Micro watershed characterization and prioritization using Geomatics technology for natural resources management
Author(s)– Binay Kumar, Uday Kumar
ABSTRACT
Management of watershed encompasses various activities from watershed delineation to monitoring. The suitability of land for development is not only based on a set of physical parameters (geography/terrain, soils, slopes, forest, geology etc.) of the land but also very much on the economic factors. The cumulative effect of these factors determine the degree of suitability and also helps in further categorization of land into different priority orders for development. Sanjai river watershed is located in the central west part of the Subernarekha basin under Kolhan Division of Jharkhand. The study area is totally rain-fed and availability of water for drinking and domestic use is a big problem. The natural recharge process in the area is very poor due to hard compact granite terrain. The response of a watershed to different hydrological processes and its behaviour depends upon various physiographic, hydrogeological and geomorphological parameters. The characterization of a watershed provides an idea about its behaviour. The various parameter characteristics of a watershed behave in more or less perceptible manner. Watershed prioritization is the ranking of different micro-watersheds of a watershed according to the order in which they have to be taken up for development. Holistic integrated planning, involving remote sensing and GIS has been found to be effective in planning for regional development based on watershed approach. Saaty’s analytic hierarchy process is a most widely accepted method for scaling the weights of parameters by constructing a pair wise comparison matrix of parameters where entries indicate the strength with which one element dominates over another vis-à-vis the relative criterion. The pair-wise comparison of parameters results into the “importance matrix” which is based on a scale of importance intensities A Composite Suitability Index (CSI) has been calculated for each composite unit by multiplying weightages with rank of each parameter and summing up the values of all the parameters. Categorization of the CSI is achieved by ranging the CSI into classes, where each range indicates the amount of limitation acceptable for each class.