for example , the farmers of southern farmers feed the united states and most other parts of the world , and indian ' s irrigation systems have enabled that region to be un - dependent in food producing before 1974 . in addition , in other places of the world floods have helped to remedy world - threatened problems such as malaria from loss of economic production , famine as a legacy of drought , devastation from floods , and continued disease from lack of sanitation water source .
Dam building prevents life-threatening situations.