Remote Sensing Cum GIS Based Assessment of Morphometric Characteristics of Chittar Basin in District Thiruvananthapuram, Kerala, South India

The use of the drainage morphometric characteristics for the investigations relating to hydrology has been amply discussed in various studies. The realization of its importance has made the analysis of drainage morphometric characteristics studies related to hydrological studies. The morphometric analysis of Chittar River Basin (CRB), a fifth order sub basin of Vamanapuram River on the south west coast, has been studied using Arc Info GIS software. The drainage patterns of the basin are delineated using IRS IC LISS III data and SOI toposheets on 1:25,000 scale as reference. The drainage pattern of the study area is dendritic with stream orders ranging from I to V. The different drainage parameters studied include drainage pattern, stream order, stream number, stream length ratio, relief ratio, bifurcation ratio, constant of channel maintenance, frequency of source head, frequency of confluence points, slope and DEM. The drainage density of the Chittar basin varies from 1 km/km² to > 4 km/km². Stream length ratios for different stream orders vary between 0.30 and 0.64, which are low to moderate and suggest the moderately resistant hard rock terrain. The bifurcation ratio of streams of different order of the basin varies from 3.21 to 5.00. The average bifurcation ratio for the Chittar basin is 3.94, which is near to 4, suggesting some structural control over the development of drainage basin. The relative relief of the basin varies from place to place and most of the basin comes under the category of 30-60 m. At some places relative relief is very high and it suggests rugged topography. It is concluded that Remote Sensing and GIS have been proved to be efficient tools in drainage delineation and updation.