The tiny Forest City dam on the border between Maine and New Brunswick doesn't look like much more than a pile of rusting iron and aged lumber. Plants and weeds grow throughout the rock-and-crib-style dam, which is home to a family of weasels, a rudimentary passage for fish and is used in summer by local kids to float inner tubes through its gates. The dam itself doesn't generate electricity. It was built to help loggers float their timber to local mills. But its three gates have maintained the waters of East Grand Lake on New Brunswick's western border at consistent levels for almost 180 years.
Rising water levels in the St. Lawrence Seaway could cost the economy more than $1 billion, shippers and port operators say. A new study from the Chamber of Marine Commerce warns that opening the floodgates further at a dam in Cornwall, Ont., would wash away between $1 billion and $1.75 billion in revenue for businesses on both sides of the border. A board of control recently increased the flow at the Moses Saunders Dam — the only control point on the St. Lawrence Seaway, which includes the Great Lakes — to allow 10,400 cubic metres of water per second out of Lake Ontario.