IAPRS & SIS, Vol.34, Part 7, *Resource and Environmental Monitoring", Hyderabad, India, 2002
MONITORING THE BRAHMAPUTRA RIVER CONFIGURATION USING MULTIDA TE
SATELLITE DATA IN THE VICINITY OF PROPOSED ROAD CUM RAIL BRIDGE
SITE NEAR BOGIBILGAON IN DIBRUGARH DISTRICT OF ASSAM, INDIA
P.N.Shah "', A. Uniyal " & N.K.Srivastava
"Remote Sensing Applications Centre, Uttar Pradesh
Sector-G, Jankipuram, Kursi Road, Lucknow - 226 021, India E-mail : rsacup ? yahoo.com
PDisaster Management & Mitigation Centre, Academy Of Administration, Dehradun, Uttaranchal, India
"Tata Consultancy Services, Lucknow, India
KEYWORDS: LISS-II/LISS-III Data, Bank bar, Braid bar, Braided river, Brahmaputra river, Bridge alignment, Embankment
ABSTRACT :
The road and rail network is still inadequate in upper Assam. It is therefore proposed to connect Dhemaji & Dibrugarh district by
constructing road cum rail bridge across Brahmaputra river near Bogibilgaon in Dibrugarh district of upper Assam. The Rail India
Technical and Economic Services Ltd. (RITES) has felt the need of obtaining information on the past behaviour of Brahmaputra
river configuration in the vicinity of proposed bridge site using remote sensing technique. Brahmaputra is one of the major river of
the world originating from Mansarovar Lake of Kailash range of Himalaya and considered as a highly active multi-channel river
system with sand bars which has attained braided pattern due to its low gradient and heavy influx of sediments during rainy season.
The braiding pattern and braid bars are dynamic in nature and changes from time to time during every flood epoch. Multidate
satellite data between 1988 and 1998 period, Survey of India topographical maps of 1916-19 & 1963-70 have been used for mapping
of the braiding patterns, extent of braid bars, bank bars and associated fluvio geomorphic features, extent of flooding, flood damages,
bank erosion and deposition, and changes in land use in the vicinity of proposed multi purpose bridge site. Comparison of
Brahmaputra river configuration maps of 1916-19, 1963-70 and 1988-98 period have demonstrated that the braid bars, bank bars and
braiding pattern have changed over time. The northern channel of the Brahmaputra river has invaded its right bank embankment near
Rajapur village during 1996-1998. Satellite data of June, 1992 and August, 1998 have also been used for mapping of flood inundated
areas. This would provide important parameters for designing engineering structures including river training, bank protection works
and active flood plain management by taking remedial measures.
1. INTRODUCTION
The Brahmaputra river in mythological term known as the son
of the 'Brahma' is one of the world's mighty braided river
system originated from Mansarovar lake of Kailash range of
Himalaya, and flowing through the Tibet, Arunanchal Pradesh,
Assam and Bangladesh before meeting it to the Bay of Bengal.
It exhibits an anomalous mobile sand bars with highly active
multi channel braiding pattern. Braided rivers are characterised
by having a number of channels with bars and islands between
meeting and dividing again and presenting from the air the
twinning effect of a braid (Lane, 1957).Rapid fluctuations in
discharge, whether short or long term have been associated with
braiding(Fahnestock, 1963). Doeglas(1951) considered
discharge fluctuation much more important in braiding than
gradient or the availability of sediment. Schumm (1960)
mentioned that bank strength, which is influenced by silt clay
content and vegetation, exerts a strong influence on river
morphology and if removed or altered can change channel
pattern. As per Oak & Appukuttan(2001) braiding is nature's
method to maintain quasi-equilibrium between the sediment
supply, water discharge, sediment transporting capacity, bed
material characteristics etc. Erosion of channel banks are a
source of bed material and widening decreases flow stability
leading to formation of mid channel bars. It is also believed
that braided rivers are aggrading system (Lane, 1957)
The road and rail network is inadequate in upper Assam. A
multi purpose rail cum road bridge is proposed to be
constructed across Brahmaputra river near Bogibilgaon to
connect Dhemaji and Dibrugarh district of Assam.
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The ultimate aim of the study is to understand the
geomorphological processes and dynamic behaviour of the
Brahmaputra river configuration using multidate satellite data
in the vicinity of proposed bridge site as the braiding pattern
and braid bars are dynamic in nature and changed from time to
time.
2. STUDY AREA
A 45 km long stretch of the Brahmaputra river between
Dibrugarh and Dighaligaon covered in Survey of India (SOI)
topographical map sheet No. 831/10,11,12,14,15 & 16, is
located between 27°14' & 27°31'N latitude and 94°34’ &
95°00'E longitude (Figure-1). A multipurpose rail cum road
bridge site alignment is proposed by RITES across
Brahmaputra river near Bogibilgaon in Dibrugarh district to
connect Rajapur in Dhemaji district of upper Assam. The study
area is also drained by a numerous tributaries of Brahmaputra
river which include Tangani, Sisi, Larua Jan, Kapardhan,
Laipula, Burhi Dihing, Dibru, Sesa, Burhi Suti river etc. The
climate of the area is humid to sub tropical. The maximum
temperature in summer ranges between 18° & 38°C whereas
minimum temperature in winter varies from 4° to 11.5°C. The
total average annual rainfall varies from 1350 to 2405 mm. The
soils of the area are sandy loam-loam silty, loam-silty clay in
texture. The bed slope of the river in the upper reaches
between Kobo and Dibrugarh is 0.26 km per km, Dibrugarh and
Neamati is 0.17 km per km. The annual flood is about 60,000
m’s™, scour depths can reach 40 m and bank erosion rates can
locally be as high as 1000 m a year. The Brahmaputra river
usually peaks in late July or early August and some over bank
