Marphometric Analysis and Prioritization of Micro Watersheds of Chandanwari Watershed of lidder Catchment Using Geospatial Techniques

Abstract

Himalayas are highly susceptible to natural hazards that are caused by the action of water such as floods, soil erosion and siltation of the hydro-electric power dams because of their mountainous nature. Soil erosion is the most devastating hazard affecting the livelihood of the people living in these regions. Therefore strategies need to be developed to reduce the impacts of soil erosion in these regions. The present study demonstrates the use of satellite based remote sensing data coupled with the observational field data framework to estimate the soil erosion susceptibility of the micro watersheds of the Chandanwari watershed of Lidder catchment falling in the western Himalaya, using geographical information system (GIS). In this study, watershed morphometry was used as an input to prioritize the micro watersheds on the basis of their different susceptibilities to soil erosion. The prioritization process identifies the highest priority watersheds in which to conduct management. Morphometric analysis has been commonly applied to prioritization of watersheds as Watershed characteristics of a basin represent its physical and morphological attributes that are employed in synthesizing its hydrological response. Various morphometric parameters, namely linear parameters and shape parameters have been determined using Survey of India (SOI) toposheets at 1:50,000 scale for each micro-watershed and assigned ranks on the basis of value/relationship so as to arrive at a computed value for a final ranking of the micro-watersheds. The analysis has revealed that the total number as well as total length of stream segments is maximum in first order streams and decreases as the stream order increases. Horton‘s laws of stream numbers and stream lengths also hold good. Results of prioritization of micro-watersheds based on morphometry analysis show that micro-watershed CMW11, CMW12, CMW13, CMW14 and CMW7 fall under the category of very Severe erosion class; CMW3, CMW4, CMW5 & CMW6 fall under severe erosion class and are more susceptible to soil erosion and are in dire need of management and planning so that the problem of environment degradation in them can be addressed.