Risk assessment of climate change impacts on Mediterranean coastal wetlands. Application in Júcar River Basin District (Spain).

Sea level rise (SLR) produced by climate change affects severely coastal ecosystems which are currently being impacted by sea level rise in many parts of the world. In relation with coastal wetlands, the most relevant induced effect will occur on water and soil's salt content, especially in areas below sea level. This could lead into a reduction of habitat for the wetlands' biota. In this context, this research assesses the SLR related risk in the Júcar River Basin District (JRBD). Hazard, exposure, impact, vulnerability, and risk maps have been elaborated. The design and application of measures is prioritized in those areas classified as Very High risk with the aim of improving coastal ecosystems' climate change adaptation. In Western Mediterranean coast, average sea level (ASL) will rise 0.16 m (2026-2045) and 0.79 m (2081-2100) referred to the reference period (1986-2005). High-end scenarios indicate that ASL will rise 1.35 m-1.92 m (2081-2100). The risk analysis results show that 90% of JRBD area affected by SLR, corresponds to coastal wetlands. Half of the affected area belongs to L'Albufera de Valencia wetland with 32.44 km below sea level, which represents a water volume of 42.64 hm (2026-2045) and a surface between 72.53 and 138.96 km representing from 118.36 to 289.70 hm (2081-2100). In the case of L'Albufera de Valencia the impact will be throughout the 21st century, the average rate of SLR will leap from 4 to 11 cm per decade, therefore MSL will reach the current wetland levels by 2040-2045. This makes necessary to modify the lake's management rules, which will lead to an increase of 40 hm3 in water storage and a reduction in water's renewal time compared to current rates (from 15 to 5 times a year).