Hydroelectric power has no air pollution or waste, but construction can cause what effect?

• A. Loss or change in habitat
• B. Increased air pollution
• C. Earthquakes worldwide
• D. No environmental impact

Answer: (A)

When evaluating hydroelectric projects, the key idea is that while the operation itself doesn’t produce air pollution or solid waste, the construction phase can disrupt ecosystems. Building a dam often requires flooding valleys to create a reservoir and clearing land, which destroys or drastically alters the terrestrial habitats that existed there. Downstream, changing the flow of the river alters aquatic habitats, affects sediment transport, water temperature, and nutrient dynamics, and can block migratory routes for fish and other species. All of this amounts to a loss or change in habitat, which is the most direct environmental impact of construction. Increased air pollution isn’t the lasting issue, earthquakes aren’t caused by building dams, and saying there’s no environmental impact understates the disruption to ecosystems.