Aijrhass15 509

American International Journal of Research in Humanities, Arts and Social Sciences

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ISSN (Print): 2328-3734, ISSN (Online): 2328-3696, ISSN (CD-ROM): 2328-3688 AIJRHASS is a refereed, indexed, peer-reviewed, multidisciplinary and open access journal published by International Association of Scientific Innovation and Research (IASIR), USA (An Association Unifying the Sciences, Engineering, and Applied Research)

Morphological characteristics of Gangotri glacier area, Uttarakhand using GIS & Remote Sensing techniques Dr. Deepa Bhattacharjee Assistant Professor, Dept. of Geography, F.C.College, Diamond Harbour, South 24 Parganas, West Bengal, India Address: 12/6, Parnasree Pally, Kolkata– 700060, West Bengal, India Abstract: Bhagirathi valley presents a well-developed watershed in which snow, glaciers, running water and mass gravity movements are the important factors in sculpturing surface geometry. The surface configuration of the Gangotri area can be analyzed with the help of different morphometric techniques like relative relief, dissection index, drainage density, drainage frequency and average slope, nature of long profile, sinuosity index etc. to find out the morphological characteristics of Gangotri Glacier area. The evaluation of landscape is an important and growing aspect of earth science. Evaluation is defined as the 'act or result of expressing the numerical value of judging concerning the worth of an object. In this paper, an attempt has been made to visualize the extent of variations in landform contrasts and it has been done by adopting advanced and current quantitative techniques in particular in the course of application of standard methods-pre field, field and post field methods in fluvial geomorphology.

Keywords: Morphology; Gangotri Glacier; landscape evaluation; Sinuosity Index; Bifurcation Ratio I. Introduction Present paper is concerned with the morphological characteristics of Gangotri Glacier area, Uttarakhand using GIS & remote sensing techniques. Terrain is defined by the New English Dictionary as a 'tract of country considered with regard to its natural features and configuration'. This is preferable to other similar terms because its meaning is more strictly confined to the surface of the earth, has fewer academic and practical, connotations, and has already been used in publications in this sense (Beckett and Webster, 1969). Geomorphology has the advantage of being more narrowly confined to landforms but is too strongly involved with considerations of process. Landscape or land are perhaps the closest equivalents, but both are somewhat wider concepts than terrain, the former rather too strongly connotes the visual and artistic aspects. Bhagirathi valley presents a welldeveloped watershed in which snow, glaciers, running water and mass gravity movements are the important factors in sculpturing surface geometry. The surface configuration of the Uttarkashi-Gangotri area can be analyzed with the help of different morphometric techniques like relative relief, dissection index, drainage density, drainage frequency and average slope, nature of long profile, sinuosity index etc. to find out the characteristics of Uttarkashi-Gangotri terrain.

II. Area of Study The study area is located between 30°43'N - 30°55'N and 79°04'E – 79°16'E, extending in height from 3000 to 7000 m.a.s.l. of Uttarkashi district in Uttarakhand. Bhagirathi basin is drained by Bhagirathi river which originates from Gangotri glacier snout known as “Gaumukh”, at an elevation of 3972 m asl. The basin covers an area of 7502 sq.km and encompasses 238 glaciers of various types and sizes. Administratively the district is divided into six tehsils namely, Bhatwari, Dunda, Chinyalisaur, Mori, Barkot and Purola. Further it is divided into six developmental blocks viz: Mori, Purola, Naugaon, Bhatwari, Dunda and Chinyalisaur. Among the six Tehsil and developmental blocks of Uttarkashi the study area (Uttarkashi-Gangotri area) falls in Bhatwari Tehsil and Bhatwari Blocks and which extending from 30º40´N to 31º4´ N latitude and 78º25´E to 79º14´E longitude approximately covers an area of 1772 sq.km.

III. Objective The main objective of this paper is to discuss the morphological characteristics of Gangotri Glacier area, Uttarakhand using GIS & remote sensing techniques.

IV. Methodology In order to fulfilment the objective of the research work this research worker has adopted modern methodology, procure the necessary data, information and evidences. Most of the observations in this study have been based upon intensive field work in the area under consideration. The study thus is based on available data and empirical observations. At first the study related maps were collected from different Govt. organization like topographical sheets (53 N/1, 53 J/13, etc.) from Survey of India, Dehradun and Kolkata, Satellite Imagery

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(LISS III and LISS IV) from National Remote Sensing Centre, Hyderabad and other maps from The Atlas of Uttaranchal by National Atlas and thematic mapping Organization (NATMO), Kolkata.

V. Assessment of morphological characteristics of Gangotri Glacier area The morphological characteristics of Gangotri Glacier can be analyzed with the help of different morphometric techniques like relative relief, dissection index, drainage density, drainage frequency and average slope, nature of long profile, sinuosity index etc. to find out the characteristics of Uttarkashi-Gangotri terrain. Bhagirathi valley presents a well-developed watershed in which snow, glaciers, running water and mass gravity movements are the important factors in sculpturing surface geometry. Efforts have been taken by the Geomorphologists since the first half of the twentieth century to find out techniques which will specifically evaluate the status of a landform in the entire gamut of an evolution process. Qualitative assessments were practiced beforehand, but they could not reveal the exactness of the landform character. Thus a trend of quantification has been in progress in order to draw very indifferent and imperative inferences. The science of morphometry has evolved in this regard comprising the aspects of identifying landform status as well as drainage network relationship.

VI. Morphometric parameters `Measurement of the shape, or geometry, of any natural form—be it plant, animal or relief features—is termed morphometry' (A.N. Strahler, 1969) but in geomorphology `morphometry may be defined as the measurement and mathematical analysis of the configuration of the earth's surface and of the shape and dimensions of its landforms' (J.I. Clarke, 1970). It has two distinct branches viz. (i) relief morphometry and (ii) fluvial morphometry. Relief morphometry includes the analysis of terrain characteristics through hypsometric curves, clinographic curves, percentage hypsometric curves, area-height curves, altimetric frequency histograms and curves, superimposed, projected and composite profiles, which assist in dealing with different aspects of landform characteristics of a drainage basin or of any geomorphic unit (S.Singh,1972). Fluvial morphometry includes the consideration of linear, areal and relief aspects of a fluvially originated drainage basin. For this purpose the entire study area covers an area of about 1772 sq.km is divided into one km  one km grid each on 1:50,000 scale topographical sheets. A total of 1717 grid value was analyzed in the computer using GIS software like Arc View and Map Info to prepare the final maps and statistical analysis was done by SPSS and Microsoft Excel. The basin morphometry includes the analysis of the characteristics of linear, areal and relief aspects of fluvially originated drainage basins.

VII. Linear aspects of the basin The linear aspects of a basin deal with hierarchical orders of stream, number and lengths of stream segments and various relationships among them. This aspect includes the discussion and analysis of stream order, stream number, bifurcation ratio, stream lengths, sinuosity indices etc. and the stream order (Nu), bifurcation ratio (Rb), stream length (Lu) results have been presented in Table 1.

Stream ordering (Nu): In the drainage basin analysis the first step is to determine the stream orders. Stream order is defined as a measure of the position of a stream in the hierarchy of tributaries' (L.B. Leopold, M.G. Wolman and J.P. Miller, 1969). In the present study, the channel segment of the drainage basin has been ranked according to Strahler’s stream ordering system. According to Strahler (1964), the smallest fingertip tributaries are designated as order 1. Where two first order channels join, a channel segment of order 2 is formed; where two of order 2 join, a segment of order 3 is formed; and so forth. The trunk stream through which all discharge of water and sediment passes is therefore the stream segment of highest order. The Bhagirathi Basin is a 7th order drainage basin . The morphometric parameters computed reveals that the Bhagirathi is seventh order stream and it is a sixth order drainage basin up to Uttarkashi. The 4 th order start from Chirbasa and 6th order start from Sainj which are 2nd and the 5th break of slope of the study area. The total number of 10004 streams were identified of which 7974 are 1st order streams, 1578 are 2nd order, 373 are 3rd order, 65 in 4th order, 11 in fifth, 2 in sixth and one is indicating 7th order streams. The properties of the stream networks are very important to study the landform making process (Strahler and Strahler, 2002). Drainage patterns of stream network from the basin have been observed as mainly herringbone type. Dendritic types are also developed in this region. While in some parts of the basin represent parallel and radial pattern types indicating that the topographical features are dipping, folded and highly jointed in the hilly terrains.

Table 1 : Linear aspects of the drainage network of the study area Stream Order

No. of Streams (Nu)

Log Nu

Stream length (km) Lu

Log Lu

1st Order 2nd Order 3rd Order 4th Order 5th Order 6th Order

7974 1578 373 65 11 2

3.901 3.198 2.571 1.812 1.040 0.301

4735.52 1061.14 521.28 384.42 107.43 24.4

3.675 3.025 2.717 2.584 2.031 1.387

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Table 2: Linear aspects of the drainage network of the Suwari Basin Stream Order

No. of Streams (Nu)

Log Nu

1st Order

142

2.152

2 Order

30

1.477

3rd Order

6

0.778

4th Order

2

0.301

1

0.00

nd

th

5 Order

Source: Topographical Map, S.O.I. , Dehradun & Satellite Image, NRSC, Hyderabad, 2005

Fig. 1: Stream ordering of Suwari Basin, Uttarakhand In the present study, the channel segment of the drainage basin has been ranked according to Strahler’s stream ordering system. According to Strahler (1964), the smallest fingertip tributaries are designated as order 1. Where two first order channels join, a channel segment of order 2 is formed; where two of order 2 join, a segment of order 3 is formed; and so forth. The trunk stream through which all discharge of water and sediment passes is therefore the stream segment of highest order. The Bhagirathi Basin is a 7th order drainage basin (Fig.1). The morphometric parameters computed reveals that the Bhagirathi is seventh order stream and it is a sixth order drainage basin up to Uttarkashi. The 4th order start from Chirbasa and 6th order start from Sainj which are 2nd and the 5th break of slope of the study area. The total number of 10004 streams were identified of which 7974 are 1st order streams, 1578 are 2nd order, 373 are 3rd order, 65 in 4th order, 11 in fifth, 2 in sixth and one is indicating 7th order streams. The properties of the stream networks are very important to study the landform making process (Strahler and Strahler, 2002). Drainage patterns of stream network from the basin have been observed as mainly herringbone type. Dendritic types are also developed in this region. While in some parts of the basin represent parallel and radial pattern types indicating that the topographical features are dipping, folded and highly jointed in the hilly terrains.

Table 3 : Linear aspects of the drainage network of the study area Stream Order

No. of Streams (Nu)

Log Nu

Stream length (km) Lu

Log Lu

1st Order

7974

3.901

4735.52

3.675

2nd Order

1578

3.198

1061.14

3.025

rd

373

2.571

521.28

2.717

th

4 Order

65

1.812

384.42

2.584

5th Order

11

1.040

107.43

2.031

2

0.301

24.4

1.387

3 Order

th

6 Order

Source: Topographical Map, S.O.I. , Dehradun & Satellite Image, NRSC, Hyderabad, 2005

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Bifurcation ratio (Rb): The term bifurcation ratio (Rb) is used to express the ratio of the number of streams of any given order to the number of streams in next higher order (Schumm, 1956). Bifurcation ratio (R b) which is related to the branching pattern of the drainage network is defined as a ratio of the number of streams of a given order to the number of streams of the next higher order and is expressed in terms of the following equation.

Considering the number of streams of order i equal to (Ni), and the number of streams in the next order is Ni+1, thus the bifurcation ratio will be calculated as: S.A. Schumm, (1956) Bifurcation ratio Rb = Ni/Ni+1 Bifurcation ratios characteristically range between 3.0 and 5.0 for basins in which the geologic structures do not distort the drainage pattern (Strahler, 1964). Strahler (1957) demonstrated that bifurcation ratio shows a small range of variation for different regions or for different environment dominates. Unusually high bifurcation ratio values (>10) are characteristics of drainage systems developed over easily erodible rocks and in areas underlain by heavily jointed rocks. The bifurcation ratio varies from one order to next because of variation in geometry of watershed (Table 4,5). The average Rb of the Bhagirathi basin is 4.73 which indicate that the drainage has been affected by the structural disturbances.

Stream Order 1 2 3 4 5 6 7

Table 4 : Bifurcation Ratio of Bhagirathi Basin No. of Streams Equation (Rb =Ni/Ni+1) 1st order / 2nd order 2nd order / 3rd order 3rd order / 4th order 4th order / 5th order 5th order / 6th order 6th order / 7th order Average

7974 1578 373 65 11 2 1

Bifurcation ratio (Rb) 5.05 4.23 5.74 5.90 5.50 2.00 4.73

Table 5: Bifurcation Ratio of Suwari Basin Stream Order

No. of Streams

Equation (Rb =Ni/Ni+1)

Bifurcation ratio (Rb)

1

142

1st order / 2nd order

4.73

2

30

2nd order / 3rd order

5.00

3

6

3rd order / 4th order

3.00

4

2

4th order / 5th order

2.00

5

1

Average

3.68

Table 6: Bifurcation Ratio of Kedar Ganga Basin Stream Order

No. of Streams

Equation (Rb =Ni/Ni+1)

Bifurcation ratio (Rb)

1

63

1st order / 2nd order

5.25

2

12

2nd order / 3rd order

4.00

3

3

3rd order / 4th order

3.00

4

1

Average

4.08

Source: Topographical Map, S.O.I. , Dehradun & Satellite Image, NRSC, Hyderabad, 2005

Stream length (lu) and length ratio (RL): Stream length is one of the most significant hydrological features of the basin as it reveals surface runoff characteristics streams of relatively smaller lengths are characteristics of areas with larger slopes and finer textures. Longer lengths of streams are generally indicative of flatter gradients.

Generally, the total lengths of stream segments are maximum in first order streams and decreases as the stream order increases. The numbers of streams of various orders in the basin are counted and their lengths from mouth to drainage divide are measured with the help of GIS software and toposheet. Stream length ratio (RL) is the ratio of the mean length of the one order to the next lower order of the stream segments.

Sinuosity indices: Sinuosity of a stream denotes the degree of deviation of its path from expected theoretic straight path (course). The analysis of sinuosity may help in studying the effect of terrain characteristics on the river course and vice versa. The degree of sinuosity may give a picture of the stage of development as well as landform evolution. A few models have been developed for the calculations of sinuosity indices.

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S.A. Schumm's model (1963) Channel sinuosity = OL/EL; Where OL = observed (actual) path of a stream and EL = expected straight path of a stream

Fig. 2: LISS III Image (2005) of Kakora & Kanauldiya Gad Basin

Fig. 3: 3D Representation of Absolut Relief of Uttarkashi-Gangotri Area On the basis of above equation Schumm identified 5 categories of channel sinuosity e.g. straight course when channel sinuosity is 1.0, transitional course, regular course, irregular course and tortous course (when channel sinuosity is more than 20). A.D.Miall (1978) presented a unified classification of alluvial channels in 1985 wherein 5 major categories of channel patterns have been identified on the basis morphological characteristics, sinuosity index and depositional behavior etc. (i) Straight channel (ii) sinuous channel, (iii) meandering channel, (iv) braided channel, (v) anastomosing channel.

VIII. Areal aspects of the basin The areal aspects of the drainage basin is very important morphometric attribute as it is related to the spatial distribution of a number of significant attributes such as drainage density, stream frequency, drainage texture, slopes, absolute and relative reliefs, dissection index etc. Area of a basin (A) and perimeter (P) are the important parameters in quantitative morphology. The area of the basin (Fig.2) is defined as the total area projected upon a horizontal plane contributing to cumulate of all order of basins. Perimeter is the length of the boundary of the basin which can be drawn from topographical maps. Basin area is hydrologically important because it directly affects the size of the storm hydrograph and the magnitudes of peak and mean runoff.

IX. Relief aspects of the basin Relief aspects of the basins play an important role in drainage development, surface and sub-surface water flow, permeability, landforms development and erosion properties of the terrain. The relief aspects of the drainage basin is very important morphometric attribute as it is related to the three dimensional features of the basins involving different morphometric methods are used to analyze terrain characteristics, which are the analysis of the relationships between area and altitude (hypsometric analysis), altitude and slope angle (clinographic analysis), average ground slope, relative reliefs, relief ratio, dissection index, profiles of terrains and the rivers etc. (Singh, 2004).

Relative Relief: Relative relief is an important morphometric variable used for the overall assessment of morphological characteristics of terrain and degree of dissection. It (Hammond 1954, Thauer 1955) is also termed as amplitude of relief or local relief which represents actual variation of altitude in a unit area with respect to its local base level. It is closely associated with slopes, and is more expressive and also useful in understanding morphogenesis. But it does not take into account the dynamic potential of the terrain and feature

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of vertical distance from the erosion base. Here, maximum height differences in each grid square from the relevant toposheets have been used as control for plotting isopleths to show varying amplitudes of relief over the Uttarkashi-Gangotri area. This morphometric attribute is found to vary from 40 to 1440 m. (approx.) within the study area. A considerable part of the surface of Gangotri glacier in the north eastern section of the area under study has low relative relief, especially near the confluence of Chaturangi, Kirti , Ghanohim, Meru, Swachhand Glacier and both side of Gangotri Glacier trough. Vast areas of Satopanth peak area, Sudarshan Parbat area, adjacent areas of Kedar and Rudugaira Gad, Bhairanghati, LohariNag, Varunavat Parbat area, Kishanpur and its adjacent areas are represented by the high relative relief zone category.

X. Concluding Remarks The morphological characteristics of the Gangotri area can be analyzed with the help of different morphometric techniques like relative relief, dissection index, drainage density, drainage frequency and average slope, nature of long profile, sinuosity index etc. to find out the characteristics of Gangotri terrain. The Uttarkashi-Gangotri area shows wide variations in relative relief. The Uttarkashi-Gangotri area shows wide variations in average slope from 3° to 69°. The mean value of average slope of the Uttarkashi-Gangotri area is 32° with a standard deviation of 14.68. The Drainage Density map of Uttarkashi-Gangotri area shows a higher degree of consistency with the spread of other morphometric attributes and reflects the nature of variation in relief, soils, rocks with hill slopes, structures etc. The map shows that the high density (>4.0 km/sq.km) is observed in near northern and north eastern part of Bhaironghati and Bhatwari and western side of Ganganani and Lohari Nag where the relief is very high characterized with steep gradient. Generally major part of the Gangotri area is under glacial, glaciofluvial and fluvial process is characterized by the development of very course and course texture. Bhagirathi valley presents a well-developed watershed in which snow, glaciers, running water and mass gravity movements are the important factors in sculpturing surface geometry.

VI. [1] [2] [3] [4] [5] [6]

[7] [8] [9] [9] [10] [11] [12]

References

Agarwal, N. C., Kumar G., (1973): Geology of the Upper Bhagirathi and Yamuna Valleys, Uttarkashi District, Kumaun Himalaya, Himalayan Geology, vol. 3, pp. 2-23.

Ahmad, S., Hasnain, S.I., Selvan, T.M. (2004): Morphometric Characteristics of Glaciers in the Indian Himalayas, Asian Journal of Water, Environment and Pollution, Vol. 1, No. 1 & 2, pp. 109-118.

Auden, J.B. (1937): The snout of the Gangotri glacier, Tehri Garhwal, Rec. Geol.Survey, India, 72 (II) pp. 135-140.

Bhattacharjee, D. (2007): Glacio fluvial problems of the Gangotri area, Indian jr. of Landscape system and ecological studies, ILEE, Calcutta, Vol.30, No.1 pp-195-204.

Bhattacharjee, D. (2009): Glacial retreat and their impact on environment of Gangotri region, Uttarkashi district, Indian jr. of Geomorphology, Vol. 13+14 (1&2), pp. 165-178.

Dutta, S.S., Sangewar, C.V., Shukla, S.P., Chitranshi, A., Puri, V.M.K., and Hampaiah, P. (2004): Some observation on Physiography and Geomorphology of Gangotri Glacier area, Bhagirathi basin, Uttaranchal, Special Publication Number 80, GSI, pp. 69-77.

Kale, V.S., Gupta, A. (2001): Introduction to Geomorphology, Orient Longman Pvt.ltd., Kolkata, pp. 1-3, 122-124, 128-130, 167-175.

Nainwal, H.C., Naithani, A.K. (2004): Glacial morphology of the Gangotri group of glaciers in Garhwal Himalaya, Uttaranchal, India, Special Publication Number 80, GSI, pp. 87-96.

Naithani, A.K., Nainwal, H. C., Sati, K. K., Prasad (2001): Geomorphological evidences of retreat of the Gangotri glacier and its characteristics, Current Science, Vol.80, No.1, pp-87-94.

Naithani, N. P., Bhatt, M (2011): Geo-environmental hazards around Bhatwari area, district Uttarkashi Garhwal Himalaya Uttarakhand, International journal of current research, vol. 33, issue, 4, pp.200-205, April, 2011.

Singh, S. (2004): Geomorphology, Prayag Pustak Bhavan, Allahabad, pp. 1-3, 43-39, 358-383, 478-486.

Strahler, A.N., and Strahler, A.H. (2002): A Text Book of Physical Geography, John Wiley & Sons, New York.

Valdiya KS (1980): Geology of Kumaun Himalaya. Wadia Inst. Of Himalayan Geology, Dehradun, pp. 22-28, 48-49, 54-55, 7887.

XI. Acknowledgments I am really grateful to Prof. S.C. Mukhopadhayay, Emeritus Fellow, Department of Geography, University of Calcutta & Prof. Sunanda Bandopadhyay, Dept. of Geography, University of Calcutta for their kind advice and encouragement in the preparation of this Research Project. I wish to express my deep regards to K. Vinod kumar, scientist, NRSA, Balanagar, Hyderabad & Dr. R.K.Dutta, H.O.D, Dept. of Geography, Kultali Dr. B.R.Ambedkar College, Jamtala. I also thankful to the local authorities at Gangotri and University Grant Commission, New Delhi for extending logistic help for financial support in the fieldwork.

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