While dams are useful to the human population in an area, what the most likely negative impact of the dam on the local environment?

Answer: Large dams have led to the extinction of many fish and other aquatic species, the disappearance of birds in floodplains, huge losses of forest, wetland and farmland, erosion of coastal deltas, and many other unmitigable impacts.

good luck!

It will probably stop fish migration

Explanation:

Fish have to migrate so they don't die from the cold or starvation. They swim upstream and eventually reach there destinations. If a dam is in the way it will cause the fish to have a block in there path and they will eventually die