– High water on the Great Lakes is delaying the start of the international shipping season, potentially costing companies millions and disrupting supply chains.

The locks that allow travel between Lake Ontario and the St. Lawrence River won’t open until April 1, nearly two weeks later than anticipated. The Ottawa-based Chamber of Marine Commerce, which advocates for shipping on the St. Lawrence Seaway, says that could delay up to 100 ships.

The Port of Duluth-Superior relies first on the Soo Locks — which is still scheduled to open on time on March 25 for domestic shipments — to get shipments in and out of Lake Superior, but officials say a lack of reliability in the system can hurt long-term prospects.

“Delayed shipments and uncertain system availability will result in lost business that may not return,” Deb DeLuca, executive director of the Duluth Seaway Port Authority, said in a statement Wednesday. “Shippers would seek alternative supply routes and supply chains, potentially resulting in permanent traffic loss for U.S. and Canadian ports, an outcome that would cause substantial, far-reaching and long-term damage to the entire Great Lakes region.”

Last year the port had 85 overseas vessel visits, the most since 2010. The first international visits, when on schedule, don’t arrive until early or mid-April.

DeLuca added that high water levels are “concerning for all involved, from perspectives of navigability, property damage, and economic and community resiliency.”

With low ice coverage, the Montreal-Lake Ontario section of the seaway could have opened as early as March 20. Water needs to be let out of the Moses-Saunders Power Dam to lower the lake’s level and prevent flooding, however, which can make it unsafe for ships to travel.

Several lakes are currently at record-high water levels, and others remain well above average, causing problems for coastal communities and the shipping industry.

“This dam is a very limited tool that does not solve this problem,” Chamber of Marine Commerce President Bruce Burrows said Wednesday. “We need to work together to develop a much broader, holistic resiliency plan that looks at every avenue including flood zoning, shoreline resiliency and infrastructure investments.”

The Welland Canal, which connects Lake Ontario and Lake Erie, is scheduled to open March 24.

By then, the Army Corps of Engineers expects water levels to rise at least an inch on all the lakes except Superior, which should drop an inch.

Lakes Michigan, Huron and Erie were all 5 inches above recorded monthly highs as of Feb. 21.

Burrows said that delaying or shutting down shipping traffic should “never be an option.”

“It’s time for politicians to start working with all the affected residents, businesses and shipping stakeholders on smart, effective solutions for high water levels.”