Ships hauling less as water levels drop in Great Lakes

Green Bay Gazette: Low water in both Green Bay and the Fox River, apparently caused by a combination of long-and short-term natural effects, could end up costing the local economy. "For every inch of water missing — and we're down 22 to 24 inches — that 1 inch equals 100 tons that can't be put on a ship," Brown County Port Director Dean Haen said. "So ships are carrying only 15,000 to 16,000 tons, when they used to carry from 18,000 to 20,000. "All the other costs of the shipping are the same — the same labor, the same amount of fuel. So the cost per unit of what you're hauling goes up. It's resulting in more ships, because they've got to come more often."

Lakes Michigan and Huron are inches from record lows, and the other Great Lakes are down, too. Some experts blame global warming or climate changes; precipitation is down, and with warmer temperatures, there's less ice coverage, so evaporation is faster. There's also a theory that the dredging of shipping channels in and around Lake St. Clair has caused Michigan and Huron to drain more rapidly than rain and snowmelt can replenish.

…The Fox typically would be higher than normal this time of year as the Army Corps of Engineers does its seasonal drawdown of Lake Winnebago, Foster said. With more water being let through, water levels should be higher, he said. But drought has affected water levels throughout most of Wisconsin, and that likely is contributing to low water in the upper Fox, he said. Recent high winds also are a likely contributor.

The winds can cause a seiche effect (pronounced "saysh") — a shifting of water mass that lingers even after the winds die down. "In the Lake Michigan area, we've had strong wind blowing out of the north and northwest for an extended period," Foster said. "That can push all of the water down toward Chicago." That's been true regionally, too.

…"In a worst-case scenario, you load your ship to a certain depth and find out there isn't enough water, so you've got to sit out in the lower bay and wait," he said. "That's not happened recently, but it happened last fall, where a ship had to drop anchor and just wait. Those ships operate at $1,000 an hour, so you sure don't want to drop anchor for a 24-hour period."