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W. Annayat and B. S. Sil
an understanding of which reaches are more susceptible to lateral migration. To
predict meander migration, existing approaches make use of geometry, water and
soil parameters in different ways [3]. Despite decades of research into bank migration prediction, knowledge of the subject is still imperfect, with much work remaining
to be done. Exact mathematical representation of such prediction has yet to achieve,
and the tools which are available produce results which possess lot of uncertainties
[4]. The process of river migration does not occur simultaneously all through the
river; rather, it occurs in some places separately at any period of time leading to
the formation of the individual meander. Main source of sedimentation in the river
is its own bank erosion although, some other parameters which are which are also
responsible for sedimentation in the river are land use, soil composition of bank and
bed materials, area of watershed, slope variability and discharge of river [5]. Also
autogenic rivers have lost their dynamic equilibrium due to some human interference like irrigation, construction of dams and infrastructural developments which
lead to the overexploitation of natural resources and changes in the variation of the
streamflow [6].
The rate of river migration may be as high as several hundred metres at several
locations and for which the habitats of the human are adversely affected. At large r c /b
(bend curvature) ratios, the radius (r c ) is large compared to the channel width (b), and
for given flow velocity, the centrifugal force which is inversely proportional to the
radius of curvature is small; this leads to a small erosion rate. At very small r c /b ratios,
the width of the channel b is large compared to the radius of curvature, the water
can actually flow almost straight through the river, and its flow tends to straighten it.
When the ratio r c /b is between 2 and 3, the centrifugal force is significant, and the
water is forced to follow the outer bank [7].
Ganguly [8, 9] found that the Barak River is structurally characterized by sequence
of meridional to sub-meridional, curved, extended, doubly plunging, uneven folds
arranged in an en-echelon pattern, trending N-S to NNE-SSW with slight convexity
towards west. Geological and morphotectonic issues of the region can be found in
the existing literature of as [10, 11, 12, 13, 14, 15, 16] during the assessment of
hydrocarbons. Fold belt region of Barak River is tectonically surrounded on all four
sides. Towards the north side, it is bounded by Dauki. Fault, and in the east side,
it is bounded by Haflong-Disang Thrust, and on the south side, it is bounded by
Arakan-Yoma Fold Belt, while as, on the west side, it is enclosed by Hail-HakaLulu Lineament and Chandpur-Barisal High [17]. In this article, we have tried to
describe and evaluate the empirical approach and time sequence maps to predict the
meander migration of the Barak River. 12 meandering reaches of the Barak River are
considered using multiperiod Landsat remote sensing images. In order to evaluate the
accuracy of these methods, both predicted migrations, as well as measured migration,
are compared.
W. Annayat and B. S. Sil
an understanding of which reaches are more susceptible to lateral migration. To
predict meander migration, existing approaches make use of geometry, water and
soil parameters in different ways [3]. Despite decades of research into bank migration prediction, knowledge of the subject is still imperfect, with much work remaining
to be done. Exact mathematical representation of such prediction has yet to achieve,
and the tools which are available produce results which possess lot of uncertainties
[4]. The process of river migration does not occur simultaneously all through the
river; rather, it occurs in some places separately at any period of time leading to
the formation of the individual meander. Main source of sedimentation in the river
is its own bank erosion although, some other parameters which are which are also
responsible for sedimentation in the river are land use, soil composition of bank and
bed materials, area of watershed, slope variability and discharge of river [5]. Also
autogenic rivers have lost their dynamic equilibrium due to some human interference like irrigation, construction of dams and infrastructural developments which
lead to the overexploitation of natural resources and changes in the variation of the
streamflow [6].
The rate of river migration may be as high as several hundred metres at several
locations and for which the habitats of the human are adversely affected. At large r c /b
(bend curvature) ratios, the radius (r c ) is large compared to the channel width (b), and
for given flow velocity, the centrifugal force which is inversely proportional to the
radius of curvature is small; this leads to a small erosion rate. At very small r c /b ratios,
the width of the channel b is large compared to the radius of curvature, the water
can actually flow almost straight through the river, and its flow tends to straighten it.
When the ratio r c /b is between 2 and 3, the centrifugal force is significant, and the
water is forced to follow the outer bank [7].
Ganguly [8, 9] found that the Barak River is structurally characterized by sequence
of meridional to sub-meridional, curved, extended, doubly plunging, uneven folds
arranged in an en-echelon pattern, trending N-S to NNE-SSW with slight convexity
towards west. Geological and morphotectonic issues of the region can be found in
the existing literature of as [10, 11, 12, 13, 14, 15, 16] during the assessment of
hydrocarbons. Fold belt region of Barak River is tectonically surrounded on all four
sides. Towards the north side, it is bounded by Dauki. Fault, and in the east side,
it is bounded by Haflong-Disang Thrust, and on the south side, it is bounded by
Arakan-Yoma Fold Belt, while as, on the west side, it is enclosed by Hail-HakaLulu Lineament and Chandpur-Barisal High [17]. In this article, we have tried to
describe and evaluate the empirical approach and time sequence maps to predict the
meander migration of the Barak River. 12 meandering reaches of the Barak River are
considered using multiperiod Landsat remote sensing images. In order to evaluate the
accuracy of these methods, both predicted migrations, as well as measured migration,
are compared.