Author : Dr.D.Soundar Rajan R Sai Yeshwanth Reddy, Sama Sowmya,T Apuroopa Sai Lakshmi, Jithenderkumar

Given the increase in flood events in recent years, accurate flood risk management and assessment is an important component of flood mitigation in urban areas. Floods represent the most frequent and expensive natural disaster affecting most of the countries around the world. They take place when the river exceeds its storage capacity and the water excess overflows the banks and fills the adjacent low-lying lands, producing significant social, economic, and environmental impacts, including: loss of human life and negative effects on population, damage to the infrastructure and essential services, damage to crops and animals, spread of diseases, and contamination of the water supply. Landsat and multispectral imageries provide reliable and accurate data for the detection of changes in the areal extents of surface water bodies in Chennai and its surrounding areas were conducted through water extraction techniques by using indexes, such as WRI, NDWI and MNDWI using GIS software.

Keywords: Open Source; Survey of India; Chennai, Disaster Management, Landsat Imagery, MNDWI, NDWI, Remote Sensing and GIS, Surface Water Bodies, Urban Planning, Water Extraction Techniques, WRI.