Over the past decade, alarmists have repeatedly made claims that the Great Lakes were drying up. However, month after month Great Lakes water levels were higher in the 2000s than low level records set in previous decades.
Humans have only been keeping consistent Great Lakes water level records for 94 years. In 1918 the Army Corps of Engineers began measuring and recording the lake levels on a monthly basis. This is a very short period in terms of natural history.
Yet, with the exception of two summer months on Lake Superior, the monthly measurements of the 2000s didn't even hit new low levels within the 94-years of record keeping.
“In August and September of 2007, Lake Superior set a new record low for those months,” Army Corps Meteorologist Keith Kompoltowicz told Capitol Confidential. “After that there were record rainfalls. The water level went up and it no longer threatened to go below the range.”
Those were the only low level marks set for the Great Lakes in the 2000s (2001-2010). That's two out of 120 monthly measurements for five lakes – which is 600 monthly reports. Other monthly low level records (58 out of 60) for the 94-year tracking period were set during the previous low level periods, such as occurred during the 1920s, 1930s and 1960s.
According to the U.S. Geological Survey, the Great Lakes have 6 quadrillion gallons of water. That's enough to spread a foot-deep layer across North America, South America and Africa. In addition, the volume of groundwater in the Great Lakes basin surpasses that of Lake Huron.
However, this hasn't prevented some news media accounts from painting an entirely different picture. These “Great Lakes are drying up” stories began appearing shortly after Lake Michigan and Huron entered a low level period in about 1999. A new batch of “disappearing Great Lakes” articles started popping up again in 2006-2007 when Lake Superior dipped to comparatively low levels.
Some articles claimed the “World's largest lake drying up.” MSNBC reported that the Great Lakes were shrinking as if it were a simple matter of fact. And some even claimed the Great Lakes were disappearing.
“You see a lot of statements and different reports,” Kompoltowicz said. “They appear to come from academic types of hypotheses. We're certainly aware that these things are being said and written. But what we always keep our focus on here in terms of trying to forecast is just the next six months.”
Global climate change has often provided the context for alarmist claims of threats to the quantity of water in the Great Lakes. This formed a backdrop for legislation at the state level; including attempts to let government encroach on private property rights.
“It's true that the two upper lakes (Superior and Michigan-Huron) have been at relatively low levels over the past decade,” Kompoltowicz said. “But levels for the lower lakes (St. Clair, Erie and Ontario) haven't been low.”
Kompoltowicz said the lake levels are tracked monthly and compared to monthly levels of previous years because Great Lakes water levels have a seasonal cycle.
“This (spring) is the time of year when we see the highest water levels on the Great Lakes,” Kompoltowicz said. “Typically, we see the levels going down as we get toward late summer and into autumn and winter.”
According to the April Great Lakes water level report from the Army Corps of Engineers, the lowest recorded level for Lake Superior for April was in 1926 and for Lake Michigan and Huron (which geologists consider to be one lake) the April low was in 1964. The lowest April mark for Lake St. Clair was in 1926; the lowest April record for Lake Erie was in 1934 and the lowest April level for Lake Ontario was in 1935.
Here are this month's Great Lakes water level gage readings compared to the long term (1918 to 2011) April averages (in meters).
- Lake Superior's long term average — 183.26, April 1 — 182.98
- Lake Michigan/Huron's long term average — 176.39, April 1 — 176.04
- Lake St. Clair's long term average — 175.04, April 1 — 175.02
- Lake Erie's long term average — 174. 22, April 1 — 174.36
- Lake Ontario's long term average — 74.88, April 1 — 74. 97