Answer:
When the water flows in the dam or reservoir is not restricted or is impossible to restrict due to flood, earth quake or some other natural calamity, life is endangered both to human beings and animals as the water may pass through the forests and may even enter the cities and residential area when the limit is reached and the dam overflows.
Dam plays an vital roles on drinking water supply, flood control, electricity generation, fishing, tourism, etc. The creation of storage and head allow dams to generate electricity. Another situation is when the construction of the dam collapses due to structural failure or leaks.
