Environmental aspects of hydro power

Although the hydro power plants emit no air pollution and sewage however barrage construction has considerable environmental impact. Construct across the river structures provide to eco-system changes in wide area, specially endangered species of plants and animals. To allow for fish migration, barrage has special ducts but that solution is related with additional costs and decrease units efficiency. Therefore in special case fish like trout are delivered to the upper reaches by human.

Local society is polarized. Proponents of ecology usually against hydro power plant in their region. That group also consist of people who can lost their realty or land (what is related with project), people whom business can suffer if would operate in their neighbourhood and generally the smallest group undecided people which opt for the most. However such a hydro investment has also many followers due to power plant brings a lot of benefit for a region. In case of large units a barrage can be used as a bridge (e.g. tidal barrage in Rance) what improves community values. Dam can also be a tourist attraction especially in case of pump storage unit which usually has large upper reservoir. The reservoir may support local tourism market what is related with workplace increase. Security of local supply is the next advantage. Moreover new workplaces for technicians and engineers are related with power plant. On flood areas barrage also improve management of water resource what may prevent local society against floods. [10], [27]

Relatively less difficulties are with small units. Before construction starts it is necessary to obtain a lot of permissions however there are no society problems. [10], [27]