DamsDamsHelpful or Hurtful?Helpful or Hurtful?

What do you already know?What do you already know?

Brainstorm with your partners what you Brainstorm with your partners what you know about dams.know about dams.

Be ready to report out!Be ready to report out!

What we know:What we know:

What is the issue?What is the issue?

Dams are Dams are structures built structures built across streams, across streams, rivers or rivers or estuaries to estuaries to retain water.retain water.

What do you already know about What do you already know about healthy river ecosystems?healthy river ecosystems?

Brainstorm with your partners: what do Brainstorm with your partners: what do they look like? What are they comprised they look like? What are they comprised of? How would this be changed if a dam of? How would this be changed if a dam is built along the river? Etc.is built along the river? Etc.

Be ready to report out!Be ready to report out!

What we know….What we know….

The Environment…before and The Environment…before and after dams:after dams:

What do you notice?

The Environment…before and The Environment…before and after dams:after dams:

What do you notice?

The Environment…before and The Environment…before and after dams:after dams:

What do you notice?

Opinions so far?Opinions so far?

Complete the final column of your note Complete the final column of your note sheet for the “What is the Issue?” section.sheet for the “What is the Issue?” section.

The process of building damsThe process of building dams

Click on the following link to observe Click on the following link to observe environmental changes and varying quality environmental changes and varying quality of dam construction. Be ready to think of dam construction. Be ready to think and share!and share!

Dam Construction

Benefits of Using DamsBenefits of Using Dams

Dams provide many benefits including:Dams provide many benefits including: RecreationRecreation flood controlflood control water supplywater supply hydroelectric powerhydroelectric power waste managementwaste management river navigationriver navigation wildlife habitatwildlife habitat

Then what is the problem?Then what is the problem? Dams flood a vast area of landDams flood a vast area of land

Approximately 400,000 sq km worldwide have been flooded by Approximately 400,000 sq km worldwide have been flooded by damsdams

Forests are flooded and decomposeForests are flooded and decompose Dams can break and cause a massive flash flood.Dams can break and cause a massive flash flood.

Riverbeds, banks, deltas, estuaries, and coastlines are Riverbeds, banks, deltas, estuaries, and coastlines are changedchanged

Disrupts natural seasonal changes in the riverDisrupts natural seasonal changes in the river Ends flooding that help to clean out the silt in rivers, causing Ends flooding that help to clean out the silt in rivers, causing

them to clogthem to clog The silt that usually flows down to the Beaches and Estuaries is The silt that usually flows down to the Beaches and Estuaries is

blocked by the dam. blocked by the dam. Sediment load changesSediment load changes Sediment settles to bottom of riverSediment settles to bottom of river The settled sediment erodes and leaves poor habitat for faunaThe settled sediment erodes and leaves poor habitat for fauna The coast beyond the mouth of the river is erodedThe coast beyond the mouth of the river is eroded

Then what is the problem?Then what is the problem?

cont.cont. Water Quality- the water stops moving and causes:Water Quality- the water stops moving and causes:

Temperature changesTemperature changes Removal of nutrientsRemoval of nutrients Dissolved gasesDissolved gases Concentration of metals and mineralsConcentration of metals and minerals pollutionpollution

Reduction of biodiversityReduction of biodiversity Species are isolated upstream and downstreamSpecies are isolated upstream and downstream Migrations are interrupted and often stoppedMigrations are interrupted and often stopped

Other ProblemsOther Problems Dams are expensive to build, and due to drought may become Dams are expensive to build, and due to drought may become

useless, or produce much less power than originally planned.useless, or produce much less power than originally planned.

Opinion Changes?Opinion Changes?

Adjust your 3Adjust your 3rdrd column as necessary! column as necessary!

Who is causing it?Who is causing it?

--Predictions??Predictions??Of course, man! BUT, why???Of course, man! BUT, why???

Who is Causing it?Who is Causing it?

Communities across the world use damsCommunities across the world use dams Farmers benefitFarmers benefit Households benefitHouseholds benefit Big business benefitsBig business benefits

More opinions?More opinions?

Complete the final column of your note Complete the final column of your note sheet for the “Who is causing it?” section.sheet for the “Who is causing it?” section.

Be sure to consider how YOU are a part of Be sure to consider how YOU are a part of the problem!the problem!

What is affected?What is affected?

-Predictions?-Predictions?

What is being affected?What is being affected?

Plant and animal species lose habitatsPlant and animal species lose habitats Migrations of fish are interrupted and often Migrations of fish are interrupted and often

stoppedstopped Ecosystems are destroyed (dried/flooded)Ecosystems are destroyed (dried/flooded) Food chains/webs are interruptedFood chains/webs are interrupted Endangered species are at risk of Endangered species are at risk of

extinctionextinction Erosion alters the landErosion alters the land

More opinions?More opinions?

Complete the final column of your note Complete the final column of your note sheet for the “What is being affected?” sheet for the “What is being affected?” section.section.

Does this elicit any emotion or concern in Does this elicit any emotion or concern in YOU?YOU?

Reflect on your learning:Reflect on your learning:

Discuss:Discuss: How are the biotic and abiotic factors on our How are the biotic and abiotic factors on our

planet are affected by the construction of planet are affected by the construction of dams?dams?

Are the causes of dams (the reasons we build Are the causes of dams (the reasons we build them) worth the consequences?them) worth the consequences?

What is being done to help?What is being done to help?

Suggestions for easing the effects of dam Suggestions for easing the effects of dam constructionconstruction make better use of the dams that already exist make better use of the dams that already exist try to make dams that have less environmental impact try to make dams that have less environmental impact

in the future in the future release more water from the reservoir that the dam release more water from the reservoir that the dam

created created inform people about what effects dams and inform people about what effects dams and

hydroelectric power are having on the environment hydroelectric power are having on the environment

Final opinions?Final opinions?

Complete the final column of your note Complete the final column of your note sheet for the “What is being done to sheet for the “What is being done to help?” section.help?” section.

What can YOU do?What can YOU do?