IAPRS & SIS, Vol.34, Part 7, "Resource and Environmental Monitoring", Hyderabad, India, 2002 
  
occupied an area of 7323.99 ha, 6 patches of bank bar occupied 
an area of 1514.43 ha, one patch of surface waterlogged land 
occupied an area of 7.42 ha whereas active braiding channels of 
the Brahmaputra river occupied an area of 8402.99 ha. Several 
large size braid bars are observed in the upstream portion of the 
Bogibilgaon. The width of the individual braiding channels 
varies from 50 m to 1200 m. 
As per Brahmaputra river configuration map of 1963-70 period, 
the total area of the Brahmaputra river bed under study is 
measured as 34467.27 ha, out of which 160 patches of braid bar 
with sand occupied an area of 13089.59 ha, 49 patches of braid 
bar with grasses occupied an area of 13146.14 ha, 10 patches of 
bank bar occupied an area of 1918.08 ha, 4 patches of surface 
waterlogged land occupied an area of 60.18 ha, whereas 
braiding channels of the Brahmaputra river occupied an area of 
6253.28 ha. Some of the small braid bars in the downstream of 
the Bogibilgaon are coalesced and formed a large bars. The 
width of braiding channels varies from 50 m to 1000 m at 
places. 
As per Brahmaputra river configuration map prepared using 
satellite data of 20.11.1988 (Plate-1), the total area of the 
Brahmaputra river bed under study has been measured as 
36866.23 ha, out of which 190 patches of braid bar with sand 
occupied an area of 16129.88 ha, 25 patches of braid bar with 
grasses occupied an area of 4440.41 ha, 29 patches of 
submerged braid bar occupied an area of 210.15 ha, 3 patches 
of bank bar occupied an area of 76.02 ha, 30 patches of surface 
waterlogged land occupied an area of 288.74 ha whereas active 
braiding channels of the Brahmaputra river occupied an area of 
15721.03 ha. The width of the individual active braiding 
channel vary from 25 m to 1600 m. 
As per Brahmaputra river configuration map prepared using 
satellite data of 1/23.12.1993, the total area of the Brahmaputra 
river bed under study has been measured as 36107.38 ha, out of 
which 171 patches of braid bar with sand occupied an area of 
13840.65 ha, 56 patches of braid bar with grasses occupied an 
area of 6238.67 ha, 27 patches of submerged braid bar occupied 
an area of 211.74 ha, 13 patches of surface waterlogged land 
occupied an area of 86.20 ha, whereas active braiding channels 
of the Brahmaputra river occupied an area of 15730.12 ha. The 
width of individual braiding channels varies from 50 m to 1500 
m. 
As per Brahmaputra river configuration map prepared using 
satellite data of 01.02.1996, the total area of the Brahmaputra 
river bed under study has been measured as 34736.74 ha, out of 
which 167 patches of braid ber with sand occupied an area of 
12402.35 ha, 63 patches of braid bar with grasses occupied an 
area of 4583.64 ha, 12 patches of submerged braid bar occupied 
an area of 387.24 ha, 7 patches of bank bar with sand occupied 
an area of 290.86 ha, 35 patches of surface waterlogged land 
occupied an area of 207.16 ha, whereas active braiding 
channels of the Brahmaputra river occupied an area of 
16865.49 ha. The width of individual braiding channels varies 
from 50 m to 2000 m. 
As per Brahmaputra river configuration map prepared using 
satellite data of 02.11.1998 (Plate-2), the total area of the 
Brahmaputra river bed under study has been measured as 
38297.42 ha(+ data gap area of 2874.54ha), out of which 224 
patches of braid bar with sand occupied an area of 12501.61 ha, 
107 patches of braid bar with grasses occupied an area of 
6206.13 ha, 120 patches of submerged braid bar occupied an 
area of 857.98 ha, 14 patches of bank bar occupied an area of 
488 
1993.36 ha, 14 patches of surface waterlogged land occupied an 
area of 103.01 ha, whereas active braiding channels of the 
Brahmaputra river occupied an area of 16635.33 ha. Most of 
the large braid bars were fragmented and several braiding multi 
channels were developed having width of 50 m to 3000 m at 
places. The northern braiding channel of the Brahmaputra river 
in 1996, 1997 and again in 1998 hit the northern right bank 
embankment near Rajapur village and breached this 
embankment in 1996, 1997 & 1998 during floods affecting 
large areas under floods. Dighaligaon on left bank of the 
Brahmaputra river in the downstream of the Bogibilgaon 
appears to be vanished during 1998 floods. Satellite data of 
06.08.1998 highlighted the extent of flooding and the width of 
the Brahmaputra river during inundation near Dignalagaon has 
attained 12.00 km and 17.30 km near Bogibilgaon. Except few, 
almost all braid bars have submerged in 1998 floods. 
The comparative study of Brahmaputra river configuration have 
indicated that the braid bars and braiding pattern of the 
Brahmaputra river are very dynamic in nature and they changed 
from time to time due to low gradient and heavy influx of 
sediment during rainy season. Keeping in view breach of 
embankment during floods of 1996, 1997 & 1998, there may be 
a potential threat in future to the proposed bridge site alignment 
located between Bogibilgaon and Rajapur section, therefore 
two alternative sites one upstream of the Bogibilgaon i.e. 
Dignalagaon-Pamuagaon section and other in the downstream 
of the Bogibilgaon i.e. Tinsukia-Kathaiguri section have been 
suggested which are more feasible as compared to the 
Bogibilgaon-Rajapur section. Moreover, the braid bar with 
grasses are comparatively resistant to erosion but none of these 
braid bars are stable because of which they could not be relied 
upon for laying approach roads of the bridge as they can vanish 
at any time during high flood discharges. 
5. CONCLUSION 
The Brahmaputra river configuration maps prepared 
using multidate satellite data of 1988 & 1998 period and 
compared with that of SOI maps of 1916-19 & 1963-70 period 
have highlighted the position & extent of braid bars & braiding 
channels which would help in planning, designing the suitable 
structure and construction of bridge across Brahmaputra river in 
economical way. The Dignalagaon-Pamuagaon alternative site 
appears to be more feasible as compared to proposed 
Bogibilgaon-Rajapur site. The breach of northern bank 
embankment near Rajapur village during 1996, 1997 & 1998 
floods indicated that the northern bank active channel has taken 
a E-W turn during high flood discharges instead of its usual 
NE-SW flow direction. It appears from the study of past ten 
years satellite data that braiding pattern of Brahmaputra river 
may extend further northward and the Tangani river etc. may 
become the part of the braiding channel system of the 
Brahmaputra river. It is therefore suggested to take 
precautionary measures to protect northern bank embankment 
and a model study be carried out considering all parameters of 
channel changes for selection of suitable site for the 
construction of multi purpose bridge across the Brahmaputra 
river. 
6. ACKNOWLEDGEMENTS 
The authors are grateful to Dr. A.N.Singh, Director, RSAC-UP 
for constant encouragement and providing technical guidance. 
We are highly obliged to the Rail India Technical and 
Economic Services Ltd., New Delhi for providing financial