Environment groups in Chiang Rai province have voiced serious concerns over a plan by the Chiang Rai municipality to dredge sections of the Kok River, fearing that the work could adversely impact the river’s ecosystem and its tributaries.
Somkiat Khuanchiangsa, president of the River for Life Association, an environmental advocacy organisation, explained that the Kok River ecosystem is divided into two parts. One lies in Myanmar and the other in Thailand, stretching from Tha Ton to Chiang Mai, with more than 30 tributaries flowing through mountains, rock formations and sandy beaches before passing through the city and draining into the Mekong River in Chiang Saen district.
Somkiat Khuanchiangsa
He said dredging the riverbed would remove sediments and deepen the river only temporarily because sediments carried by the river would pile up again in a matter of months due to a weir blocking their onward flow.
He also questioned where the dredged sediment, contaminated with heavy metals from gold mining operations in Myanmar, would be disposed of to prevent toxic substances from contaminating the environment.
Dr Suebsakun Kidnukorn, a lecturer at Mae Fah Luang University, said the Kok River is currently contaminated with more than nine types of heavy metals and that sediments dug from the riverbed and piled up on the shore may threaten the environment if not properly disposed of.
He suggested that the Chiang Rai municipal administration and the Pollution Control Department rethink the project.
The municipal administration believes, however, that the dredging project is necessary to deepen the river and improve water flow following the devastating 2024 flood, when the Kok River breached its banks and overwhelmed Mae Sai district with muddy water.
The dredging is estimated to cost about 223 million baht and will be conducted in four sections of the Kok River. The first section covers 13km, the second about 520 metres, while the third and fourth sections cover distances of 1.7km and 2.1km respectively.
Many food shops once located along the Kok River in Mae Sai district have closed after tourists disappeared due to concerns over contamination of the river and the fish caught in it.
