Photonirvachak 123 J. Indian Soc. Remote Sens. (March 2009) 37:157–166 RESEARCH ARTICLE GIS-based Morphometric Analysis of Five Major Sub-watersheds of Song River, Dehradun District, Uttarakhand with Special Reference to Landslide Incidences Arpita Pankaj . Pankaj Kumar Received: 10 March 2008 / Accepted : 26 February 2009 Keywords Drainage channel . Morphometric analysis . Constant channel maintenance . Sub-watershed . Asymmetric factor and GIS Abstract Evaluation of the morphometric parameters requires preparation of drainage map, contour map, ordering of the various streams and measurements of catchment area, perimeter, relative relief, relief ratio, length of drainage channels, drainage density, drainage frequency, bifurcation ratio, texture ratio, circulatory ratio and constant channel maintenance, which help to understand the nature of the drainage basin. The present study involves the Geographic Information System (GIS) A. Pankaj ( ) . P. Kumar Geological Survey of India, Lucknow – 226024, India email : pankaj.arpita@gmail.com analysis techniques to evaluate and compare linear, relief and aerial morphometry of the five subwatersheds of Song River (tributary of the Ganga River) with special reference to landslide incidences, for future development and planning of the watershed. Jakhan Rao, Song River, Bandal Nadi, Baldi Nadi and Suswa Nadi are the five major subwatersheds of the Song River basin. All the subwatersheds are basically of 5th to 6th order. Drainage patterns are mainly dendritic to sub dendritic. The drainage pattern of the Song River basin is mainly structurally controlled and the area is characterized by high to moderate relief. The asymmetric factor indicates that the tectonic rotation of the four subwatersheds is upward on the right side of the drainage basin and only one sub-watershed is downward. The numbers of the landslide incidences are also more in the upward side, than the downward side of the Song River basin. 158 Introduction The study area (Fig. 1) is located in the sub-tropical, humid and temperate type of climate between 30°00′ to 30°30′ North latitude and 77°45′ to 78°15′ East longitude, Dehradun District, Uttarakhand. The rock exposed in the area ranges from Neo-Proterozoic to Quaternary. J. Indian Soc. Remote Sens. (March 2009) 37:157–166 limestone, occasionally conglomerate, dolomite, limestone, calcareous shale, shale with limestone intercalation, carbonaceous shale, slate and phyllite. Physiographically, the area features piedmont fans and Doon Valley in the southern part and the elevated rugged mountainous terrain of lesser Fig. 1 Location of the Song River watershed. Lithologically Jakhan Rao sub-watershed comprises loose material of gravel, boulder bed, dolomite, limestone, calcareous shale, slate, phyllite, shaly slate, tilloids and quartzite. The Song River, Bandal Nadi and Baldi Nadi sub-watersheds comprise, quartzite with limestone, shale, chert with phosphorite, carbonaceous shale, calcareous shale, slate, phyllite, shaly slate, tilloids, marl and olive green carbonaceous shale. Suswa Nadi subwatershed consists of fan alluvium, Doon gravel, coarse sandstone, boulder bed, conglomerate, clay and grit of Upper Siwalik rocks, quartzite with Himalaya in the north part having both peaks and ‘U’ & ‘V’ shaped valleys. Majority of the ridges (locally called as Dhar) in the area are structurally controlled. Longitudinal ridges, transverse ridges and intermittent deep dissected valleys are the normal features in this area. The area experiences temperature ranging from below freezing point in winter to as high as 36°C in summer. A large amount of precipitation occurs during the months of June to September due to monsoon whereas little rains occur during December–February due to western climate disturbance. 159 J. Indian Soc. Remote Sens. (March 2009) 37:157–166 The general trend of the rocks except near the fold closure is NW–SE, with dips varying from 15° to 60° on either side. The Lesser Himalayan rocks show polyphase deformation with major axes running NW–SE direction. The refoldation of antiforms and synforms is manifested in the form of several structural culminations and depressions. The rocks of ‘Mussoorie Syncline’ are folded into doubly plunging syncline, with its axis trending in general NW–SE direction. Morphometric analysis Methodology The five sub-watersheds drainage networks were delineated from rectified, mosaiced SOI topographic maps of 53J/03, 04, 07, 08 and 53F/11 (1:50,000 scale) on polyconic projection system with the help of GIS software. With the help of the vector module of Erdas software 8.4, drainage was digitized. The stream order was calculated using the method proposed by Strahler’s (1964). The methodology adopted for the computation of morphometric parameters are given below:All the above parameters of five sub-watersheds were calculated using GIS software. Discussion Jhakhan Rao, Song River, Bandal Nadi, Baldi Nadi and Suswa Nadi sub-watersheds are of 6th, 5th, 6th, 5th and 5th order, respectively. The number of streams in various orders is countered and the total length of each order stream is calculated at sub watershed level with the help of GIS software (vector module of ERDAS software). The mean stream length is characteristic property related to the drainage network and its associated surfaces (Vijith and Sathesh, 2006) (Table 1). Table 1 Methodology adopted for the computation of morphometric analysis Morphometric parameters Symbol/Formula Area (km2) A Perimeter (km) P Stream order (u) Hierarchical order Stream length of all order (Lu) Total number of stream segments in all order Nu Mean stream length (Lsm)=Lu/Nu Bifurcation Ratio Rb= Nu/Nu+1 Drainage density (km/km2) Dd=Lu/A Stream frequency Fs=Nu/A Drainage texture Rt=Nu/P Circularity ratio Rc=4 Π A/P2 Form factor Rf=A/Lb2 Constant channel maintenance C=1/Dd Basin relief Bh Elongation ratio Re=2{(√A/Π)/ Lb Total number of first order N1 Texture ratio T=N1/P Π 3.14 The Bifurcation ratios (Rb) of Jhakhan Rao, Song River and Suswa Nadi sub-watersheds are 2.644, 2.009 and 2.213, on the other hand Bandal Nadi and Baldi Nadi sub-watersheds are 1.839 and 1.813. High Bifurcation Ratios of Jhakhan Rao, Song River and Suswa Nadi sub-watersheds indicate structural complexity and low permeability of the terrain. Bandal Nadi and Baldi Nadi have a low value of Bifurcation Ratio (Rb), which indicates that the drainage of the basin is not affected by structural disturbance (Table 2). It is also suggested that the sub-watershed is highly permeable and covered by thick vegetation. The computed Rb value is given in Table 3. The Bifurcation Ratio is also an indicative tool of the shape of the basin. Elongated basins have low Rb value, while circular basins have high Rb value (Morisawa, 1985). 160 J. Indian Soc. Remote Sens. (March 2009) 37:157–166 The mean stream length (Lsm) of Song watershed and its sub-watershed is given in Table 4. The plot (Fig. 2) of logarithm of stream length (ordinate) as a function of stream order (abscissa) yields a set of points lying essentially along a straight line fit following Horton’s (1945) law of stream length. The straight line fit indicates that the ratio between Lu and u is constant throughout the successive order of a basin and suggests that geometrical similarity is preserved in basins of increasing order. It also indicates that all the sub-watershed homogeneous rock material is subjected to weathering-erosion characteristics of the watershed. The important parameters describing the shape of the basin are Form Factor (Rf), Circulatory Ratio (Rc) and Elongation Ratio (Re), which are computed Table 2 Linear aspect of the drainage network of Jakhan Rao, Song River, Bandal Nadi, Baldi Nadi and Suswa Nadi sub-watershed Sub watershed Stream order Number of streams Nu Jakhan Rao 1 2 3 4 5 6 478 213 125 52 60 10 Song River 1 2 3 4 5 Bandal Nadi Total length of streams in km Lu Log Nu Log Lu 243.7858 62.79 27.0106 14.3687 28.1052 44.1678 2.6794 2.3284 2.0969 1.7160 1.7782 1.0000 2.3870 1.7979 1.4315 1.1574 1.4488 1.6451 654 312 129 57 120 306.6672 82.7787 31.8959 13.9175 40.8019 2.8156 2.4942 2.1106 1.7559 2.0792 2.4867 1.9179 1.5037 1.1436 1.6107 1 2 3 4 5 6 463 223 121 61 19 234 210.3721 54.4947 26.4759 16.0984 7.1893 16.6099 2.6656 2.3483 2.0828 1.7853 1.2788 2.3692 2.3230 1.7364 1.4229 1.2068 0.8567 1.2204 Baldi Nadi 1 2 3 4 5 301 126 81 62 31 135.4406 30.1424 18.9846 11.3629 15.9678 2.4786 2.1004 1.9085 1.7924 1.4914 2.1317 1.4792 1.2784 1.0555 1.2032 Suswa Nadi 1 2 3 4 5 518 278 162 41 31 384.4645 173.9737 153.3263 88.3536 40.5547 2.7143 2.4440 2.2095 1.6128 1.4914 2.5849 2.2405 2.1856 1.9462 1.6080 161 J. Indian Soc. Remote Sens. (March 2009) 37:157–166 Table 3 Calculative value of Bifurcation Ratio and Mean Bifurcation Ratio Sub-watershed Bifurcation ratio R b st 1 order/ 2nd order nd 2 order/ 3rd order rd Mean bifurcation ratio th 3 order/ 4th order 4 order/ 5th order th 5 order/ 6th order Jakhan Rao 2.244 1.704 2.404 0.867 6 2.644 Song River 2.096 2.419 2.263 0.475 2.791 2.009 Bandal Nadi 2.076 1.843 1.984 3.211 0.081 1.839 Baldi Nadi 2.389 1.556 1.306 2.000 0 1.813 Suswa Nadi 1.863 1.716 3.954 1.323 0 2.213 Table 4 Calculative value of Length Ratio and Mean Length Ratio Sub-watershed Length ratio Rb nd rd 2 order/ 1st order 3 order/ 2ndorder Jakhan Rao 0.258 Song River Bandal Nadi th Mean length ratio th th 4 order/ 3rd order 5 order/ 4th order 6 order/ 5th order 0.430 0.532 1.956 1.572 0.949 0.270 0.385 0.436 2.932 0.349 0.845 0.259 0.486 0.608 0.447 2.310 0.822 Baldi Nadi 0.223 0.630 0.599 1.405 0 0.714 Suswa Nadi 0.453 0.881 0.576 0.459 0 0.592 and given in Table 5. The Jakhan Rao, Song River and Suswa Nadi sub-watersheds with Form Factors of 0.121, 0.117 and 0.134, indicate elongated basin, and have a flatter peak of low flow for longer duration. Bandal and Baldi Nadi sub-watersheds with Form Factors of 0.319 and 0.215 indicate basin as semi circular in nature, and have a high peak flow for shorter duration. Flood flows of elongated basin are easier to manage than that of the circular basin (Nautiyal, 1994). The values of Circulatory Ratio (Rc) of Jakhan Rao, Song River, Bandal Nadi, Baldi Nadi and Suswa Nadi sub-watersheds vary from 0.300, 0.528, 0.603, 0.437 and 0.351 respectively and Elongation Ratio varies from 0.393, 0.385, 0.637, 0.523 and 0.413 respectively, which indicates that Jakhan Rao, Song River and Suswa River sub-watersheds are elongated in nature and Baldi and Bandal subwatersheds are semicircular in nature and the area is characterized by high to moderate relief and the drainage system is structurally controlled. Calculative value of Drainage density (Dd) is represented in Table 5, Jakhan Rao, Song River, Bandal Nadi, Baldi Nadi and Suswa Nadi subwatersheds have a Drainage Density of 2.897, 3.663, 4.002, 4.002 and 2.899 respectively. Bandal Nadi, Baldi Nadi and Song sub-watersheds have a high Drainage Density which indicates that the region is weak and consists of impermeable subsurface material and sparse vegetation cover and mountainous relief. Jakhan Rao and Suswa Nadi have a low Drainage Density which indicates that the area is covered by resistant permeable rocks with a dance vegetation cover. 162 J. Indian Soc. Remote Sens. (March 2009) 37:157–166 Fig. 2a Regression of logarithm of number of streams versus stream order. Constant Channel Maintenance (C) is inverse of Drainage Density and the computed value is given in Table 5. The Constant Channel Maintenance of Jakhan Rao and Suswa Nadi sub-watersheds are same i.e., 0.345, on the other hand Song River, Bandal Nadi and Baldi Nadi sub-watersheds are 0.273, 0.249 and 0.247 respectively. It indicates that the above (Song River, Bandal Nadi and Baldi Nadi) subwatersheds are under the influence of high structural disturbance, low permeability, steep to very steep slopes and high surface runoff. Stream Frequency (Fs) is related to permeability, infiltration capacity and relief of the sub-watershed. In all the sub-watersheds, except Suswa Nadi subwatershed, the Stream Frequencies are high i.e., 6.467, 9.824, 13.61 and 11.487 respectively. On the other hand the Stream Frequency of Suswa Nadi sub-watershed is 3.552. High Fs indicate the high relief and high infiltration capacity of the bed rocks pointing towards the increase in stream population respectively and is categorized as moderate to high in nature, which indicate erodibility of the rock 163 J. Indian Soc. Remote Sens. (March 2009) 37:157–166 Table 5 Arial aspect of drainage network of Jakhan Rao, Song River, Bandal Nadi, Baldi Nadi and Suswa Nadi subwatershed Sub-watershed Area Perimeter Jakhan Rao 145.05 77.99 Song River 133.86 Bandal Nadi 82.35 Baldi Nadi Suswa Nadi Basin order Bh Re Dd Fs 6 1560 0.393 2.897 6.467 56.42 5 1800 0.385 3.663 41.40 6 1835 0.637 4.022 52.32 38.78 5 1912 0.523 4.044 11.487 7.76 0.22 0.44 0.25 290.01 101.94 5 1440 0.413 2.899 5.08 0.13 0.35 0.35 Fig. 2b Regression of logarithm of streams lengths versus stream order. T 6.12 9.824 11.59 13.61 3.552 11.18 Rf Rc C 0.121 0.30 0.35 0.117 0.53 0.27 0.32 0.60 0.25 164 J. Indian Soc. Remote Sens. (March 2009) 37:157–166 surface as moderate to high in nature and infiltration capacity and relief aspect of the terrain are also moderate to high. Asymmetric factor was developed to detect tectonic tilting at drainage basin scale. The asymmetric factor (AF) is defined as : been affected by the tectonic disturbance. Low value of Drainage Density (Jakhan Rao and Suswa Nadi) indicates that the areas are covered by the resistant permeable rocks with vegetative cover. High value of Drainage Density (Song River, Baldi Nadi and Bandal Nadi) indicates that the region is weak and AF=100 (Ar/At) where, Ar = Area of the right (facing down stream) of the trunk stream, and At = Total area of the drainage basin. In Jhakhan Rao, Song River, Badli Nadi and Suswa Nadi sub-watersheds the asymmetric factors are 55%, 56%, 58% and 65% respectively indicating that tectonic rotation is upward to the right side of the drainage basin and in the case of Bandal Nadi the asymmetric factor is 48% indicating that the tectonic rotation is down to the right side of the drainage basin (Figs. 3a, b, c, d, e). Landslide incidences have been recorded in 29, 47, 28, 28 and 52 respectively in the Jhakhan Rao, Song River, Bandal Nadi, Badli Nadi and Suswa Nadi sub-watershed represented in Fig. 3. Maximum landslide incidences are recorded in the 1st order stream. The right sides of the main stream of Bandal river sub-watershed, landslide incidences are 10 nos and in the left side it is 18 nos. So, the numbers of the landslide incidences are more in upward tilting side, than the downward rotational side. On the other hand Jhakhan Rao, Song River, Badli Nadi and Suswa Nadi sub-watershed, landslide incidences are 21, 36, 18 and 51 nos and in the left side it is 8, 11, 10 and 21 nos. So, the numbers of the landslide incidences are more in upward tilting side, than the downward rotational side (Figs. 3a, b, c, d, e). Fig. 3(a) Block diagram showing tilting of Jhakhan Rao sub-watershed with landslide incidences. Conclusions The Jakhan Rao and Bandal Nadi are of 6th order and Song River, Baldi Nadi and Suswa Nadi subwatershed are of 5 th order respectively. The Bifurcation Ratios indicate that the drainage has Fig. 3(b) Block diagram showing tilting of Song River sub-watershed with landslide incidences. J. Indian Soc. Remote Sens. (March 2009) 37:157–166 165 Fig. 3(c) Block diagram showing tilting of Bandal Nadi sub-watershed with landslide incidences. Fig. 3(e) Block diagram showing tilting of Suswa Nadi sub-watershed with landslide incidences. Fig. 3(d) Block diagram showing tilting of Badli Nadi sub-watershed with landslide incidences. covered by impermeable subsurface material, sparse vegetation and high mountainous relief. The linear pattern of the graphical representation indicates the homogeneous weathering erosional characteristic of the study area. Elongation Ratio, Circulatory Ratio and Form Factor values shows that the sub-watershed of Jakhan Rao and Suswa Nadi possess an elongated shape which indicates the low runoff and flatter peak of flow while Song River, Baldi Nadi and Bandal Nadi sub-watershed are semicircular in shape, have high peak flow for shorter duration. Texture Ratio indicates that infiltration capacity and relief aspect of the terrain are moderate to high in nature. Thus the study shows that GIS techniques have efficient tools in delineation of the drainage pattern 166 to understand terrain parameters such as nature of bedrock, infiltration capacity, surface run off etc., which helps in better understanding the status of land form and their processes, drainage management and evolution of groundwater potential for watershed planning and management. In Jhakhan Rao, Song River, Badli Nadi and Suswa Nadi sub-watersheds the asymmetric factors are 55%, 56%, 58% and 65% respectively indicating that tectonic rotation is upward to the right side of the drainage basin. In Bandal Nadi the asymmetric factor is 48% indicating that the tectonic rotation is down to the right side of the drainage basin. The numbers of the landslide incidences are more in the upward tilting side, than the downward rotational side. References Coasta John E and Fleisher P Jay (1984) Developments and application of Geomorphology, Springer Verlag, New York J. Indian Soc. Remote Sens. (March 2009) 37:157–166 Horton RE (1945) Erosional development of streams and their drainage basins; Hydrophysical approach to quantative morphology. Bull, Geo. Soc. Am. Vol 56, pp. 275–370 Leopold LB, Wolman M Gordon and Miller John P (1964) Fluvial processes in geomorphology, Chapter 5, “Drainage basin as a geometric unit”. Ed. WH Freeman and Company; San Francisco and London Morisawa M (1985) Geomorphology texts books: rivers, forms and process, Chapter 5, “Structural and lithological control” Nautiyal MD (1994) Morphometric analysis of a drainage basin using arial photographs: A case study of Khairkuli Basin, District Dehradun, U.P. Strahler AN (1964) Quantative geomorphology of drainage basins and channel networks, Hand book of Aplied Hydrology; Ed. By Ven Te Chow, McGraw Hill Book Company, New York Strahler AN (1968) Physical Geography, 3rd Edition, Chapter 29, “Quantative analysis of erosional landform” Vijith H and Sathesh R (2006) GIS based morphometric analysis of two major upland sub-watersheds of Meenachil River in Kerala