Advantages of Dams

8/10/2019 Advantages of Dams

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What is a dam? A dam is an engineering structure built to block a valley

or other low lying area for the purpose of storing water

(Hancock and Skinner, 2000).

How many?

From 1992 there was over 10 thousand dams worldwide.About 500 dams are being creating every year, whichexceed 15metres in height. (Jiles and Spencer, 1995).


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The main Advantages

Regulate water flow and Flood ControlSediment ControlDrought ControlTime for endangered species to be movedTo another suitable location.

IrrigationNavigation ImprovementGeneration of hydro-electric powerCan be made to suit geology, can be placed in narrow and

Wide valleys. In rock or soil types.


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60% of total stream flow is regulated by dams andreservoirs for flood control (Jiles and Spencer, 1995).

This is due to flood peaks being reduced, and the

uniformity in base flow being increased throughout.


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40% of rivers in Africa, Europe, North America were stabilized by dams.

Below is a map showing the Europe dams.

Map taken fromhttp//www.grid.unep.ch/product/publication/freshwater_Europe/images/eurodam.jpg


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There is a reduction as the naturally erodingCliffs now have basal protection. (Less fluvialInputs).

Deposition location has changed, sedimentIs no longer built up in wetlands. Resulting in lessErosion in drainage basins.


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Dams are needed in places of permanentDrought. To act as barriers to hold drinkingWater.


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Looking at three Gorges Dam scheme in China.What were its advantages?

Prevent floodingHydro-power electricityIrrigation (agriculture)Domestic use

Navigation

http://www.digitalglobe.com/images/qb/three_gorges_dam_july13_2003_dg.jpg


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Advantagesof the aswam dam:Prevent flood and drought catastrophic conditionsFor irrigation4000km2s of dessert can now be used by farmersFloodplain has been converted from 1 crop rotationto 3 crop rotation.Hydro-electricity.Countries income has increased by 500 million per year

Since it was built.

http://www.thirdworldcentre.org/aswpres

a.jpg


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Endangered species can be removed and putInto a suitable habitat. This occurred with theSpecies Percina tanasi (Snail darter minnow).However the dam did not really affect thePopulation as they were found naturally occurring

In a near by stream. This was at the site ofTellico Dam on the Little Tennessee river inTennessee (Freeman, 1995).

http://bryonfreeman.com/v-web/gallery/albums/album15/res374114578.jpg


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Transport on the River

Ferry transportation began in 1860s, they now use

barges

Economical

Consumer Benefits

Relieves rail congestionThe Pacific Northwest Barge Industry on the Columbia-Snake River

System by American Waterways Operation 1992-3

http://www.bluefish.org/pnbarge.htm


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http://www.saveourdams.com

16 cents per bushel by

barge

32 cents per bushel

by rail (if

available)

92 cents per bushel

by truck

DAMS How important are they?

Provide waterfor transport


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Provide Electricity for the communityRoll on Columbia By Beth Gibson http://members.aol.com/Gibson0817/river.htm

Columbia and Snake River supply 63% of hydro electric energy

Grand Coulee when built provided work after great depression

Brought cheap electricity to the area

Helped with the war effortLater Industry moved to Pacific west because of

cheap energy supply

http://www.deniskingphoto.com/coulee_dam/coulee_dam3.html


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Ecology Friendly

96%-98% pass safely through turbines

Dams and turbines are not huge blenders


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Ecology Friendly

H:\COLUMBIA RIVER BASIN - DAMS AND SALMON.htm

Fish Barges are a partial solution


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A Commissioners Story

Les Wigen

Whitman County Commissioner


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References

Anon, 1998 acessed at: http//www.grid.unep.ch/product/publication/freshwater_Europe/images/eurodam.jpg

Buchal James NG & 60 Min

http://www.saveourdams.com

Gibson Beth Roll on Columbia By http://members.aol.com/Gibson0817/river.htm

Hancock and Skinner, 2000, The oxford companion to the earth. Oxford University Press, Great ClarendonStreet, Oxford. Park, C., 1997, The environment, 29 West 35thStreet, New York. S Army Corps of Engineers, Northwestern Division POC: Adele Merchant, Pacific Salmon Coordination, (503)

808-3722 Page Updated: Thursday September 05 2002 H:\COLUMBIA RIVER BASIN - DAMS AND SALMON.htm http://www.deniskingphoto.com/coulee_dam/coulee_dam3.html The Pacific Northwest Barge Industry on the Columbia-Snake River System by American Waterways Operation 1992-3

http://www.bluefish.org/pnbarge.htm

Spencer, T., and Jules, H. 1995, Coastal Problems, Oxford University Press Inc, 198 Madison Avenue, New York.

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