The spring runoff did little to counter the effec ts of evaporation. It could be the most radical three-year decline ever. Since the summer of 1997, the water levels on lakes Michigan, Huron and Erie have fallen 3.5 feet and are receding at a pace that could soon hit all-time lows. Lake Superior is down about 8 inches. Low water levels, in turn, have led to problems for carriers, forcing many ships to lighten their loads to avoid running aground in suddenly shallower waters.
Lighter loads mean less efficiency and, bottom line, the transport of less cargo.
Weather permitting, we expect fewer laker layups in December and more traffic than usual in January. Nonetheless, we can move only so much cargo in our defined shipping season. Great Lakes levels are affected by natural and man-made factors. The largest are evaporation and precipitation. Water levels were generally within inches of record high levels during 1997, following two years of above-normal rain and snowfall, especially on the Lake Superior basin.