INTEGRATED ANALYSIS OF SEAWATER INTRUSION DYNAMICS IN THE NORTHERN BLACK SEA COAST OF BULGARIA

Managing water deficits in coastal areas presents significant challenges amid current climate fluctuations. This study examines the hydrological and water management factors contributing to seawater intrusion along the Bulgarian Black Sea coast. Utilizing data from field monitoring and hydrological model simulations, the research highlights the anthropogenic impacts shaped by the structure and dynamics of water supply. Findings reveal that rainfall levels in the Bulgarian Black Sea coastal region are below the national average. Coupled with excessive groundwater extraction for domestic purposes, this has led to seawater intrusion in the central and northern coastal areas. Over the past 50 years, marine intrusion processes in the area have remained inactive, primarily due to reduced economic and demographic activities following political changes in 1989. However, no significant improvements have been observed. Groundwater levels in the recharge zone, approximately 30 km inland, have risen by 1 meter, but no changes have been recorded in the marine intrusion zone. A decline in spring flow rates in coastal zones and continuous contamination of groundwater with chloride and sodium underscore the severity of the issue. The containment and mitigation of marine intrusion in Northeast Bulgaria require the implementation of unconventional methods. The persistence of this issue emphasizes the urgent need to explore alternative water sources and adopt specific water treatment methods.