Environmental and management constraints on tourism in Varna Bay, Bulgarian Black Sea coast

We used a systems approach to examine the conflict between the development of tourism and marine environmental quality in Varna Bay, a critical regional policy issue selected for study after stakeholder consultation. Water quality is of central importance to the tourist industry, since a minimum of water clarity is required to make the water attractive for swimming and bathing. Rampant resort development in Varna Bay in recent years has led to water quality deterioration, because tourist capacity has expanded without concurrent increases in the capacity to collect and treat sewage. We used a numerical model to simulate the Secchi depth (a proxy for bathing water quality) in Varna Bay, as a function of the loading of nutrients and total suspended solids. The model proved valuable for illustrating the relation between bathing water quality and the capacity of sewer systems and waste-water treatment plants, and was helpful in evaluating policy options, even though it does not yet allow precise quantitative prediction of water quality. Results still indicate that a combination of storm water management by sewer system improvement (reducing direct runoff by 80%), combined with construction and upgrading of waste-water treatment plants to 75% N removal could achieve the improved water quality needed to prevent a failure of recent major investments in the tourist industry, with losses of jobs and profit.JRC.H.1-Water Resource