Shallower Great Lakes mean multi-million dollar losses for shipping companies whose more profitable, fully-loaded cargo freighters run the risk of running aground.
The New York Times of October 22nd and other media have provided useful formulas to translate the falling water levels in the Great Lakes to economic losses suffered by cargo shippers - - which is also bad news for the buyers and users of the goods moving on those ships, too.
The Great Lakes are under great stress from warming temperatures that have led to water loss through evaporation, and also from leakage from channels, through to the St. Lawrence Seaway to the Atlantic Ocean, from suspect dredging by the US Army Corps of Engineers.
Studies are underway to ascertain the extent of the dredging damage and costs to repair it, though that remediation does not address other causes of falling levels.
As as you read about the Great Lakes falling an inch or more, remember the formulas below and don't get fooled into thinking that an inch here and there is insignificant:
For every one-inch drop in water levels:
- A Great Lakes freighter leaves 540,000 pounds (270 tons per shipload) of cargo on the docks.
- And costs that ship's owners between $35,000-$45,000.
Here are relevant paragraphs from the Times story.
"Water levels in the Great Lakes are falling; Lake Ontario, for example, is about seven inches below where it was a year ago. And for every inch of water that the lakes lose, the ships that ferry bulk materials across them must lighten their loads by 270 tons — or 540,000 pounds — or risk running aground, according to the Lake Carriers’ Association, a trade group for United States-flag cargo companies.
"As a result, more ships are needed, adding millions of dollars to shipping companies’ operating costs, experts in maritime commerce estimate."A separate report by the Canadian Broadcasting Corporation, citing US shipping sources, comes up with the dollar figure.
This problem has become acute on Lake Superior, where new rock islands are protruding near the shoreline and freighters have to ride higher in the water to avoid striking them.
The full Times story is here, which focused on Oswego, New York, where water level declines have not been as dramatic as they are on Lake Superior, where levels have fallen more than three feet since 1999 and are at historic, measurable lows.
Coal shippers carrying supplies to power plants have also indicated that their Great Lakes loads are running lighter: a workable analogy is the inefficiency of flying airplanes with empty seats, something the airlines are loathe to do.
So it's hardly smart policy and good economics to add new large users to the lakes - - such as an expanded Murphy oil refinery in Superior, or out-of-basin communities looking to divert water - - as water levels are on the decline.
All the more reason to press the Wisconsin legislature to adopt a strong Great Lakes Compact because the eight-state agreement establishes first-even rules and standards for diversions and water conservation planning - - all designed to minimize more water losses in the Great Lakes basin.