Prioritization of Mago Basin based on erodibility through morphometric analysis using GIS technique: A PCA-based approach

Abstract

Remote sensing (RS) and Geographical Information System (GIS) techniques have become very important these days as they aid planners and decision makers to make effective and correct decision and designs. Geomorphological characteristics of a watershed are commonly used for developing the regional hydrological models for solving various hydrological problems of ungauged watersheds or inadequate data situations. A morphometric analysis of Mago basin of Arunachal Pradesh was carried out using RS and GIS techniques. The Watershed was delineated using ArcGIS10 software and divided into 15 subwatersheds and prioritized based on principal component analysis (PCA) using SPSS 14.0 software. The basic parameters (area, perimeter, stream order, stream length and stream number) of each sub-watershed were carried out separately using the ArcMap10. The linear morphometric parameters (stream order, total stream length and bifurcation ratio); aerial morphometric parameters (drainage density, stream frequency, form factor, circulatory ratio, elongation ratio, texture ratios, compactness constant and Ruggedness number); and relief morphometric parameters (relief ratio, relative relief, average slope and hypsometric integral) were computed with the help of standard formulae. The principal components were selected and then ranked based on their relationship with erodibility. The sub-watershed having the least compound parameter was assigned the highest priority and so on. The study area was found to have streams of highest order of 3, with order 1, having highest frequency. The obtained low drainage density of the basin indicates that the region is highly permeable. From the prioritization analysis, it was found that sub-watershed 2, 4, and 14 were the most erosion prone areas with rank 1. Therefore, these sub-watersheds need to be considered first and given prior importance for the implementation of any soil and water conservation measures for watershed management. Hence, RS and GIS techniques and PCA are important tools in the morphometric analysis and prioritization of watershed.