Dune restoration through ecological engineering

Climate impacts
Changes in sea conditions, Sea level rise, Storms
Sectors
Biodiversity, Coastal management, Disaster Risk Reduction, Sectors specific

Geographical context and climate challenges 

The Bellocchio area (Lido di Spina, Municipality of Comacchio near Ferrara in Italy) is part of the coastal plain in the valley of Comacchio. It is a system consisting of lagoons, wetlands and coastal sandbars covered by fossil dunes that get progressively younger as they get closer to the sea, mostly destroyed by human settlements and bathing sites. The dune restoration is going to take place in the northern part of Bellocchio beach, which includes a 3 km long sandbar between the Adriatic Sea and the Bellocchio lagoon, and the inhabited area of Lido di Spina in the north and the mouth of the Reno River in the south. This stretch of coastline falls within the park Parco del Delta del Po dell’Emilia – Romagna (EUAP0181) and within protected natural areas of Community interest or relevant for the conservation: a site of Community Importance (SCI) – a Special Protection Area (SPA) “Vene di Bellocchio, Sacca di Bellocchio, Foce del Fiume Reno, Pineta di Bellocchio” (IT4060003), a national nature reserve (NNR) “Riserva Naturale Sacca di Bellocchio II” (EUAPP0072) and the Important Bird Area (IBA) “Valli di Comacchio and Bonifica del Mezzano”.

20 years ago, Bellocchio beach was characterised by morphologically well-developed dunes, the landscape which has now been largely destroyed as a result of erosive phenomena connected with the reduced sediment transport in the Reno river, which was observed as early as in the first half of the 20th century. This kind of erosion is associated with the littoral drift of sediment transport towards the north, which has led to the progressive destruction of the mouth and the strong retreat of the neighbouring beaches. If this phenomenon continues, along with marine ingression, this will result in the complete destruction of the intertidal sandbar, the complete loss of the existing protected lagoon habitat and, finally, the exposure of the backshore anthropized areas to coastal risks. 

Objectives

Specifically, the intervention involves the restoration of a small portion (100 m long) of the pre-existing dune morphology, which today has been largely washed away as a result of intense erosion. The intervention will adapt to the natural morphology of the beach, help block marine ingression to the hinterland, and protect one of the existing natural vegetated dunes in the northern part of Bellocchio beach from erosion. 

The intervention is included in a series of experimental projects planned under the European OPERANDUM Project  (for more details, see point 6). 

Adaptation measures implemented in the case

Dune construction and strengthening (Adaptation options /Dune construction and strengthening)

Solutions

The Bellocchio beach was identified as an area of intervention by analysing the following aspects: 

  • geographical characteristics
  • morphological and environmental structure of the beach 
  • coastal erosion situation 
  • climate and weather regime 
  •  coastal hydrodynamics regime 
  •  coastal defence management and planning strategies 
  •  environmental and regulatory constraints 

The Bellocchio beach was selected as one of the few natural beaches that still exist on the coast of Emilia-Romagna which, despite the intense erosion phenomena to which it has been exposed for decades, has not been protected by interventions. The intervention itself, based on the nature-based construction techniques, will be applied in the natural context of the Bellocchio Park where traditional interventions would be too invasive. 

An artificial sand dune strengthened by a completely natural and biodegradable structure made with ecological engineering techniques has been selected as the nature-based solution, which will have to adapt to the natural morphology of the beach. The dune will be about 100 m long and about 2.5 m above the sea level. Two types of structural solutions will be adopted: 

  • Solution 1, which is more innovative, consisting of coconut fibre sacks coupled, for the main part of the structure, to a zipper closure system (currently being patented) that allows the coupling of several individual sack modules and facilitates maintenance activities; 
  • Solution 2, which is more traditional, involves the use of a construction technique called “reinforced soil”, while maintaining an innovative component linked to the use of coconut fibre sheets as a reinforcing element. 

Both the part facing the sea and the terminal parts of the construction will be reinforced with a protective structure made of bundles of wood, which will have the twofold function to serve as a defence against wave energy and as a sand trap. 

Different dune covering configurations will be tested. The upper part of the dune will be divided into sectors, consisting of the layers of sand, coconut fibre nets and the greening techniques. As for the latter, indigenous plant species will be planted both in an innovative way, through the placement of pre-vegetated mats, and through the conventional insertion of individual plants. 

The innovative structural and covering solutions, being of a purely experimental nature, will be applied to a portion of the dune, favouring a more traditional approach and solutions for most of the intervention, albeit enriched by innovative elements, in order to reduce the level of uncertainty of the intervention performance. 

The dimension-related choices were based on the analysis of the weather conditions and the morphological structure of the area. The height and profile of the dune have been studied both to ensure adequate resistance to flooding, wind deflation and erosion caused by waves, and to be in line with what may be its natural morphology. The footprint area of the new dune is such as to minimize interference with the currently existing vegetation. Given the morphology of the area, the dune will be positioned as far as possible from the shoreline, in order to minimize any interference with the marine environment. 

The intervention is planned to be carried out outside the spring/summer period in order not to interfere with the swimming activities and not to disturb the fauna population (in particular avifauna) during the reproductive period. 

Leader of the initiative and key partners

The Bellocchio pilot site is part of a series of experimental projects under the OPERANDUM Project (OPEn-air laboRAtories for Nature baseD solUtions to Manage environmental risks). 

OPERANDUM is a Horizon 2020 European research project led by the University of Bologna involving 26 international partners. The Italian partners are: Struttura IdroMeteoClima Unit of the Regional Agency for Environmental Protection and Energy of Emilia-Romagna (Arpae – SIMC), RINA Consulting, the Italian Aerospace Research Centre (CIRA) and the Euro-Mediterranean Centre on Climate Change (CMCC). 

Among the main objectives of OPERANDUM is the testing of natural design solutions that can mitigate natural events such as floods, landslides, coastal erosion and drought. The interventions will be developed in 10 open-air laboratories (Open-Air-Lab) and the intervention planned in Bellocchio is one of the nature-based mitigation solutions (NBS) that will be implemented in the Italian Open-Air-Lab under the leadership of the University of Bologna.  

Arpae SIMC’s task is to coordinate the working group involved in the realization of the nature-based solution planned for Bellocchio and to contribute to the following four macro-activities: design, permit applications, implementation and monitoring. 

The working group consists of the following entities: 

  • RINA Consulting – partner for the OPERANDUM project – the entity responsible for the design, operational in all macro-activities 
  • NATURALEA – partner for the OPERANDUM project – the entity specializing in nature-based solutions, operational in the design and implementation of the intervention 
  • IRIS SAS – service provider contracted by Arpae SIMC – the entity specializing in nature-based solutions that will support the design, intervention implementation and monitoring. 
  • Regional Agency for Territorial Defence and Civil Protection (hereinafter: ARSTePC) – Local Authority involved through a Collaboration Agreement with Arpae for co-design, permit application procedures and in charge of the intervention implementation 
  • The Carabinieri for biodiversity – Punta Marina Territorial Office – Park management authority incorporating the pilot site that will contribute to all the macro-activities, in particular the permit-related ones. 

As for the environmental authorisations and construction permits, various authorisation and permit applications will have to be submitted to different relevant bodies during the regional authorities conference. At present, Arpa-SIMC has on file the report by the Emilia-Romagna Region Environmental Impact Assessment and Sustainability Promotion Service (hereinafter: VISPA) that has set forth that the relevant intervention is a small-scale one, excluding potential significant and negative environmental impacts, and certifies that the intervention does not need to be subjected to an EIA inspection. 

Stakeholder participation

In addition to the entities listed in point 6, the stakeholders involved so far are the Emilia-Romagna Region Coastal Protection Service and Land Reclamation and the Emilia-Romagna Po Delta Park. Initial contacts have been made with the Municipality of Comacchio and Archaeology, Fine Arts and Landscape Department for the Bologna metropolitan area, as well as the provinces of Modena, Reggio Emilia and Ferrara. 

Success and limiting factors

The in-depth knowledge of the physical system and the management and planning systems of the coastal area has made it possible to identify a site and a type of nature-based solution that, in addition to being suitable for the testing envisaged by the OPERANDUM research project, are of great interest to the local authorities responsible for the management and defence of the territory, which are constantly searching for innovative solutions and alternatives to traditional coastal defence structures, which often have a significant impact on the environment and are not always fully effective. The availability of a wide range of data on morphological structure, coastal erosion dynamics and weather conditions facilitated the preliminary design phases of the project. 

The design, as well as the definition of authorization, permit and implementation procedures, required a shared approach that led to the creation of a working group (see point 6) that brought together the skills necessary to address the many steps that will lead to the implementation of the work and to evaluate its effectiveness. 

In order to achieve the goals of the research project, there were many obstacles caused by long and complicated authorization, permit application and bureaucratic procedures, and they will probably not go away in the future. Another critical aspect concerns the involvement of stakeholders: more effective awareness raising channels are needed. In addition, the stakeholders who have actively contributed so far have operated in a context of limited availability of staff, who are mostly engaged in their regular and often emergency-related tasks. 

Costs and benefits

The project is funded by OPERANDUM under grant agreement 776848. The main benefits of this type of ecological engineering intervention will be: a reduced environmental impact compared to traditional construction works and the restoration of the pre-existing natural dune system and their twofold function of 1) a natural source of sedimentary supply to the beach, 2) a dam that can limit the ingression of the sea into the lagoon habitat. 

Implementation time and lifetime

Intervention 

The drafting of the project, the permit and authorization application related to a part of the environmental authorizations, the preparation and signing of the Collaboration Agreement between Arpae and ARSTePC took about a year and a half. The Regional Authorities Conference to obtain different authorization opinions and permits will last a maximum of 90 days, the subsequent tender procedure will take a few months. The intervention will take about two months and can only be carried out during the autumn and winter months, certainly not during swimming periods or periods of reproduction of some protected species that live in the concerned area. 

Contacts

Ms Margherita Aguzzi – Arpae Emilia-Romagna Struttura IdroMeteoClima Bologna (maguzzi@arpae.it). 

Coordinator of the Operandum Project: prof. Silvana Di Sabatino – University of Bologna 

Leader of the Italian Open Air Lab: prof. Beatrice Pulvirenti – University of Bologna 

Project managers: Paola Robello, engr. and Fabrizio Tavoroli, engr. – RINA Consulting
Other partners:

  • NATURALEA 
  •  IRIS SAS 
  • Regional Agency for Territorial Defence and Civil Protection – Emilia-Romagna Region 
  • Carabinieri for Biodiversity – Territorial Office of Punta Marina

Source for more detailed information

The River Po Delta Park in Emilia-Romagna http://www.parcodeltapo.it/it/mappa.php   

OPERANDUM project https://www.operandum-project.eu/

Pilot Area: Po di Goro – Bellocchio Beach – Panaro River (documentation and maps) https://storymaps.arcgis.com/stories/30e3c3143c42408bb081a252bfd9cb1f