The national parks preceded the National Park Service, but the first great natural park was a state park. Californiaâs Yosemite State Park was established in 1864, by a federal cession approved by President Abraham Lincoln, and on October 21, 1880, President Rutherford B. Hayes toured Californiaâs Yosemite in an open carriage.
In fact, humans have been capturing the energy of moving water for thousands of years. Today, harnessing the power of moving water to generate electricity, known as hydroelectric power, is the largest source of emissions-free, renewable electricity in the United States and worldwide.
Hydroelectric dams produce electricity by using falling water to spin a turbine that is connected to a generator through a large metal shaft. The power that the generator receives from the turbine is...