What are some environmental problems with bridges?

Answer 1

Bridges narrow or confine stream/river channels not allowing lateral movement which is natural for flowing water bodies. This allows the river to incut degrading stream banks and deepening channels to unnatural levels. This changes the natural orders of streams making the former habitat which matched those of the native fish population change. It is the processes of building and maintaining the bridges that cause the environmental problems not the bridges themselves along with car emissions