Question

is dam harmfull for us

Answer 1

no it is very useful for us to get proper water . when the water comes in a very much quantity the dam stops the excess water and won't release it into the river and helps us from floods.

Answer 2

it has benefits that ,it produces electric power and made water disease free.

consequences of large dams are numerous and varied, and includes direct impacts to the biological, chemical and physical properties of rivers and riparian (or "stream-side") environments.

The dam wall itself blocks fish migrations, which in some cases and with some species completely separate spawning habitats from rearing habitats.  The dam also traps sediments, which are critical for maintaining physical processes and habitats downstream of the dam (include the maintenance of productive deltas, barrier islands, fertile floodplains and coastal wetlands).