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

valley or other low lying area for the purpose of valley or other low lying area for the purpose of storing water” (Hancock and Skinner, 2000).storing water” (Hancock and Skinner, 2000).

How many?How many?

From 1992 there was over 10 thousand dams From 1992 there was over 10 thousand dams worldwide. worldwide.

About 500 dams are being creating every year, About 500 dams are being creating every year, which exceed 15metres in height. (Jiles and which exceed 15metres in height. (Jiles and Spencer, 1995).Spencer, 1995).

The main Advantages The main Advantages Regulate water flow and Flood ControlRegulate water flow and Flood ControlSediment ControlSediment ControlDrought ControlDrought ControlTime for endangered species to be movedTime for endangered species to be movedTo another suitable location.To another suitable location.IrrigationIrrigationNavigation ImprovementNavigation ImprovementGeneration of hydro-electric powerGeneration of hydro-electric powerCan be made to suit geology, can be placed in narrow andCan be made to suit geology, can be placed in narrow andWide valleys. In rock or soil types.Wide valleys. In rock or soil types.

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

This is due to flood peaks being reduced, and the This is due to flood peaks being reduced, and the uniformity in base flow being increased uniformity in base flow being increased throughout.throughout.

40% of rivers in Africa, Europe, North America were stabilized by 40% of rivers in Africa, Europe, North America were stabilized by dams.dams.Below is a map showing the Europe dams.Below is a map showing the Europe dams.

Map taken from Map taken from http//www.grid.unep.ch/product/publication/freshwater_Europe/images/http//www.grid.unep.ch/product/publication/freshwater_Europe/images/eurodam.jpgeurodam.jpg

There is a reduction as the naturally eroding There is a reduction as the naturally eroding Cliffs now have basal protection. (Less fluvial Cliffs now have basal protection. (Less fluvial Inputs). Inputs).

Deposition location has changed, sedimentDeposition location has changed, sedimentIs no longer built up in wetlands. Resulting in less Is no longer built up in wetlands. Resulting in less Erosion in drainage basins.Erosion in drainage basins.

Dams are needed in places of Dams are needed in places of permanent permanent Drought. To act as barriers to hold Drought. To act as barriers to hold drinkingdrinkingWater. Water.

Looking at three Gorges Dam scheme in China. Looking at three Gorges Dam scheme in China. What were its advantages?What were its advantages? Prevent floodingPrevent floodingHydro-power electricityHydro-power electricityIrrigation (agriculture)Irrigation (agriculture)Domestic useDomestic useNavigationNavigation

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

AdvantagesAdvantages of the aswam dam: of the aswam dam:Prevent flood and drought catastrophic conditionsPrevent flood and drought catastrophic conditions For irrigationFor irrigation 4000km4000km22s of dessert can now be used by farmerss of dessert can now be used by farmersFloodplain has been converted from 1 crop rotation Floodplain has been converted from 1 crop rotation to 3 crop rotation.to 3 crop rotation.Hydro-electricity. Hydro-electricity. Countries income has increased by 500 million per Countries income has increased by 500 million per yearyearSince it was built.Since it was built.

http://http://www.thirdworldcewww.thirdworldce

ntre.org/ntre.org/aswpresa.jpgaswpresa.jpg

Endangered species can be removed and putEndangered species can be removed and putInto a suitable habitat. This occurred with theInto a suitable habitat. This occurred with theSpecies Species Percina tanasi Percina tanasi (Snail darter minnow). (Snail darter minnow). However the dam did not really affect the However the dam did not really affect the Population as they were found naturally occurringPopulation as they were found naturally occurringIn a near by stream. This was at the site ofIn a near by stream. This was at the site of““Tellico Dam on the Little Tennessee river in Tellico Dam on the Little Tennessee river in Tennessee” (Freeman, 1995).Tennessee” (Freeman, 1995).

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

Transport on the RiverTransport on the River Ferry transportation began in 1860s, they now use Ferry transportation began in 1860s, they now use

bargesbarges EconomicalEconomical

Consumer BenefitsConsumer Benefits

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

System by American Waterways Operation 1992-3System by American Waterways Operation 1992-3

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

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 theyDAMS How important are they??

Provide water Provide water for transportfor transport

Provide Electricity for the Provide Electricity for the communitycommunity

Roll on Columbia By Beth Gibson http://members.aol.com/Gibson0817/river.htmRoll on Columbia By Beth Gibson http://members.aol.com/Gibson0817/river.htmColumbia and Snake River supply 63% of hydro electric energyColumbia and Snake River supply 63% of hydro electric energyGrand Coulee when built provided work after great depressionGrand Coulee when built provided work after great depression

Brought cheap electricity to the Brought cheap electricity to the areaareaHelped with the war Helped with the war

efforteffortLater Industry moved to Pacific west because Later Industry moved to Pacific west because ofof

cheap energy supplycheap energy supply

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

Ecology FriendlyEcology Friendly

•96%-98% pass safely through turbines96%-98% pass safely through turbines

•Dams and turbines are not huge blendersDams and turbines are not huge blenders

Ecology FriendlyEcology Friendly

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

Fish Barges are a partial solutionFish Barges are a partial solution

A Commissioner’s A Commissioner’s StoryStory

Les WigenLes WigenWhitman County CommissionerWhitman County Commissioner

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

eurodam.jpg eurodam.jpg Buchal James NG & 60 MinBuchal James NG & 60 Min http://www.saveourdams.com Gibson Beth Gibson Beth Roll on Columbia ByRoll on Columbia By http://members.aol.com/Gibson0817/river.htmhttp://members.aol.com/Gibson0817/river.htm Hancock and Skinner, 2000, “The oxford companion to the earth”. Oxford University Press, Great Hancock and Skinner, 2000, “The oxford companion to the earth”. Oxford University Press, Great

Clarendon Street, Oxford.Clarendon Street, Oxford. Park, C., 1997, “The environment”, 29 West 35Park, C., 1997, “The environment”, 29 West 35thth Street, New York. Street, New York. S Army Corps of Engineers, Northwestern Division 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.htmH:\COLUMBIA RIVER BASIN - DAMS AND SALMON.htm http://www.deniskingphoto.com/coulee_dam/coulee_dam3.htmlhttp://www.deniskingphoto.com/coulee_dam/coulee_dam3.html The Pacific Northwest Barge Industry on the Columbia-Snake River System by American Waterways Operation 1992-3The Pacific Northwest Barge Industry on the Columbia-Snake River System by American Waterways Operation 1992-3 http://www.bluefish.org/pnbarge.htmhttp://www.bluefish.org/pnbarge.htm Spencer, T., and Jules, H. 1995, “Coastal Problems”, Oxford University Press Inc, 198 Madison Avenue, New York. Spencer, T., and Jules, H. 1995, “Coastal Problems”, Oxford University Press Inc, 198 Madison Avenue, New York.