The bathing waters of the Balearic Islands have always been known for their clarity, life, and color. Since the 60s, these characteristics have been used to create a pole of tourist attraction. However, the quality of the bathing waters has started to be threatened with the rise of the tourism industry especially during the high season. The main reason for the degradation of bathing waters is that, during these periods, wastewater treatment plants (WWTPs) are forced to work at maximum capacity and, in those cases where WWTP inject wastewater into the subsoil of karstified coastal aquifers, they cause the discharge of groundwater mixed with treated wastewater into the sea. The periodicity of algae blooms in bathing water has increased in recent decades mainly due to two factors; i) the increase in water temperature in coves due to warmer summers; ii) the transfer of high levels of nutrients from submarine groundwater discharge (SGD) into coastal waters. 

This project relates the impact of SGD on coastal algal bloom proliferation and the social perception derived from these changes in a touristic region such as the Balearic Islands. Thus, the aim of this project is to evaluate the changes produced by SGD as a conveyor of nutrients from a karstified limestone coastal aquifer affected by the injection of WWTP effluents to the coastal waters of Deià (Mallorca, Balearic Islands) and how stakeholders perceive it. 

Cala Deià during low tourism season (Photo: Aaron Alorda Kleinglass)

The specific objectives of this project will be focused on: 

• Quantify groundwater fluxes of nutrients into the bay and compare them temporarily to provide a correlation with the increase of the tourist season. 
• Define the different perceptions of stakeholders to provide a complete overview of social perception. 
• Create participatory activities to integrate future perspectives on the role of Climate Change on the future of SGD in coastal Mediterranean societies. 
• Upscale the process that is occurring in the study site to the regional level to create awareness and proof of the consequences of massive tourism in the Balearic Islands. 

This project is a collaboration of Iniciatives pel Mediterrani and the UAB.