http://dx.doi.org/10.5593/sgem2021/2.1/s11.89 Section Cartography and GIS THE NEGATIVE IMPACT OF HUMAN ACTIVITIES ON UNDERWATER CULTURAL HERITAGE: CASE STUDIES FROM THE BULGARIAN BLACK SEA LITTORAL Assist. Prof. Dr. Nayden Prahov 1, 3 Assist. Prof. Dr. Bogdan Prodanov 2 Assist. Prof. Dr. Kalin Dimitrov 1,3 Eng. Kiril Velkovsky 3 1 National Archaeological Institute with Museum, Bulgarian Academy of Sciences, Bulgaria 2 Institute of Oceanology, Bulgarian Academy of Sciences, Bulgaria 3 Centre for Underwater Archaeology, Ministry of Culture, Bulgaria ABSTRACT The article presents some case studies of the negative impact of human activities on underwater cultural heritage from the Black Sea. A serious problem is pollution and litter disposal in the historical harbours. The resulting conditions often endanger some impressive and well-preserved underwater cultural heritage sites. An advanced methodology for litter registering and assessment was developed and applied using remote sensing with side-scan sonar, subbottom profiler and orthophotography using a drone. The survey of deep-sea shipwrecks using remote operated vehicles (ROV’s) discovered that some of them are almost covered with litter. The ancient remains act as traps which catch light litter objects (mostly items made of plastic), transported by the deep-sea currents. The litter seriously reduced the possibility for exploration and recording of some shipwrecks and their presentation to the public. The ROV and submarine surveys revealed the extent of the damage to numerous originally well-preserved shipwrecks as a result of the fishing industry practice of bottom trawling. All these cases of negative impact by human activities on the cultural heritage and its rapid deterioration raise the question of the necessity of prompt and adequate reactions and measures for the prevention of further damage to these endangered underwater archaeological monuments. Keywords: Underwater Cultural Heritage, Marine litter, Black Sea Shipwrecks, Bottom trawling, Black Sea currents INTRODUCTION Archaeological surveys conducted during recent decades in the Bulgarian part of the Black Sea have revealed numerous cases of negative impact on underwater cultural heritage caused by various human activities. These activities are not deliberate or intentional malicious acts towards the archaeological sites but are rather the result of actions undertaken without any knowledge about their existence or concern for their value. The use of advanced remote sensing techniques helped to determine, assess, and record various case studies of ruined, endangered and neglected archaeological sites. Preprint 743