Mapping Spatio-temporal Variations of Surface Water Area of Tanks in Coimbatore Corporation Using Google Earth Engine

Surface water is one of the most significant elements of the earth's ecosystem. It is the basic information for analysing the changes in the environment. Therefore it is important to monitor water resources accurately. Nowadays remote sensing plays a major role in extraction of water spread area. In this study, change in water spread area of tanks was mapped for Coimbatore corporation from 2000 to 2021. The analysis was performed in Google earth engine platform using Landsat ETM+ and Landsat OLI datasets. The images for pre monsoon and post monsoon season were scrutinized and classified using random forest classifier in Google earth engine. The area of each tanks and their deviations were calculated for the study period. Results of the study showed that the lowest water spread area was observed in the period from 2000 to 2005 for both pre monsoon and post monsoon season. The tank has maximum water spread area during post monsoon season. The difficulties that has been confronted during the research is the unavailability of images due to cloud cover. The study shows that the random forest classifier can be effectively used to extract water features and water spread area.