Decadal Changes in Land use and Land Cover of Noyyal River Basin using Geo-spatial Techniques

Aims: River Noyyal was the life line of the people of Coimbatore, Tirupur and Karur districts of Tamil Nadu and has nurtured a rich civilization. The river is mentioned in many ancient travelogues by European travelers which suggest the importance of the river. But over the years, the condition of the river, both in terms of quantity and quality has deteriorated owing to the expanding population size and its related land use changes.

Place and Duration of Study: The study was conducted to investigate the decadal land use and land cover changes of the Noyyal basin for the year of 2000 to 2020 in the year 2021- 2022.

Methodology: The study was undertaken to produce the land use/land cover map and to explore the change detection analysis of the Noyyal river basin for 20 years. Based on RS and GIS for monitoring the temporal variations of land use land cover, multi-temporal Landsat satellite 30m spatial resolution images of Landsat 4/5 MSS and TM 2000, 2010, and Landsat 8 (OLI) 2020 were obtained from the google earth engine. At the first stage NDVI calculation was done by using ArcGIS software and the second stage supervised classification maximum likelihood classification was done for 3 years 2000,2010 and 2020.

Results: The analysis suggests that Normalized Difference Vegetation Index NDVI of without any vegetation (Class1), medium density (Class3), and high density (Class4) increased by 8.37%, 1.29%, 0.42% respectively. Low density (Class2) decreased by 10.1%. The urban area and agriculture land increased by 13.82% and 18.46%.The forest cover, waste land and barren land decreased by 12.24% 11.99% and 7.90% over the 2 decades and water bodies increased in the year of 2010 and then decreased.

Conclusion: The study has revealed a decline in area under forest and wasteland and an increase in area under built up activities and agriculture land.