There's a trade off. I'll take a dam that disrupts a local river ecosystem to coal fired power plants that throw millions of tons of CO2 and other hazardous mat

There's a trade off. I'll take a dam that disrupts a local river ecosystem to coal fired power plants that throw millions of tons of CO2 and other hazardous material into the air impacting a much larger area. In the case of the Hoover Dam it's roughly 4 coal plants to produce the same power generation capacity.