Bozcaada (Türkiye): Nature-based Solutions for climate-resilient water management

Bozcaada has great relevance in the area geographically and geopolitically, being the third larger Turkish island. Bozcaada island has a surface of 37.600 ha, with a population of 3.120 inhabitants (2022). Climate is characterised as hot-summer Mediterranean, with warm and dry summers and long, cold and wet winters; wind is a common factor throughout the whole year. The island counts on two amphibian species, 14 of reptiles, 11 of mammals and 103 of birds, from which eleven are endangered according to the IUCN Threatened Species List. Existing vegetation is typical from the eastern Mediterranean regions, mostly dominated by shrubs and herbs, but also small forest patches appear on the landscape. It has natural protected areas, according to Turkish legislation and archaeological relevant sites dating from the Greek era. Nowadays, tourism, winemaking and fishing drive the socio-economic structure of Bozcaada.  Most of the people is dedicated to tourism activities and around 10% develop agricultural activities.

Given the characteristics of the island, there are no continuously flowing rivers or streams; water needs are covered thanks to a small number of interconnected wells and one fountain, but, during summer months, when population hugely increases due to tourism, the supply does not meet the demand. The exploitation of the wells has led to a decrease in the water table, risking salt intrusion from the surrounding Aegean Sea standing as a major challenge from the water resources point of view. To cope with increased demand during summer months, from the 2000s a constructed pipeline transfers water from mainland to the island. In summary, the main challenges of the island are related to water stress: increased demand, risk of aquifer salinization, the existing precipitation regime, the island’s morphology and increasing temperatures due to climate change.

The main objective of this case study was to improve the quantity and quality of groundwater, improve natural infiltration, reduce surface runoff and improve agriculture practices and distribution systems efficiency.

NATMed, EU-funded project through the PRIMA Programme (n. 2221)

• Improved water efficiency and reduction of agricultural water consumption, reducing the reliance on freshwater resources and enhancing drought resilience. 
• Improved soil moisture and higher soil porosity level. Increased porosity enhanced water infiltration, soil aeration, and root development, supporting healthier crop growth.
• Improved water retention and reduced surface runoff. Vegetation cover has increased across the study area and has enhanced soil water retention, reduced surface runoff, and contributed to greater ecosystem resilience, while also lowering soil erosion rates.
• Increased carbon sequestration by planted vegetation. Additionally, enhanced organic matter content contribute to long-term carbon storage in the soil. 
• Improved soil fertility by improving soil structure and organic matter level in agriculture study area.

• Natural infiltration techniques and recharge wells: Implementation of vegetated terracing and infiltration systems to reduce surface runoff, enhance soil water retention and recharge groundwater while preventing seawater intrusion.
• Managed Aquifer Recharge (MAR): Recharge of an artificial aquifer using surface water from seasonal streams, supported by vegetated streambeds and retention embankments to reduce flooding, runoff and sedimentation.
• Conservation agriculture and soil management: Application of minimum soil disturbance, permanent soil cover, optimised nutrient and water management and biodiversity-friendly practices to improve soil structure and moisture.
• Climate-resilient agriculture: Reuse of treated wastewater for irrigation to reduce pressure on freshwater resources and support agricultural productivity.
• Monitoring and stakeholder engagement: Deployment of smart sensors and SCADA systems for adaptive management, combined with active stakeholder involvement through co-design and maintenance activities.

• Strong local representation and close collaboration with local authorities is crucial for identifying and prioritising societal challenges and effectively representing the needs of the users. The strong working relationship between the municipality and the technical team enabled smoother implementation and higher-quality NbS design.
• Data-informed decision-making can effectively guide adaptive management even in the absence of formal financial analyses. Continuous site-level monitoring combined with qualitative feedback from farmers provided strong, practice-based evidence of environmental improvement and potential long-term benefits and supported informed adjustments to the NbS.
• Hybrid solutions are more effective than single interventions. In CS4, natural infiltration techniques alone were insufficient to ensure aquifer recovery or prevent salinisation, while recharge wells on their own did not deliver ecological co-benefits. Combining both approaches resulted in more stable groundwater recharge and improved overall performance of the NbS.
• Active stakeholder involvement is essential for the long-term sustainability of nature-based solutions. In CS4, the engagement of local farmers, municipal staff, and landowners in routine maintenance, damage monitoring, and malfunction reporting increased system reliability and ensured continuity of operations. 
• Long-term monitoring is indispensable for real impact validation. Continuous monitoring is necessary to evaluate effectiveness and adapt management measures.

Izmir Institute of Technology (Case Study Leader)

EGE University (Case Study Leader)

Demir Enerji (Case Study Leader)

Bozcaada Municipality (Case Study Leader)

NBSCLIMATE (IUCN Assessment Leader)

CARTIF Technology Center (Project Coordinator)

Başar Şirin (IZTECH), Alper Baba (IZTECH), Orhan Gündüz (IZTECH), M. Tolga Esetlili (EGE), Irem Orman (Demir Enerji), Claudia Sánchez (NBSCLIMATE), Raquel Marijuan (CARTIF)