Flood risk and context of land-uses: Chennai city case

Abstract

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, paved-up 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 un-organised
trade added to challenge. Spatial dimensions of all these flood factors are often characterised by land-use
and changes. Chennai, a coastal mega-city 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 over the temporal and spatial scale has been undertaken for Chennai city in order to
understand the patterns on green-cover, built-up area and consequences on hydrological settings. Land-use
issues like decreased natural areas, loss of water bodies, encroachment of river/streams and other drainage
channels, uncontrolled multiplication of built-up areas, have been identified as contributory factor to flood
risk in Chennai. The paper discusses flood risk reduction and management strategies 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.