They wanted to stop it because they thought it would be bad for the economy.
It would be the economic policy of "mercantilism" that was based on the idea that the American colonies primarily were meant to provide economic benefits for Great Britain, since this philosophy held that trade between two entities benefits mainly the larger entity (in this case Britain), and that it is in that entity's best interest to protect its trading partner (the colonies).
The purpose of the 1903 construction project is to protect from flooding by hurricanes
