Presented By : Talha ArfiRegistration # 20090498

PRESENTATION SCHEME

Why Dams?What is Dam?Types of DamsUses Of DamsDams-StatisticsImpacts of DamsConclusion

WHY DAMS?Water is essential for sustaining all life.Population movement and increase require

water year round in remote areas.Water collection and utilization is important.Ability to sustain dough and dry situations.

WHAT IS DAM?A structure to contain water.A solid barrier constructed at a suitable

location across a river valley.Has mechanically engineered structure to

direct and control flow of water and storage.

TYPES OF DAMS

Gravity Dam

Buttress Dam

Arch Dam

Embankment Dam

USES OF DAMSDirect Water UsageIndirect Uses

DIRECT WATER USAGEPrivate/DomesticCommercialIrrigationLivestockIndustrialMiningGeneral Public Supply

INDIRECT USESHydroelectric PowerFlood ControlTransportation

DAMS STATISTICSBy the end of the 20th century , there were 45,000

large dams built in 150 countries .International Commission on Large Dams (ICOLD)

Displacement of 4 million people annually due to dams.

Approximately 1,700 dams are being built , at the cost of about 50 million dollars per year.

19% of electricity from hydro power-more than 50% in 63 countries.

12% of all dams have a water supply function.75 countries have dams for flood control.Dam supports 30-40% of irrigated area and 12-16%

of global food production.World Commission on Dams (WCD)

IMPACTS OF DAMSEnvironmental ImpactsSociological ImpactsEconomical ImpactsEffects of Dams on Water Quality

Environmental ImpactsRiver PollutionErosionLoss of Aesthetic ViewAir PollutionNoise PollutionDust

SOCIOLOGICAL IMPACTSIndigenous People AffectedLoss of EcosystemsLoss of SpeciesDisplacement Of People

DISPLACEMENT OF PEOPLE BY DAMS

ECONOMICAL IMPACTSAgriculturePower GenerationWater SupplyEmployment

EFFECTSON WATER QUALITYChange in TemperatureTurbidityDissolved Gas in the WaterEutrophication

CONCLUSIONSmall dams should be built instead of large

damsCareful planning throughout the site

selection , design and construction of dam is critical

Sociological impacts should be considered along with the main objectives of water supply , power generation and flood control

Economic incentives should be weighed against sociological impacts

QUESTION & ANSWERS SESSION