In Lidder Valley (Kashmir Himalaya)
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International Journal of Marine, Atmospheric & Earth Sciences, 2013, 1(2): 47-58 International Journal of Marine, Atmospheric & Earth Sciences ISSN: 2327-3356 Journal homepage:www.ModernScientificPress.com/Journals/IJMaes.aspx Florida, USA Article Drainage Basin Characteristics and Soil Erosion Intensity of Lidder Watershed (Catchment) in Lidder Valley (Kashmir Himalaya) Sumira Rasool1, Ashok K. Pandit2, Ashwani Wanganeo1, Bhat Mohd Skinder2,* 1Department of Environmental Science and Limnology, Barkatullah University Bhopal, (M.P.), India 2Aquatic Ecology Lab, Centre of Research for Development, University of Kashmir, Srinagar-190006 (J&K), India *Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +91 9469037200. Article history: Received 26 March 2013, Received in revised form 15 April 2013, Accepted 19 April 2013, Published 22 April 2013. Abstract: The present investigation was carried out on Lidder drainage basin (catchment) in Kashmir Himalaya supporting a varied topography and exhibiting altitudinal extremes of 1592 m and 5500m (asl). The drainage density (Dd) and stream frequency (Fu) of the Lidder drainage basin is 2.52 km km-2(km length per km2 area) and 3.32 km-2 respectively. Drainage density class of Lidder stream is coarse (Dd<5 km km-2) which signifies that it has efficient drainage. Lidder stream is sixth order stream in which the largest share is contributed by first order streams (60.32%). The different soil erosion levels have been used to classify the Lidder catchment into four soil erosion zones (Zone I, Zone II, Zone III, and Zone IV) with respect to soil erosion intensities. Keywords: erosion levels, catchment, topography, bifurcation ratio, drainage density. 1. Introduction Valley of Kashmir, nestled in the northwestern folds of Himalaya, is surrounded on almost all sides by mountain ranges and abounds in a vast array of beautiful valleys and freshwater bodies. The Lidder valley has been carved out by River Lidder, a right bank tributary of River Jhelum. It has a Copyright © 2013 by Modern Scientific Press Company, Florida, USA Int. J. Mar. Atmos. & Earth Sci. 2013, 1(2): 47-58 48 catchment area of 1159.38 km2 which constitute about 10 per cent of the total catchment area of River Jhelum (Bhat et al., 2007). The steep slopes in the Lidder valley along with depleted forest cover have been major factors of soil erosion and sedimentation. These factors have also affected the drainage patter of Lidder stream significantly and made the system extremely fragile as it has started showing signs of degeneration. In the present study, stream number, stream order, stream frequency, stream density and bifurcation ratio have been derived on the basis of drainage lining and linear properties of drainage channels as represented over the topographical maps (scale 1:50,000). Soil erosion is an important social and economic problem and an essential factor in assessing ecosystem health and function (Lu et al., 2005; Santhi et al., 2006; Miller et al., 2007). Soil erosion study was carried in the Lidder valley to ensure the status of land and watershed management scenarios and offset the ill effects of erosion and sedimentation. 2. Study Area The catchment area of Lidder stream occupies the south eastern part of the Kashmir valley and is situated between 33º 45′ 01″ N - 34º 15′ 35″ N and 74º 06′ 00″ E–75º 32′ 29″ E (Fig. 1). The Lidder valley forms part of the western Himalaya and lies between the Pir Panjal range in the south, south- east, and southwest Zanskar range. The Lidder valley has been carved out by Lidder river, a right bank tributary of River Jhelum. The valley begins from the base of the two snow fields, the Kolahoi and Sheshnag where from its two main upper streams; the West and the East Lidder originates and join each other near the famous tourist spot Pahalgam town and finally joins the Jhelum at Gur village (Anantnag). Figure 1. Lidder (catchment) valley: location map Copyright © 2013 by Modern Scientific Press Company, Florida, USA Int. J. Mar. Atmos. & Earth Sci. 2013, 1(2): 47-58 49 Thousands of pilgrims visit every year on Rakshabandan the famous holy Amarnath Cave of Lidder valley, at a height of 5372 metres above sea level. The pilgrims pass through the Mahagunas pass (1475 metres) on their way to Shri Amarnathji. Sheeshnag the bare mountain peaks resembling the heads of seven big snakes also forms a part of the Lidder stream catchment area. All sorts of mountain transport viz., horses and pittos are used to carry the luggage as well as humans to the shrine and back. This also adds to the anthropogenic activity though once in a year 3. Methodology The drainage map of Lidder basin was prepared and demarcated from SOI Toposheet maps of Survey of India (No. 43 N/4, 43 N/8, 43 N / 12, 43 O/1) III edition year 1985 of scale 1: 50,000. Morphological properties viz., Bifurcation ratio (Rb) was calculated by using formula: Where Rb is Bifurcation ratio, Nu is total number of stream segments of u order and Nu+1 is number of segments of next higher order. Drainage density (Dd, km-2) by the following equation: Number of Streams (Nu), Basin area (Au) and Length of the stream of different orders (Lu) were measured with the help of a Rotometre and thread directly from the map. The method proposed by Strahler (1964) was used to calculate the stream order. The Universal Soil Loss Equation (USLE) given by Wischmeier and Smith (1978) was used to estimate the soil erosion. A = RKLSCP Where, A is soil loss (tons/hectare/year), R is rainfall and runoff factor, K is soil erodibility factor, L is slope length, S is slope steepness factor and CP is cover management practice factor. Copyright © 2013 by Modern Scientific Press Company, Florida, USA Int. J. Mar. Atmos. & Earth Sci. 2013, 1(2): 47-58 50 4. Result and Discussion 4.1. Drainage Basin Characteristics and Pattern of Lidder Stream The Lidder stream originates from the slopes of Pir Panchal range of western Himalaya. The high mountain range of western Himalaya forms the drainage basin of Lidder stream and segregates it from the other adjacent basins. The western part of the upper Lidder stream gathers its water from the slopes of Kohali glacier, Tarsar lake and surrounding peaks in north and north-west respectively forming West Lidder stream while Sheshnag lake and allied glaciers in the north-east supply water to the East tributary part of Lidder stream. These two streams (East Lidder and West Lidder) run as separate two streams which confluence just ahead of proper Phalgam village. After Phalgam confluence Lidder stream flows through comparatively less inclined region in a wide valley and merges into River Jhelum. The trunk stream showed systematic changes in average width (2-200m), mean depth (10-229 cm) and average velocity downstream (0.5-3.6 ms-1) as given in Table 1. The longitudinal profile of the stream is upward concave. The curve exhibited by the gradient is flat towards mouth of stream (Shakeel et al., 2007). The course of east and west Lidder segment is highly inclined as it passes through narrow mountainous range and is studded with massive boulders till it reaches the flat part of the valley near Bumzoo village. The West Lidder stream commences from Kholi glacier at an altitude of 4800m (a.s.l) and also it receives water from Tarsar lake at Lidderwat and descends towards Phalgam (2110 m, a.s.l). It records a fall of 1 m in every 12m in first 32km of slop down from its origin. Similarly the East Lidder descends from Sheshnag Lake (3570m, a.s.l) to Phalgam (2110m, a.s.l) and in its 27.5 km distance it records an average fall of one meter in every 11 m, up to Phalgam. From Phalgam (2110m, a.s.l.) to its confluence point with Jhelum (1596m) the fall is 1 m in every 74m after flowing a distance of 58 km. The fall in the lower stretch is more gradual which is responsible for widening of stream (causing maximum sedimentation and bund erosion). In fact, most settlements in the valley lie in the wider part and most of the land is under cultivation of different crops as this part has easy water availability and fertile soil (floodplains of Lidder stream). Table 1. In stream measurements of Lidder stream In stream features Min Max Average width(m) 2 200 Mean depth (cm) 10 229 Average velocity (ms-1) 0.5 3.6 Copyright © 2013 by Modern Scientific Press Company, Florida, USA Int. J. Mar. Atmos. & Earth Sci. 2013, 1(2): 47-58 51 Drainage density (Dd) of Lidder is 2.52 km km-2 which denotes that there is 2.52km of channel length available per square kilometer of area, signifying that Lidder stream has efficient drainage with less probability of flooding as the runoff is diluted into the stream segments. Drainage density class of Lidder stream is coarse (Dd<5 km km-2). Stream frequency (Fu) of the Lidder stream is 3.32 km-2 which tell us that there are 3.32 stream segments present per square kilometer of the area in Lidder basin depicting the basin as a whole is well-organized. However, the larger number of segments in the lower order need due consideration as most of them are often non-perennial during autumn and covered with snow during winter. Drainage density measurements revealed that length of stream segment goes on increasing with the increase in stream order. It can be seen from the data that first order segment have shorter mean length (0.59 km) while the fifth order segment has the longest mean length (11.2 km).