Marine erosion is shrinking the delta, an environmental assessment workshop in Yangon heard last month, while the Ayeyarwady River is becoming increasingly clogged with sediment, reducing its flow.
About 13 square kilometres (5 square miles) of land along the Aye-yarwady coast are being lost each year – a trend that remained steady from 1990 to 2006, according to U Maung Maung Aye, an expert in fluvial geomorphology.
Natural and manmade changes along the Ayeyarwady’s length have also left the river clogged with sediment – 330 million tonnes a year, researchers estimate, compared to 261 million tonnes in the 19th century.
As a result, U Maung Maung Aye told a workshop last month, the “discharge of our mighty Ayeyarwady has significantly decreased over the past 100 years”.
A retired rector at the Yangon University of Distance Education, U Maung Maung Aye is now chief adviser at the Myanmar Environment Institute. He said his conclusions were based on a long-term analysis of aerial photos, ground photos and geographical maps.
As the river silts up, he said, people living in the delta face greater difficulties earning their living.
“The chain reaction of damages to the river system will affect agriculture, biodiversity and the ecosystem that locals depend on for their livelihood,” he said.
Speaking at the workshop, a resident of Kyaw Zan village group, in Ayeyarwady Region’s Mawlamyinegyun township, said that one of the branches of the Ayeyarwady River in the delta area, the War Rakhine river, has become heavily silted.
“War Rakhine river was quite a big river and an important transportation link between Yangon and Kyaw Zan for large ferries over last 50 years,” he said. “Now the river has silted up and changed to a small creek. Only small boats can pass during summertime.”
Other small river branches nearby had also dried up, he said. “These changes delay the fresh water flow and increase salt intrusion, which affects drinking water and growing summer paddy.”
He blamed improper disposal of polluted water from rice mills and other local businesses, as well as pesticides and chemical fertilisers from farms, for the reduction in volume of the river’s flow. The destruction of mangrove forests in the area had also hastened the degradation of rivers and creeks in the village group, he said.
While there are a number of theories, the exact factors in the decline of delta waterways are unclear.
U Soe Myint, retired director general of the Ministry of Transport’s Department of Water Resources and Improvement of River Systems, said lack of conservation programs has led to the “degradation” of the Ayeyarwady River.
“Water levels have significantly decreased since 1998,” he said, “but we don’t know why because there has been no research on it.”
This lack of study is something U Maung Maung Aye aims to correct.
“The Ayeyarwady is our national river. It is very important for our country. We can say the history of the country has developed based on that river. But we don’t have systematic research and data … This is the huge need for our country.”
Research should take a “holistic approach” to the whole river basin, U Maung Maung Aye said. He suggested a National Commission for the Development of Ayeyarwady Basin be formed, to bring together experts from various sectors in support of sustainable development along the river.