Question

how are multipurpose project and dams being the cause of many social movement

Answer 1

Dams submerge the soil in flood plain and lead to land degradation there. The setup of dams also make the locals displace to another place for living. So many movements by ngo's such as "narmada bachao movement", "tehri dam andolan".

Answer 2

1.  river water gets diverted 
2. population gets displaced
3.aquatic life gets affected
4. extensive forests subje under water