RISKS FOR THE POPULATION ALONG THE BULGARIAN BLACK SEA COAST FROM FLOODING CAUSED BY EXTREME RISE OF SEALEVEL

The geographical status of coastal zone as a boundary between sea andland makes it especially attractive, both for settlement and the implementation ofvarious human activities. This in turn leads to accelerated urbanization of coastalareas. Generally, coastal areas cover only a fraction of the surface of the Earth, butthey concentrate around 60 % of the world’s population. Bulgarian Black Sea coastis also no exception to this trend. According to data from the last national census, Black Sea municipalities comprise 5.21 % of the country’s territory and 8.85 % ofthe population. At the same time, as a consequence of global climate change andthe trend towards increasing sea levels, natural risks of extreme weather events arebecoming more important and more dangerous. This study assesses the risks of risingsea level for the population defined in different scenarios of increase in thelevel. It uses official data on the population in coastal towns and topographic mapsto determine low-laying coastal areas. Analysis was conducted using a GISArcInfo 9.1. The most vulnerable coastal areas are identified and assessed on preliminarygiven scenarios of sea level rise from 1 to 5 meters. As a case study, therisk for the coastal population of the biggest Bulgarian Black Sea resort SunnyBeach is analysed in detail. Applying 3D GIS modeling, visualisation and accurateassessment of flooded coastal areas are performed, and numbers of population potentiallyendangered in case of different scenarios of sea level rise are estimated. The obtained results have significant practical importance and could serve as a primarybase in coastal decision-making, for the needs of civil protection authoritiesand other prevention/mitigation measures in hazard prone coastal zones