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Large scale RESToration of COASTal ecosystems through rivers to sea connectivity

Periodic Reporting for period 1 - REST-COAST (Large scale RESToration of COASTal ecosystems through rivers to sea connectivity)

Reporting period: 2021-10-01 to 2023-03-31

Problem / issues being addressed

REST-COAST deals with coastal restoration upscaling, aiming to improve the status of coastal systems that are now suffering progressive degradation and escalating risks. These negative trends affect a large part of the world population, which either lives or benefits from the coast, a narrow fringe between land and sea that presents some of the highest population densities and whose habitats are among the most productive environments in the planet. These coastal ecosystems feature an often underappreciated carbon storage potential that could clearly contribute to the present efforts on climate mitigation. The combined pressures from climatic factors and human interventions result in escalating risks for natural and socio-economic coastal assets, illustrated by the accelerated rise of sea level and water/air temperatures, which will amplify the degradation of coastal ecosystems, increasing erosion and flooding damages for coastal infrastructures and socio-economic activities. Traditional coastal protection relies on rigid infrastructures, with high costs and carbon footprint that are not well suited for climate mitigation. The alternative of nature-base solutions (NBS) has been applied at local scales with short term views, leading to inconclusive results for a wider uptake of NBS.


The coastal population, socioeconomic assets (including harbours, coastal tourism and renewable marine energies) and the uniqueness of coastal ecosystems make coastal zones a key element for society and the planet. The reversal of negative trends in the evolution of coastal systems is therefore essential for maintaining biodiversity in healthy and thus attractive (for socioeconomic purposes) coastal zones, whose biodiversity and coastal blue carbon are considered crucial for many of our societal endeavours towards sustainability. Coastal protection, as we have known it, presents fragmented approaches, short term objectives and intermittent funding, which have not been enough to curb the current degradation of coastal zones. This negative trend, projected to increase under future physical and socioeconomic scenarios, can only be sustainably reverted by nature based solutions (NBS), that reduce risks while maintaining our coastal natural capital. Otherwise the cost, environmental impacts and carbon footprint, may turn unsustainable many vulnerable but highly valuable coastal systems such as deltas and estuaries (Arcachon Bay, Ebro Delta, Foros Bay, Nahal Dalia, Rhone Delta, Sicily Lagoons, Venice Lagoon, Vistula Lagoon and Wadden Sea).

Overall objectives

REST-COAST deals with coastal restoration, aiming to demonstrate that large scale restoration projects, based on NBS blocks, can provide a low carbon and cost solution to coastal climate adaptation and risk reduction (figure 1). This type of solution combines gains in coastal biodiversity with an increase in coastal blue carbon. Within this general objective, REST-COAST is developing, for vulnerable coastal systems such as deltas, estuaries and lagoons, the following specific objectives: a) feasibility of new coastal restoration techniques, based on enhanced connectivity and accommodation space; b) risk reduction from restoration and supported by early warning systems built from the project models; c) new financial arrangements and bankable business plans that make financially viable the long-term maintenance of restoration; d) scalable plans for coastal adaptation-through-restoration, based on adaptation pathways for each of the pilot sites, with their corresponding tipping points; e) innovative governance and policy transformations aligned with the EU Green Deal, to overcome present restoration barriers; f) coastal restoration platforms, which will build a structure for site-specific coastal restoration contracts that will remain after the project.
Work performed

REST-COAST has gathered information on restoration projects in the Pilots and worldwide to learn from the successes/failures and, from that basis, design large scale restoration interventions. The project advances on techniques, finances and governance enable a “decarbonised” coastal adaptation aligned with climate mitigation, paving the way for a peaceful restoration revolution that reduces risks by ecosystem services from seagrass beds, coastal wetlands and beach dunes that damp storm impacts, improve biodiversity and enhance blue carbon in coastal systems.

Main results

REST-COAST has prepared a database on restoration projects, together with identified barriers and enablers for upscaling. From that experience and the advances from hands-on restorations at the nine pilot sites studied (figure 2), we are proposing: a) new techniques such as a new approach to artificial sand nourishment with limited sand volumes; b) new financial arrangements, combining public and private co-funding; c) new models to predict storm impacts with/without ecosystem services. These models support sustainable management decisions under present climate and provide criteria to design adaptation pathways with NBS that reduce coastal risks and improve the biodiversity status under future climates. These results are discussed and tailored to the nine pilots within coastal restoration platforms that based on project results are co-designing restoration interventions within adaptation pathways with consensus tipping points.
REST-COAST is advancing on restoration techniques, hydro-morpho-ecological observations and models, new financial arrangements and governance transformations in support of large scale projects within long term plans that enhance river-delta-coast connectivity and accommodation space for coastal zones. The proposed new financial arrangements and restoration business plans are having a positive impact to promote restoration and fill the implementation gap with adaptation-through-restoration pathways. The coastal restoration platforms (figure 3) that have been established at the nine pilots contribute to a governance transformation that favours NBS and co-determine tipping points for consensus coastal restoration trajectories.

The benefits from these advances, leading to risk reductions and biodiversity gains, attract more continued funding for restoration that enables the long-term delivery of ecosystem services. The increase in coastal blue carbon by larger and healthier coastal habitats is being presented to stakeholders so that it is explicitly considered in nationally determined contributions. The proposed restorations, designed as a combination of NBS building blocks and supported by early warning systems, increase coastal attractiveness and welfare, in particular for less favoured groups such as fishermen and farmers. The project contributes to reduce erosion and flooding risks, improve coastal water quality, decrease salinization and control coastal pollution, favouring a more harmonic development for coastal systems in dynamic equilibrium with changing climates and their extremes.