Dirt built up at the junction of the Tonle Sap and Mekong rivers has changed the flow of the rivers, causing river banks to collapse, disturbing fish migrations and damaging aquaculture projects, according to the Mekong River Commission.
The organization recently launched a project studying the impacts of the soil buildup on the region and its possible removal.
The area, known as the Chaktomuk Junction, controls the distribution of water between the Mekong, Bassac and Tonle Sap rivers.
As river erosion causes dirt to build up, the junction is moving downstream at a rate of 10 meters per year, according to the commission.
The buildup has reduced the number of large ships able to reach Phnom Penh port and has caused flooding and sewage problems in Phnom Penh. The change in river currents is also threatening the Monivong bridge. At least one pillar of the bridge could collapse if action is not soon taken, said Hong Sinnara, director for the Chaktomuk Project Management Unit in the Ministry of Public Works. The bridge collapsed under similar circumstances in 1964.
“We want good routes for fish migration from the Mekong entering the Tonle Sap and ship navigation along the river,” Hong Sinnara said.
The 14-month study, a joint effort by the MRC and several ministries, is being funded through a $500,000 grant from Japan. The research team will be studying stretches of the three rivers upstream and downstream of the junction and will be analyzing fisheries statistics and interviewing local fishermen.
Joern Kristensen, the MRC’s chief executive officer, stressed the importance of gathering reliable data before altering the river junction. “A wrong decision for works in the Chaktomuk area is irreversible and can cause great damage to the environment upstream and downstream,” he said. He said the commission will propose a plan for the area only after comprehensive environmental and social impact assessments.