What effects do humans have on the geosphere when building a dam

The dam goes up-> the river gets starved and dries up-> Animals have noi water source and as a result die-> the flow of the river is changed.

answer; in the united states the plains include the great plains of the west and the tail grass prairie to the south of the great lakes extending east to the appalachian plateau

answer; i thinking 4.5 million. in sydney australia;