Mitigation of flooding and cyclone hazard in Orissa, India

Storm surges generated by the strong tangential wind stresses and normal atmospheric pressure gradients at the sea surface due to tropical cyclones (TC'S) have been studied with the goal of detecting any significant and systematic changes due to climate change. Cyclone and storm surge data for the 19th and 20th centuries for the Bay of Bengal coast of the state of Orissa in India are available to varying degrees of quality and detail, the data being more scientific since the advent of the India Meteorological Department in 1875. Based on more precise data for the period 1971 to 2000, statistical projections have been made on the probable intensities of tropical cyclones for various return periods. The super cyclone of October 29, 1999 (SC1999) appears to have a return period of about 50 years. The cyclones of 1831, 1885 and possibly the one in 1895 could have been super cyclones. During the 19th century, there were 72 flooding events associated with cyclones, whereas in the 20th century there were only 56 events. There was no observational evidence to suggest that there was an increase either in the frequency or intensity of cyclones or storm surges on the coast of Orissa. However, the impact of cyclones and surges is on the increase due to increase of population and coastal infrastructure.