morphometric analysis of gostani river basin in andhra ... · stud y, the channel segment of the...

INTERNATIONAL JOURNAL OF GEOMATICS AND GEOSCIENCES Volume 1, No 2, 2010

© Copyright 2010 All rights reserved Integrated Publishing services Research Article ISSN 0976 – 4380

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Morphometric Analysis of Gostani River Basin in Andhra Pradesh State, India Using Spatial Information Technology

Nageswara Rao.K 1 ,Swarna Latha.P 2 , Arun Kumar.P 3 ,Hari Krishna.M 2 1 Department of Civil Engineering, GIT, GITAM University, Visakhapatnam530 045.

2 Department of Geography, Andhra University, Visakhapatnam530 003. 3 Department of Geology, Andhra University, Visakhapatnam530 003.

[email protected]

ABSTRACT

Spatial information technology (SIT) i.e. remote sensing (RS), geographical information system (GIS) and global positioning system (GPS) has proved to be an efficient tool in delineation of drainage pattern and water resources management and its planning. GIS and image processing techniques have been adopted for the identification of morphological features and analyzing their properties of the Lower Gostani River Basin (LGRB) area in Andhra Pradesh state, India. The basin morphometric parameters such as linear and aerial aspects of the river basin were determined and computed. The area is occupied by 96% khondalite group (quartzfeldspargarnetsillimanitegneiss) of rocks. It is 7 th order drainage basin and drainage pattern mainly in subdendritic to dendritic type. It is observed that the drainage density value is low which indicates the basin is highly permeable subsoil and thick vegetative cover. The circularity ratio value reveals that the basin is strongly elongated and highly permeable homogenous geologic materials. This study would help the local people to utilize the resources for sustainable development of the basin area.

Keywords: Morphometry, Gostani river basin, spatial information technology

1. Introduction

Drainage basins or basins should be the study area for the better understanding of the hydrologic system. The optimal and sustainable development of the resource is prerequisite so that it is assessed rationally to avoid any future problems regarding its qualitative and quantitative availability. About 70% of population in India is dependent on agriculture, directly or indirectly. India has diverse geographical features and varied climates. It has 14 major basins through which drain numerous rivers, while rivers in the southern India are rainfed, with little perennial water. According to CWC (2001) report, the Andhra Pradesh (A.P) state has total number of 1157 blocks/watershed areas, out of which 106 are over exploited and 79 are in critical stage. Accordingly, the importance of water has been recognized and greater emphasis is being laid on its economic use and better management. The basin morphomatric characteristics of the various basins have been studied by many scientists using conventional (Horton, 1945; Smith, 1950; Strahler, 1957) and remote sensing and GIS methods (Krishnamurthy and Srinivas, 1995; Srivastava and Mitra, 1995; Agarwal, 1998; Biswas et al., 1999; Narendra and Nageswara Rao, 2006). The fastly emerging spatial information technology (SIT) viz. remote sensing, GIS, and GPS has effective tools to overcome most of the problems of land and water resources planning and management on the account of usage of conventional methods of data process.

The present study area, lower Gostani river basin (LGRB), a part of the Eastern Ghat Mobile Belt region is drained for a variety of agricultural fields, industrial purposes and also major source for the water supply to Vizainagram and Visakhapatnam cities. The main objective of this study,



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using advanced remote sensing and GIS technology is to compute basin morphometric characteristics for various parameters.

2. Physiography of the Study Area

The investigated area is enclosed between latitudes 17°53′N and 18°17′N and longitudes 83°01′E and 83°30′E, covering an area of 1255.5 sq. km falling in Survey of India (SOI) toposheet Nos: 65 N/3, N/4, N/7, N/8, O/1, and O/5 on 1:50,000 scale (Figure 1). Geologically, the area under study is occupied by 96% khondalite group (quartzfeldspargarnetsillimanitegneiss) of rocks. The area is well represented by structural hills, denudational hills, burried pediments, valley fills and alluvial plains forming soil covers of silty clay, red sandy and red loamy and alluvium. The area enjoys tropical climate of semi arid in nature and the temperature ranges from 19 to 28º C in December and 25 to 40º C in May. The fluctuations in temperature are fairly uniform in character, except during the dry months when the rise in temperature is higher than it is during the monsoon period and the level of humidity is high (80%) due to close proximity to the sea. The average annual rainfall in the basin is 110 cm with maximum contribution from southwest monsoon. Monsoon depressions in the Bay of Bengal also cause heavy precipitation.

Figure 1: Location map of the study area

3. Materials and Methods As reference and base map preparation, six SOI toposheets on 1:50000 scale in paper format

were used. The digital data format from Indian Remote sensing Satellite (IRS1D) of LISSIII with 23.5 m spatial resolution with four spectral bands i.e. B2: 0.520.59 (Green), B3: 0.620.68 (Red), B4: 0.770.86 (Nearinfrared), B5: 1.551.70 (Shortwaveinfrared) was used to meet the requirement of area under study. The image taken was false colour composite (FCC) on 1:50,000 scale, having band combination of 3:2:1 (NIR:Red:Green) (Figure 2). The SOI toposheets and digital satellite data were geometrically rectified and georeferenced to world space coordinate system using digital image processing software (ERDAS IMAGINE ver: 8.7). The assigned



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projection system was Polyconic, IndoBangla datum and spheroid Everest. The root mean square error achieved was less than a pixel. Automatic digital techniques of edge detection and linear enhancement, filters were applied to extract the drainage layer from FCC for better interpretation of the stream order. Digitization work has been carried out for entire analysis of basin morphometry using GIS software (ArcGIS ver: 9.0). The order was given to each stream by following Strahler (1964) stream ordering technique. The attributes were assigned to create the digital data base for drainage layer of the river basin. The map showing drainage pattern in the study area (Figure 3) was prepared after detailed ground check with GPS survey on channel network and water tanks. Various morphometric parameters such as linear aspects of the drainage network: stream order (Nu), bifurcation ratio (Rb), stream length (Lu) and areal aspects of the drainage basin: drainage density (D), stream frequency (Fs), texture ratio (T), elongation ratio (Re), circularity ratio (Rc), form factor ratio (Rf) of the basin were computed.

4. Results and Discussion The various morphometric parameters of the lower Gostani river basin area were determined

and are summarized in Tables 1 and 2.

4.1 Linear Aspects of the Channel System The linear aspects of drainage network such as stream order (Nu), bifurcation ratio (Rb),

stream length (Lu) results have been presented in Table 1.

4.1.1 Stream Order (Nu) In the drainage basin analysis the first step is to determine the stream orders. 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 firstorder 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 study area is a 7 th order drainage basin (Figure 3). The total number of 1869 streams were identified of which 1292 are 1 st order streams, 394 are 2 nd order, 117 are 3 rd order, 44 in 4 th order, 19 in fifth, 2 in sixth and one is indicating 7 th order streams. Drainage patterns of stream network from the basin have been observed as mainly dendritic type which indicates the homogeneity in texture and lack of structural control. This pattern is characterized by a tree like or fernlike pattern with branches that intersect primarily at acute angles. 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. A parallel drainage pattern consists of tributaries that flow nearly parallel to one another and all the tributaries join the main channel at approximately the same angle. Parallel drainage suggest that the area has a gentle, uniform slopes and with less resistant bed rock. A radial drainage pattern forms when water flows downward or outward from a hill or dome. The radial drainage pattern of channels produced can be linked to a wheel consisting of a circular network of parallel channels flowing away from a central high point (Jensen, 2006). The properties of the stream networks are very important to study the landform making process (Strahler and Strahler, 2002).



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Figure 2: False colour composite of IRS LISS III data showing the basin area

Figure 3: Drainage pattern and their order identified from the study area



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Table 1: Linear aspects of the drainage network of the study area River basin Stream order

u

Number of streams Nu

Total length of streams in km

Lu

Log Nu Log Lu

1 1292 790.1 3.111 2.898 2 394 310.0 2.595 2.491 3 117 131.6 2.068 2.119 4 44 133.1 1.643 2.124 5 19 70.0 1.279 1.845 6 2 16.8 0.301 1.226

LGRB

7 1 30.8 3.111 1.489 Bifurcation ratio

Rb 1 st order/ 2 nd order

2 nd order/ 3 rd order

3 rd order/ 4 th order

4 th order/ 5 th order



Mean bifurcation

ratio

3.279 3.368 2.659 2.316 9.500 2.000 3.854

Table 2: Aerial aspects of the study area

Morphometric parameters Symbol/formula

Area (sq. km) A 1255.5

Perimeter (km) P 195.0

Drainage density (km/sq. km) 1.18

Stream frequency 1.5

Texture ratio 6.63

Basin length (km) Lb 71.6

Elongation ratio 0.56

Circularity ratio 0.42

Form factor ratio 0.25

Where Lu = Total stream length of all orders Nu = Total no. of streams of all orders N1= Total no. of 1 st order streams П = 3.14



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The order wise total number of stream segment is known as the stream number. Horton’s (1945) laws of stream numbers states that the number of stream segments of each order form an inverse geometric sequence with plotted against order, most drainage networks show a linear relationship, with small deviation from a straight line. The plotting of logarithm of number of streams against stream order is given in Figure 4a, according to the law proposed by Horton gives a straight line. This means that the number of streams usually decreases in geometric progression as the stream order increases.

4.1.2 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 (Schumn, 1956). 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. The mean bifurcation ratio value is 3.854 for the study area (Table 1) which indicates that the geological structures are less disturbing the drainage pattern.

4.1.3 Stream Length (Lu) 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 length of stream segments is maximum in first order streams and decreases as the stream order increases. The number 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. Plot of the logarithm of stream length versus stream order (Figure 4b) showed the linear pattern which indicates the homogenous rock material subjected to weatheringerosion characteristics of the basin. Deviation from its general behavior indicates that the terrain is characterized by variation in lithology and topography.

4.2 Areal Aspects of the Drainage Basin Area of a basin (A) and perimeter (P) are the important parameters in quantitative

morphology. The area of the basin 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. It is interesting that the maximum flood discharge per unit area is inversely related to size (Chorley, et al., 1957). The aerial aspects of the drainage basin such as drainage density (D), stream frequency (Fs), texture ratio (T), elongation ratio (Re), circularity ratio (Rc) and form factor ratio (Rf) were calculated and results have been given in Table 2.

4.2.1 Drainage Density (D) Horton (1932), introduced the drainage density (D) is an important indicator of the linear

scale of landform elements in streameroded topography. It is the ratio of total channel segment lengths cumulated for all orders within a basin to the basin area, which is expressed in terms of mi/sq. mi or km/sq. km. The drainage density indicates the closeness of spacing of channels, thus



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providing a quantitative measure of the average length of stream channel for the whole basin. It has been observed from drainage density measurements made over a wide range of geologic and climatic types that a low drainage density is more likely to occur in regions of highly resistant of highly permeable subsoil material under dense vegetative cover, and where relief is low. High drainage density is the resultant of weak or impermeable subsurface material, sparse vegetation and mountainous relief. Low drainage density leads to coarse drainage texture while high drainage density leads to fine drainage texture (Strahaler, 1964).

a) b)

Figure 4. a) Regression of logarithm of number of streams versus stream order, b) Regression of logarithm of stream lengths versus stream order

The drainage density (D) of the study area is 1.18 km/sq. km indicating low drainage density. It is suggested that the low drainage density indicates the basin is highly permeable subsoil and thick vegetative cover (Nag, 1998). The type of rock also affects the drainage density. Generally, lower values of D tend to occur on granite, gneiss and schist regions. The chief rock of type in the study area is Khondalite, which falls under the gneissic group of rocks. This corroborates the low drainage density observed in the drainage basin.

4.2.2 Stream Frequency (Fs) Stream frequency or channel frequency (Fs) is the total number of stream segments of all

orders per unit area (Horton, 1932). The stream frequency value of the basin is 1.5. The value of stream frequency (Fs) for the basin exhibit positive correlation with the drainage density value of the area indicating the increase in stream population with respect to increase in drainage density.

4.2.3 Texture Ratio (T) Texture ratio (T) is an important factor in the drainage morphometric analysis which is

depending on the underlying lithology, infiltration capacity and relief aspect of the terrain. In the present study the texture ratio of the basin is 6.63 and categorized as moderate in nature.

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 1 2 3 4 5 6 7

Stream order, u

Log of stream

num

bers,

log Nu

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 1 2 3 4 5 6 7

Stream order, u

Log of stream

lengths,

log Lu



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4.2.4 Elongation Ratio (Re) Schumm (1956) used an elongation ratio (Re) defined as the ratio of diameter of a circle of

the same area as the basin to the maximum basin length. It is a very significant index in the analysis of basin shape which helps to give an idea about the hydrological character of a drainage basin. Values near to 1.0 are typical of regions of very low relief (Strahler, 1964). The value Re of the study area is 0.56 indicates that the low relief of the terrain and elongated in shape.

4.2.5 Circularity Ratio (Rc) Miller (1953) defined a dimensionless circularity ratio (Rc) as the ratio of basin area to the

area of circle having the same perimeter as the basin. He described the basin of the circularity ratios range 0.4 to 0.5 which indicates strongly elongated and highly permeable homogenous geologic materials. The circularity ratio value (0.42) of the basin corroborates the Miller’s range which indicating that the basin is elongated in shape, low discharge of runoff and highly permeability of the subsoil condition.

4.2.6 Form Factor Ratio (Rf) Quantitative expression of drainage basin outline form was made by Horton (1932)

through a form factor ratio (Rf), which is the dimensionless ratio of basin area to the square of basin length. Basin shape may be indexed by simple dimensionless ratios of the basic measurements of area, perimeter and length (Singh, 1998). The form factor value of the basin is 0.25 which indicate lower value of form factor and thus represents elongated in shape. The elongated basin with low form factor indicates that the basin will have a flatter peak of flow for longer duration. Flood flows of such elongated basins are easier to manage than of the circular basin.

5. Conclusions The quantitative analysis of morphometric parameters is found to be of immense utility in

river basin evaluation, watershed prioritization for soil and water conservation, and natural resources management at micro level. The morphometric analysis carried out in the lower Gostani river basin shows that the basin is having low relief of the terrain and elongated in shape. Drainage network of the basin exhibits as mainly dendritic type which indicates the homogeneity in texture and lack of structural control. In some parts of the basin, the dipping and jointing of the topography reveals parallel and radial pattern. The linear pattern of the graphical representation indicates the weathering erosional characteristics of the area under study. The morphometric parameters evaluated using GIS helped us to understand various terrain parameters such as nature of the bedrock, infiltration capacity, runoff, etc. Similar studies in conjunction with high resolution satellite data help in better understanding the landforms and their processes and drainage pattern demarcations for basin area planning and management.

6. References 1. Agarwal,C.S.,1998, “Study of drainage pattern through aerial data in Naugarh area of

Varanasi district, U.P.”, Jour. Indian Soc. Remote Sensing,26,pp 169175. 2. ArcGIS,2004, “GIS software, version 9.0”, Environmental Systems Research Institute

(ESRI), New York.



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3. Biswas,S., Sudhakar,S., and Desai,V.R.,1999,: “Prioritisation of subwatersheds based on morphometric analysis of drainage basin a remote sensing and GIS approach”, Jour. Indian Soc. Remote Sensing,27,pp 155166.

4. Chorley,R.J., Donald,E.G., Malm., and Pogorzelski,H.A.,1957,: “A new standard for estimating drainage basin shape”, Amer. Jour. Sci.,255,pp 138141.

5. CWC., Water Resources of India, Introduction, Central Water Commission, New Delhi, India,2001.

6. ERDAS IMAGINE.,2003, “Digital Image Processing Software, version 8.7”, Leica Geosystems & GIS Mapping, Atlanta, U.S.A.

7. Horton,R.E.,1932, “Drainage basin characteristics”, Trans. Amer. Geophys. Union.,13,pp 350361.

8. Horton,R.E.,1945, “Erosional development of streams and their drainage basins: hydrophysical approach to quantitative morphology”, Bull. Geol. Soc. Amer.,5,pp 275370.

9. Jensen,J.R., Remote Sensing of the Environment, Dorling Kindersley (India) Pvt. Ltd., New Delhi, 1 st edition, 2006.

10. Krishnamurthy,J., and Srinivas,G.,1995,: “Role of geological and geomorphological factors in groundwater exploration: a study using IRS LISS data”, Int. Jour. Remote Sensing,16,pp 25952618.

11. Miller,V.C.,1953, “A quantitative geomorphic study of drainage basin characteristics in the Clinch Mountain area, Varginia and Tennessee”, Project NR 389042, Tech. Rept. 3.,Columbia University, Department of Geology, ONR, Geography Branch, New York.

12. Nag,S.K.,1998, “Morphometric analysis using remote sensing techniques in the Chaka sub basin Purulia district, West Bengal”, Jour. Indian Soc. Remote Sensing,26,pp 6976.

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14. Schumn,S.A.,1956, “Evaluation of drainage systems and slopes in badlands at Perth Amboy, New Jersy”, Bull. Geol. Soc. Amer,67,pp 597646.

15. Singh,S., Physical Geography, Prayag Pustak Bhawan, Allahabad, India, 1998. 16. Smith,K.G.,1950, “Standards for grading texture of erosional topography”, Amer. Jour.

Sci.,248,pp 655668. 17. Srivastava,V.K., and Mitra,D.,1995,: “Study of drainage pattern of Raniganj Coalfield

(Burdwan District) as observed on LandsatTM/IRS LISS II imagery, Jour. Indian Soc. Remote Sensing,23,pp 225235.

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

19. Strahler,A.N.,1957, “Quantitative analysis of watershed geomorphology”, Trans. Amer. Geophys. Union.,38,pp 913920.

20. Strahler,A.N., Quantitative geomorphology of drainage basins and channel networks In. Handbook of Applied Hydrology, McGraw Hill Book Company, New York, Section 4II, 1964.

morphometric analysis of gostani river basin in andhra ... · stud y, the channel segment of the...

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