A methodology for the nature-based management of the reservoir sediment: Supporting decision-making to enhance the resilience of local communities

Sardinia has an integrated water reserve system comprising more than 30 dams on rivers. Built in the last century, these dams have become part of the modern landscape, while also continuing to affect sediment transport. The trapping of sediment has hindered its natural movement towards the coastal system ever since, thereby reducing the supply of sediment to sandy beaches and increasing their vulnerability to coastal erosion. On the other hand, the reservoirs' capacity to store water is also impacted. These two issues are of particular concern in the context of climate change.For this reason, the present study addresses both issues by proposing a methodology to assess the feasibility of using reservoir sediment as a source of material for beach replenishment. The Autonomous Region of Sardinia and its regional partners are currently developing this methodology as part of the DesirMED project, which is funded through the HORIZON-MISS-2022-CLIMA-01 call, which addresses climate change adaptation through a nature-based approach.The methodology was designed and structured in the following steps: the development of a database of sediment characteristics and reservoir locations; the application of multi-criteria analysis using a defined set of indicators; the selection of case studies where to conduct technical visits involving measurements and sampling; a technical feasibility study on sediment-sand compatibility; and the assessment of the results from the perspective of potential sediment reuse for beach replenishment.This study is part of the ongoing process of implementing adaptation measures. The Autonomous Region of Sardinia incorporates this process into its Regional Adaptation to Climate Change Strategy, which was adopted in 2019 and recently revised. Although the methodology is still in its early stages, it will contribute to improving the resilience of coastal communities and the implementation of adaptation measures at a local level.