Hydroelectric projects, if not planned strategically can cause several environmental problems, even though they burn no fuel. Damming rivers may permanently alter river systems and wildlife habitats. Fish, may no longer be able to swim and breed in upstream. Hydropower plant operations may also affect water quality by churning up dissolved metals that may have been deposited by industry long ago. Hydropower operations may increase silting, change water temperatures, and lower the levels of dissolved oxygen. Landslides, rock fall, soil erosion, air pollution and water pollution, seismic...