Wave height selection criteria for beach hazard rating and its implication along south Orissa, East coast of India

Beach hazard rating for wave and tide dominated beaches are based on the prevailing wave or breaker wave height and breaker type. Monthly Littoral Environmental Observation (LEO) is the selection criteria for classification of beach type, and the hazard rating. However computation of breaker wave height during LEO observation varies with local climatic conditions, longevity and period of observation (high/low tide, spring/neap tide etc.). An attempt has made by taking measured wave heights from a directional wave rider buoy 2.5 km off Gopalpur and is compared with breaker wave height measured from LEO, for computation of hazard rating.

A survey was conducted on four beaches of south Orissa for the period June 2008 to May 2009. The beach hazard rating and the level of risk involved in different beach hazards have been attempted for the first time for the south Orissa beaches. In the present study, the beach types has been classified and corresponding hazard rating, for different beach system, with the help of Littoral Environmental Observation (LEO) and is compared with the wave information, measured at Gopalpur. The type of hazards that are consider here are not shoreline erosion or the low frequency major storm events, but rather the ambient conditions of the south Orissa beaches. Result shows that, hazard rating based on monthly average maximum wave height (H_max) bears good correlation with monthly average breaker wave height measured by LEO. Beaches of south Orissa are moderately hazardous and monthly average maximum wave height (H_max) is the best selection criteria for computation of hazard rating along this coast.