6. The Weight of the World’s Dams Speed of the earth’s rotation Tilt of the earth’ axis Shape of the earth’s gravitational field
7. Dams have caused flash floods Italy’s VajontDam In 1963 a 330 foot wave rushed over the top of the dam into the valley below and drowned about 2,600 people.
8. Dams can cause earthquakes China’s Zipingpu Dam is 500 meters from a fault line. Some believe it caused the Sichuan earthquake in May 2008, a 7.9 magnitude temblor, killed about 80,000 people.