to another

Convert Seawater to Freshwater

Reduce the amount of water needed

13-2 Is Extracting Groundwater the Answer?

Concept 13-2 Groundwater that is used to supply cities and grow food is being pumped from aquifers in some areas faster than it is renewed by precipitation.

Aquifers

Can be renewable resources unless;• Water becomes contaminated (salt or pollution)• Removed faster than replaced

Aquifers provide water for nearly ½ the world’s people

• In US aquifers supply • almost all drinking water in rural areas• 1/5th of urban areas • about 40% of irrigation

Water Tables Fall When Groundwater Is Withdrawn Faster Than It Is Replenished

India, China, and the United States• Three largest grain producers• Overpumping aquifers for irrigation of crops

India and China• Small farmers drilling tubewells • Effect on water table (drops, requiring more expensive

equip)

Saudi Arabia• Aquifer depletion and irrigation• Irrigated farming will disappear in SA in 10-20 years

Natural Capital Degradation: Irrigation in Saudi Arabia Using an Aquifer

What happens to the global food market once cheap groundwater runs out?

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: Aquifer Depletion in the United States

Ogallala aquifer: largest known aquifer• Irrigates the Great Plains• Water table lowered more than 30m• Cost of high pumping has eliminated some of the

farmers• Government subsidies to continue farming

deplete the aquifer further• Biodiversity threatened in some areas (loss of

wetlands derived from springs)

California Central Valley: serious water depletion

Natural Capital Degradation: Areas of Greatest Aquifer Depletion in the U.S.

Fig. 13-9, p. 322

Groundwater Overdrafts:

Moderate

Minor or none

High

Natural Capital Degradation: The Ogallala is the World’s Largest Known Aquifer

Fig. 13-10, p. 323

WYOMINGSOUTH DAKOTA

NEBRASKA

COLORADOKANSAS

OKLAHOMANEW MEXICO

Miles

0

100TEXAS

Saturated thickness of Ogallala Aquifer

Less than 61 meters (200 ft.)61–183 meters (200–600 ft.)More than 183 meters (600 ft.) (as much as 370 meters or 1,200 ft. in places)

0

160Kilometers

Other effects of ground water pumping

• Lower water table requires greater cost to farmers to continue to pump

• Land subsidence: Take water out, allows land to compact (shrink). Compaction prohibits future recharge

• Sinkholes: underground cavern collapse after being drained of water

• Contamination of the groundwater with saltwater. Undrinkable and unusable for irrigation

Sinkholes

Sinkholes• New sinkholes have been correlated to land-use practices,

especially from ground-water pumping and from construction and development practices. Sinkholes can also form when natural water-drainage patterns are changed and new water-diversion systems are developed. Some sinkholes form when the land surface is changed, such as when industrial and runoff-storage ponds are created. The substantial weight of the new material can trigger an underground collapse of supporting material, thus causing a sinkhole.

• The overburden sediments that cover buried cavities in the aquifer systems are delicately balanced by ground-water fluid pressure. The water below ground is actually helping to keep the surface soil in place. Groundwater pumping for urban water supply and for irrigation can produce new sinkholes In sinkhole-prone areas. If pumping results in a lowering of ground-water levels, then underground structural failure, and thus, sinkholes, can occur.

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

Science Focus: Are Deep Aquifers the Answer?

Locate the deep aquifers; determine if they contain freshwater or saline water

Major concerns• Geological and ecological impact of pumping

water from them• Flow beneath more than one country• Who has rights to it?

Exit Questions 13-2

• List 3 disadvantages to over using groundwater

• One of the control solutions is to raise the price of water to discourage waste. Do you agree with the solution? What suggestions would you give in order to make this choices more agreeable to the average taxpayer.

How much water does your family use a month?

• Identify source of water used in home

• Determine the amount of water used by month/day

• Determine cost for water Daily/Monthly

• Water weights 14 lbs per gallon

• Estimates?

Possible choices for sources of water

• Extract more Groundwater

• Build More Dams

• Transfer water from one place to another

• Convert Seawater to Freshwater

• Reduce the amount of water needed

13-3 Is Building More Dams the Answer?

Concept 13-3 Building dam and reservoir systems has greatly increased water supplies in some areas, but it has disrupted ecosystems and displaced people.

Large Dams and Reservoirs Have Advantages and Disadvantages (1)

Main goals of a dam and reservoir system• Capture and store runoff

• Release runoff as needed to control:• Floods• Generate electricity• Supply irrigation water• Recreation (reservoirs)


Advantages• Increase the reliable runoff available for

farming/drinking• Reduce flooding• Grow crops in arid regions• Recreation


Disadvantages• Displaces people• Flooded regions• Impaired ecological services of rivers• Loss of plant and animal species• Fill up with sediment within 50 years

Advantages and Disadvantages of Large Dams and Reservoirs

Hoopes Reservoir

The Ataturk Dam Project in Eastern Turkey

San Clemente dam - California

San Clemente Dam- California

The 89-year old, 106-foot high dam, which once helped bring water to residents of Monterey County, is at risk of failing during a significant earthquake or flood. Sediment has been building up behind the dam for years, making it a hazard for those living below it and almost useless as a water storage reservoir. If the dam were to fail, an estimated 2½ million cubic yards of sediment and more than 40 million gallons of water could rush downstream with potentially disastrous consequences.

The dam removal will also aid in the recovery of steelhead trout by opening up access to more than 25 square miles of spawning and rearing habitat. Steelhead in Carmel River were listed as threatened under the Endangered Species Act in 1997.

“The removal of the San Clemente Dam will help restore richness to the entire ecosystem of the Carmel River while eliminating this major safety threat to the people and their property along it,” said Rodney McInnis, NOAA’s Fisheries Service southwest regional administrator. “The dam removal is vital to the recovery of this important steelhead trout run.”

Some Rivers Are Running Dry and Some Lakes Are Shrinking

Dams disrupt the hydrologic cycle Major rivers running dry part of the year• Colorado and Rio Grande, U.S.• Yangtze and Yellow, China• Indus, India• Danube, Europe• Nile River-Lake Victoria, Egypt

Lake Chad Africa: disappearing

The Colorado River Basin

Case Study: The Colorado River Basin— An Overtapped Resource (1)

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


Supplies water and electricity for more than 25 million people

Irrigation of crops, cheap water from dams

Recreation


Four Major problems• Colorado River basin has very dry lands• Modest flow of water for its size• Legal pacts allocated more water for human

use than it can supply• Amount of water flowing to the mouth of the river

has dropped

• Silt buildup because of slowing water- filling up the resevoirs


What will happen if some of the reservoirs empty out?• Economic and ecological catastrophe• Political and legal battles over water

What can be done

Enact and enforce strict water conservation measures

Sharply increase the price of water Slow population growth/urban development Stop subsidizing use of water for agriculture in

the region Stop building golf courses/green lawns

Aerial View of Glen Canyon Dam Across the Colorado River and Lake Powell

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

Fig. 13-16, p. 328

35

30 Hoover Dam completed (1935)

25

20

15 Glen Canyon Dam completed (1963)

10

Flo

w (

bil

lio

n c

ub

ic m

eter

s)

5

0

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

Year

Case Study: China’s Three Gorges Dam (1)

World’s largest hydroelectric dam and reservoir

2 km long across the Yangtze River

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

Three Gorges Dam

Flooding Natural and Cultural Icons

Trash at the dam

Case Study: China’s Three Gorges Dam (2)

Harmful effects• Displaces about 5.4 million people• Built over a seismic fault• Significance?

• Rotting plant and animal matter producing (Methane) CH4

• Worse than CO2 emissions as a greenhouse gas

• Will the Yangtze River become a sewer?

Exit questions

6) Do the advantages (name some) outweigh the disadvantages (name some) of large dams?

7) List the top 3 measures you would make to deal with the water problems of the Colorado River

13-4 Is Transferring Water from One Place to Another the Answer?

Concept 13-4 Transferring water from one place to another has greatly increased water supplies in some areas, but it has also disrupted ecosystems.

CA, U.S., Transfers Water from Water-Rich Areas to Water-Poor Areas

Water transferred by• Tunnels• Aqueducts• Underground pipes

May cause environmental problems

California Water Project

The California Water Project and the Central Arizona Project

Fig. 13-17, p. 330

CALIFORNIAShasta Lake NEVADA

Sacramento River

UTAH

North Bay Aqueduct

Feather River

Lake Tahoe

San FranciscoSacramento

South Bay Aqueduct

Hoover Dam and Reservoir (Lake Mead)

Los Angeles Aqueduct

Colorado River

California AqueductColorado River

Aqueduct Central Arizona Project

ARIZONA

Fresno

Santa Barbara

Los Angeles

San DiegoSalton Sea

Phoenix

Tucson

MEXICO

San Luis Dam and Reservoir

San Joaquin V

alley

Oroville Dam and Reservoir

Case Study: The Aral Sea Disaster (1)

Large-scale water transfers in dry central Asia• Water diverted from rivers

Wetland destruction and wildlife (85%)

Fish extinctions and fishing industry collapse

Case Study: The Aral Sea Disaster (2)

Wind-blown salt (salinization of the land)

Farmer’s response to poorer yields…resulting health problems

Water pollution (concentrated, dumped)

Climatic changes (thermal buffer, now hotter drier summers)

Natural Capital Degradation: The Aral Sea, Shrinking Freshwater Lake

Fig. 13-18a, p. 331

Stepped Art

1976 2006

Ship Stranded in Desert Formed by Shrinkage of the Aral Sea

The threat of anthrax

Buried 100’s of metric tons of anthrax spores and other deadly toxins on island

Water level is reduced to point that island is not connected to mainland

Rats, fleas could carry disease to humans

China Plans a Massive Transfer of Water

South-North Water Transfer Project Water from three rivers to supply 0.5 billion

people Completion in about 2050 Impact• Economic• Health• Environmental

Tibet : The water tower of the world

Global Warming its possible effect on the projects

Exit questions for 13.4 Water transport

1. Describe the California water project

2. Describe the Aral Sea disaster

3. Describe the proposed China South-North water project

4. What are common benefits of transporting water

5. What are common problems involved with transporting water

13-5 Is Converting Salty Seawater to Freshwater the Answer?

Concept 13-5 We can convert salty ocean water to freshwater, but the cost is high, and the resulting salty brine must be disposed of without harming aquatic or terrestrial ecosystems.

Removing Salt from Seawater Seems Promising but Is Costly (1)

Desalination (2 main methods)• Distillation• Reverse osmosis, microfiltration

Already used to produce water 15,000 plants in 125 countries• Saudi Arabia: highest number (who is 2nd?)• Mainly wealthy, energy rich countries

Distillation - Boiling

Heating separates

water from salts Use cool incoming

water to condense

vapor

Reverse Osmosis: Screens and Pressure

Desalination steps

1. Bring seawater into plant

2. Remove solids

3. Desalinate water

4. Get rid of waste brine

5. Treat freshwater

6. Store and use

Cost comparison of methods

Microfilters

Benefits

Adding usable water to system Huge potential resource Most countries have access to the ocean

Removing Salt from Seawater Seems Promising but Is Costly (2)

Problems1. High cost and energy footprint

2. Use chemicals to keep down algal growth potential to kill many marine organisms, if released

3. Large quantity of chemically contaminated brine( highly concentrated salt water) where do you dispose of it?

4. Water may be too pure, minerals have to me added back into water for it to be useful

Science Focus: The Search for Improved Desalination Technology

Desalination on offshore ships

(what is the advantage?)• Solar or wind/wave energy

Better membranes

Better disposal options for the brine waste

Reduce water needs, conserve water

Exit questions for 13.5

What does desalination mean?

What is the difference between the Distillation process and the Reverse Osmosis process?

What solutions were presented to overcome the problems associated with desalination?

13-6 How Can We Use Water More Sustainably?

Concept 13-6 We can use water more sustainably by cutting water waste, raising water prices, slowing population growth, and protecting aquifers, forests, and other ecosystems that store and release water.

Reducing Water Waste Has Many Benefits (1)

We have the potential the impending global water shortage just by not wasting (conserving) water we already use.

Water conservation• Improves irrigation efficiency• Improves collection efficiency• Uses less in homes and businesses

Reducing Water Waste Has Many Benefits (2)

Worldwide: 65–70% loss • Two largest sources of waste:• Evaporation, leaks

Big reason for waste• Water prices: low cost to user

Government subsidies: more needed? What should government support with your money?

We Can Cut Water Waste in Irrigation

Flood irrigation• Wasteful

Center pivot, low pressure sprinklers• Low-energy, precision application sprinklers

Drip or trickle irrigation, micro-irrigation• Costly; less water waste

Flood Irrigation

Center pivot irrigation

Drip irrigation

Fig. 13-20, p. 335

Center pivot (efficiency 80% with low-pressure sprinkler and 90–95% with LEPA

sprinkler)Drip irrigation

(efficiency 90–95%)

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

Gravity flow (efficiency 60% and 80% with surge valves)

Above- or below-ground pipes or tubes deliver water to individual plant roots.

Water usually comes from an aqueduct system or a nearby river.

Effluent spray system

Major Irrigation Systems

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

Developing Countries Use Low-Tech Methods for Irrigation

Human-powered treadle pumps

Harvest and store rainwater

Create a canopy over crops: reduces evaporation

Fog-catcher nets

Human Treadle Pumps

Fog Catcher nets

We Can Cut Water Waste in Industry and Homes

Recycle water in industry

Fix leaks in the plumbing systems

Use water-thrifty landscaping: xeriscaping

Use gray water

Pay-as-you-go water use

Xeriscaping

Solutions: Reducing Water Waste

We Can Use Less Water to Remove Wastes

Can we mimic how nature deals with waste?

Waterless composting toilets

We Need to Use Water More Sustainably

“The frog does not drink up the pond in which it lives”

Blue revolution

What can cities, industries, governments do to reduce water consumption?

Fig. 13-23, p. 337

SOLUTIONS

Sustainable Water Use

Waste less water and subsidize water conservation

Preserve water quality

Protect forests, wetlands, mountain glaciers, watersheds, and other natural systems that store and release water

Get agreements among regions and countries sharing surface water resources

Raise water prices

Do not deplete aquifers

Slow population growth

What can you do to reduce water consumption

What Can You Do? Water Use and Waste

Why do you think people do not conserve water?

Reasons

Takes time Costs more money than doing nothing Benefit is not immediate

Exit questions 13.6

What actions can you take to reduce the amount of water that you consume?

What methods of irrigation use the least amount of water? Which method could you use in your own garden?

Name 3 important solutions in reducing water waste in cities.

13-7 How Can We Reduce the Threat of Flooding?

Concept 13-7 We can lessen the threat of flooding by protecting more wetlands and natural vegetation in watersheds and by not building in areas subject to frequent flooding.

Some Areas Get Too Much Water from Flooding (1)

Flood plains • Highly productive wetlands• Provide natural flood and erosion control• Maintain high water quality• Recharge groundwater

Benefits of floodplains• Fertile soils• Nearby rivers for use and recreation• Flatlands for urbanization and farming

Some Areas Get Too Much Water from Flooding (2)

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

Natural Capital Degradation: Hillside Before and After Deforestation

Fig. 13-25a, p. 339

Oxygen released by vegetation

Diverse ecological habitat

Evapotranspiration

Trees reduce soil erosion from heavy rain and wind

Agricultural land

Tree roots stabilize soil

Vegetation releases water slowly and reduces flooding

Forested Hillside

Fig. 13-25b, p. 339

Tree plantation

Roads destabilize hillsides

Evapotranspiration decreases

Overgrazing accelerates soil erosion by water and wind

Winds remove fragile topsoil

Agricultural land is flooded and silted up

Gullies and landslides

Heavy rain erodes topsoil

Silt from erosion fills rivers and reservoirs Rapid runoff causes flooding

After Deforestation

Fig. 13-25a, p. 339

Oxygen released by vegetation

Diverse ecological habitat Evapotranspiration

Trees reduce soil erosion from heavy rain and wind

Tree roots stabilize soil

Vegetation releases water slowly and reduces flooding

Forested Hillside

Agricultural land

Stepped Art

Tree plantation

Roads destabilize hillsides

Overgrazing accelerates soil erosion by water and wind

Winds remove fragile topsoil

Agricultural land is flooded and silted up

Gullies and landslides

Heavy rain erodes topsoil

Silt from erosion fills rivers and reservoirs

Rapid runoff causes flooding

After Deforestation

Evapotranspiration decreases

Case Study: Living Dangerously on Floodplains in Bangladesh

Dense population

Located on coastal floodplain

Moderate floods maintain fertile soil

Increased frequency of large floods

Effects of development in the Himalayan foothills

Destruction of coastal wetlands

We Can Reduce Flood Risks

Rely more on nature’s systems• Wetlands• Natural vegetation in watersheds

Rely less on engineering devices• Dams• Levees

Solutions: Reducing Flood Damage

Fig. 13-26, p. 340

SOLUTIONS

Reducing Flood Damage

Prevention Control

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

Active Figure: Effects of deforestation

water resources chapter 13. what would you do exercise in the future of the middle east many...

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