DOOMDOOMA, Aug 3 - �As the entire north-eastern region lies in a highly seismic zone, hence 3,000 MW Dibang Valley Hydro Power Project over river Dibang in Lower Dibang Valley district of Arunachal Pradesh may bring threat to the newly-constructed Dr Bhupen Hazarika Setu, India�s longest river bridge,� said Dr Manik Kar.
While interacting with the local scribes at Doomdooma Press Club recently after paying a visit to the 9.15-km-long bridge at Dhola, Dr Manik Kar, a geomorphologist and specialist in flood hazard of international repute also said, �The river Brahmaputra has its origin in the Manas Sarobar in the Himalayas, the geological formation of which is comparatively young and still continuously changing. The character of the river Brahmaputra is itself very problematic. So, taming of the river is not easy as it is thought to be.�
�The people of Assam are yet to experience the real danger of flood. If all the 165 hydro power projects come up in Arunachal Pradesh, then only people of Assam will experience the real danger of flood,� said Dr Kar.
�The dredging of the river Brahmaputra as a flood control measure will be a futile effort if we don�t introduce the river navigation as was done by the British during pre-Independence era. Only the movement of big cargo ships will reduce the process of siltation on bed of the river. Unlike in the hills, the slope of the river in the plains is almost horizontal. So, the �Burha Luit� (as sung by Bhupen Hazarika) is unable to carry forward the huge amount of debris and silt that is accumulated on its bed due to soil damage in the hills. The flow of the single river channel of the Brahmaputra near Pandu is only 78 cubic metres per second during winter. As Assam lies in a highly seismic zone, where on an average 120 tremors of minimum intensity take place every day, the construction of the bridge should not have been made of concrete, but of iron. At least on the river portion, it should have been a steel bridge like that of the bridges constructed in California, which also lies in a highly seismic zone,� he added.
�However, the height of the present bridge is not sufficient for movement of ships under it. The width of the bridge also should have been more than what is now to facilitate the free flow of vehicles in either direction,� he said.
Dr Kar also said, �The longest bridge of the nation constructed in this region after 70 years of Independence is not a showpiece of technological marvel if we compare it with the bridges constructed in China. Significantly, out of the total 27 longest bridges in the world, the first seven bridges are in China itself. The longest one is 164.8-km long and all the bridges on the river portion are steel extension type. The concrete pillars of Dr Bhupen Hazarika Setu have, in fact, narrowed down the width of the river and together with huge amount of water released from the big dams of hydro power projects of Arunachal Pradesh, it will give rise to flash floods in the downstream of Assam.�
The internationally reputed geomorphologist Dr Manik Kar expressed surprise at the callous attitude of the government in not giving due importance to its security aspects. There should at least be provision of light and armed guards to counter the threat of conventional explosives, collision of structure, fire, chemical/biological weapons and extremists, he added.
Dr Kar, however, also pointed out the positive aspects of the bridge and said that it was the duty of every citizen to protect this national property.
