In November 2017, the Siang turned dark with sediment, so much so that fish and animals were dying. As the turbidity of the river began before it entered the Indian territory, there was much speculation about Chinese activity being behind the change which prompted political leaders from the region to write to Prime Minister Narendra Modi requesting him to take up the matter with China.
While several scientific studies in subsequent periods held an earthquake of 6.4 magnitude on the Richter scale in Tibet as a strong reason for generating enough dirt to turn the colour of the water from crystal clear to black, there had been no official version so far.
On August 29, 2018, China alerted India of a massive cloudburst in Tibet that forced the Chinese authorities to release more water down the Brahmaputra than at any time over the last 50 years. The discharge was measured at 9,020 cubic metres per second (cumec) at 8 a.m. on August 29 and led to huge waves on the Siang in Arunachal Pradesh. Eyewitness said the wave heights at up to four metres, uncharacteristic of a river.
China warned India about the release in the trans-boundary river – known as Yarlung Zangbo in China – and Assam and Arunachal Pradesh were put on high alert for floods. The district administrations of East Siang in Arunachal Pradesh, and Dhemaji and Dibrugarh in Assam had sounded alert of deluge due to unprecedented rise of water in Siang River, creating panic among the people living in downstream Assam.
Tamiyo Tatak, the Deputy Commissioner of East Siang district in Arunachal Pradesh, sent out a warning the same day, asking people “to refrain themselves from venturing into Siang river for fishing, swimming etc. to avoid any eventualities.”
The Yarlung Zangbo takes the name of Siang as it enters India at Geling in Upper Siang district. Two other rivers– Lohit and the Dibang –join the Siang at Kobu Chapori in Assam about 30 km downstream of Pasighat, which is about 230 km from the international border to form the mighty Brahmaputra.
Downstream, the Assam State Disaster Management Authority (ASDMA) warned the Dibrugarh district administration in the eastern part of the state to be on high alert on August 30.
Indian Air Force helicopters rescued 19 people stranded on an island in the Siang in the Sille-Oyan area on the morning of August 31.
Early warning a must to cope with floods
Indian authorities were able to prepare for this 50-year high in Brahmaputra water discharge well in advance because of early warning by the Chinese counterparts. The trans-boundary cooperation on hydrological data sharing that was stopped after the Doklam face-off, resumed between the two countries this May under a Memorandum of Understanding (MoU).
Early warning is must to cope with floods and people along the Brahmaputra heaved a sigh of relief as authorities in Assam and Arunachal geared up to face any eventualities. This simply did not happen in the preceding weeks, when people in Kerala or in Nagaland and Assam were caught off guard in some of the worst man-made disasters.
This year the Meteorological Department has been warning of a deficit monsoon and there prevailed a drought-like situation in many parts of upper Assam. In the eastern part of the Golaghat district villagers resorted to the age-old practice of Bhekulir biya (marrying of frogs) to satisfy the rain gods! When conditions were such, the news of the Dhansiri river breaking the highest flood level mark at Numaligarh in Golaghat district in the early hours of Aug 2, 2018 not only confused the weather forecasting authorities, but caught almost a million people off-guard. It was simply unprecedented.
Going by the IMD’s daily district level rainfall, there has not been unprecedented rainfall in the Dhansiri River catchment in the preceding week of August 2. Rather the unprecedented flash floods in Dhansiri and the Doyang rivers that flow through Nagaland and Assam was brought by the Doyang dam situated on the River Doyang, a tributary of the River Brahmaputra, located in Wokha district of Nagaland.
The 75 MW Doyang Hydroelectric Power Project owned by North Eastern Electric Power Corporation Limited (NEEPCO)– the Central government company that owns and operates the dam wreaked havoc downstream claiming five lives as NEEPCO opened the gates of the dam.
“This misfortune was brought upon us by the NEEPCO project in Nagaland. We were not warned previously that the dam gates would be opened. As a consequence almost all the households in our village lost most of their belongings. This disaster turned us to paupers within a few hours,” says thevillage headman of Kenduguri under Marangi Revenue Circle.
By August 6, the Assam State Disaster Management Authority put the number of affected persons at 87,300 and 7,086 hectares of land in Golaghat district were under water. The deluge left a trail of destruction ravaging some 120 villages. Sediment and slush filled up hundreds of wetlands in the catchment.
The earlier Highest Flood Level of Dhansiri River at Numaligarh was 79.87 m (September 24, 1985). The new HFL was 80.18 m–a full 31 cm above the previous HFL which has been rather rare. What was unusual was that, the water level remained above 79.87 cm, the old HFL, for over 60 hours.
In its defence, the NEEPCO authority released a report on August 7 in which it stated that flood levels in the Doyang River increased due to extreme rainfall in Nagaland and Myanmar. The release added that the inflow to the Doyang reservoir was more than 600 cu m/sec since July 27, which increased to more than 1,150 cu m/sec or about a little more than 54 acres filling up with one feet of water in a minute on July 30.
The live storage capacity of the dam is only 370 million cubic metres. NEEPCO officials say that the rain in the catchment area of the dam was much higher than the normal, despite India Meteorological Department officials stating a 30 per cent rainfall deficit in 2018.
But downstream victims countered the company accusing it for deliberately keeping the water level high so that there was more electricity generation. The Krishak Mukti Sangram Samity (KMSS), a farmers’ organization that has been spearheading the anti-big dam movement in Assam said that the Doyang Project produced thrice the amount of electricity the dam was supposed to produce in July.
In a press meet held in Guwahati on August 8, KMSS leader Akhil Gogoi said that the Doyang Project produced 45.52 million units, which is thrice the amount of electricity the dam was supposed to produce while the target was 14.28 million units for July by the Central Electricity Regulatory Authority. Almost a million people were severely affected and more than 7,500 hectares of crop land submerged. Political parties and organizations came together leaving aside their differences to demand adequate compensation for the affected and punitive action for those guilty.
The Doyang project led to very serious impacts in the downstream areas in the past too. Affected people in the ten villages of Mengshanpen, Tsopo, Chudi, Longtsung, Sheruechuk, Morakjo, Lotsu, Pyangsa, Moilan and Pyotchu had in August 2015, submitted a representation to the Chairman and Managing Director of NEEPCO under the banner of the Downstream Affected People’s Organization (DAPO). Their memorandum cited death of at least five persons between 2003 and 2014 due to the sudden “release of huge volumes of water”; and destruction of access to river, fisheries, water sources, hanging bridges, sand and boulder sources and river bed cultivation.
Dam safety and other questions
Located in Wokha district of Nagaland, the Doyang dam with a capacity of 3 X 25 MW and an estimated annual generation of 227 Million Units was commissioned on the 2nd week of July’2000. The Project has gross storage capacity of 535 Million Cubic Meters (MCM) and live storage capacity of 370 or 400 MCM as per sources. Further, the spillway of the dam has a capacity to release 5977 cumecs of water.
This is massive, massive quantity for Doyang-Dhansiri rivers. So the dam certainly has the capacity to bring massive flood disaster in the downstream area if it is not operated properly. The dam has live storage capacity of 216.5 MCM at EL 324.0 M and intercepts a catchment area of 2606 sq.km.
In a meeting as early as February 2018, the Golaghat district administration had told NEEPCO to keep the both the spillways of the 394 metre-tall concrete dam open. “However, it appears that these procedures were not followed leading to this disaster,” an official from the district administration said.
Mrinal Saikia, Member of Assam Legislative Assembly from Khumtai- a constituency severely hit by the dam-induced flood, filed a police complaint with the Golaghat Police Station, alleging that as many as 116 villages in Golaghat district were under water due to the negligence of NEEPCO.
The Head of the Project, Priyabrata Das was interrogated by Golaghat Police in this connection on August 16. Meanwhile, members of the student wing of the KMSS, allege that the district administration were well aware of the water release but did not take necessary measures for evacuation pushing people to the brink of disaster.
Chandan Kr Duarah is a Guwahati-based science journalist. He can be reached firstname.lastname@example.org
Mubina Akhtar is an environmental journalist and wildlife activist. She can be reached email@example.com