Advantages of multi-purpose river projects: Multi-purpose river projects, as the name suggests, makes water available for multiple uses. It provides water for irrigation and domestic use. This water is also used for hydroelectricity. This also prevents floods, and is used for fish breeding and inland navigation Example, Hirakund project in the Mahanadi basin helps in conservation of water and flood control. Disadvantages: Collecting water in dams disturbs the natural flow. This means that the sediment deposition on the river banks will be lesser. This also causes excessive sediment deposition at the bottom of the reservoir, disturbing the natural aquatic life. This has also caused disputes between states regarding the sharing it's costs and water availability. If the water is in a still state, there are chances of diseases being spread. Collecting the water in a reservoir also means that a lot of land will be covered which was, once, a forest cover or a village. The reservoir water also causes pollution due to excessive use of water.