Water Pollution

CASE STUDY: WATER CONFLICTS

Water shortages in the Middle East

Nile River

Jordan Basin

Tigris and Euphrates Rivers

WILL WE HAVE ENOUGH WATER?We are using available freshwater unsustainably

wasting it polluting it charging too little for this irreplaceable natural

resource.

One of every six people do not have sufficient access to clean water, and this situation will

almost certainly get worse.

IMPORTANCE AND AVAILABILITY OF WATER

Why is water so important?

Earth as a watery world – 71%

Freshwater availability – 0.024%

Poorly managed resource

Hydrologic cycle

Water pollution

Confining impermeable rock layer

Less permeable material such as clay

Stream

Wellrequiringa pump Lake

Unconfined aquifer

Flowingartesian well

Runoff

ConfinedRechargeArea

Watertable

Confined aquifer

Infiltration

EvaporationEvaporation and transpiration

Infiltration

Unconfined Aquifer Recharge Area

Recharge Unconfined Aquifer

Precipitation

GROUNDWATER

Zone of saturation

Water table

Aquifers

Natural recharge

SURFACE WATER

Surface runoff

Watershed (drainage) basin

Reliable runoff – 1/3 of total

Runoff useDomestic – 10%Agriculture – 70%Industrial use – 20%

CASE STUDY: FRESHWATER RESOURCES IN THE UNITED STATES

Uneven distribution

Contamination

Eastern U.S.

Western U.S.

Groundwater withdrawal – 50%

HOW CAN WE INCREASE WATER SUPPLIES?

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.

SALTWATER INTRUSION INTOCOASTAL WATER WELLS

ARAL SEA DISASTER

Large-scale water transfers in dry central Asia

Salinity

Wetland destruction and wildlife

Fish extinctions and fishing

ARAL SEA DISASTER

Wind-blown salt

Water pollution

Climatic changes

Restoration efforts

REMOVING SALT FROM SEAWATER

Desalination

Distillation

Reverse osmosis

15,000 plants in 125 countries

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

HOW CAN WE USE WATER MORE SUSTAINABLY?

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 (1)

Benefits of water conservation

Worldwide – 65-70% loss Evaporation, leaks

Water prices, government subsides, waste

REDUCING WATER WASTE (2)

Improve irrigation efficiency

Improve collection efficiency

Use less in homes and businesses

REDUCING IRRIGATION WATER WASTE

SUSTAINABLE WATER USE

WHAT CAN YOU DO?

HOW CAN WE REDUCE THE THREAT OF FLOODING?

We can improve flood control by protecting more wetlands and natural vegetation in watersheds and by not building in areas

subject to frequent flooding.

BENEFITS OF FLOODPLAINS (1)

Highly productive wetlands

Provide natural flood and erosion control

Maintain high water quality

Recharge groundwater

BENEFITS OF FLOODPLAINS (2)

Fertile soils

Nearby rivers for 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 CoastRemoval of coastal wetlands

BEFORE AND DURING A FLOOD INST. 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

WATER POLLUTION SOURCES

Water pollution

Point sourcesDischarge at specific locationsEasier to identify, monitor, regulate

Nonpoint sourcesRunoff of chemicals and sedimentAgricultureControl is difficult and expensive

POLLUTION IN STREAMS

LAKE POLLUTION (1)

Dilution less effective than with streamsStratificationLow flow

Lakes are more vulnerable than streams

Eutrophication – natural aging processOligotrophic

OLIGOTROPHIC AND EUTROPHIC LAKES

GROUNDWATER POLLUTION (1)

Sources

Slow flow, dilution, dispersion

Low dissolved oxygen

Fewer bacteria

Cooler temperatures

GROUNDWATER POLLUTION (2)

Longtime scale for natural cleansingDegradable wastes – organic matterSlowly degradable wastes – DDTNondegradable wastes – lead, arsenic, fluoride

SOURCES OF GROUNDWATER POLLUTION

EXTENT OF GROUNDWATER POLLUTION

Global scale – not much known

Monitoring is very expensive

Underground fuel tank leakageMTBE

Arsenic

Protecting groundwater – prevention is best!

OCEAN POLLUTION

Coastal areas – highly productive ecosystemsOccupied by 40% of populationTwice that population by 2050About 80% marine pollution originates on land

Deep ocean watersSome capacity to dilute, disperse, degrade

pollutantsOcean dumping controversiesAssimilative capacity?

COASTAL WATER POLLUTION

OIL POLLUTION IN OCEANS

Crude and refined petroleum

Tanker accidents – Exxon Valdez

Urban and industrial runoff

EFFECTS OF OIL POLLUTION ON OCEAN ECOSYSTEMS

Volatile organic hydrocarbonsKill larvaeDestroys natural insulation and buoyancy

Heavy oilSinks and kills bottom organismsCoral reefs die

OIL CLEANUP METHODS

Current methods recover no more than 15%

Prevention is most effective methodControl runoffDouble haul tankers

PREVENTING NONPOINT SOURCE POLLUTION (1)

Mostly agricultural waste

Use vegetation to reduce soil erosion

Reduce fertilizer use

PREVENTING NONPOINT SOURCE POLLUTION (2)

Use plant buffer zones around fields and animal feedlots

Keep feedlots away from slopes, surface water and flood zones

Integrated pest management

LAWS FOR REDUCING POINT SOURCE POLLUTION

Clean Water Act

Water Quality Act

Discharge trading controversies

SEWAGE TREATMENT SYSTEMS

Rural and suburban areas – septic tank

Urban areas – wastewater treatment plantsPrimary treatment – physical processSecondary treatment – biological processChlorination – bleaching and disinfection

PRIMARY AND SECONDARY SEWAGE TREATMENT

IMPROVING SEWAGE TREATMENT

Systems that exclude hazardous waste

Nonhazardous waste substitutes

Composting toilet systems

REDUCING WATER POLLUTION FROM POINT SOURCES IN THE U.S.

Impressive achievements

Bad news – 2006 survey45% of lakes and 40% of streams too polluted for

fishing and swimmingRunoff polluting 7 of 10 riversFish caught in 1/4 of waterways unsafe to eat

SHOULD THE CLEAN WATER ACT BE STRENGTHENED?

Yes – environmentalists

No – farmers and developers

State and local officials want more discretion

DRINKING WATER QUALITYPurification of urban drinking water

Developed versus developing countries

الطالبة :عملالهومي أحمد . أمجاد