Is hydropower a fossil fuel or alternative?

Hydroelectric is considered a renewable resource (although sometimes ignored in alternative energy discussions).

Like many practices for generating electricity, it has both costs and benefits.

On the benefit side, other than electricity generation, it can be used for flood control, irrigation, and even aiding with barges and navigation.

On the cost side, it changes soil sediment patterns. Can slow down the movement of water, change water temperatures, change the species that live in the water, and can impose difficulties for aquatic species migration.

Furthermore, it changes the land and rivers.... forever... and in some cases has displaced Native American communities and destroyed Native American traditional fishing and sustenance.