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

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, Visakhapatnam 530 045. 2 Department of Geography, Andhra University, Visakhapatnam 530 003. 3 Department of Geology, Andhra University, Visakhapatnam 530 003. prof.mharikrishna2008@gmail.com 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 (quartz feldspar garnetsillimanite gneiss) of rocks. It is 7 th order drainage basin and drainage pattern mainly in sub dendritic 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 rain fed, 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, 179

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 (quartz feldspar garnetsillimanite gneiss) 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 south west 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 (IRS 1D) of LISS III with 23.5 m spatial resolution with four spectral bands i.e. B2: 0.52 0.59 (Green), B3: 0.62 0.68 (Red), B4: 0.77 0.86 (Near infrared), B5: 1.55 1.70 (Shortwave infrared) 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 180

projection system was Polyconic, Indo Bangla 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 (N u ), bifurcation ratio (R b ), stream length (L u ) and areal aspects of the drainage basin: drainage density (D), stream frequency (F s ), texture ratio (T), elongation ratio (R e ), circularity ratio (R c ), form factor ratio (R f ) 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 (N u ), bifurcation ratio (R b ), stream length (L u ) results have been presented in Table 1. 4.1.1 Stream Order (N u ) 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 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 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). 181

INTERNATIONAL JOURNAL OF GEOMATICS AND GEOSCIENCES Volume 1, No 2, 2010 Research Article ISSN 0976 4380 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 182

River basin Table 1: Linear aspects of the drainage network of the study area Number of streams Stream order u N u Total length of streams in km Log N u Log L u L u 1 1292 790.1 3.111 2.898 2 394 310.0 2.595 2.491 3 117 131.6 2.068 2.119 LGRB 4 44 133.1 1.643 2.124 5 19 70.0 1.279 1.845 6 2 16.8 0.301 1.226 7 1 30.8 3.111 1.489 Bifurcation ratio R b Mean bifurcation 1 st order/ 2 nd order/ 3 rd order/ 4 th order/ 5 th order/ 6 th order/ ratio 2 nd order 3 rd order 4 th order 5 th order 6 th order 7 th order 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) L b 71.6 Elongation ratio 0.56 Circularity ratio 0.42 Form factor ratio 0.25 Where L u = Total stream length of all orders N u = Total no. of streams of all orders N 1 = Total no. of 1 st order streams П = 3.14 183

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 (R b ) The term bifurcation ratio (R b ) 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 (L u ) 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 weathering erosion 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 (F s ), texture ratio (T), elongation ratio (R e ), circularity ratio (R c ) and form factor ratio (R f ) 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 land form elements in stream eroded 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 184

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). Log of stream numbers log Nu 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0 1 2 3 4 5 6 7 Stream order, u Log of stream lengths log Lu 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0 1 2 3 4 5 6 7 Stream order, u 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 (F s ) Stream frequency or channel frequency (F s ) 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. 185

4.2.4 Elongation Ratio (R e ) Schumm (1956) used an elongation ratio (R e ) 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 R e of the study area is 0.56 indicates that the low relief of the terrain and elongated in shape. 4.2.5 Circularity Ratio (R c ) Miller (1953) defined a dimensionless circularity ratio (R c ) 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 (R f ) Quantitative expression of drainage basin outline form was made by Horton (1932) through a form factor ratio (R f ), 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 169 175. 2. ArcGIS,2004, GIS software, version 9.0, Environmental Systems Research Institute (ESRI), New York. 186

3. Biswas,S., Sudhakar,S., and Desai,V.R.,1999,: Prioritisation of sub watersheds based on morphometric analysis of drainage basin a remote sensing and GIS approach, Jour. Indian Soc. Remote Sensing,27,pp 155 166. 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 138 141. 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 350 361. 8. Horton,R.E.,1945, Erosional development of streams and their drainage basins: hydrophysical approach to quantitative morphology, Bull. Geol. Soc. Amer.,5,pp 275 370. 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 geo morphological factors in groundwater exploration: a study using IRS LISS data, Int. Jour. Remote Sensing,16,pp 2595 2618. 11. Miller,V.C.,1953, A quantitative geomorphic study of drainage basin characteristics in the Clinch Mountain area, Varginia and Tennessee, Project NR 389 042, 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 subbasin Purulia district, West Bengal, Jour. Indian Soc. Remote Sensing,26,pp 69 76. 13. Narendra,K., and Nageswara Rao,K.,2006,: Morphometry of the Mehadrigedda watershed, Visakhapatnam district, Andhra Pradesh using GIS and Resourcesat data, Jour. Indian Soc. Remote Sensing,34,pp 101 110. 14. Schumn,S.A.,1956, Evaluation of drainage systems and slopes in badlands at Perth Amboy, New Jersy, Bull. Geol. Soc. Amer,67,pp 597 646. 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 655 668. 17. Srivastava,V.K., and Mitra,D.,1995,: Study of drainage pattern of Raniganj Coalfield (Burdwan District) as observed on Landsat TM/IRS LISS II imagery, Jour. Indian Soc. Remote Sensing,23,pp 225 235. 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 913 920. 20. Strahler,A.N., Quantitative geomorphology of drainage basins and channel networks In. Handbook of Applied Hydrology, McGraw Hill Book Company, New York, Section 4 II, 1964. 187