Water Levels

Coastal property owners who plan to own the property for a long time are advised to anticipate future lake levels beyond the ranges indicated in the historical records.

The Great Lakes have had their present connections for the past 3,000-4,000 years. Water level fluctuations over this time were due to natural climate variability, except for some effects from diversions and dredging of connecting channels since the 1850s. There has been a lot of experience in dealing with high levels over the last half of the last century but relatively little experience with low lakes levels.

The very short recorded history of Great Lakes water levels is inadequate to forecast lake levels that will occur in the next 20, 50 or 100 years. Future climatic conditions may be quite different.

The lake level adjustment process does not work well when natural climate changes are rapid and/or extreme. At such times, human actions to alter lake levels are often too little and too late-producing water level changes of a few inches when changes of several feet are needed. Only part of the effects of these human actions can be realized in the three years (or more) during which some of the lakes may have risen or fallen three to five feet (1-1.5 meters). Efforts to adjust Lake Ontario 's water levels have had considerably better results than efforts with the other lakes.