A US government watchdog recommends improved oversight of assets in the Great Lakes and St. Lawrence Seaway.
A US Government Accountability Office report looks at challenges facing the waterways, where commodities traffic has declined but boxship and passengership presence has risen.
Problems include rising pilot costs, ageing locks, inadequate infrastructure and a decline in US manufacturing.
"We reviewed modernization efforts and found that US agencies have completed almost $100 million in projects to improve locks over the past decade," the report said.
"We recommended better monitoring of the challenges and assessment of improvement efforts."
The Army Corps finished 18 projects worth $53m, and has $257m in work through 2035.
The US Seaway Corp has completed 16 projects totaling $45m and has almost $144m in work through 2023.
The Great Lakes-Seaway system extends 2,300 miles and serves more than 100 US and Canadian 100 ports through 17 locks, four of which are managed by the US.
A 2007 US-Canada study noted the system could handle more traffic and led to US renewal plans to improve lock infrastructure.
