What are the advantages hydroelectricity energy over electricity generated by a traditional power plant run by fossil fuels?

* Dams have a major impact on rivers and their surrounding ecosystems.

* hydroelectricity does not effect fossil fuels and does not use fossil fuels to get energy/electricity .

* the way hydroelectric energy works is by water from a dam that holds water goes down through a generator and then there is energy that powers are electricity.

URL:
http://app.discoveryeducation.com/techbook2:concept/view/guidConceptId/4
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URL:
http://www.instituteforenergyresearch.org/wp-content/uploads/2013/06/Hy
droelectric-graphs-2.png

URL: http://water.usgs.gov/edu/graphics/wuhytypicalplant.gif