This is a very common question and a very common confusion that prevails to a large extent, this is right actually that’s why you are reading this article. Anyways, the reason for such a confusion is genuine and indisputable because of countless similarities that persist about them.
A Dam and a Barrage both are artificial manmade structures that are constructed across a river, between the two banks, Reason for their construction can be to maintain the flow of water, or to divert water to canal for irrigation purpose or for generating electricity. Thus, it often is confusing to find a different between them.
Before going into the detail differences lets first examine the definition of both the structures :-
There is one structure like that of dam and a barrage that is called a weir,
Weir is basically an impermeable blockade and obstruction build artificially across the stream throughout its width to raise the level of water in the upstream in order to check the flood, store water or to measure discharge.
In the simplest of all meanings, a gated weir is known as a barrage. To be gated means that a barrage is an artificial obstruction constructed across the flow of the river that can regulate the flow of river and divert the river water into the canal after raising the water to a small elevation as needed for the irrigation of the catchment area of the canal.
The dam on the other hand is an impervious obstruction built across the flow of the river in order to store water, generate electricity for aesthetic purpose and to control floods.
The basic difference is actually now already explained in the definitions as cited above; however, lets explain it for the ones who not have yet understood the trick of difference.
We can differentiate a dam and a barrage in two ways; either difference in function or difference in structure.
Difference in function
The main function behind the construction of dam is to create a water reservoir which will in turn use for drinking purpose or with the help of the energy stored in the water electricity can be generated where water through penstocks are taken to the turbines which after generation of electricity through the water out through tailrace back to river.
This implies that dam are actually multipurpose like one purpose is water storage, electricity or power generation, aesthetic or artistic purpose.
The barrage on the other hand have no such storage of water, barrage cannot be considered as head raising headworks, the basic function of a barrage is just to regulate the flow of river of water into the canals in the amount as needed for agriculture use.
The word “barrage” is actually a French word having meaning of “a dam”. Actually this word was originated by two French who were employed in Egyptian Public works who built Delta Barrage across Nile-Branches near north of Cairo. British after seeing them taken the word barrage and called similar structures with this name when constructed in British India. This is the reason why this word is still used for structures constructed in Middle East, Iran, Pakistan and India.
Difference in Structure
As we know that gates and sluices are constructed both in barrages and dams so whats the difference:- the answer is; that in dams the gates and sluices are always at the top having concrete structure beneath to retain sufficient amount of water and if required the water is allowed to move through gates in the structure called spillway.
Whereas in Barrages, the gates are from the top upto the bed of the river thus the water storage capacity of barrage is just dependent on the height of gates.
I hope so after this discussion your question that what is the difference between a dam and a barrage? What is barrage? What is a dam? What is a weir? Where the word “barrage” is originated? Etc have been answered.
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What Is The Difference Between A Barrage And A Dam