Economic – Provides low operating and maintenance costs – Provides long life span (50 to 100 years and more) – Provides reliable service – Includes proven technology – Instigates and fosters regional development – Provides highest energy efficiency rate – Creates employment opportunities – Avoids fossil fuel use and cost High upfront investment Requires long-term planning Requires long-term agreements Often requires foreign contractors and funding Conflicting water uses can occurSocial – Leaves water available for other uses – Often provides flood protection – May enhance navigation conditions – Often enhances recreation – Enhances accessibility of the territory and its resources – Improves living conditions – Sustains livelihoods (fresh water, food supply)– May involve resettlement – May restrict navigation – Local land-use patterns will be modified – Waterborne disease vectors may need to be checked – Requires management of competing water usesEnvironmental – Produces no pollutants but only very few GHG emission – Enhances air quality – Produces no waste – Avoids depleting non-renewable fuel resources – Often creates new freshwater ecosystems with increased productivity – Neither consumes nor pollutes the water it uses for electricity generation purposes– Inundation of terrestrial habitat – Modification of hydrological regimes – Modification of aquatic habitats – Water quality needs to be managed – Species activities and populations need to be monitored – Barriers for fish migration, fish entrainment