Ships harming river
While the ships plying the St. Lawrence River is a majestic sight, the seaway has done far more harm than good for this country as a whole. It never became the economic boon it was envisioned to be. It has cost this country billions economically by destroying the ecology of the Great Lakes, and serves as the primary vector for aquatic invasive species. Invasive species cost billions per year in management and control, and the economic benefit of the seaway is a drop in the bucket in comparison.