Can’t opening or closing locks on the Great Lakes be used to control the levels of the lakes?
—Bob Corni, Chicago
Adjusting locks on the Great Lakes is not a solution to controlling the levels of the lakes. The insignificance of any human actions that could be taken became clear when employees of the U.S. Army Corps of Engineers office in Detroit simulated opening the gated control structures on the St. Mary’s River allowing a state of “freeflow” from Lakes Huron, Michigan and Superior. The exercise found that, after a full month with locks wide open, Lake Superior dropped only two inches and Lake Michigan/Huron levels declined only 0.5 to one inch. After another month, lake levels returned to pre-freeflow levels. Opening or closing locks to control lake levels does not work.