Author(s)

J. Letha, B. Thulasidharan Nair & B. Amruth Chand

Abstract

A watershed is an area from which runoff resulting from precipitation flows past a single point into large streams, rivers, lakes, or oceans. Land use describes how a parcel of land is used whereas land cover refers to the materials that are prevailing on the surface. The change in land use type has considerable impact on the nature of runoff and related hydrological characteristics. In some area, land cover remains constant for long periods, revealing equilibrium between various human activities, natural hazards, and climate. In other areas, land cover undergoes progressive to drastic changes more frequently or over a larger expanse. Availability of remote sensing data from earth observation satellites has made it convenient to map and monitor land use/land cover at regional to local scales. The aim of this study is to analyse the discharge data of a river basin for a period of 40 years and to check whether there is any changes in the pattern of river flow due to the changes in the factors affecting runoff like land use/land cover during the study period The trend analysis of the runoff data shows that the peak discharge has an increasing trend over the period of time and low flow values have a decreasing trend. The rainfall runoff relationship derived for different periods revealed that the runoff generated from the same rainfall amounts showed an increasing trend towards the end of the study period. The land use land cover analysis showed that there is considerable increase in the built up area and barren lands at the expense of forest and other dense vegetations. Thus it is seen that the increasing pattern of peak flow and the decreasing pattern of low flow values are the result of land use/land cover change. Keywords: land use, land cover, runoff, trend analysis, remote sensing, supervised classification, built up area.

Keywords

land use, land cover, runoff, trend analysis, remote sensing, supervised classification, built up area