Damns by Sarah and Allen

JUST KIDDING WE KNOW HOW TO SPELL DAM

How

Disadvantages

Case studies

By Clip Art

Why do we build dams?

Dams can store rain water or water directly from the river itself. Then, in case of a Drought, the dam will still have a relatively constant supply of water.

Producing Power.

Controls flooding & provides recreational activities such as boating fishing and swimming, if the lake is not being used for drinking water (Dam Society).

Simple design makes for inexpensive repairs and maintenance costs (Dam Society).

From: http://www.waterencyclopedia.com/images/wsci_01_img0129.jpg

Advantages of Building a Damn

Simple design makes for inexpensive repairs and maintenance costs (Dam Society).

Produce inexpensive (after completion) and clean power.

Renewable energy source, because the water is not destroyed by passing through the dam.

If needed, dams can be shut down instantly, where thermal plants take hours, and nuclear plants can take days! (Dam Society).

Very few breakdowns.

From: http://www.waterencyclopedia.com/images/wsci_01_img0129.jpg

River diversion and the Aral sea

Aral Sea in Central Asia.

Evaporation matched by inflows of water from the Amu Darya and Syr Darya rivers.

1960 building of dams

eliminated the flow of water into the sea

From: http://landsat.gsfc.nasa.gov/graphics/img/f0012.jpg

MORE INFO

From: http://landsat.gsfc.nasa.gov/graphics/img/f0012.jpg

River diversion and the Aral sea

1995, the area of the Aral Sea was only 30,000 square kilometers,

1960 64,500 square kilometers.

fishing industry which once supported 60,000 workers halt

20 of the 24 fish species once caught in the sea have been extinct

bird species found in the Amu Darya Delta had declined from 319 to 168,

the delta forests had died

only 30 out of 70 species of mammals remained.

From :http://malaysiafishingtour.com/wp-content/uploads/2010/11/Fresh-Water-Fish.jpg

Sediments & Erosion

From: http://www.aperfectworld.org/clipart/Nature/river02.GIF

Sediments & Erosion

From: http://www.aperfectworld.org/clipart/Nature/river02.GIF

• velocity of the water drops • Sediment carried by the river dropped • erosive potential of the river is

increased• sediment deprivation affects shoreline

processes and biological productivity of coastal regions.

Grand Canyon

Grand Canyon below Glen Canyon Dam –1963

Erosion of the sediment along the beaches began because of the lack of incoming sediment.

Beaches disappeared!!

1996 project recovered beaches but was short-lived

Want to know more?

From:http://1.bp.blogspot.com/_gbzApcV7MwY/SNE64u2XpgI/AAAAAAAAAQI/jCxvHTL0jAI/s400/nemo_4.jpg

From: http://www.aperfectworld.org/clipart/Nature/river02.GIF

Columbia River

averaged between 10 and 16 million fish before non-native settlers first arrived in the 19th century.

130 or so dams in the basin,

1.5 million salmon and steelhead enter the Columbia each year

Thirsty for more knowledge??!!

Works cited

" Dams - Impact Of Dams - Water, River, Flow, Sediment, Colorado, and Lake ." Science Encyclopedia. N.p., n.d. Web. 14 Apr. 2011. <http://science.jrank.org/pages/1942/Dams-Impact-dams.html>.

"Dams and Migratory Fish | International Rivers." International Rivers. N.p., n.d. Web. 14 Apr. 2011. <http://www.internationalrivers.org/en/node/1639>.

"Hydrological Effects of Dams | International Rivers." International Rivers. N.p., n.d. Web. 14 Apr. 2011. <http://www.internationalrivers.org/node/1640>.

"Hydrology | Carl Renshaw." Dartmouth College. N.p., n.d. Web. 14 Apr. 2011. <http://www.dartmouth.edu/~renshaw/untitled_text/hydrology.html>.

"PROS AND CONS." Sir Francis Drake High School Website. N.p., n.d. Web. 14 Apr. 2011. <http://drake.marin.k12.ca.us/stuwork/rockwater/Upload%20this%20doc--dams%20and%20hydropower%20report/pros%20and%20cons.html>