On the east coast of America inside its bays & marshes...?

Question

...what is the two worst things mankind has done so far in harming the waterways???

Answer 1

Hard to pick just two.

Both the Chesapeake Bay Foundation and the University of Maryland have indicated that the destruction of shoreline habitat (such as riparian forests, smaller tributaries, marshlands, beaches, etc.), and a vast array of pollutants (chemicals, lead, fertilizer, etc.) are two of the most significant contributors to conditions the Easter Seaboard's waterways find themselves in.

The link below is a good look into the damage the Chesapeake has undergone.

Answer 2

running waste waters into the harbors and sounds. second is not replanting mussels that filter more water per minute then any other shell fish.which inturn kept our waters cleaner and healthier.

Answer 3

Filling wetlands and polluting the water..

Answer 4

first answerer is right but also boat bottom anti-fouling paints have devastated the shellfish growing beneath them,better more healthful ways should be made.