It's Spring time, and the warmer temperatures mean this is the time of year when harbors along the Great Lakes thaw and shipping begins.
But many shippers say they're frustrated over low water levels, which are forcing them to lighten their loads so they can move safely into harbors.
Great Lakes ships carry 10% of the country's waterborne cargo. A warmer-than-normal winter this year means more evaporation, because the lakes weren't protected by ice cover.
A spokesman for the Lake Carriers' Association says the federal government can't keep up with needed harbor dredging.
The group says that ships have to cut their loads between 50 and 270 tons for every inch the lakes recede.