What are the advantages and disadvantages to build dams?

Explanation

Advantages of dams:(1) Storage of adequate water ensure the water supply to crop field round the year for irrigation.
(2) The water from dams is used to generate electricity.
(3) To stop the flow of rain water to sea and help to control flood to some extent.
( 4 ) Canal systems leading from the dams can transfer large amounts of water over great distance i.e., to semi-arid and arid regions.
Disadvantages of dams :( 1 ) Poor tribals loose their habitat.
(2) Agricultural land is submerged.
(3) Large ecosystem is lost.
(4) There is no equitable distribution of water.
Due to it, people close to the source grow water intensive crops like rice, sugarcane, etc. while people farther downstream do not get any water.