In recent years, the multi-purpose projects and large dams have come under great scrutiny and opposition for a variety of reasons : (i) Regulating and damming of rivers affect their natural flow causing poor sediment flow and excessive sedimentation at the bottom of the reservoir, resulting in rockier streambeds and poorer habitats for the rivers, as well as the aquatic life. (ii) Dams also fragment rivers making it difficult for the aquatic fauna to migrate, especially for spawning. (iii) The reservoirs that are created on the flood. Plains also submerge the existing vegetation and soil leading to its decomposition over time. (iv) Irrigation has also changed the cropping pattern of many regions with farmers shifting to water intensive and commercial crops. This has great ecological consequences like salinisation of the soil.