Land use/land cover change assessment of Kosasthalaiyar sub basin using remote sensing and GIS

Abstract

Understanding Land use land cover (LULC) changes in the Kosasthalaiyar sub basin is vital for the sustainability of the watershed. Hence mapping of these changes can help visualize the spatio-temporal dynamics in the area. Remote sensing and GIS provides valuable tools to map these changes. In this present study, Remote sensing and GIS techniques has been used to prepare LULC maps for the years 1988, 1998, 2008, and 2018. The changes that has happened from 1988 to 1998, 1998 to 2008, and 2008 to 2018 has been assessed. Images from Landsat-5 and Landsat-8 Thematic Mapper (TM) have been used. Maximum Likelihood Classifier was adopted to produce the LULC maps of the watershed. Ground truth points using GPS was used to check the accuracy of the work. Five major land use classes viz; Built up land, agriculture, forest, waste land and water bodies were identified in the watershed for the study. During the 30-year period from 1988 to 2018, major changes can be observed in a number of LULC classes. About 66.05 Km2 of crop land got converted to barren land. Out of 588.86 Km2 of crop land only 176.99 Km2 remained unchanged. About 119.94 Km2 has been converted to settlements. Settlements increased from 59.89 Km2 to 341.86 Km2. Barren land increased from 168.73Km2 to 228.59 Km2. The analysis and the results obtained can help policy makers make appropriate policies for the sustainability of the Kosasthalaiyar sub basin.