Dams are important because they provide water for domestic, industry and irrigation purposes. Dams often also provide hydroelectric power production and river navigation. ... Dams and their reservoirs provide recreation areas for fishing and boating. They help people by reducing or preventing floods.

Is building dams good or bad?

Dams can create a reservoir to hold water, protect areas from floods, or generate clean electricity. All good, right? But wait, there's more: A dam also physically blocks migrating fish and changes the overall biology of the life in the river by changing the natural water flow.

Why should we not build dams?

These off-channel dams share many of the environmental drawbacks associated with traditional dams: they may block fish migration, harm water quality and temperature, flood valuable riparian and terrestrial wildlife habitat, strain a river basin's overall water budget, and reduce or alter river flows.