Flood Mapping Analysis of Chennai City using Geomatics

India witnessed increased flooding incidences during recent past especially in urban areas reportedly since Mumbai (2005) as a mega disaster. Other South Asian cities like Dhaka, Islamabad, Rawalpindi, besides many other cities in India, are also reportedly been affected by frequent floods. Flood risk in urban areas are attributed to hazards accelerated by growth in terms of population, housing, pavedup areas, waste disposal, vehicles, water use, etc. All contributing to high intensity – high load of runoff. Reduced carrying capacity of drainage channels is also a key concern. Haphazard growth of low income habitations and unorganized trade added tochallenge. Spatial dimensions of all these flood factors are often characterized by land use and changes. Chennai, a coastal megacity is fourth largest metropolis in India, has a history of over 350 years of growth. Meteorologically there is no major upward or downward trend of rainfall during 200 years, and a decrease in last 20 years with a contrast record of increasing floods have been experienced. Analysis of land use changes and generation of thematic maps over the temporal and spatial scale has been undertaken for Chennai city in order to understand the patterns on green cover, buildup area and consequences on hydrological settings and flood inundation map. The paper discusses flood analysis and land use change detection analysis using GIS in urban context with example of the Chennai city and draws attention of land use planners and disaster management experts to integrate their efforts for better and sustainable results.