Hydropower uses a substance that is almost as old as the Earth itself--water.  Water covers almost three quarters of the Earth's surface today!  Nothing on Earth could exist without water.  Water is always moving through the Earth's natural systems which is called the water cycle.  As with sunlight, humans have benefited from the energy available by the movement of water.
   
    Waterwheels turned by the flow or rush of water generate electricity.  Dams are another way to generate electricity by water. Dams block a river using large concrete structures. The amount of hydroelectricity a dam can produce is very high if there is a considerable amount of water flowing at a given time. 
   
    Hydroelectricity accounts for 80 percent of the renewable energy used in the United States.  Hydropower provides low cost electricity, produces abundant amounts of electricity, and doesn't pollute the air in the environment around us.  It is estimated that using hydropower instead of fossil fuels reduces the amount of carbon dioxide released into the atmosphere. 
   
    Though there are many good things about hydropower there are also some downsides as well.  A downside to hydropower is that some countries relocate their citizens, causing job and home loss.  When the movement of a river's water is changed as a result of a dam, sediment can build up, causing loss of nutrients for some species while harming aquatic life that lives close to the dam. 

    Did you know that using hydropower and not fossil fuels WILL make our world a safer place to live?  You do now!!!