A key Canadian shipping corridor is the latest waterway struggling with dwindling water levels.

Parts of the St. Lawrence River near Montreal have hit 10-year lows, said Bryce Carmichael, hydraulic engineer and U.S. section secretary for the International Lake Ontario-St. Lawrence River Board. Seaway managers in 

Canada and the U.S. are monitoring the conditions and considering boosting the flow of water from Lake Ontario to make conditions safer for commercial ships, according to Carmichael.

“Right now, we’re expecting two to three weeks of lower levels,” he said.

The shrinking water levels in Canada come as closures on the Mississippi River threaten exports of corn and soybeans just as farmers are in the thick of harvest, threatening to cause a buildup of supplies. The phenomenon has also hit Europe and China, where the Rhine River and Yangtze shrunk this year.

River levels on the St. Lawrence have “decreased considerably” and the latest forecasts by the Canadian Coast Guard call for further drops, according to a customer bulletin from global shipping line Hapag-Lloyd AG. The company has increased rates to move cargo to and through Montreal’s port until November 1.

“It’s been very low for a while,” said Frank Seglenieks, Canadian co-chair of the International Lake Ontario-St. Lawrence River Board of Control, noting the basin has been dry this spring and summer, impacting water levels. “In general, when we have lower water levels ships do have to lighten their loads.”