GUWAHATI, Dec 12 - Noted flood and river bank erosion mitigation expert Prof Arvind Phukan, a former Professor of Civil Engineering, the University of Alaska Anchorage in the US, today attributed the present turbid condition of the Brahmaputra water to a tunnel which is under construction in the Chinese part of this trans-boundary river.
He was delivering the keynote address at a two-day international seminar organised by Assam Down Town University on �landslides and river bank erosion� here. The seminar got underway today.
In his address, Prof Phukan said, �I am sure that China is digging a tunnel and this is what is making the Brahmaputra water turbid.�
On the issue of checking floods and erosion, he mentioned the technologies like submerged bend weirs, bank walls, etc. applied in the rivers like the Mississippi and the Alaska in the United States.
These technologies are used to divert the water current of the Mississippi and to protect the bank of the Alaska from erosion. These are now well-established technologies in the United States, he maintained.
Prof Phukan observed that dredging of the bed of the Brahmaputra is crucial to solve the problems of flood and erosion. Dredging should be done in that way that the Brahmaputra�s course is divided into three channels so as to lessen the intensity of its current, he mentioned.
However, Jogen Sarma, a former Professor of Geology, Dibrugarh University, said the Brahmaputra carries an average silt load of 400 metric tonnes in a year. During the high flood season, the average silt load of this river is 2.2 million tonnes. Under such a situation, the issue of dredging the Brahmaputra should be considered very scrupulously, added Prof Sarma.
When asked to explain as to whether the technologies used in the Mississippi and the Alaska are applicable in the rivers of the North-east region of India, considering their hydro-meteorological and geological conditions. Prof Phukan maintained that since 1985 no attempt has been made to study the entire course of the Brahmaputra.
He asserted that the soil of the region, especially in areas like Majuli, is highly erodible. Moreover, the braided channels of the river at various locations, channel behaviour and sediment loads, geological conditions, etc. are the major factors responsible for river bank erosion, he said.
The Brahmaputra is characterised by multi-channel character. It has three to six channels separated by islands and mid-channel bars under low flow condition.
Nearly 4,000 square kilometre of the State�s area has been lost due to river bank erosion since 1954, at the rate of 80 square km per year. Over 2,500 villages have been eroded away by the rivers, affecting over 90,000 families, comprising a population of over five million.
The loss of production is estimated to be around US$790 million, while there is no account of intangible social costs, said Prof Phukan. He also informed the audience that northern tributaries of the Brahmaputra have exhibited higher erosion in comparison to its southern tributaries, while the Brahmaputra is found to be more eroding in its southern bank.
Prof Hemanta Hazarika from the Department of Civil Engineering, Kyushu University, Fukuoka, Japan, Prof Jogendra Nath Sarma and Dr Diganta Barman also made presentations in the seminar.
Earlier, the event was inaugurated by Dispur MLA Atul Bora. Assam Down Town University Vice Chancellor Prof Amarjyoti Choudhury delivered the welcome address, while Chancellor Dr NN Dutta and member secretary of the organising committee, Dr Arnob Bormudoi also spoke at the inaugural function.