The tourist town of Vang Vieng sits along the Xong River in northwestern Laos' Vientiane province in a file photo.

The Lao-Chinese railway project has released polluted water from construction work into the Xong River in Vientiane province’s Vang Vieng district, one of the most popular destinations in the country for tourists, a local resident and an environmental official told RFA’s Lao Service.

Workers allowed polluted runoff from a tunnel construction site along the railway to flow into the river for two to three months after the work had been completed in Vang Vieng, located about 150 kilometers (93 miles) north of the capital Vientiane, said one district resident who declined to give his name out of fear of retribution.

“We have seen the railway project releasing the polluted water to the river, so people do not want to bath in the river,” he said, calling on relevant officials to take samples of the muddy water to test it for possible contamination.

Officials have acknowledged that the release of wastewater from the railway project has caused pollution.

An official from Vientiane province’s Department of Natural Resources and Environment, who declined to be named because he is not authorized to talk to the media, told RFA on Nov. 9 that polluted water flowed down to the river after the Chinese companies working on the project dug deeply into the ground while carving out the tunnel.

“Now we are planning to find a solution for this by storing water in one place so that we ensure that the polluted water is blocked from flowing to the river,” he said.

“In addition, we will check wastewater released from hotels and restaurants along the Xong River,” he added.

Vang Vieng, which sits beside the Xong River amid karst hills that surround the area, bills itself as an adventure travel hub replete with opportunities for tubing, kayaking, caving, zip-lining, hiking, and rock-climbing.

“If the authorities manage the activities, keep the river clean and limit the noise, the destination will have a bright future and enjoy the benefits of tourism for a long time to come,” Inthy Deuansavan, president of the Vientiane-based travel agency Green Discovery, told CNN Travel in October.

Besides the environmental impact of the U.S. $6 billion Lao-Chinese railway, whose construction began in December 2016 as part of a longer rail line that will link China to mainland Southeast Asia, the project is forcing the relocation of upwards of 4,400 families in Laos.

Fewer than 150 families have received compensation for homes and farmlands lost to the railway project, but have yet to see any money for lost livestock and fruit trees.

Lao law requires that citizens who must give up land to development projects be compensated for lost income, property, crops, and plants. And project owners must guarantee that living conditions for those displaced will be as good as, or better than, they were before the project began.

Plans now call for work on the railway to end in 2021, with Chinese companies promising completion by that date despite the challenges of boring tunnels in mountainous areas of the country’s north.

Reported by RFA’s Lao Service. Translated by Ounkeo Souksavanh. Written in English by Roseanne Gerin.