The study is based on investigations and collection of necessary information on the super cyclone in Orissa in October 1999. It examines cyclonic phenomenon in the country in general and Orissa in particular, and stresses the need for preparing a comprehensive plan for dealing with such disasters.
The phenomenon of cyclone and cyclonic surges have been explained and the factors affecting storm surge in the Bay of Bengal described such as the topographic effects on the wind field, coastal flooding, wave set-up, river flooding, change in topography due to sediment transport, geological setting and climate. Cyclones have been classified based on the magnitude of the combined effect of wind velocity, surge height and rain amount. The distribution of the National Hydrological Stations in the coastal belt of Orissa has been presented.
The disturbance of the hydrologic regime of the region necessitates the fixing of the design criteria for hydraulic structures particularly the probable maximum precipitation and design discharges accounting for the backwater effect of surges, and this entails instrumentation for data collection. The study underlines the need for specialized studies on aspects like the impacts of cyclonic surges on surface & ground water quality and soil salinity. Some issues from the hydrologic research and action viewpoint have been identified like –
- Specialized hydro-meteorological study for coastal areas - revision of runoff coefficient, probable maximum precipitation, hydrological zoning and regional storm-surge modeling studies.
- Remote sensing applications in cyclone studies in general and cyclone prediction in particular.
- Special instrumentation for coastal areas.
- Optimization of manual observational errors during cyclonic storms.
- Evolution of the concept of delta safety program on the lines of dam safety program in the country.
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