River Siang
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Pollution
2017: China is the primary suspect
The crystal clear waters of the Siang river, one of the major constituents of the Brahmaputra and lifeline of northern Arunachal Pradesh for centuries, has suddenly turned black triggering panic in the frontier state. The East Siang district authorities have pressed the alarm bell as the water of the river, containing large volumes of heavy slag, is no longer fit for consumption. “The water can’t be used for any purpose because it contains a cement-like thick material. A lot of fish died one and half months ago,” said East Siang district deputy commissioner Tamyo Tatak.
He added, “In the last monsoon season, the river turned dark and we thought that it was because of mud being carried by the river. The rainy season is long over but the river water is still black. Usually, from November to February, the water is crystal clear and pure.”
Tatak said water samples have been collected and China is the primary suspect. “It seems that some major cement work is on in the upper reaches of the river in China… may be China is carrying out some deep water boring work. What else could be the reason for such a big river remaining black for nearly two months,” Tatak said.
Brahmaputra also affected
The Centre is closely monitoring the unusual change in the waters of the Siang river in Arunachal Pradesh — which flows from southern Tibet as the Yarlung Tsangpo and as the Brahmaputra in Assam — which has now spread downstream to the Brahmaputra. The colour of the water has gone from crystal to black with the presence of slag in the stream.
“We are observing the black colour of the Siang river right from its entry point in India at Geling in Upper Siang district on the international border,” a central government source said. There are reports of several varieties of fish dying in the Siang, which is an aquatic life hotspot. “The change of colour has now been observed in the Brahmaputra river as well in the downstream reaches,” the source added.
The Siang flows more than 500 km in China. After joining the Lohit river, also from China, it becomes the Brahmaputra in Assam. The waters have turned dark in Dibrugarh town as well. Dibrugarh is at a straight line distance of 77 km from Pasighat in East Siang district, where the Siang’s water is darkest. The Central Water Commission (CWC), responsible for monitoring water level and quality of all rivers in the country, has also observed a change of colour as far as Tezpur and Guwahati in downstream areas.
The CWC started monitoring the blackened Siang from November 18, the source said. It will soon engage other departments, including ISRO, to find out why this is happening, the source said. “There was an earthquake in eastern Arunachal Pradesh on November 17 and initially we thought that there must have been landslides which might have blocked the Siang river. But the dark colour has remained the same and is still continuing. We can’t conclusively say anything now,” the source added.
“As of now, we cannot come to any conclusion about the cause for this unusual change. We don’t know what the situation is across the border (in China) as we don’t have jurisdiction over the river and its quality there. If necessary, Indian government has to take help from the Chinese government,” the source said.
No toxic content in Brahmaputra water: CWC
Prabin Kalita, December 16, 2017: The Times of India
The Central Water Commission (CWC) has found no evidence of China diverting the waters of the Yarlung Tsanpgo, which flows through southern Tibet into India, first as the Siang in Arunachal Pradesh and then as the Brahmaputra in Assam, to build dams.
It also has been unable to conclude why the Siang has turned black due to a cementlike slag flowing from across the McMahon Line for over a month now.
The contamination has also been noticed in the Brahmaputra at various places in Assam. Water samples of the Siang sent to the CWC laboratory in New Delhi have tested negative for toxic content. “We were worried about the possibility of toxic content but with the negative results now the water is still fit for human consumption after proper filtering,” a central government official said.
