Grade 10 Geography Units 12, 13, 14 Essay - Effects of Dam Building Many people have already dammed a small stream using sticks and mud by the time they become adults. Humans have used dams since early civilization, because four-thousand years ago they became aware that floods and droughts affected their well-being and so they began to build dams to protect themselves from these effects.1 The basic principles of dams still apply today as they did before; a dam must prevent water from being passed. Since then, peopl ....