All Subjects



AP Enviro



Unit 6

6.9 Hydroelectric Power

2 min readmay 29, 2020

Karla Jauregui Sandoval

Hydropower is energy that comes from the force of moving water which turns a turbine. Hydroelectric power generation converts the potential and kinetic energy of water into electrical energy. 
There are two ways to generate hydroelectric power: dams and tidal waves. 

Image Courtesy of AZoM


How it works 🌊

Dams are built on rivers where the terrain will produce an artificial lake or reservoir. A  dam serves two purposes at a hydropower plant. A dam increases the height of the water to create potential gravitational energy. Secondly, it can control the flow of water. When electricity is needed, the water is released. Electricity is generated through the water spinning turbine generators. The water flows through penstocks that turn the turbine which is connected to a generator. The output is electricity that gets fed to the electrical grid.

Benefits and Drawbacks

Benefits 👍🏻
Drawbacks 👎🏻
  • Water is a replenishable source
  • Flood control below the dam 
  • Source of irrigation to croplands 
  • Does not release chemical or gas pollutant 
  • Costly 
  • Sedimentation  ➱ Accumulation of sediment and toxins behind the dam 
  • Human Displacement ➱ the placement of dams can affect indigenous land, violating their rights
  • Ecosystem Destruction ➱ affects fish migration patterns because dam blocks path 

Important Dams to know 

  1. Hoover Dam ➱ provides flood control, water and irrigation for industrial and domestic use 🏠  provides hydroelectric power 
  2. Grand Coulee ➱ Largest hydropower producer in the united states 
  3. Three Gorges Dam ➱ Controls flood and provides power . Causing landslides and erosion of reservoirs downstream

Was this guide helpful?

FREE AP enviro Survival Pack + Cram Chart PDF
Sign up now for instant access to 2 amazing downloads to help you get a 5
Join us on Discord
Thousands of students are studying with us for the AP Environmental Science exam.
join now
Browse Study Guides By Unit
Big Reviews: Finals & Exam Prep
Free Response Questions (FRQs)
Multiple Choice Questions (MCQs)
Unit 1: The Living World: Ecosystems
Unit 2: The Living World: Biodiversity
Unit 3: Populations
Unit 4: Earth Systems and Resources
Unit 5: Land and Water Use
Unit 7: Atmospheric Pollution
Unit 9: Global Change
Play this on HyperTyper
Practice your typing skills while reading Hydroelectric Power
Start Game