Record low water levels for this season on the Upper Great Lakes are creating concern for commercial shipping lines.
Jim Weakley, president of the Lake Carriers Association representing the U.S. flagships on the Great Lakes, estimates that 75 per cent of their ships are carrying less cargo than they could if they had appropriate water levels.
He has noticed a decline since approximately 1998, when water levels peaked.
The U.S. flagships generally travel in the upper four Great Lakes.
“Every inch of water we lose for the 1,000-foot boats, is about 250 to 270 tons per inch of water,” Weakley says. “For smaller boats, it is about 100 to 150 tons of cargo they give up per inch of water loss.”
Lightening loads leads to a big inefficiency in the system. It requires more trips using more fuel, manpower and time.
Wayne Smith, vice president of marketing and vessel traffic for Seaway Marine Transport, says they have been impacted by the lower levels, but not dramatically, yet.
“For the water levels to be this low for this time of the year, I think, certainly, we are concerned. From here on in (Oct. 13) we’re going to be carrying below our target levels.”
Environment Canada’s website (Level news) states water levels on each of the Great Lakes have fallen at a rate faster than average so far this year, since attaining their seasonal highs during the first week of August. Lake Superior’s level is 38 centimetres below beginning-of-month average (1918-2005) for October; and lakes Huron-Michigan are 49 cm below. The other lakes’ declining levels are not as severe.
These sharp declines have ship owners and carriers wondering what the lake levels will be like in the spring, if they are already lower than average for the fall of this year.
Tim Heney, CEO of the Thunder Bay Port Authority, aware of the cyclical nature of water levels in Lake Superior, says they are usually low in the spring, come up in the summer and then trail off again into the winter.
“Already (they) have trailed off back to where they were in the spring,” he says. “What concerns us is where is it going to be in the spring, if it is this low now?”
The waters of the Great Lakes Basin have been described as part of a natural and cultural heritage to the regions of Ontario, Quebec, and eight bordering states in the United States.
Despite the vastness of this non-renewable resource, the International Joint Commission’s final report says less than one per cent of Great Lakes water is renewed annually by precipitation, surface water runoff, and inflow from groundwater sources.
Consequently, water levels can fluctuate from 30 to 60 cm in a single year.
Both the Canadian Hydrographics Service and the U.S. Army Corps of Engineers publish monthly bulletins on their websites comparing current with past record low and high water levels, and the average levels as well as a six-month future forecast.
Even though the upper lake levels are unseasonably low, they are not at historic lows.
Thunder Bay’s Port Authority harbour master Guy Jarvis and Heney attribute Lake Superior’s low level to a dry spring and summer.
“There was 80 per cent less precipitation than the average,” Jarvis says. “There has been very little snow fall and snow melt, so all the rivers that flow into Lake Superior are low to begin with.”
During the winter months, ice cover on the lakes reduces evaporation. If global warming is a factor, warmer temperatures will diminish ice cover, thus, increasing evaporation. Warmer summers also result in warmer water and more evaporation in the fall.
So far, Heney says they have not seen “anything too dramatic yet,” with respect to ships lightening their loads, because Thunder Bay’s harbour is naturally deep.
“Everybody is getting what they want,” Jarvis says, but that may change if water levels continue to drop.
Ports are continually monitoring water depth for changes. Heney says port authorities have been performing surveys of the harbour to determine the proper dredging program, which he expects will be undertaken next year in order to make sure Thunder Bay isn’t a restriction in the seaway.
“They haven’t dredged here in a long time, but they are looking at it now,” he says.
Costs for dredging harbours are the responsibility of the port authorities.
Individual elevator slips or ports where ships load and unload commodities are maintained by the company stationed at the slip. If low lake levels continue to persist, more dredging will occur in order to accommodate shipping.
As shorelines increase, other problematic areas throughout the Great Lakes are the channels and rivers, such as the St. Mary’s River in Sault, Michigan, St. Clair and
Detroit Rivers, and the Welland Canal. Often referred to as bottlenecks, the Welland Canal’s 26-foot six-inch draft (how deep the ship sits in the water) is the restricting point.
Most of the lakers travelling the Great Lakes are designed with the Welland Canal in mind; consequently, they have not had adverse affects to date.
Tom Brodeur, vice president of marketing and customer service for Canada Steamship Lines, says they do a lot of trading through the St. Lawrence River where they are restricted by the seaway draft. So lightening loads has not impacted trades in that area.
However, they are affected on trades in certain ports in lakes Huron and Michigan.
Many factors come into play in commercial shipping, such as the size of the ship, type of cargo, the port, and the season. The average laker ranges in length from 700 to 740 feet and approximately 120 to 140 tonnes an inch. The American U.S. flag ships are larger at 1,000-feet long. Brodeur says loads like salt and stone are deadweight trades, which affect how the ship will carry the load.
“You have different times in the season when you have midsummer draft, summer draft, intermediate draft, and winter drafts,” he says, explaining some companies have commercial agreements in place to cover some of the concerns of low water.
At the time of the interview, the low water levels had not affected the fleet, because much of their trade is governed by the draft in the Welland Canal.
“It hasn’t been an impact,” he says. “If water levels continue to go down, then it will have an impact.”
In an attempt to address low lake level concerns, Canada Steamship Lines use technology such as bathymetrics, to take an underwater profile of the bottom of a river, providing a truer picture of the depth. With the U.S. Army Corps of Engineers and others, knowledge of true depth allows selective dredging in higher spots, saving costs.
“We’re being squeezed by two things: the natural reduction of water levels and the lack of dredging,” Weakley says, adding the Army Corps of Engineers has not been funded within the Great Lakes region to maintain the waterways both at the connecting channels and the harbours. He estimates they are about $200 million behind where they should be with respect to dredging in ports and channels.
“We are actively engaging with the Army Corps of Engineers and with our congressional representatives to try and increase the amount of dredging . . . so we can have the deep water where we need to,” he says.
Until then, companies involved in commercial shipping on the waterways will be hoping for a cold winter, solid ice cover on the lakes, and a lot of precipitation to replenish water levels.
