Send it off a dam? If it’s deep enough why not? When it comes to dams they are quite controversial. Hydro power accounts for 15 percent of the world’s current electricity generation. Other renewable sources of energy contribute just four percent. However the alteration of a river’s flow and sediment transport downstream of a dam often causes the greatest sustained environmental impacts. Life in and around a river evolves and is conditioned on the timing and quantities of river flow.