ENVIRONMENTAL IMPACTS OF HYDROPOWER

About hydropower

The water behind the dam flows through an intake and pushes against blades in a turbine, causing them to turn. The turbine spins a generator to produce electricity. The amount of electricity that can be generated depends on how far the water drops and how much water moves through the system. The electricity can be transported over long-distance electric lines to homes, factories, and businesses.

Hydropower (from hydro, meaning water) is energy that comes from the force of moving water. The fall and movement of water is part of a continuous natural cycle called the water cycle.

A typical hydro plant is a system with three parts: an electric plant where the electricity is produced; a dam that can be opened or closed to control water flow; and a reservoir where water can be stored.

About hydropower

Clean and renewable energy source

Hydropower is the cheapest way to generate electricity today. That's because once a dam has been built and the equipment installed, the energy source—flowing water—is free.

It's a clean fuel source that is renewable yearly by snow and rainfall.

Furthermore, hydro plants do not emit pollutants into the air because they burn no fuel.

Hydropower is also readily available; engineers can control the flow of water through the turbines to produce electricity on demand. In addition, reservoirs may offer recreational opportunities, such as swimming and boating.

Hydropower plants produce power cheaply due to their sturdy structures and simple equipment. Hydro plants are dependable and long-lived, and their maintenance costs are low compared to coal or nuclear plants.

Summary of the Environmental Impacts of Dams

Damming rivers may permanently alter river systems and wildlife habitats.

The impact of dams on river ecosystems

Negative effects

Negative environmental effects due to construction activities

Loss of wild lands, wetlands and wildlife habitat Effects of stopping the flow of nutrients

downstream Reduced biological activity downstream Anaerobic decomposition of vegetation and

production of greenhouse gasses Water-loss due to evaporation Changes in water quality due to the lack of

dissolved oxygen near the bottom of reservoirs. This is toxic to fish and can lead to the death of aquatic life. It is also corrosive to turbines.

The impact of dams on river ecosystems

Negative effects

Accomodation of amphibians, riparian fauna and birds to a new environment

Migration of animals to new areas, where new equilibrium may favour some species over others

Blocking fish migration Introducing of new species of fish in the

reservoirs Inappropriate reservoir operation with

large variations in water levels could threaten fish by drying up shallow-breeding and flood producing areas.

The impact of dams on river ecosystems

THE PYRAMID

OF IMPACTS

www.labond.com/Dams/...

The Iron Gates Dams and disruption of spawning migration of Danube sturgeons

Sturgeons are very sensitive to habitat changes. Altered habitats can immediately impact on their spawning, wintering and feeding success, and ultimately lead to their extinction.

Iron Gates is the largest hydropower dam and reservoir system along the entire Danube. The system consists of two main dams, Iron Gates I and II, built in 1972 and 1985 respectively. The dams are constructed at river km 942 and river km 863 upstream of the Danube delta, in effect confining migratory sturgeons to 863 km of the river and cutting off important spawning sites in the Middle Danube.

The Iron Gates dams do not have technical equipment such as fish passes or bypasses, designed to assist fish migration.

Danube sturgeons species

Danube sturgeons species

Danube sturgeons species

Danube sturgeons species

Danube sturgeons species

REFERENCES

Florin BalaciLaurentiu Buse

http://www.need.org/needpdf/infobook_activities/SecInfo/HydroS.pdf

http://www.alternative-energy-news.info/technology/hydro/ http://environment.nationalgeographic.com/environment/global-

warming/hydropower-profile/

http://danube-sturgeons.org/

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