Cambodia’s Prime Minister Hun Manet on Monday launched a controversial $1.7-billion canal project that aims to provide a new link from the Mekong River to the sea.

At a launch event in Prek Takeo, southeast of the capital Phnom Penh, Manet called the 180-kilometer (110-mile) project “historic,” as drums sounded and fireworks shot into the air.

The event was attended by thousands wearing t-shirts bearing images of Manet and his father Hun Sun, who ruled the country for nearly four decades.

“We must build this canal at all costs,” said Manet, who drew cheers as he launched the project by pressing a ceremonial button with his wife Pich Chanmony.

The Funan Techo canal will run from a spot on the Mekong river, about an hour’s drive southeast of Phnom Penh, to the sea in the Gulf of Thailand and is due to be completed in 2028.

Around a third of cargo coming to and from Cambodia uses Vietnamese ports via the Mekong, but authorities hope this number will fall to around 10 percent once the canal is completed.

The limited capacity of the waterway — 100 meters wide and 5.4 meters deep — has raised questions about whether the lofty economic goals can be reached.

The project also comes shrouded in uncertainty, including its main purpose — whether for shipping or irrigation — who will fund it, and how it will affect the flow of the Mekong — one of the world’s longest rivers.

Conservationists have long warned that the river, which supports up to a quarter of the world’s freshwater fish catch and half of Vietnam’s rice production, is at risk from infrastructure projects, pollution, sand mining and climate change.

Cambodia, Laos, Vietnam and Thailand are signatories to the 1995 Mekong River Agreement, which governs the distribution of the river’s resources.