Content area
Full Text
Environ Earth Sci (2011) 64:373381 DOI 10.1007/s12665-010-0860-4
ORIGINAL ARTICLE
Morphometric evaluation of Papanasam and Manimuthar watersheds, parts of Western Ghats, Tirunelveli district, Tamil Nadu, India: a GIS approach
N. S. Magesh N. Chandrasekar
John Prince Soundranayagam
Received: 24 November 2009 / Accepted: 8 November 2010 / Published online: 25 November 2010 Springer-Verlag 2010
Abstract A morphometric analysis was carried out to describe the topography and drainage characteristics of Papanasam and Manimuthar watersheds. These watersheds are part of Western Ghats, which is an ecologically sensitive region. The drainage areas of Papanasam and Manimuthar watersheds are 163 and 211 km2, respectively and they show patterns of dendritic to sub-dendritic drainage. The slope of both watersheds varied from 0 to 59 and 0 to 55, respectively. Moreover, the slope variation is chiey controlled by the local geology and erosion cycles. Each watershed was classied as a fth-order drainage basin. The stream order of the basin was predominantly controlled by physiographic and structural conditions. The increase in stream length ratio from lower to higher order suggests that the study area has reached a mature geomorphic stage. The development of stream segments is affected by rainfall and local lithology of the watersheds.
Keywords Morphometric analysis
Papanasam and Manimuthar watersheds
Western Ghats GIS Watershed management
Introduction
The geographic and geomorphic characteristics of a drainage basin are important for hydrological investigations
involving the assessment of groundwater potential, water-shed management and environmental assessment. The correlation between physiographic characteristics of drainage basins such as size, shape, slope of drainage area, drainage density, size and length of the tributaries, etc., to various hydrologic phenomena has been reported by Rastogi and Sharma (1976). The morphodynamic evaluation of drainage data provides a quantitative explanation of basin geometry used to reveal the geological and geomorphic history of each drainage basin. This necessitates the analysis of various drainage parameters such as ordering of various streams, measurement of drainage area and perimeter, length of drainage channels, drainage density (Dd), stream frequency (Fs), bifurcation ratio (Rb), texture ratio (T), basin relief (Bh) and length of overland ow (Lg) to predict the approximate behavior of the watersheds during periods of heavy rainfall (Verstappen 1983; Kumar et al. 2000). GIS-based evaluation using Shuttle Radar Topographic Mission (SRTM) data has given a precise,...