Which one of the following statements is not true for hydropower generated from river dams?

The correct answer is Dams encourage sustainable growth.

Explanation:

To determine which statement is not true about hydropower generated from river dams, let us analyze each of the given statements:

1. "Dams encourage sustainable growth." - This statement is not true. While hydropower is a renewable energy source, building large river dams often disrupts river ecosystems, submerges huge areas of land, destroys natural habitats, disrupts local livelihoods, and displaces communities. Therefore, large dams are generally not considered fully sustainable due to their significant ecological and socio-economic footprints.

2. "It does not pollute water or air." - This statement is generally considered true in terms of direct operational emissions, as hydroelectric power generation does not emit air pollutants or directly poison water like fossil fuel combustion does.

3. "Hydropower facilities can have large environmental impacts." - This statement is true because constructing dams causes habitat destruction, affects fish migration routes, alters water flows, and impacts river basin biodiversity.

4. "Dams displace indigenous people from their river lifelines." - This statement is true as large reservoir flooding frequently forces local and indigenous communities to relocate away from their traditional homelands and resources.

Thus, the statement that is not true is that "Dams encourage sustainable growth."