hydrodynamic changes of river course of part of bhagirathi ... · sandipta das, kathika adak,...

INTERNATIONAL JOURNAL OF GEOMATICS AND GEOSCIENCES

Volume 5, No 2, 2014

© Copyright by the authors - Licensee IPA- Under Creative Commons license 3.0

Research article ISSN 0976 – 4380

Submitted on October 2014 published on November 2014 284

Hydrodynamic changes of river course of part of Bhagirathi – Hugli in

Nadia district - A Geoinformatics appraisal Sandipta Das, Kathika Adak, Kaberi Samanta

School of Oceanographic Studies, Jadavpur University, Jadavpur, Raja S.C. Mallick Road,

Kolkata – 700032, West Bengal, India

[email protected]

ABSTRACT

River shapes surrounding landscapes and is changed by several hydrodynamics and

subsequent morpho dynamic prosesses. Bhagirathi-Hugli is the main river of the Nadia

district. In this paper a part of the course of Bhagirathi-Hugli river through Nadia district is

taken as the study area. The present study is mainly oriented towards the morphometric

measurement of river through temporal changes during 1977, 1990, 2010 of LANDSAT MSS

and LAND SAT TM satellite data. In this paper an attempt has been made to get the nature of

shifting, direction of shifting, erosion and deposition along the river bank, ox-bow lake

formation, sinuosity index measurement, meander ratio and cut off of the river channel has

also been calculated.

Key words: River shifting, changing river course, erosion and deposition, sinuosity, Remote

sensing.

1. Introduction

River is a general term applied to a natural stream of water flowing regularly or intermittently

over a bed in a definite channel following the slop of the land. The American

Geomorphologist, W.M. Davis (1899) first presented a general theory of landform

development called “normal cycle of Erosion” which describes a genetic classification and

systematic description of land forms developed by the fluvial process. According to this

theory, there are three successive stages in the evolution of fluvial landforms like Youthful

stage, Mature Stage and Old Stage.

The study area is in old stage of fluvial process. The old stage of river is characterized by the

low elevation with very gentle slope of land. Meandering streams are one of the few

morphological system for which an abundant historical record exists of changes of channel

pattern and associated flood plain erosion and deposition (Panda and Bandyopadhyay, 2010).

In this stage meander, abandoned channels oxbow lakes are developed. It’s mostly flood

plain area. In this study the area which is selected is a section of “Bhagirathi-Hugli” river of

Nadia district (Figure 1) is around 170 km length in stretch and has been divided into 5

reaches and each reach also divided into 17 equal part by 2 km interval. A detailed analysis

has been taken up to do with the morphometric and hydrographic of each reaches.

The district of Nadia is situated in the heart of the Bengal delta held within the arms of the

Ganga, namely, the Bhagirathi on the West and Mathabhanga on the North. The entire district

lies in the alluvial plain of the Ganga and its tributaries. The latitudinal and longitudinal

extensions of the districts are 2300’0”N to 240 0’0”N and 8800’0”E to 88045’0”E. The River

extended from Kaliganj to Shantipur named as “Bhagirathi”, from Shantipur it’s named as

“Hugli River” (Figure 2).

Hydrodynamic changes of river course of part of Bhagirathi – Hugli in Nadia district- A geoinformatics

appraisal

Sandipta Das et al.,

International Journal of Geomatics and Geosciences

Volume 5 Issue 2, 2014 285

2. Materials and methods

This paper aims to evaluate and detect the changes of river bank line of Bhagirathi-Hugli.

Then the nature of changes, measurement of the morphological parameters of different part of

the river has been studied. At first the problem has been identified and then objectives have

been set up accordingly. Data are analysed from Landsat MSS of 1977, Landsat TM of 1990

& 2010 and block maps of study area. Images are rectified (ERDAS IMAGINE-9.0) after

registration (ERDASIMAGINE-9.0). Then all the images has been mosaiced for three years.

Then sub setting of images using ERDAS IMAGINE 9.0 & Arc GIS 10 to identify the study

area. After that, the river bank line from three images has been digitized and extracted by

using Arc GIS 10 software. Next, the extracted layers of three images of different decades

have been over lapped on each other. Then RS & GIS approach has been implemented for

measurement of length, width, center line radius, shifting length, shifting direction. The river

has been divided into 5 reaches which are identified as Kaliganj, Nakashipara, Krishnanagar-

Nabadwip, Shantipur-Ranaghat and Chakdah.

2.1 Some morphometric technique which is used are as follows

Sinuosity Index: Sinuosity coefficient of a continuously derivable curve having at least

one inflection point, is the ratio of the curvilinear length (along the curve) and the distance

(straight line) between the end points of the curve.

SI = meandering length/ straight length (Singh, 2003)

Meander Belt (Mb), Meander belt is the distance between the outer edge of clockwise and

anticlockwise loops of meander.

Mb = (2+√3) rc From the above equation Mb will be ‘0’ neck distance will be ‘0’and ox-

bow lake will be formed. (Singh, 2003)

Meander cut off: River width /central line radius of bend (rc). Where rc is central line radius

of bend (Garde, 2005)

Figure 1: Location map of the study area


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3. Results and discussions

3.1. Shifting of river

Shifting of river has been discussed with reach wise within a temporal window from 1977 to

2010. Estimation of shifting and direction of river course has also been assessed by

Bhagirathi- Hugli River. In reach 1, near Kaliganj, shifting of left bank towards east direction

in 10 times and 7 times towards west. Right bank shifted towards west direction about 6

times. Mostly in this section, shifting of river is towards east direction (Figure 7). In reach 2 it

has been observed that left bank shift is towards east direction about 6 times and maximum

shifting is towards west direction (Figure 8). In this section, river shifted towards mainly in

the west direction. In this part near Nakashipara ,with respect of 1977 river pattern in 1999 or

2000 river cut off meander and goes through the straight lines and at present create an oxbow

lake. In reach 3 near Krishnanagar –Nabadwip left and right bank of the river shifted towards

east direction (Figure 9). In reach 4, near Shantipur-Ranaghat, shift of left bank towards east

direction and right bank towards west direction. So, here river width has been increased

(Figure 10). At last, in reach 5 river shifting towards east direction (Figure 11) has been

noticed.

Figure 2: Cross section along the river Figure 3: Drainage system in 1977

Figure 4: Drainage system in 1990 Figure 5: Drainage system in 2010


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Figure 6: Demarcated river bank line of different reach from Landsat MSS and landsat TM

image from 1977 – 2010

3.2. Erosion and deposition

The erosion and deposition processes are active due to change in river course. At the bend of

the river, the flowing water dashes straight into the outer bank and erodes it into a steep river

cliff. The water piles up on the outside of the bend because of the centrifugal force. A bottom

current is set up in a corkscrew motion and is hurled back into mid-stream and inner bank.

Thus deposition occurs in the inner bank forming the very gentle slip-off slope (Morisawa,


appraisal




1985). The change of areal extension occurs due to such simultaneous erosion and deposition

processes.

Figure 7: Shifting of river bank in Reach 1

Table 1: River shifting from 1977 to 2010 in Reach- 1

Sl No.

Left bank Right bank Change in

channel width

in Km Length in Km Direction Length in

Km Direction

1 0.15 E 0.11 E +0.04

2 0.26 E 0.084 E +0.176

3 0.89 W 0.98 W +0.09

4 0.39 W 0.39 W 0

5 0.062 E 0.063 E 0

6 0.31 E 0.15 E +0.16

7 0.074 W 0.36 W +0.286

8 0.093 E 0.10 W +0.19

9 0.15 E 00 +0.15

10 0.021 W 0.074 E -0.05

11 0.059 E 0.033 E +0.05

12 0.19 E 0.035 E +0.15

13 0.29 W 0.13 W -0.13

14 0.21 E 0.45 E -0.24

15 0.26 E 0.24 E +0.02

16 0.11 W 0.48 W +0.37

17 0.25 W 0.11 E +0.14


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Table 2: River shifting from 1977to2010 in Reach- 2

Sl no.


channel width

in Km Length In Km Direction Length in

Km Direction

1 0.53 E 0.48 E +0.05

2 5.9 W 5.9 W 0

3 0.092 W 0.15 E +0.05

4 0.060 W 0.0 0.060

5 0.29 W 0.13 W -0.16

6 0.18 W 0.13 W +0.05

7 0.70 E 0.80 E -0.01

8 0.68 E 0.64 E +0.04

9 0.33 W 0.34 W +0.1

10 0.68 W 0.44 W -0.24

11 0.52 W 0.46 W -0.06

12 0.24 W 0.19 W -0.005

13 0.76 E 0.51 W +1.27

14 0.62 W 0.63 W 0.0

15 0.56 E 0.35 E +0.21

16 0.11 W 0.082 E -0.028

17 0.26 E 0.18 E +0.08


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Table 3: River shifting from1977to2010 in Reach-3

Sl No.


channel width

in Km Length in Km Direction Length in

Km Direction

1 0.61 E 0.13 E +0.48

2 0.48 W 0.46 E 0.02

3 1.11 E 1.02 E +0.09

4 0.64 W 0.57 W -0.07

5 0.16 W 0.15 W -0.01

6 0.034 W 0.58 W +0.54

7 4.75 E 4.7 E +0.05

8 0.62 W 0.80 W +0.22

9 0.44 E 0.46 E -0.02

10 0.048 E 0.13 E -0.1

11 0.37 E 0.057 E +0.32

12 0.12 E 0.093 W +0.21

13 0.67 W 0.87 W +0.2

14 0.97 E 0.95 E 0.2

15 0.012 E 0.032 W +0.04

16 0.53 E 0.28 E +0.25

17 0.19 W 0.13 W -0.06


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Table 4: River shifting from 1977 to 2010 in Reach- 4

Sl No. Left bank Right bank Change In

Channel

Width In Km Length in Km Direction Length in Km Direction

1 0.028 W 0.10 E -0.97

2 0.18 E 0.29 E -0.11

3 0.20 E 0.0 +0.20

4 1.27 E 1.1 E +0.02

5 0.28 W 0.041 E -0.23

6 0.39 W 0.16 W -0.23

7 0.98 E 0.72 E +0.26

8 0.14 W 0.41 E -0.27

9 0.12 E 0.46 E -0.34

10 0.54 E 0.44 E +0.1

11 0.50 W 0.46 W -0.04

12 0.018 E 0.22 W +0.23

13 0.15 E 0.12 W +0.27

14 0.45 E 0.41 W 0.86

15 0.31 E 0.64 E -0.33

16 0.33 W 0.48 W +0.15

17 0.61 W 0.36 W -0.25


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4. Conclusions


Table 5: River shifting from 1977 to 2010 in Reach-5

Sl no.


channel

width in Km Length in Km Direction Length in

Km Direction

1 0.20 E 0.38 W +0.58

2 0.095 E 0.082 E 0.01

3 0.0 E 0.033 E -0.033

4 0.26 E 0.095 E +0.16

5 0.66 E 0.68 E -0.02

6 0.83 E 0.85 E -0.02

7 0.73 W 0.41 W -0.32

8 1.24 E 1.42 E -0.18

9 1.70 E 0.54 E +1.16

10 0.051 E 0.06 E -0.1

11 0.14 E 0.44 W +0.58

12 0.23 E 0.17 W +0.4

13 1.12 E 1.28 E -0.2

14 0.31 W 0.027 E -0.28

15 0.20 E 0.15 E +0.05

16 0 0.20 E -0.20

17 0.68 E 0.72 E -0.06


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Figure 12: Change of River course between1977 - 2010

Figure 13: Reach wise area change from 1977 to 2010


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Table 6: Computed reach wise erosion and deposition

Reach 1 Reach 2 Reach 3 Reach 4 Reach 5

Erosion

-5.78954186 -9.5537217 -8.8855 -7.41477 -8.234091

Deposition 5.411666642 11.55257081 8.351249 8.644334 8.234091

No change 8.215309445 5.358918099 7.764167 11.139875 16.31847

Channel bar 0.222028107 1.82360122 1.4584 1.058927

Here it has been calculated for each reach wise areal change due to erosional and depositional

activity from 1977 to 2010. In reach 1 amount of eroded land is 5.79 km2 and deposited land

is 5.41 km2, which is approximately same. Maximum erosion occurred near Matiari village

where Noya Char, Char Sriharipur, Rajnagar are deposited land. Maximum river area remain

unchanged i.e. 8.26 km2. In reach 2 depositional activities are more dominant than erosion.

The amount of deposited land is 11.55 km2 where 9.55km2 land eroded. Maximum erosion

occurred near Akandanga, Udaychandrapur village where Char Chuadanga, Char Khosalpur,

Jayrambati, Narayanpur are deposited land. In reach 3 amount of eroded land is 8.88 km2 and

deposited land is 8.35 km2, which is approximately same. Maximum erosion occurred near

Kasthashali, Kalinagar where Indrakpur, Sankarpur are deposited land. In reach 4

depositional activity is more dominant than erosion. The amount of deposited land is 8.64

km2 where 7.41km2 land eroded. Maximum erosion occurred near Satkulta, Malatipur where

Char Malatipur, Char Krisnabati are deposited land. In reach 5 both amount of eroded land

and deposited land is same i.e. 8.23 km2. Maximum erosion occurred near Jagapur,

Pyaradanga village where Balagari Char, Char Srikrisnapur, Char Raghunathpur, Char Jajira,

Majherchar are deposited land. Maximum river area remain in the no change category i.e.

19.32 km2. The area occupied by channel bar is 1.92 km2. In the totality of the district 35%

(48.8km2) river area remain unchanged where 31% (42.19km2) area deposited and 29%

(38.88km2) area eroded by river. The area occupied by channel bar is 5% (6.48km2) (Figure

12).

3.3. Sinuosity Index

Sinuosity index vary from 1.9 to 1.8 (Figure 14) in the year from 1977 to 2010 within study

area (from Kaliganj to Chakdah).The river has widening as well as straight line pattern when

the value of sinuosity index is above 2 (Singh, 2003).The upper portion of river at Kaliganj,

sinuosity index is 1.6. In this part river is in meander stage. Then reach 2, the sinuosity index

is 2.0, near Nakashipara cut off the river and moves in a straight line. Then at Krishnanagar –

Nabadwip, Shantipur-Ranaghat and Chakdah are 1.7, 1.5, and 1.4. In this study, it can be

concluded that if index is less 1.5, then the river is in between straight to regular stage and if

1.5 it is in the meander stage and above 2.0 is in the straight flow stage (Sen, 1993).


appraisal




Figure 14: Sinuosity index between1977 to 2010

Table 7: Computed sinuosity index of Bhagirathi – Hugli River from 1977 to 2010

Years Channel

Length(m) Straight Length(m) Sinuosity index

1977 190756.23 98797.37 1.93

1990 185973.05 97021.20 1.91

2010 180591.21 97484.09 1.85

Table 8: Computed sinuosity index at different locations in 2010 of Bhagirathi – Hugli River

Location Channel length Straight length Sinuosity index

Kaliganj 34976.32 20953.0 1.6

Nakashipara 38520.33 18616.30 2.0

Krishnanagar-

Nabadwip 35237.30 20765.58 1.7

Shantipur-Ranaghat 35059.18 23484.81 1.5

Chakdah 36351.91 24891.96 1.4

3.4. River width

Measurement of length of the river Bhagirathi-Hugli from Kaliganj to Chakdah which is near

about 170 km, which is divided in 5 reaches, each near about 34 km and each section into 17

sections (2km interval). River width varies through erosion and deposition of divided bank

line in each case (Sarkar, 2011).

3.5. Cut off places

In this study area, three different locations have been identified where several cutoff to be

formed at “Bhagirathi-Hugli ’’ river in near future. Meanders are the result of erosion and

deposition both (Dayal, 2007), It may be pointed out that meandering is a natural process

which is governed by a number of environmental factors (Singh, 2003). Due to sediment

transportation and deposition of sediment, in the upper course of river near Kaliganj cutoff

the section in 1999 or 2000. Near Kaliganj a high chances of cut off meander in 2020 on the

basis of present situation.

1977 1990 2010


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Figure 15: Reach wise river width changes

3.6 Soil and geology

Mostly Nadia is alluvial soil based plain.The soil character along the river line is fine loamy

soil. The physical properties (in%) of the soil are coarse sand 2.20%, fine sand 31.06%, silt

40.00%,clay 24.20% loss ansulation 2.0%, organic matter 0.54% .chemical Properties (in%)

of the soil are c=0.31%, n=0.3% fe203=3.92,coa=0.54,Al203=5.8,air dry moisture =2.02 soil

structure of nadia district ,specially along the river are fine coarse loamy soil. So pore spacing

of the soil particles are huge. During monsoon season soils get wet due to rain and soil

1977

1990

2010


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particles are liquified. But when the water is returned back to the river in the winter months,

the soil particles are loose and the reaches are fall, causing bank erosion (Panda and

Bandyopadhyay, 2010) Geological structure of Nadia district is that there saturated one sub

surface fault, which is along the river left bank from Krishnanagar to Kalyani. This fault

affects the river course. On the basis of that, we calculate the sinuous properties to evaluate

the effect of this fault on river course. On north eastern part of the district there is a lineament

situated near Mahisbathan.

Figure 16: Meander cut-off at different locations

Figure 17: Meander belt at different locations


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Table 9: Computation of meander cut off and meander belt of different locations

Figure 18: Soil map and geological map


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4. Conclusion

The Ganga river course shifted gradually towards east from 1977 to 2010. Major change

located near Nabadwip- Krisnanagar. Change of river width occurred due to shift of left bank

towards east and right bank towards west direction. Near Ranaghat-Shantipur, river becomes

wider near about 0.58km.The process of river course shifting and its subsequent erosion and

deposition process causes simultaneously loss and newly formation of land. The total amount

of land loss is 38.88 km2 (29%) where total amount of deposition is 42.19 km2 (41%) and

6.48 km2 (5%) land is under channel bar. The channel morphology indices i.e. sinuosity index

value ranges from 1.9 to 1.7 from 1977 to 2010 which actually indicates meandering stage in

this area. The analysis of cut off ratio indicates near Kaliganj, river already cuts its course

creating an ox bow lake. Near Nabadwip and Nakasipara there is high chance of river cut off.

The rail way track between Samudragarh to Kaliganj which is parallel to the river become a

high risk zone of river erosion. In this study it has been observed that the erosional and

depositional process of river Bhagirathi-Hugli till continuing. It may cause severe problem in

the future which can be prevented by taking proper planning and management activities in the

recent years.

5. References

1. Dayal, P., (2007), Text Book of Geomorphology, published by Rajesh Publication.

2. Garde, R. J., River Morphology, (2005), (Edition first), published by New Age

International Publishers, 4835/24, Ansari Road, Daryaganj, New Delhi-110002,

p 127.

3. Morisawa, M.E., (1985), Rivers (Forms and Processes), Published by Longman,

London and Newyork.

4. Panda, S and Bandyopadhyay, J., (2010), Morphodynamic Changes of Bhagirathi

River at Murshidabad District Using Geoinformatics, Journal of Geographic

Information System, 2011, 3, pp 85-97

5. Sarkar, A., Garg, A. R. D., Sharma, N., (2011), RS-GIS Based Assessment of River

Dynamics of Brahmaputra River in India, Journal of Water Resource and Protection,

2012, 4, 63-72

6. Sen, P. K., (1993), Geomorphological analysis of drainage basins, The University of

Burdwan, Burdwan.

7. Singh, S., (2003), Geomorphology, Published by Prayag Pustak Bhawan, Allahbad,

India, pp 65-67.

hydrodynamic changes of river course of part of bhagirathi ... · sandipta das, kathika adak,...

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