America's promised bounty of LNG exports could be at risk if ship channels aren't properly maintained, a government official has warned.

Melanie Kenderdine, director of the Office of Energy Policy and Systems Analysis at the US Department of Energy (DoE), said that government budget constraints are preventing the US Army Corps of Engineers from keeping federal channels dredged to their authorised widths and depths.

"It's an ongoing problem in the Gulf of Mexico, because ports silt up quicker there than in other ports," Kenderdine told an audience at the Center for Strategic & International Studies in Washington, DC, on July 14.

She noted that LNG exports are particularly vulnerable due to silting in the Calcasieu Ship Channel, which connects Lake Charles, Louisiana, to the US Gulf of Mexico. The channel can only accommodate one-way traffic - not two-way, as would be the case if the channel were maintained to its proper width and depth, Kenderdine said.

She pointed out that DoE has given final approval to 9.9 billion cubic feet per day (roughly 70 million tonnes per year) of US LNG exports - much of which will be moving through Lake Charles-Calcasieu Ship Channel system.

Kenderdine said that her department supports finding "innovative funding mechanisms" to make up for dredging budget shortfalls versus increasing the Harbor Maintenance Tax.

"Maintaining our waterways and ports is essential to energy reliability, security, and commerce," she said.