Best Dam Lecture Ever!!

US has 75,000 Large Dams (25 ft or higher) China = 80,000 Dams

Colorado River Dams Hoover Dam Used to provide energy and water to So. Calif and Vegas. Reservoir: lake formed behind dam. Lake Mead Hoover Dam

Hoover Dam

3 Gorges Dam Largest Dam, 1 mi. long on Yangtze River Helps switch from coal  hydroelectricity. Dislocation of 1 mill. peeps, burial of artifacts, loss of fertile soil on floodplains. 1` 32en

Aswan Dam, Nile River: Creates Lake Nasser

How this Dam Water Works Water released from behind reservoir Enters Dam Water spins a turbine machine in dam Turbine gens. hydroelectricity Electricity delivered 2 cities via power lines. Glen Canyon Dam

Dam Pros Supply water year round Electrical Power Recreation benefits; boating & fishing No air pollution Water used for agriculture Inexpensive electricity Long economic life

Dam Cons Expensive to build, loss of human lives Sediments don’t flow downstream  loss of nutrients Evaporation of fresh water behind dam  increases salinity Fish can’t travel upstream.

Dam failure  flood

Increased risk of disease  stagnant water (Mosquitoes and malaria)

Case Study: Steelhead/ Rainbow Trout Born in freshwater rivers (rainbow) Swim out to ocean (steelhead) Return to same river (travel upstream) to have their babies. If dam is in place, cannot return to have babies  die

Case Study: Columbia River Story about fish… Fixing problem

Fish Ladder Series of steps the fish hop over to travel upstream (get over dam).

Water Diversion Diverts or directs water to places in need. (Irrigation, Drinking Water) Exs: LA and Colorado Aqueducts

Sharing Water Resources 3/4 of the worlds major river basins are shared b/t at least 2 nations International cooperation!!

Water Diversion Disaster Aral Sea: In Glorious Nation of Kazakhstan Rivers to inland sea have been diverted for irrigation

Case Study: Aral Sea Evaporation has increased salinity, no fish species exist Salt is blown to surrounding area health problems and decreasing crop production

Aral Sea-Was the 4th largest freshwater lake 1989 2003

And Now, 2009

Water Conservation

Irrigation Farmers must heavily irrigate-water crops- so plants can grow and to remove salt Efficient irrigation systems exist to lessen water: use of lasers, central pivot watering systems, timers. Central Pivot System

Agriculture H2O Conservation Water crops at night (less evaporation) Breed/select crops that are drought tolerant Cover surface with mulch

Reducing City Water Use Use Reclaimed Water: Treated Sewage Water: irrigate crops/water parks City Conservation Efforts: Consumer ed. (If it’s yellow, be mellow; if it’s brown, flush it down)

Conserving Water at Home Install low flow shower heads Install low flush toilets Use dishwasher rather than by hand Take shorter showers (once a day, 10 mins/less)

Personal Fix leaks Don’t use water to clean sidewalks Reduce amount of grass