Foreword
The Brahmaputra is one of the largest rivers in the world traversing a distance of about 2900 km through China (Tibet), India and Bangladesh and draining an area of 5,80,000 square kilometres. In India, the basin lies in the States of Arunachal Pradesh, Assam, Nagaland Meghalaya and West Bengal.

The water wealth of the Brahmaputra basin amounts to about two fifth of the country's total hydropower potential. An integrated approach for utilizing surface waters on watershed basis shall be the most efficient way to manage the water resources of the basin.

The level of urbanisation in the basin area is quite low and Guwahati is the only city in the basin having population over five lakhs. The important industries in the basin are Jute and petroleum products at Guwahati;

petroleum and its by products at Digboi; plywood and hard and soft board at Darjeeling, Cooch Behar, Guwahati and Dibrugarh; paper and card board and newsprint at Nagaon, Guwahati and Shillong; matches at Siliguri, Dhubri and Guwahati; glass and ceramics at Dibrugarh; fertilizers at Dibrugarh; and drugs & pharmaceuticals at Darjeeling; Guwahati, Nagaon and Shillong.

The major industrial complexes and units within Brahamputra basin are mainly concentrated in Assam. Coal mining operations are in the districts of Dibrugarh and Tinsukia. The oil exploration, drilling and production operations are confined to the districts of Dibrugarh, Tinsukia, Sibsagar, Jorhat and Golaghat. Likewise petroleum refining units are located in the districts of Tinsukia, Kamrup and in Bongaigaon districts. These industries are contributing major part of the industrial pollution load into the basin. A large number of medium and small industries are coming up in and around the urban areas like Tinsukia, Dibrugarh, Sibsagar, Jorhat, Tezpur, Nagaon, Guwahati, Bongaigaon, Dhubri etc. ..

The water quality of the main stream and tributaries of Brahmaputra is meeting the desired quality in terms of physico- chemical criteria and parameters related to organic pollution for multiple uses. However the bacteriological 'water quality is not meeting the desired level in terms of coliform organism.

The major problem in the river and its tributaries is related to heavy silt load owing to soil erosion in the catchment area. Any action plan to restore and maintain water quality of this river should focus on preventive measures for land slide and soil erosion, the most important of which is massive afforestation, controlled Jhum cultivation and scientific management of soil in agriculture.

The study was undertaken to assess the pollution potential in river basin and to identify the nature and extent of point and non point sources of pollution. The State Pollution Control Board of Assam collected the dry and wet study data of the Brahmaputra Basin.

Shri R.M. Bhardwaj, Scientist 'C' coordinated with the State Pollution Control Board in planning, collection of data and for preparation of this document, under the supervision of Dr. R.C.Trivedi, Senior Scientist and Dr. B.Sengupta, Member Secretary Central Pollution Control Board.

The cooperation received from State Pollution Control Board of Assam in this important assignment is gratefully acknowledged.

I trust, the document will be useful to all concerned with the quality of river waters.