GUWAHATI, Aug 30 � Experts today called for efforts to find out the alternatives to the mega dam hydroelectric projects proposed to be set up in the NE region. They also suggested that there should be an intense debate on the issue of the mega dam hydroelectric projects.
For, they say, the NE region is located in the highest seismically sensitive region and it is one of the �hottest� of the 22 biodiversity hotspots on the earth. They were speaking at a workshop organised by the All Assam Students� Union (AASU) on the Lower Subansiri Hydroelectric Power Project (LSHEP) and the other mega dam projects being set up in the NE region.
Prof Sushil Goswami, a former professor of applied geology of Dibrugarh University, said that the Arunachal part of the Himalayan range is the area where the Indian geological plate has met the Eurasian geological plate. Since the stress it released in August 1950, stress is building in our area and it is experiencing at least two low intensity earthquakes in a day.
The Indian plate is also in conflict with the Burmese plate.
The LSHEP is located 10 km below the main geological boundary fault. The project is also located above the foothill fault.
The project report of the LSHEP has totally ignored the foothill thrust and those who calculated the peak ground acceleration in the area have none of their works published in any of the international journals. With such lapses in their approach they suggested construction of the LSHEP dam at its present site, said Prof Goswami.
Moreover, the soil condition of the Himalayan region in Arunachal Pradesh is also peculiar. If heavy rain occurs here it leads to landslide and will thus create flash flood by filling up the dams proposed to be built here. The dams may remain intact, but the downstream areas will be devastated.
There is also the aspect of dam-induced earthquake to be addressed, he said, referring to the 1967 Koyna earthquake in Maharashtra.
He also asserted that the peak ground acceleration in the 1897 earthquake exceeded 1g referring to the famous seismologist Richard Dixon Oldham�s observations on the earthquake and said that the peak ground acceleration mentioned in the project reports of the LSHEP was erroneous.
Prof Jatin Kalita of Gauhati University (GU) Zoology Department, who was the coordinator of the expert team engaged by the NHPC and the State Government following the decision of their meeting with the AASU, said that there is the danger of extinction of several ecologically important components due to the intervention of the dam in the natural flow regime of the river.
The power project will make the river bed go up and the river water sediment hungry. These will result in elimination of various micro-organisms and make the water released from the reservoir sediment hungry. Finally such water will accelerate the process of erosion, he said.
Their habitat fragmentation will result in the extinction of the river dolphins found in the Subansiri. In 2008-09, 29 river dolphins were sighted in the Subansiri, he said.
The intervention in the natural flow regime of the river will be such that for about 20 hours only 6 cubic metres of water per second (cumecs of water) will be released to the downstream course of the river, which has a minimum flow of about 400 cumecs of water. In the rest about four hours, around 2400 cumecs of water will be released from the reservoir, said Prof Kalita.
He also expressed serious apprehensions over the cumulative impacts of the 168 dam projects, which are coming up in the region, on their downstream areas.
Neeraj Vagholikar of the environmental group Kalpavriksh said that in the country, the downstream impact assessment studies are confined only to a 10-km-long reach from the reservoirs.
He also referred to an official report which stated that when they will be in operation, the Lower Demwe Project, Dibang Project and Lower Siang Project will lead to the rise in the water level in the Dibru Saikhowa National Park area by 4 metres.
He also criticised the approach of the Government of India in making it obligatory for the clearing authorities not to block the environment clearance certificates to the LSHEP and the Lower Siang Project till the studies on their cumulative impacts are completed.
The people of the State should also call for cumulative studies of the hydel power projects being undertaken in Bhutan. These projects are being implemented by the Indian agencies, he said.
The function was also addressed by Prof Chandan Mahanta and Prof Arup Kumar Sarma of the IIT, Guwahati, Prof Sarbeswar Kalita and Dr Bhagawatpran Duorah of GU. The experts also interacted with the representatives of 26 students� bodies.