Water levels in the Great Lakes and the St. Lawrence Seaway are highly variable. Record lows have recently been reported, and by 2050 the decline could reach as far as one meter (3 feet) below current levels. Such a dramatic change would have significant consequences for port infrastructures and for almost all aspects of waterway activity.
Does anyone really know what's going on here? There are conflicting opinions on both sides of this issue, ranging from the passive 'natural causes' line of thought through to the pointing of a hard finger at the U.S. Army Corps of Engineers for their gross miscalculation in allowing the bottom of the St. Clair river to be scraped deep for navigational purposes, only to result in the 'co-incidental' draining of the Great Lakes to water golf courses in the south-western states.
Who knows?
Maybe the truth lies somewhere in between. Surely this cannot be so great a mystery that a solution cannot be found. Climate is known to be a dominant factor affecting water levels in the Great Lakes. Precipitation in southern Canada, the volume of runoff in the Great Lakes basin, evaporation losses — all of these are functions of climate, and they all affect lake levels. With a changing climate, the rate of evaporation is expected to increase dramatically, especially in winter when higher temperatures will result in more open water.
