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INDIAN JOURNAL OF GEOMORPHOLOGY
Volume 19 (1), Jan-June, 2014, pp.67-80

MORPHOMETRIC ANALYSIS OF SOPU CATCHMENT IN PHEK DISTRICT, NAGALAND

Sakhoveyi Lohe
Dept. of Geography, Kohima Science College, Jotsoma, Nagaland

Abstract

Sopu river catchment is a 5th order stream consisted of 126 streams with 99 first, 19 second, 5 third, 2 fourth and 1 fifth order streams with a total stream length of 49.22 km, basin area of 18.2 km2 and basin perimeter of 19.5 km. The stream length ratio ranges between 1.53 and 1.98 and the ratio decreases as the order of the stream increases. Bifurcation ratio of the different order streams of Sopu catchment ranges between 2 and 5.21 and shows tendency of developing constant nature. The basin length of Sopu catchment is 6.5 km and decreases as the order of stream decreases. The catchment has high drainage density of 2.70 km/km2 and stream frequency of 6.9 no/km2 and both decrease as the order increases. The shape of the Sopu catchment as a whole is semi-circular to rectangular. The relative spacing between the channels is low (i.e., very close) and increases as the order of the basin increases. The catchment is characterized by high range of Absolute and Relative reliefs. The absolute relief increases from North-West to West and South. High and low Relative relief groups alternate but the catchment is characterized by high relative relief with higher relative relief groups in the North-East. Absolute and Relative relief shows very low degree positive correlation. The best positive correlation between Absolute and Relative relief is found next to the boundary grids. The catchment is characterized by steep slope. The slope factor is more depended with relative relief rather than absolute relief. The catchment is rugged and highly dissected. Hypsometry indicates that the catchment is passing through young to early mature stage of geomorphic development. River profile shows steep gradient of river course indicating active vertical cutting of river bed- a characteristic feature of juvenile stage of cycle of erosion. Sopu catchment has a gentler and wider slope in the west limb and steeper and narrower slope in the east showing tendency of shifting of river course eastward.

INTRODUCTION

Measurement of the shape or geometry of any natural form is termed morphometry (Strahler, 1969). 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 dimension of its landforms (Clarke, 1970). In fact morphometry incorporates quantitative study of the area, altitude, volume, slope, profiles of the land and drainage basin characteristics of the area concerned (Singh, 1972). It has two distinct branches viz. (i) relief morphometry and (ii) fluvial morphometry. Relief morphometry includes the analysis of terrain characteristics which assist in dealing with different aspects of landform characteristics of a drainage basin or of any morphometric unit. Fluvial morphometry includes the consideration of linear, areal and relief aspects of a fluvially originated catchment. The morphometry presented in this study includes linear aspects of the catchment such as stream ordering, stream length, stream length ratio, Bifurcation ratio. Areal aspects include Basin area, Basin perimeter, Basin length, Drainage density, Stream frequency, Basin circularity ratio, Drainage texture. Relief Aspects includes Absolute relief, Relative Relief, Average slope, Ruggedness number, Dissection index, Hypsometry and profiles of rivers and terrain.

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