Canadian shipping has clear passage while Mississippi cargo could be stuck high and dry before the end of the year as the worst drought in half a century reduces water levels across the continent.

Depths on the Mississippi and across the Great Lakes are approaching record lows, but because of geographic differences and a key winter shipping hiatus north of the border, shipping in Canada isn’t facing the same crisis that has businesses and politicians across the border scrambling for quick solutions.

The U.S. Army Corps of Engineers is blasting rocks in shallow parts of the river because there is no water in the reservoirs left to release.

“We’ve never really had a drought quite so severe as this year,” said Bob Anderson, spokesperson for the Mississippi Valley division of the Army Corps of Engineers.

Barges on the Mississippi have had to lighten their loads, reducing underwater draft by three feet to get through a shallow stretch of the river between St. Louis, MO and Cairo, IL.

But on this side of the border, ships called lakers on the Great Lakes-St. Lawrence Seaway have only cut their drafts by six inches for the final two weeks before the shipping season closes.

“Water levels until recently did not constrain shipping on the Seaway to any extent,” said Andrew Begora, spokesperson for the Seaway. “The effect on the Great Lakes Seaway has been very modest. We have not had in any way the same impact that has held true on the Mississippi,” he said.

Environment Canada reports current water levels on all the Great Lakes except Erie are well below average, with the lowest levels on Lake Michigan and Lake Huron since records started being kept in 1918.

The U.S. Army Corps of Engineers says levels on the Mississippi system are tying or surpassing historic records for this time of year set in 1940, before the system of reservoirs was set up to regulate flow.

The U.S. Weather Service predicts that without significant rainfall, the Mississippi will fall to nine feet — the level at which traffic is impeded — by December 26.

That is around the time that the Canadian shipping route will close for the year. When the seaway opens again sometime next March, water levels will be higher with spring run-off.

But that’s not to say that Canadian shipping hasn’t been affected.

“The lower water level in Great Lakes & St. Lawrence Seaway has a big impact on the larger ships,” wrote Paulo Pessoa, Vice President of McKeil Marine Ltd, which ships cargo throughout eastern and central Canada. “Lower water levels are usually a commercial issue, hitting the ship owners' bottom line,” he added in an email to the Star.

For a typical laker that carries 26,000 tonnes of cargo, each inch of draft translates to 100 tonnes of cargo. Under the shallower draft regulations, shippers will have to run 600 tonnes lighter, he wrote.

Shipping remains a far cheaper method of transport than trucks. On the Mississippi, one barge carries the equivalent of 60 truckloads of cargo and a tow can incorporate as many as 35 barges or 2100 truckloads.

On the Seaway, a typical laker carries the equivalent to 870 highway tractor trailers or 225 railroad cars.

According to official statistics, 37.5 million tonnes of goods passed through the Seaway in 2011 — a rise of 2.5 per cent over the previous year.

The Army Corps of Engineers reports the Mississippi River System carried 601 million tonnes of cargo in 2011.

While worries about low water levels have pushed the Americans into action, with work being carried out up and down the Mississippi to ensure the future of shipping on the river, Canadian shipping isn’t feeling the same threat.

Satellite technology and bottom imaging is allowing ships to chart the best course through the deepest waters. Begora says even with lower water on the Great Lakes, ships are actually running heavier on average than they did 10 years ago.

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Extreme weather is becoming more common, and implications for shipping on the Mississippi are great.

Only last year, the Mississippi experienced record flooding, forcing the army corps to blow up a levee to reduce pressure.

“We’re starting to have 100 year floods and 100 year droughts twice a decade,” Anderson said.

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