CHAPTER 1 AWESOME POWER Han stood in awe in front of the Three Gorges Dam in China The dam was more than (cid:11)(cid:10)(cid:10) feet (cid:8)(cid:7)(cid:6) m tall It was more than (cid:8) (cid:6) miles (cid:2) (cid:8) km long Powerful floodwaters emerged from the dam Most impressive though was the dam’s ability to generate energy It is the largest hydroelectric plant in the world The Three Gorges Dam spans the Yangtze River in central China 5
Water is necessary for people to survive and people have always tried to control it Dams achieve this goal They are built across a river or stream to block the flow of water This creates a reservoir or lake behind the dam Outlets allow people to release the water downstream in a controlled way This water might be needed for crop irrigation or drinking water Or it might simply supply downstream flow One of the earliest dams was built in ancient Egypt around 3,000 BCE The dam protected the capital city from the Nile River’s flooding The Roman Empire also built dams Two of them are still used 6
The Romans built the Proserpina Dam in Spain in the first or second century CE today Both are in Spain They were built during the first and second centuries CE In the past people built dams for flood control and irrigation Ancient Roman dams had openings at the bottom These released floodwater downstream 7
