What is the different between Dam and Barrage?
 

What is the different between Dam and bridge?

DAM:
A dam is a barrier across flowing water that obstructs, directs or slows down the flow, often creating a reservoir or lake......

BARRAGE:
A barrage is an artificial obstruction at the mouth of a tidal watercourse used to increase its depth or maintain a separation between fresh and salt water or reduce the risk of tidal flooding up the river.

Both the dam and barrage are barriers constructed across a river or natural water course for diverting water into a canal mainly for purposes of irrigation, water supply etc. or into a channel or a tunnel for generation of power.
In case of a barrage, its entire length across the river i.e. between the banks is provided with gates having their bottom sill near the river bed level. Thus, the storage behind the barrage is solely created by the height of the gates.
The dam on the other hand has spillway gates almost near its top level and the storage behind the dam is mainly due to the height of concrete structure and partially due to the gate height.
In both the cases, however, the number and size of gates is adequate to pass the design flood during monsoons.

A dam stores surplus flood water and distributes this additional water through the power / irrigation tunnels in the dam or through the canals from its reservoir. In both cases it is the stored water that is distributed, and not river water which continues to flow normally as before.

It is at the barrages, for there is neither reservoir nor storage, that the canals take water directly from the rivers. Simply it can be differentiated that Dams add water , but barrages subtract it. :)

there is also this electricity factor too:

Dams, due to their huge sizes and more capacity, are used to generate hydro-electricity. The size and purposes of Barrages on the other hand do not allow for electricity generation!!