
Your traveling reporters went to Snoqualmie Falls, one of the most popular tourist destinations in Washington State. At 276 feet, Snoqualmie Falls are higher than Niagara Falls but carry far less water because the Snoqualmie River is smaller than the Niagara River. Flow through the falls varies considerably, depending on the season.
The Falls can generate enough electricity for thousands of houses and are part of the Washington State electrical generation system, which generates 75% of Washington’s electricity. The falling water is drawn into pipes (called penstocks, as shown in the left picture below) and then used to spin turbines, which actually generate the electricity by spinning a magnet inside a wire coil. The amount of electricity that can be generated depends on the height of the falls and the amount of water that flows over them.
Other major United States hydroelectric projects that generate electricity include Grand Coulee Dam (where the Columbia River was dammed to create an artificial drop in water level) and Niagara Falls (where the Niagara River drops more than a hundred feet naturally).

While hydroelectric plants generate “clean” electricity, without producing carbon dioxide or other pollutants, they do have environmental impacts. Artificial dams (rather than natural waterfalls) may prevent migrating fish (such as salmon) from going upriver to spawn. Even with natural waterfalls, the lowered water flows caused by the hydroelectric generation may cause the river to be warmer than usual, as has happened in the Grand Canyon where the Colorado is dammed at Hoover Dam. In China, the Three Gorges Dam destroyed many villages and archaeological sites.