Great Lakes Water Levels At High-Level Marks

Water levels in all the Great Lakes are now above their recorded long-term averages. The rise has submerged portions of beaches and washed away past Internet postings proclaiming man-made global warming as the cause of low water levels.

On July 3, Lake Superior was two inches higher than its historic average for that date. Lake Ontario was three inches higher, and the other lakes were between 11 and 13 inches higher. The readings that day were also higher than the historic averages for the month of July. Lake Superior was seven inches higher, Lake Erie was 16 inches higher, and Lake Ontario was eight inches above its average. Lakes Michigan and Huron, or Lake Michigan-Huron, as hydrologists call the two, were 6 inches above the average.

The averages are based on measurements that the U.S. Army Corps of Engineers has taken on an ongoing basis since 1918. This 97-year period is, in geologic terms, brief. The Corps observed generally low-water periods in the mid-1920s, the mid-1930s, the mid-1960s, and the years from 1999 through 2013. Generally high-water periods came in the late 1920s and the mid-1950s, as well as the early 1970s to the mid-1980s.

Anecdotally, evidence of lake level fluctuations also can be found in countless 8 millimeter home movies shot over the past 80 years when families visited beaches. In addition, measurements reported in newspapers dating back to the mid-1880s indicate a history of fluctuations.

This history is consistent with sedimentary evidence that reveals water level fluctuations going back to the beginning of the modern Great Lakes era, or roughly 4,000 years ago.

During the most recent low-level period (1999-2013), which lasted longer than the previous three, climate-change activists and politicians such as Sen. Dick Durbin (D-Ill.) insisted that global warming was at work.

But according to Corps data, the lowest Great Lakes water levels recorded came long before the words "global warming" or "climate change" entered the political lexicon. The lowest observed level for the month of July came in 1926 for Lake Superior, 1964 for Lake Michigan-Huron, and 1934 for lakes Erie and Ontario. Notice the conspicuous absence of the years 1999 to 2013.

The Corps has tabulated the monthly highs and lows for each lake. With four Great Lakes to measure (remember, Michigan and Huron are considered one lake for hydrologic purposes), that translates into 48 monthly records for low-water levels. How many were recorded recently?

“There were four monthly low-water-level records set during the recent lower-than-average period,” said Keith Kompoltowicz, chief of watershed hydrology for the Corps in Detroit.“Two were set for Lake Superior in August and September of 2007 and two were set for Lake Michigan-Huron in December 2012 and January 2013."

“For Lake Michigan-Huron, all of the other record lows were set back in 1964,” Kompoltowicz continued. “For the other lakes, some of the low-level records were set in the earlier (mid-1920s and mid-1930s) low-level periods or during the one in the 1960s.”

An article written by the chief meteorologist of statewide media outlet MLive claimed that if water levels on the upper Great Lakes rose in the fall of 2014, it would be only the fifth time such a rise had occurred in 155 years. Kompoltowicz was asked if he knew who had been tracking Great Lakes water levels for 155 years.

“There have been people keeping track of Great Lakes water levels longer than the Army Corps of Engineers has, some dating back to about the 1860s,” Kompoltowicz said. “Whether they’ve done it consistently, on a monthly basis, I can’t say. I think most of them have relied on a single gauge at a certain location. The Army Corps of Engineers uses multiple gauges at various locations. A potential problem with using just a single gauge is that factors such as wind direction can affect readings.”

According to the U.S. Geological Survey, the recorded levels have been affected not only by natural causes, but also by government regulation. Water levels in Lake Superior have been regulated since about 1914 and levels of Lake Ontario have been regulated since about 1960. For example, according to the agency, unregulated Lake Michigan-Huron and Lake Erie had extremely high-water-level peaks in 1929, 1952, 1973, 1986, and 1997, and extremely low levels in 1926, 1934, 1964, and 2003. But some of those extreme levels, especially the lows, were muted in Lakes Superior and Ontario after regulation began.