This year's water quality index at three main rivers in Southern Viet Nam has improved since 2013 and 2014, the conference "Rivers and Challenges" reported yesterday in Ha Noi.
The water quality index of the Dong Nai, Sai Gon and Vam Co rivers has improved considerably, said Tran Thi Le Anh, from the General Department of Environment, at the conference jointly organised by Viet Nam Rivers Network and the ministries of Agriculture and Rural Development and Natural Resources and Environment.
However, Anh said, tests revealed the increase of organic substance pollution in some areas and solid pollution at Thac Mo lake (Dong Nai River) and in the middle stream area of Vam Co River.
Tests also revealed an increase of microorganism pollution in the middle stream area of Sai Gon River. Microbiological water pollution is usually a natural form of water pollution caused by microorganisms. Scientists and environmental managers at the conference raised red flags over water environment management in river valleys.
At the conference, a research group of the Ha Noi-based Centre for Sustainable Development of Water Resources and Adaptation to Climate Change (CEWAREC) reported that the Hong River section that crosses Ha Noi had changed considerably in recent years with the construction of new urban areas along both banks of the river.
The group's survey was carried out from June to October 2015 in the two districts of Dong Anh and Long Bien.
Doctor of Environment Dao Trong Tu from CEWAREC said, "Via field work and data surveys, we witnessed that the transgression of residential houses along the two riversides and illegal sand exploitation makes the river section crossing the city worse."
The main cause of riverside erosion could be attributed to a change in the stream flow during flood season, causing it to collide with concrete and stone blocks of illegally-built residential districts, Tu said.
Hai Boi Commune (Dong Anh District) and Ngoc Thuy-Bo De Ward (Long Bien District) have been seriously impacted by riverside erosion.
Tu said efforts must be enhanced to inform communities along Hong River banks about river protection and sustainable development.
"The city authorities need to have a comprehensive analysis about the influence of human activities to Hong River's water quality," Tu said.