Nature-based solutions for hydro-meteorological risk reduction 

Severe hydro-meteorological phenomena (i.e. extreme weather in terms of precipitation, heat waves and wind storms) on land and sea have a high impact globally as well as in European territories. The increasing frequency and severity of hydro-meteorological events such as hurricanes, intense cyclones, or destructive thunderstorms appear to be associated with climate change and an increasing number of people is exposed to climate-related hazards each year – particularly the most vulnerable. The science behind these phenomena is complex, but advancement in evidence-based knowledge, together with progress in technology and data-driven measurement systems, allow more detailed monitoring and forecasting capability to target interventions at the appropriate time-scale. The employment of nature-based solutions (NBS) to mitigate the impact of hydro-meteorological phenomena could be a viable approach requiring coordinated efforts.
The session intends to stimulate the international scientific community across several fields to demonstrate how nature-based solutions (NBSs) could contribute to disaster risk reduction in line with the EU Roadmap for achieving the goals of the Sendai Framework. It aims to promote and share experience with the best available science and knowledge to establish a coherent approach towards risk mitigation. Results from the EU H2020 projects NAIAD, OPERANDUM, PHUSICOS and RECONECT are encouraged as well as contributions discussing the main drivers and barriers for NBSs implementation . Also contributions documenting how NBS can be beneficial in land use planning, risk assessment, climate change impact, disaster prevention are welcome.
Specific topics are related to the following questions
- How can we mainstream the adoption of innovative, systemic and locally-attuned nature-based solutions for hydro-meteorological risk reduction at watershed/landscape scale? - What are the required features of comprehensive framework for comparing green and blue/grey/hybrid hydro-meteorological risk prevention and reduction solutions? - What is the evidence on the effectiveness of these solutions? How can we capture the potential (insurance) value of ecosystems?
Additional topics are
- Methods for NBS co-designing and co-development - Methods for the identification and assessment of barriers related to social and cultural acceptance and in regulatory frameworks that hinder the adoption of NBS

Convener: Silvana Di Sabatino | Co-conveners: Elena Lopez-Gunn, Amy Oen, Zoran Vojinovic
vPICO presentations
| Wed, 28 Apr, 14:15–17:00 (CEST)

vPICO presentations: Wed, 28 Apr

Chairpersons: Amy Oen, Silvana Di Sabatino, Zoran Vojinovic
NBS examples
Francesco Faccini, Andrea Benedettini, Valentina Brodasca, Umberto Bruschini, Riccardo Giammarini, Fabio Luino, Cristiana Mortola, Francesca Neonato, Paolo Noce, Andrea Robbiano, Laura Turconi, and Guido Paliaga

The Horizon 2020 RECONECT - Regenerating ECOsystems with Nature-Based Solutions for hydro-meteorological risk rEduCTion - Project aims to contribute to a European reference framework on NBS by demonstrating, upscaling and spreading large-scale NBSs in natural areas.

The Italian RECONECT demonstrator is set in the Portofino Park, which represents a unique natural and cultural landscape but is severely endangered by geo-hydrological hazards.

The most frequent processes are shallow landslides and flash floods, sea-storm surges, rockfalls and mud-debris flows. Often, several different processes can occur simultaneously during an intense meteorological event, causing a location specific multi-hazard effect.

This research introduces the NBSs interventions designed within the RECONECT Italian case study in two pilot catchments (San Fruttuoso and Paraggi basins), accessed by thousands of tourists throughout the year.

Amongst all possible interventions that can be implemented in the protected area, NBSs are considered to be most suitable due to their minimal impact and the possibilities for integration within the natural environment. The Portofino Park has already been promoting interventions aimed at reducing the impact of geo-hazards within the protected area in response to climate change. As part of the RECONECT project, and in order to achieve sound engineering and technological solutions which can also preserve unique landscapes of natural and cultural heritage, the Park authority is realizing a set of NBSs in San Fruttuoso and Paraggi catchments. The purpose of the design is to demonstrate how NBSs can be integrated into such areas and how to reduce geo-hydrological risk for given climate change scenarios within the framework of an ecosystem based holistic approach for risk reduction.

The main scope of NBSs in San Fruttuoso is to address following basic challenges: stabilizing of rock masses; reduction of geo-hydrologic risks in order to intercept and reduce suspended and solid transport along the streams as well as reducing erosion; forest management focused to improve biodiversity, to remove non-native species and dangerous old specimen (Pine trees), not suitable in a Mediterranean climate, in order to select the climax species (i.e. Quercus ilex); restoration of dry-stone walls with the aim to valorize the terraced landscape as well as stabilizing the slopes.

The reconstruction of terraces and the regeneration of natural and man-made ecosystems will also be implemented within the Paraggi basin. In addition, hydraulic-forestry arrangements on water courses will be undertaken to improve the outflow and decrease solid transport and floating debris. Furthermore, other measures such as riverbed and tributary implementations, maintenance along hiking paths, slope stabilization, and cleaning and removing dead vegetation and dirt will also be undertaken.

The project also includes hydro-meteorological monitoring activities in the selected basins and the periodic checking of NBSs performance indicators. Lastly, remote sensing surveys are used to quantitatively assess the ongoing gemorphogical processes.

In relation to future projections of natural and socio-economic impacts of climate change, NBS represent a relevant mitigation and adaptation strategy for the Portofino case study, which may be upscaled to national and international level.

How to cite: Faccini, F., Benedettini, A., Brodasca, V., Bruschini, U., Giammarini, R., Luino, F., Mortola, C., Neonato, F., Noce, P., Robbiano, A., Turconi, L., and Paliaga, G.: Nature-Based solutions for geo-hydrological risk reduction: the Portofino Park (Italy) experience in the H2020 RECONECT project, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1501, https://doi.org/10.5194/egusphere-egu21-1501, 2021.

Guido Paliaga, Francesco Faccini, Fabio Luino, Laura Turconi, and Zoran Vojinovic

Man-made terraces are widely diffused in hilly-mountainous areas, representing an ancient anthropogenic landscape modification for agricultural purposes. Then, terraces have been involved in several changes through times: socio-economic evolution caused a progressive general abandonment of terraced areas causing land use change and even their obliteration or collapse. In some cases, terraces deeply shaped the landscape and then their maintenance is considered crucial for cultural, aesthetic and even touristic value.

Terraces belong to the soil and water conservation measures as they allow to reduce erosion, improve slope stabilization and retain water runoff; as such they fit perfectly into the Natured-Base Solution definition. The artificial immobilization of debris and stone in terraces may turn in a possible source of geo-hydrological hazard in case of heavy rains, as happened in the Riviera Ligure in the last 20 years; a sequence of events was associated to landslides and flash flood, causing damages and casualties. Then, the proper terraces maintenance and monitoring is crucial for the maintenance of the geomorphological and geotechnical slope stability.

We focused on terraces identification and on the evaluation of debris/stones volume trapped after centuries of human activity in the pilot area of the Portofino Park, which represents a unique natural and cultural landscape that is severely endangered by geo-hydrological hazards. The further step has been the spatial relationships assessment with the exposed elements like buildings, infrastructures and culverted stream, that is the basis of risk assessment and land use planning activities.

The research has been carried out within the framework of the Horizon 2020 RECONECT - Regenerating ECOsystems with Nature-Based Solutions for hydro-meteorological risk rEduCTion; the Italian RECONECT demonstrator is set in the Portofino Park.

Using a detailed Lidar survey, the edges of dry-stone walls were firstly identified, allowing a detailed mapping. Focusing to terrace bases allowed to recognize a possible natural surface through their interpolation along the slope: the difference between the terraced slope profile and the interpolated one allowed a preliminary volume assessment.

Dry-stone wall basis has been detected applying a local upslope curvature routine that is the weighted mean of local curvatures of the directly neighboring upslope contributing cells, controlled with 5 cm orthophoto. In very steep areas terraces stored volume mediumly accounts about 0.35 m3/m2, which agrees with the back analysis estimation of volumes collapsed after recent geo-hydrological events in the Ligurian Riviera.

Stored volume is an essential parameter for prioritizing terraces restoration interventions for risk reduction through NBS techniques. Finally, the survey and analysis outcome may be useful to investigate the recent numerous geo-hydrological events that have been triggered in terraced areas in large sectors of the Mediterranean.

How to cite: Paliaga, G., Faccini, F., Luino, F., Turconi, L., and Vojinovic, Z.: The role of man-made terraces as NBS measure for geo-hydrological risk reduction in the Portofino Park (Italy) - H2020 RECONECT project, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3977, https://doi.org/10.5194/egusphere-egu21-3977, 2021.

Thomas Zieher, Jan Pfeiffer, Annemarie Polderman, Kent von Maubeuge, Helmut Hochreiter, Christian Ribis, Veronika Lechner, and Daniel Bergmeister

Deep-seated landslides can pose a serious threat to settlement areas and their assets in mountain regions across the world. An important step of a holistic landslide management is the implementation of suitable mitigation measures. However, technical mitigation measures against the impacts of natural hazards often rely on synthetic materials. Progress in materials science and development often makes it possible to replace synthetic components with renewable, bio-degradable materials that provide the same functionality. These alternative, nature-based solutions can simultaneously offer co-benefits such as environmental sustainability, less maintenance efforts and a greater societal acceptance. In this context, an experimental setup was installed in the upslope catchment area of an active deep-seated landslide in Vögelsberg (community of Wattens, Tyrol, Austria). At the chosen location the infiltration losses along the unconsolidated streambed potentially contribute to groundwater recharge, which is considered a main hydrological driver of the landslide. The goal of the experiment was to efficiently seal a 25 m long section of a stream without relying on synthetic materials. To reach this goal, a prototype of a bio-degradable bentonite mat was implemented as an impermeable layer in the subsurface of the leaky stream section. The efficacy of the mat is continuously monitored by several soil moisture probes installed below and above the layer and repeated measurements of subsurface characteristics with the help of electrical resistivity tomography. Furthermore, topographic changes due to erosion or sagging of the embankments are periodically monitored using a terrestrial laser scanner. Currently, the implemented solution must be considered a concept case to help raise awareness for this nature-based alternative to conventional engineering measures based on synthetic materials. If the experiment proves successful, it could be upscaled in the upstream catchment area of the landslide to prevent infiltration along leaky streams in the same way and reduce the hydrological forcing of the landslide.

The present study has been carried out in the OPERANDUM project. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 776848.

How to cite: Zieher, T., Pfeiffer, J., Polderman, A., von Maubeuge, K., Hochreiter, H., Ribis, C., Lechner, V., and Bergmeister, D.: Nature-based sealing of leaky streams - Testing a bio-degradable bentonite mat for preventing infiltration losses in alpine stream, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2052, https://doi.org/10.5194/egusphere-egu21-2052, 2021.

Giacomo Bernello, Elena Mondino, and Lucia Bortolini

Heavy rainfall is one of the hydrogeological hazards increasingly connected with climatic changes. Natural Water Retention Measures (NWRMs) implementation represents a chance to build resilient communities and to reduce potential damage. This water management approach has several designs and can be adopted at different scales. However, NWRMs are not widespread, and in some cases they are even ignored by both citizens and public administrations. Understanding how people perceive NWRMs is the first step to promote the implementation of these structures. This study aims at exploring people’s knowledge of NWRMs and their attitudes towards them. We conducted a survey in the Veneto Region (Northeastern Italy) in 2020. Preliminary data exploration shows that the overall knowledge of NWRMs varies depending on the type of retention measure. Respondents’ attitudes towards NWRMs are positive in public areas (e.g. green spaces, parking lots), but are more heterogeneous when it comes to private properties (e.g. houses, private gardens). Further investigations are therefore needed concerning the last point. This study provides a deeper understanding of the dynamics behind water management systems’ implementation to reduce heavy rainfall and flood damage and can inform policymakers dealing with flood risk management.

How to cite: Bernello, G., Mondino, E., and Bortolini, L.: Exploring Perceptions of Natural Water Retention Measures and Their Implementation: A Case Study in Northeastern Italy, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3249, https://doi.org/10.5194/egusphere-egu21-3249, 2021.

Giorgia Verri, Sahameddin Mahmoudi Kurdistani, Nadia Pinardi, Giovanni Coppini, Andrea Valentini, and Dario Conte

A 2-layer Estuary Box Model, named CMCC EBM (Verri et al., 2020), has been devised by the CMCC Foundation to offer a proper representation of the estuarine overturning circulation and mixing processes in a coupled modelling framework with hydrology models and ocean models. The regional to global ocean models reaching the mesoscale cannot solve the estuarine dynamics because they cannot represent the estuary geometry due to their low resolution. Thus, the idea of an estuary box model that gives reasonable values of water volume flux and salinity at the river mouth, which in turn affects the ocean dynamics.

A further development of the model equations (Verri et al. 2021, under revision) considers the estuary length, i.e.  the length of the salt wedge intrusion, as a model unknown which depends on the competition between the riverine freshwater and the salt ocean water.

The physical core of the model consists of two conservation equations for volume flux and salt flux both averaged over the diurnal tidal cycle. Moreover, two non-dimensional equations based on the Buckingham theorem have been conceived to provide the estuary length and the along-estuary eddy diffusivity (Verri et al., under revision) as time-variable parameters instead of assuming they are static as most box models do.

The input fields required by the CMCC EBM are the river runoff at the estuary head and the ocean inflow at the river mouth in terms of both barotropic tidal inflow through the water column and baroclinic inflow at the bottom. The estuary width and depth at the river mouth are the only tunable parameters of the CMCC EBM.

The model capability to estimate the length of the salt wedge intrusion has been tested and validated. The Po di Goro branch of the Po delta system has been selected as case study. It is representative of the river-dominated estuaries in a micro-tidal sea, the so called “salt wedge estuaries”, with a multiannual average of the salt wedge intrusion around 15 km according to the ArpaE monitoring campaigns.

Overall the high statistical performance, the short computation time and the minimal calibration encourage to use the CMCC EBM in coupled mode with mesoscale ocean models to produce more realistic operational forecasts and climate scenarios.

In the framework of the Operandum H2020 project (https://www.operandum-project.eu), the CMCC EBM has been used to provided historical simulations (1981-2010 time window) and mid-term scenarios (2021-2050 time window under RCP 8.5) of both the salt wedge length and the salinity at the Po di Goro mouth. The final aim is to design and develop a site-specific nature-based solution which may address the pressing issue of the salinization of the inland waters. The CMCC EBM results clearly showed a stronger intrusion of saltier ocean water in the middle term. The average, the minimum and the maximum values of salinity at the river mouth provided by the model projections are assumed as reference values to investigate the behaviour of two halophyte species which have been selected to reduce the saline intrusion problem because of their high salinity absorption capacity.

How to cite: Verri, G., Mahmoudi Kurdistani, S., Pinardi, N., Coppini, G., Valentini, A., and Conte, D.: Future salt intrusion climate scenarios: the case of the Po river, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14887, https://doi.org/10.5194/egusphere-egu21-14887, 2021.

Chloé Duffaut, Nathalie Frascaria-Lacoste, and Pierre-Antoine Versini

Hydro-meteorological risks are increasing and this could be due to global changes. These risks are particularly important in the urban context where most human beings live. Indeed, the impervious surfaces present in cities increase the risk of flooding, for example. Nature-Based Solutions can help to reduce these risks by creating permeable soils or storing water while promoting biodiversity. In this context, it is essential to understand what hinders the development and sustainability of these Nature-based Solutions in the city and what could help to deploy them on a large scale. For this purpose, various professionals working on Nature-Based Solutions in the city in France, were interviewed between 2020 and 2021, both in the academic and operational sectors, or even at the interface between the two: researchers in ecology or hydrology, IUCN (International Union for Conservation of Nature) project manager, project managers at the Regional Biodiversity Agency, director and natural environment manager of a watershed union, agro-economists engineer among others. They were asked what are the barriers and potential opportunities for Nature-Based Solutions implementation and sustainability in city. By analysing their answers, it emerges that the obstacles are more often cultural, political or financial than technical. The potential levers often mentioned are education and awareness-raising at all levels, especially for elected officials and the general public. Regulations such as the PLU (Local Urban Plan) and new funding for more natural spaces in the city also seem to be means of promoting Nature-based Solutions in urban areas. These interviews with diverse professionals directly involved in Nature-Based Solutions in cities allow to give real courses of action to be taken to democratize these Solutions throughout the French territory, or even internationally, and therefore ultimately reduce the risks of hydro-meteorology. This is one of the objectives of the French ANR project EVNATURB (Assessment of ecosystem performance of a renaturation of the urban environment), in which this study has been carried out.

How to cite: Duffaut, C., Frascaria-Lacoste, N., and Versini, P.-A.: Barriers and levers for implementing sustainable Nature-Based Solutions in cities, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5801, https://doi.org/10.5194/egusphere-egu21-5801, 2021.

Francesca Perosa, Marion Gelhaus, Veronika Zwirglmaier, Leonardo F. Arias-Rodriguez, Aude Zingraff-Hamed, Bernd Cyffka, and Markus Disse

Countries located in the Danube River Basin (DRB) are in danger of being affected by major catastrophic floods along the Danube and its tributaries. Floodplain restoration measures are among win-win nature-based solutions (NBS) for flood risk reduction but practitioners see their limitations in comparison to technical measures, when looking at their effectiveness and profitability. Within the framework of the EU Interreg Danube Floodplain project, this presentation shows the benefits of floodplain restoration in terms of monetized ecosystem services (ES). Our work focused on multiple ES groups for four study areas in the Danube catchment, located in Czech Republic, Romania, Serbia, and Slovenia. This was done with the help of stakeholder engagement, hydrodynamic models results, and the Toolkit for Ecosystem Service Site-Based Assessment (TESSA). Moreover, the approach was complemented with alternative methodologies (e.g. surveys on social media). Results show positive annual combined benefits of floodplain restoration measures, suggesting the helpfulness of evaluating these NBS through ES assessment. The work done will help increasing the knowledge on floodplain and their ES, and on how to rapidly evaluate them. Moreover, it will bring decision-makers further evidence in favor of floodplain restoration measures to be implemented for a general benefit of the communities.

How to cite: Perosa, F., Gelhaus, M., Zwirglmaier, V., Arias-Rodriguez, L. F., Zingraff-Hamed, A., Cyffka, B., and Disse, M.: Examples of Floodplain Restoration Evaluation Studies in the Danube River Basin, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7039, https://doi.org/10.5194/egusphere-egu21-7039, 2021.

Alejandro Gonzalez Ollauri, Slobodan Mickovski, Rohinton Emmanuel, and Albert Sorolla Edo

Live cribwalls are Nature-based solutions consisting of timber-based structures acting as retention walls at the toe of slopes and embankments subjected to instability and erosion events. The structure of live cribwalls resembles a multi-level crib made of timber logs from different plant species (e.g. pine, spruce, hazelnut, etc.). The crib structure is then backfilled with earth materials in which locally-available plant cuttings and/or saplings are inserted to establish a dense cover of native vegetation, providing added reinforcement and stability to the cribwall over time; particularly after the complete decay of the timber structure is reached. However, the effect of vegetation on the reinforcement of live cribwalls has not been examined systematically. Information on how vegetation can contribute to reinforce cribwalls hydrologically and mechanically is essential to evaluate the long-term performance of these Nature-based solutions against hydro-meteorological hazards. In this study, we propose a novel conceptual, numerical model based on empirical knowledge to evaluate the reinforcement effect of vegetation on live cribwalls over time. We also demonstrate how the proposed model can be applied to other Nature-based solutions concerned with slope protection and erosion control, such as live gratings or palisades.

How to cite: Gonzalez Ollauri, A., Mickovski, S., Emmanuel, R., and Sorolla Edo, A.: The reinforcement effect of vegetation on live cribwalls, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5858, https://doi.org/10.5194/egusphere-egu21-5858, 2021.

Aude Zingraff-Hamed, Gerd Lupp, Jonathan Schedler, Josh Huang, and Stephan Pauleit

Nature-based solutions (NBS) are increasingly recognized as robust, sustainable and cost-effective measures for reducing the risk of extreme weather events. Their widespread implementation has become an important goal of the European Union’s political agenda. Many types of measures are included under the umbrella term of NBS. As their number is increasing, knowledge transfer should support effective implementation. Efforts have been made by a number of EU funded projects to develop and assess NBS implementation and enhance the transfer of experience. European databases as OPPLA has been created for this purpose. Interestingly, while mountain areas are highly vulnerable and already have experienced numerous extreme hydro-meteorological events and related natural hazards, NBS implementation in mountain area have received very little attention in both the research and practices until recently. The EU funded project PHUSICOS intends to partly fill this research gap by contributing in the knowledge transfer effort in making an inventory of NBS at their case study sites located in mountain areas. Given this background, the goal of our study is to provide a detailed overview of the NBS implementation effort for the case of German Alps. In this contribution, we present a systematic survey performed in the German Alps. We found 156 solutions implemented. Descriptive and qualitative analyses provided an overview of the implementation efforts in the German Alpine areas. Most of the measures were located within river systems and targeted flood protection. Few measures were implemented in the upper catchment to retain water on the land. Furthermore, few solutions exist to mitigate soil erosion and landslide. Further analysis concentrated on the stakeholders driving the NBS implementation. This survey may help, in the future to develop practical guidelines, identify governance enablers, ease cross-fertilization and identify successfully strategies.

How to cite: Zingraff-Hamed, A., Lupp, G., Schedler, J., Huang, J., and Pauleit, S.: 156 Nature-based solutions in the German Alps to mitigate hydro-meteorological risks, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8522, https://doi.org/10.5194/egusphere-egu21-8522, 2021.

James Bishop, Gareth Old, Ponnambalam Rameshwaran, Andrew Wade, David Gasca-Tucker, John Robotham, Ann Berkeley, David McKnight, and Jo Old

Catchment-based approaches that work with natural processes for fluvial flood risk reduction are currently the subject of much interest both internationally and in the UK, where they are known as Natural Flood Management (NFM). NFM schemes typically seek to replicate, restore, or enhance natural features of the environment so as to store and/or slow floodwaters during storm events. Benefits over traditional hard-engineered flood management approaches include reduced capital costs and carbon emissions, and they can deliver positive outcomes for both water quality and biodiversity. Despite a small number of studies indicating their potential value, the further uptake of NFM schemes is limited by a lack of empirical evidence demonstrating their effectiveness.

We present results from an intensive monitoring network within a tributary (catchment area 3.4 km2) of the Littlestock Brook, a lowland agricultural catchment within South East England that presents a flood risk to the downstream village of Milton-under-Wychwood. The catchment forms part of the first NFM scheme of its kind within the River Thames basin, currently being delivered in partnership by the Evenlode Catchment Partnership and the Environment Agency as part of a five-year project (2016-2021). Precipitation, stream discharge, and water level within eight offline storage areas have been continuously monitored since September 2019. High resolution topographic surveys of each storage area enable filling, storing, and drainage dynamics to be determined and compared with downstream hydrograph metrics. A series of storm events between October 2019 and February 2020 have provided a unique dataset for investigating the performance of the NFM scheme.

Data from four storms with estimated peak-discharge return periods ranging from 2.7 to 5.5 years demonstrate the potential for reducing peak discharge. During the largest storm, flood volume across the peak of the hydrograph was reduced by 22%, with 64% of total storage capacity remaining unused. Variations in the filling, storing, and drainage characteristics of each storage area have consequences for the overall effectiveness for reducing downstream flood risk and these will be discussed.

How to cite: Bishop, J., Old, G., Rameshwaran, P., Wade, A., Gasca-Tucker, D., Robotham, J., Berkeley, A., McKnight, D., and Old, J.: Offline Storage Areas as a Natural Flood Management intervention: Evidence from the Evenlode catchment, UK, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9779, https://doi.org/10.5194/egusphere-egu21-9779, 2021.

Chairpersons: Silvana Di Sabatino, Zoran Vojinovic
NBS examples
Bidroha Basu, Arunima Sarkar Basu, Srikanta Sannigrahi, and Francesco Pilla

Increase in extreme rainfall and storm events due to climate change and decrease in water retention in soil due to urbanization has increased the risk of flooding in cities globally. Since majority of the cites are mostly developed, expanding the conventional urban drainage system to account for the excess runoff produced by the rainfall event has limited scope. The challenge is to develop sustainable urban drainage systems (SUDS) to reduce runoff and create a flood control system in major cities. One of the SUDS that are becoming popular is the use of nature-based solutions (NBSs). A set of conventional NBSs to mitigate flood risk include bioswales, bio-retention, tree pits, infiltration trenches. However, even though their performance in flood control is found to be effective, they require considerable land area for deployment, which might be difficult to obtain in cities. For this purpose, green roofs have becoming popular as an alternative NBS in flood control, as it does not require any additional land area for deployment. This study investigates the effectiveness of a green roof in reduction of runoff via real-world case study. A green roof deployed in the CHQ building located at the city centre in Dublin, Ireland has been considered for the study. The green roof has a total size of 70 sq. m. Performance of the green roof in runoff reduction was measured based on rainfall and water retention data collected at four modular units, each having 1 sq. meter area, located at the centre of the roof with an IoT weight scale. The data has been collected for 1 week at 3-minute interval, and the reduction in runoff with and without the presence of the green roof has been estimated. The performance of the green roofs in runoff reduction was found to vary between 20-40% depending on the intensity of storm events.

How to cite: Basu, B., Sarkar Basu, A., Sannigrahi, S., and Pilla, F.: Effectiveness of green roofs in reduction of rainfall-fed runoff: A case study in Dublin, Ireland, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14461, https://doi.org/10.5194/egusphere-egu21-14461, 2021.

Gabrielle Powell, Joanna Clark, and Tom Nisbet

Natural Flood management (NFM) is a nature-based solution and catchment-based approach to flood mitigation.  Leaky barriers are a form of NFM and are popular amongst community groups working with natural processes as an affordable and sustainable action that they themselves can implement without investment in large infrastructure. At our research site, over 30 Leaky barriers have been implemented along a mile-long stretch of flashy river by a local community flood group and landowner in an attempt to decrease flood risk downstream in partnership with the Environment Agency. The effectiveness of these leaky barriers is being monitored in a number of ways, including: river flow, river level, geomorphic surveys and time-lapse footage. We describe the project dynamics and operational context that shaped the adopted control-intervention monitoring design. Based on previous studies, we hypothesize that leaky barriers will be most effective at mitigating smaller, rather than large flood events, such as in 2007. This is tested by examining the data collected over 2019-20, which includes storm Dennis (13th-19th February 2020) that caused widespread flooding across England and Wales. The results will contribute to a wider evidence base being collected by the Environment Agency, exploring the context in which community projects and monitoring take place against the changing expectations of funders and the evaluation of data produced.

How to cite: Powell, G., Clark, J., and Nisbet, T.: Monitoring Leaky Barriers for Natural Flood Management (NFM) within a community-led project, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7508, https://doi.org/10.5194/egusphere-egu21-7508, 2021.

NBS platform and methods for evaluating their efficacy
Laura S. Leo, Sisay Debele, Joy Ommer, Saša Vranić, Zahra Amirzada, Irina Pavlova, Edoardo Bucchignani, Mohammad Aminur Rahman Shah, Alejandro Gonzalez-Ollauri, Slobodan B. Mickovski, Prashant Kumar, Milan Kalas, and Silvana Di Sabatino

Nature-Based Solutions (NBS) refer to the sustainable management, protection and use of nature to preserve the ecosystem and prevent the loss of biodiversity. Given the multiple environmental, social, and economic benefits they provide to society, NBS have been increasingly promoted and implemented in cities, especially for air pollution mitigation and the improving of human thermal comfort and well-being. Several databases and web platforms already exist, which document these beneficial impacts of NBS in our cities by collecting and exposing existing NBS case studies and projects from around globe. However, the effort of cataloging and storing NBS data according to common and harmonized principles and standards seems yet sporadic and uncoordinated at the global and European level, especially in the context of natural hazard-related disasters. Nature-based solutions have been indeed recently emerged as viable and effective measures to mitigate the impacts of hydro-meteorological phenomena such as floods, landslide, etc. in both urban and rural environments, an aspect not often emphasized in the existing databases.

Driven by the ambition of overcoming these two main gaps, an innovative geo-catalogue of existing NBS has been developed within the framework of GeoIKP, the NBS web-platform newly created by the EU H2020 project OPERANDUM.

The geo-catalogue represents a comprehensive, geo-referenced, database of NBS case studies which are specifically designed to mitigate the risk and impacts of hydro-meteorological hazards, under a variety of environmental setting and hazard categories. It therefore represents a novel and open-access data source to learn about, and explore, the usability of NBS in fulfilling climate mitigation and adaptation objectives over a wide range of hydro-meteorological hazards.

Case studies collected from various resources (NBS platforms, scientific literature, technical reports, OPERANDUM living labs, etc.) are revised, classified and harmonized according to internationally recognized standard and classification schemes (e.g., INSPIRE legislation, MAES classification, etc.) which allow to characterize each NBS through a comprehensive set of parameters, including the type of hazard and ecosystem, the societal challenges and driving policies linked to it, the type of intervention and its spatial coverage, among many others.

The highly structured and comprehensive data model adopted here enables to query the database and/or filter the results based on a multitude of individual parameters which encompass all different dimensions of NBS (e.g. geophysical, societal, environmental, etc.). This not only allows for a straightforward and automatic association to one or more thematic aspects of NBS, but also enhances standardization, discoverability and interoperability of NBS data.

How to cite: Leo, L. S., Debele, S., Ommer, J., Vranić, S., Amirzada, Z., Pavlova, I., Bucchignani, E., Shah, M. A. R., Gonzalez-Ollauri, A., Mickovski, S. B., Kumar, P., Kalas, M., and Di Sabatino, S.: Nature-Based Solutions for Hydro-Meteorological Hazards: the OPERANDUM Database, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1380, https://doi.org/10.5194/egusphere-egu21-1380, 2021.

Joy Ommer, Edoardo Bucchignani, Laura S. Leo, Milan Kalas, Saša Vranić, Sisay Debele, Prashant Kumar, Hannah L. Cloke, and Silvana Di Sabatino

Nature-based solutions are increasingly implemented to tackle disaster risk reduction and climate change adaptation. Their rising popularity over grey solutions is partially explained by their number of additional benefits (so called co-benefits) for the socio-ecological system (SES). Frameworks are available to monitor and assess co-benefits, however, these frameworks are lacking clear guidance and ex-ante quantification of co-benefits and potential disbenefits of NBS. Another limitation is the accessibility and quality (representativeness) of data for computing indicators, especially, going towards larger scales (regional, pan-European). To develop a comprehensive framework and method for assessing and estimating possible side effects in advance, this paper aligns to existing frameworks but goes beyond those by providing practical guidance on data sourcing (including possible proxy variables) and quantification of both co-benefits and disbenefits. The resulting framework will support decision-making on area specific suitability of NBS for disaster risk reduction. Furthermore, it will enhance the planners’ knowledge and understanding of linked processes which can lead to potential positive and negative side effects; thus, this guidance will build a base for selecting suitable locations and NBS interventions.

How to cite: Ommer, J., Bucchignani, E., Leo, L. S., Kalas, M., Vranić, S., Debele, S., Kumar, P., Cloke, H. L., and Di Sabatino, S.: Quantifying co-benefits and potential disbenefits of NBS for Disaster Risk Reduction: a practical framework for ex-ante assessment, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7874, https://doi.org/10.5194/egusphere-egu21-7874, 2021.

Paolo Ruggieri and the OAL-Italy

The Open-Air Laboratory is a novel concept developed by the EU-funded Operandum project (OPEn-air laboRAtories for Nature baseD solutions to Manage Environmental risk) to co-design, implement and assess the effectiveness of Nature-Based Solutions (NBSs). 

In this work we present the Open-Air Laboratory Italy (OAL-Italy) and discuss the application of the OAL as a framework for the development of innovative NBSs to mitigate the impact of hydro-meteorological hazards in present and future climate.  By combining consolidated practices in an original multidisciplinary frame, the OAL-Italy deploys novel modelling strategies, laboratory measurements and targeted monitoring open-field campaigns. In three operational sites, the NBSs are implemented via a co-design, co-development  and co-deployment approach based on a thorough interaction with key stakeholders. By describing the structure and the approach of the OAL we illustrate salient features of the methodology developed in Operandum that are instrumental for the replicability and the upscaling of the NBSs. 

Presented results address the use of the NBSs to mitigate a range of hydrometeorological hazards such as coastal erosion, flooding, storm surge and salt wedge intrusion. Innovative NBSs tested and developed by the OAL include: deep-rooted plants installed on a river embankment to prevent levee failures, special plants that can live in high salt concentration and remove salt from the river mouth water, an artificial dune and marine seagrass to mitigate the impact of storm surges and coastal erosion. We argue that the OAL constitutes an unprecedented holistic effort towards sustainable land management, adaptation to climate change and the acceptance of Nature-Based Solutions. 

How to cite: Ruggieri, P. and the OAL-Italy: The Open-Air Laboratory Italy, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9495, https://doi.org/10.5194/egusphere-egu21-9495, 2021.

Margherita Aguzzi, Maurizio Bacci, Nunzio De Nigris, Laura Sandra Leo, Maurizio Morelli, Beatrice Pulvirenti, Paola Robello, Paolo Ruggieri, Fabrizio Tavaroli, Silvia Unguendoli, Andrea Valentini, and Carlo Cacciamani

The natural reserve in Sacca di Bellocchio, Lido di Spina (Italy) is affected by frequent marine floods and intense erosive phenomena which threaten the freshwater ecosystem and biodiversity at the site. Floods and erosion are linked to the reduction of river sediment transport and a progressive ground subsidence and sea level rise. The persistence of these conditions and the future rise in sea level can expose neighboring anthropized areas to coastal risk.

This work presents the project of a nature-based solution (NBS) as a possible defense and mitigation action against coastal erosion and marine flooding along the Bellocchio beach. The NBS has been newly designed   within the European project H2020 OPERANDUM (OPEn-air laboRAtories for Nature baseD solutions to Manage Environmental risk) and consists of an artificial sand dune made of natural materials, such as sand, wood, geotextiles and geomembranes through naturalistic engineering techniques. On the new dune will then be inserted native herbaceous and shrubby vegetation. The dune design was supported by an accurate hydro-morphodynamic modeling of the site combined with data concerning the morphological structure, the erosive dynamics and the local climate.

This study discusses in detail the modeling techniques and the monitoring system that guided the design of the dune and that constitute a basis for the assessment of performance and effectiveness of any future NBS intervention at the site. The monitoring campaign is still ongoing and allows the collection of critical and updated information on the impacts of coastal storms, storm surges and flood events in the area. The dataset clearly highlights that the site morphology is constantly changing due to a multitude of factors, such as seasonality, the increasing incidence and/or intensity of coastal storms, sea level rise, etc. These rapid, and sometimes drastic, morphological changes pose a substantial challenge to NBS's design and, most importantly, to its deployment planning and timing phase.


How to cite: Aguzzi, M., Bacci, M., De Nigris, N., Leo, L. S., Morelli, M., Pulvirenti, B., Robello, P., Ruggieri, P., Tavaroli, F., Unguendoli, S., Valentini, A., and Cacciamani, C.: Design and pre-assessment of NBS for coastal erosion and marine flooding: a case study., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10094, https://doi.org/10.5194/egusphere-egu21-10094, 2021.

Silvia Unguendoli, Andrea Valentini, Luis Germano Biolchi, Umesh Pranavam Ayyappan Pillai, Alessandri Jacopo, and Pinardi Nadia

Nature based solutions (NBSs) address key societal challenges through the protection, sustainable management and restoration of both natural and modified ecosystems. In this work we present a modeling application of this innovative approach, inspired by nature, with the goal of mitigating coastal erosion. Within the framework of the OPEn-air laboRAtories for Nature baseD solUtions to Manage environmental risks (OPERANDUM) project, the natural reserve of Bellocchio in Lido di Spina (Italy) faces frequent marine floods and intense erosive phenomena, hence being chosen as Open-Air Laboratory for the NBS implementation. The project aims to mitigate coastal erosion through the realization of an artificial sand dune made of natural materials, such as sand, wood, geotextiles and geomembranes and covered by native herbaceous and shrubby vegetation. We present the modeling activities carried out in the context of the project, aiming on the performance and efficiency evaluation  of the designed NBS, with a specific focus on the coastal morphological modelling. Thus, a numerical modeling chain has been set-up to simulate a long-term current scenario with and without the NBS. The chain is composed of the wave model WAVEWATCH III, the oceanographic model SHYFEM and the morphodynamic model XBeach for the coastal area.

XBeach was validated with available and specific (for the project) topo-bathymetric surveys of the area of interest as means to define the more accurate set-up of the model parameters. The 10 years period 2010-2019 was defined as the time range for modelling simulations. Sea level outputs from SHYFEM and wave outputs from WAVEWATCH III for the 10 years simulations are used to force the coastal model XBeach. Given the huge computational costs related to long-term simulations, an input-schematization was applied (so called “input reduction”). The approach followed for the long-term morphodynamic modelling of the NBS-XBeach setting will be shown. Moreover, the chosen coastal model domain, the model set-up and the input reduction applied will be presented.

How to cite: Unguendoli, S., Valentini, A., Germano Biolchi, L., Pranavam Ayyappan Pillai, U., Jacopo, A., and Nadia, P.: Modelling Nature-based Solutions: an application to mitigate coastal erosion, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11914, https://doi.org/10.5194/egusphere-egu21-11914, 2021.

Silvia Maria Alfieri, Fatemeh Foroughnia, Beatrice Pulvirenti, Paolo Ruggieri, Margherita Aguzzi, Roderik Linderberg, Nunzio De Nigris, Maurizio Morelli, Fabrizio Tavaroli, Silvia Unguentoli, Andrea Valentini, Paola Robello, Carlo Cacciamani, and Massimo Menenti

A protected natural area in the Emilia Romagna region, Northern Italy is threatened by hydro-meteorological hazards, particularly sea storms. In the last 50 years the northern part of the Bellocchio Park (Sacca Bellocchio II Nature Reserve, Site code EUAPP0072 - Ferrara, Italy)  was interested by an intensive urbanization (Lido di Spina) with the realization of infrastructures, e.g. roads and residential settlements. This land use change led to the construction of embankments and to the conversion of wetlands. These modifications, in combination to even more frequent storm surge events increased coastal erosion. In addition, inland flooding caused by storm surges acts with the reduction of the lagoon and the increase of soil salinity. As an example, the last event occurred in December 2020  eroded a large portion of the Bellocchio beach.   

Co-design, co-development and deployment of NBS solutions to reduce storm surge risk in the Bellocchio Park is one of the objectives of the H2020 project OPEn-air laboRAtories for Nature baseD solUtions to Manage environmental risks (OPERANDUM). BellocchioBellochio park is in fact one of the 10 Open Air Laboratories (OAL) where the evidence of mitigation of hydro-meteorological risk by NBS will be demonstrated by the combination of different models, approaches and data.

During the co-design process in the Bellocchio park, potential deployment locations of sand dunes have been identified in collaboration with local authorities devoted to the management of the natural area and to the coast defense (CB and ARSTePC-RER) and an environmental engineering consultant assisting Arpae (IRIS sas). Field visits were devoted to the analysis of the environmental features, strengths and weaknesses of candidate sites.

This work aims to explore the usefulness of the combined use of multisource remote sensing and modeling in decision making during the co-design process of a NBS. The impacts of the most intense extreme storm surge events in the last 30 years have been documented by delineating flooded areas along the coast using Synthetic Aperture Radar and Multispectral image data. Coastal erosion has been also described by means of change detection analysis and very high resolution multispectral EO data. This screening has given a picture of areas at the risk, i.e. the area most likely to be affected by storm-surge events. Auxiliary data like Digital Terrain Models has been assimilated in a dedicated model to produce flood maps under different scenarios, i.e. different locations and size of NBS and different intensities of storm surge.  

The integrated analysis was helpful in defining the priority sites, among the ones defined by the stakeholders and engineers, in term of effectiveness for storm surge risk reduction.

How to cite: Alfieri, S. M., Foroughnia, F., Pulvirenti, B., Ruggieri, P., Aguzzi, M., Linderberg, R., De Nigris, N., Morelli, M., Tavaroli, F., Unguentoli, S., Valentini, A., Robello, P., Cacciamani, C., and Menenti, M.: Supporting co-development phase of Nature Based Solution by combined use of Earth Observation and modeling, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14269, https://doi.org/10.5194/egusphere-egu21-14269, 2021.

Sisay Debele, Jeetendra Sahani, Silvia Maria Alfieri, Paul Bowyer, Nikos Charizopoulos, Michael Loupis, Massimo Menenti, Fabrice Renaud, Mohammad Aminur Rahman Shah, Christos Spyrou, Thomas Zieher, Silvana Di Sabatino, and Prashant Kumar


Under climate change scenarios, it is important to evaluate the changes in recent behavior of heavy precipitation events, the resulting flood risk, and the detrimental impacts of the peak flow of water on human well-being, properties, infrastructure, and the natural environment. Normally, flood risk is estimated using the stationary flood frequency analysis technique. However, a site’s hydroclimate can shift beyond the range of historical observations considering continuing global warming. Therefore, flood-like distributions capable of accounting for changes in the parameters over time should be considered. The main objective of this study is to apply non-stationary flood frequency models using the generalized extreme value (GEV) distribution to model the changes in flood risk under two scenarios: (1) without nature-based solutions (NBS) in place and; (2) with NBS i.e. wetlands, retention ponds and weir/low head dam implemented. In the GEV model, the first two moments i.e. location and scale parameters of the distribution were allowed to change as a function of time-variable covariates, estimated by maximum likelihood. The methodology is applied to OPEn-air laboRAtories for Nature baseD solUtions to Manage hydro-meteo risks, which is in Europe. The time-dependent 100-year design quantiles were estimated for both the scenarios. We obtained daily precipitation data of climate models from the EURO-CORDEX project dataset for 1951–2020 and 2022–2100 representing historical and future simulations, respectively. The hydrologic model, HEC-HMS was used to simulate discharges/flood hydrograph without and with NBS in place for these two periods: historical (1951-2020) and future (2022-2100). The results showed that the corresponding time-dependent 100-year floods were remarkably high for the without NBS scenario in both the periods. Particularly, the high emission scenario (RCP 8.5) resulted in dramatically increased flood risks in the future. The simulation without NBS also showed that flooded area is projected to increase by 25% and 40% for inundation depth between 1.5 and 3.5 m under RCP 4.5 and RCP 8.5 scenarios, respectively. For inundation depth above 3.5 m, the flooded area is anticipated to rise by 30% and 55% in both periods respectively. With the implementation of NBS, the flood risk was projected to decrease by 20% (2022–2050) and 45% (2071–2100) with a significant decrease under RCP 4.5 and RCP 8.5 scenarios. This study can help improve existing methods to adapt to the uncertainties in a changing environment, which is critical to develop climate-proof NBS and improve NBS planning, implementation, and effectiveness assessment.

Keywords: Nature-based solutions; flood frequency analysis; climate change; wetlands; GEV model


This work has been carried out under the framework of OPERANDUM (OPEn-air laboRAtories for Nature baseD solUtions to Manage hydro-meteo risks) project, which is funded by the European Union's Horizon 2020 research and innovation programme under the Grant Agreement No: 776848.

How to cite: Debele, S., Sahani, J., Alfieri, S. M., Bowyer, P., Charizopoulos, N., Loupis, M., Menenti, M., Renaud, F., Shah, M. A. R., Spyrou, C., Zieher, T., Di Sabatino, S., and Kumar, P.: Evaluating nature-based solutions in a non-stationary climate with changing risk of flooding, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8012, https://doi.org/10.5194/egusphere-egu21-8012, 2021.

Andrea Mandarino, Andrea Vigo, Andrea Cevasco, Patricia Varona Prellezo, Emilio Valbuena-Ureña, Abraham Guillén-Villar, Montserrat Traver-Vives, Dolors Garcia-Martínez, and Marco Firpo

Stonewalls4life is an E.U. Life project started in the second half of 2019 involving many subjects, both public bodies and privates, in a multidisciplinary working group. The main objective of the project is to demonstrate how an ancient technology for land use, drystone walling, can be effectively considered to improve the resilience of the territory to climate change by adopting a socially and technically innovative approach.

The project actions are being performed at Manarola, within the Cinque Terre National Park (eastern Liguria, north-western Italy). The pilot site is a narrow strip of land close to the seaside and characterized by small valleys with steep terraced slopes. This anthropogenic landscape represents a high-value peculiarity attracting more than three million tourists every year.

Three replication sites were identified in order to demonstrate the transferability and replicability of the project actions: two are located within the Cinque Terre Natural Park territory and one is in the Can Grau area (Garraf Park, Catalunya, Spain).

The Spanish site is currently under evaluation. An extensive geological, geomorphological, and land-use-land-cover (LULC) analysis is now being carried out in the Can Grau area to define its environmental features, especially concerning geological aspects and land use, and focusing on terraced areas and their state of conservation. This study aims to identify a specific suitable site for the replication of the project actions that will be carried out in Manarola, namely for dry-stone walls recovery, and is based on a multitemporal analysis of aerial images performed in a GIS environment and a wide collection and review of bibliographic data.

This contribution illustrates the preliminary results of the Can Grau area analysis, focusing in particular on the distribution of terraced areas and the variation of LULC from the 1950s to the present day. From this study emerges a progressive abandonment of terraced areas used for cultivation, although, according to historical sources, this process mostly occurred after the phylloxera appeared in the late 19th century, seriously affecting the most important agricultural activity in the Garraf, namely the viticulture.

The outcomes from this study will be useful in terms of both Stonewalls4life project implementation and overall land management, particularly aiming to restore a man-made geomorphological heritage and mitigate geo-hydrological risk.

How to cite: Mandarino, A., Vigo, A., Cevasco, A., Varona Prellezo, P., Valbuena-Ureña, E., Guillén-Villar, A., Traver-Vives, M., Garcia-Martínez, D., and Firpo, M.: Geo-environmental analysis of terraced slopes and dry-stone walls in Can Grau area (Garraf Park, Catalunya, Spain): preliminary results from the Stonewalls4life project., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10696, https://doi.org/10.5194/egusphere-egu21-10696, 2021.

Umesh Pranavam Ayyappan Pillai, Nadia Pinardi, Ivan Federico, Salvatore Causio, Jacopo Alessandri, Silvia Unguendoli, and Andrea Valentini

Nature Based solutions (NBS) have been presented in the recent past as a potential solution to natural and climate change adverse effects on human well-being and socio-economic activities.  In this study, we present a simulation design methodology for NBS that can mitigate the effect of storm surges and coastal erosion. The chosen NBS is marine seagrass and it will be applied to the coastal strip of the Emilia-Romagna coasts. Within the framework of the OPEn-air laboRAtories for Nature baseD solUtions to Manage environmental risks (OPERANDUM) project, the seagrass NBS is presented within a simulation design methodology consisting of the comparison between validated wave numerical simulations for the present climate and modified wave simulations with marine seagrass. In this context, the unstructured version of WAVEWATCH III (WW3) model has been implemented for simulating the wave characteristics across the Emilia-Romagna coastal strip with and without seagrass.

The calibration/validation of WW3 was carried out and sensitivity experiments using the various wind-input dissipation source packages and bottom friction formulations were also attempted to evaluate the model performances (validation results presented here are for the entire 2017 year). The ST6 physics along with SHOWEX bottom friction formulations were chosen ideal for the study area. To evaluate the model results a directional wave rider buoy data was utilized. The model simulated significant wave parameters namely Hs (significant wave height), Tm (mean wave period) were compared with buoy observations and high correlations (0.93) were found with Hs comparison. Further the WW3 model was modified by including the modified bottom dissipation stress due to submerged vegetation, thereby incorporating the NBS as a potential mechanism for wave amplitude reduction. The seagrass species ‘Zostera marina’ was chosen in this study and comparisons showed that seagrass is capable to reduce the wave energy in the study area. Furthermore, the dependence on seagrass plant high-density and low-density scenarios, together with seagrass parameters (height and width of the seagrass) and species show the sensitivity of the results even on reduction of wave energy as obtained with different degrees by all NBS scenarios.    

Keywords: Nature-based solutions, WW3, marine seagrass, storm surge, Zostera marina.

How to cite: Pranavam Ayyappan Pillai, U., Pinardi, N., Federico, I., Causio, S., Alessandri, J., Unguendoli, S., and Valentini, A.: Nature Based Solution simulation design methods – A storm surge seagrass application, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10465, https://doi.org/10.5194/egusphere-egu21-10465, 2021.

Jeetendra Sahani, Sisay Debele, and Prashant Kumar

Global warming due to anthropogenic emission of green-house gases has induced climate change which is disturbing and will continue to impact the ecology and energy balance of our earth environment. The duration, frequency and intensity of extreme hot days in summers called heatwaves have increased with the beginning of the 21st century worldwide and have been projected to increase. Associated human health loss or damage can be managed or mitigated by planning proper management strategies, such as nature-based green and/or blue solutions in advance, along with proper evaluation of the risk of heat. Since heat stress is more pronounced in urban and built areas, most studies for heatwave risk assessment have been limited to big cities. The risk variation in semi-urban, sub-urban and rural areas has not been much investigated. The heat risk develops with time because of changing climate and socio-demographics, and risk assessment is needed to be done utilising recent data on climate and population characteristics. In this study, the heatwave or extreme hot (99 percentile) temperature risk has been estimated by using statistical approach on summer daily temperature and mortality data from Aberdeenshire and South East (SE) England, UK for the duration 1981-2018. A distributed-lag nonlinear model from Poisson regression family was applied to model the relationship between daily temperature and mortality. We calculated relative risk (RR) and mortality attributable fraction (AF) due to high temperature by comparing the extreme heat with the minimum mortality temperature. AF was calculated by dividing the number of excess deaths due to heat from all the days of the time-series by the total number of deaths. The overall risk in SE England was noted 56 % higher (RR 1.067) than Aberdeenshire (RR 1.043), with 36% more excess death in SE England (AF 0.15% and 0.11% respectively) due to different levels of people’s adaptation and resilience to different climate conditions.  The outcome of this study can help in site focused mitigation strategies to certain areas at most risk and develop a scientific framework for early warning, planning and managing the health impacts of heatwave in more rustic regions.


Acknowledgements: This work is supported by the European Union's Horizon 2020 research and innovation programme; funded by and carried out within the framework of OPERANDUM project (Grant no. 776848).

How to cite: Sahani, J., Debele, S., and Kumar, P.: Heatwave risk for two regions of the UK: Aberdeenshire and South East England , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8018, https://doi.org/10.5194/egusphere-egu21-8018, 2021.

Co-design approaches
Teresa Carlone, Matteo Mannocchi, Edoardo Bucchignani, Paolo Ruggeri, Laura Sandra Leo, Beatrice Pulvirenti, Annemarie Polderman, Depy Panga, Katriina Soini, and Zahra Amirzada

The OPERANDUM project is designed to address major hydro-meteorological risks through the deployment and assessment of Nature-Based Solution (NBS). The project pursues a co-creation approach and sets up 7 Open Air Laboratories (OAL) in which a user-centric method, characterized by the active participation of the stakeholders, is promoted. Stakeholder engagement in co-designing, co-developing, and co-deploying NBS is becoming a prominent practice in environmental projects and a crucial part of the process is monitoring and impact evaluation of the engagement strategy and actions. Monitoring aims at providing information about the stakeholder engagement processes throughout the project and should not be seen as a separate part of the stakeholder engagement processes or an aim in itself but as a continuous and integral element of the co-creation process. The poster shows the results of preliminary empirical research conducted among the OALs in order to propose some key indicators useful to evaluate the process and the impact generated by the OPERANDUM co-creative approach.  Starting from a theoretical framework, the research selected and discussed some crucial indicators in order to propose an action plan for the monitoring and impact evaluation of OPERANDUM strategy to involve and support the participation of stakeholders, with a specific focus on the tools used so far and those that are in the pilot phases (i.e Stakeholder Forum experimented in OAL Italy). Both qualitative and quantitative methods have been included in the evaluation for the engagement strategy outcome of the projects to be fully understood and, not secondarily, to identify a sustainability strategy beyond the conclusion of OPERANDUM to reinforce the social acceptance, the shared knowledge, and the upscaling of NBS at local, national and global level.

How to cite: Carlone, T., Mannocchi, M., Bucchignani, E., Ruggeri, P., Leo, L. S., Pulvirenti, B., Polderman, A., Panga, D., Soini, K., and Amirzada, Z.: “Stakeholder engagement strategy: monitoring and evaluate the impact in OPERANDUM project”, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13481, https://doi.org/10.5194/egusphere-egu21-13481, 2021.

Takehito Yoshida

Rainfall-induced floods and landslides have occurred and caused devastating impacts in recent years in Japan, and adaptation to natural disaster risks is a key to the sustainability of local communities. Traditional ecological knowledge in Japanese communities exists abundantly, such as those in disaster risk reduction and natural resource use, and it has been passed down from generation to generation. These traditional knowledge and skills have been used to benefit from nature’s gifts or ecosystem services as well as to avoid devastating impacts from natural disasters. Collaboration and cooperation by diverse stakeholders are crucial for recognizing and utilizing traditional ecological knowledge in actual solutions and actions. In this presentation, I introduce how traditional ecological knowledge has been used in disaster risk reduction in Mikatagoko Lakes area located in Fukui Prefecture, Japan. Rainfall-induced floods occur frequently in this area, but traditional land use helps to reduce inundation damage of houses and conserve biodiversity and ecosystem services including local food culture. Embankment built around the lakes has been renovated not only for flood risk reduction but also for biodiversity conservation, also supported by traditional ecological knowledge in this area. The Mikatagoko nature restoration committee, in which diverse local stakeholders participate and collaborate, has played a significant role in these actions and solutions. Our experiences suggest that transdisciplinary ecosystem-based approaches contribute to the sustainability of local communities and the collaborative platform among local stakeholders is important in taking advantage of traditional ecological knowledge in actual solutions and actions.

How to cite: Yoshida, T.: Transdisciplinary ecosystem-based approaches to flood risk reduction supported by traditional ecological knowledge in Mikatagoko Lakes, Japan, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5678, https://doi.org/10.5194/egusphere-egu21-5678, 2021.

Arunima Sarkar Basu, Bidroha Basu, Srikanta Sannigrahi, and Francesco Pilla

Hydro-meteorological hazards such as floods have been a long-standing challenge for urban planners. A substantial increase in urbanization has undeniably pressurized the existing drainage network which has increased the flood proneness. The OPERANDUM project (H2020, grant agreement No 776848) has proposed a unique methodology for handling urban flooding by setting up open-air laboratories (OALs). As a pilot study of open-air laboratory Ireland (OAL-IE), an interdisciplinary methodology is adapted. Flood modeling techniques are identified for better flood risk assessment and flood management. Nature-based innovations are proposed to help identify and improve the existing urban drainage systems. The adaptability of nature-based systems and their efficacy as a supplemental tool to better flood management is a predominant and significant question. The awareness of citizens on their experience, challenges, and narratives are an equally reliable parameter to examine whether the spatio-temporal viability of new flood management techniques through nature-based innovations is a promising path for sustainable urban management. The intermittent relationship of flood hazard and the citizen access to infrastructure such as schools, childcare, old age homes, offices, transportation network holds a place of relevancy. The dynamics of “lived experiences” can help urban planners to pull out the traditional and formal strategies to be implemented for better liveability of citizens. Moreover, the willingness of citizens to maintain and share activities for co-deployment as a successful participatory process for innovative nature-based solutions support the social purpose of the OPERANDUM project. This research focuses on understanding the social background, cognitive thinking, and ideology that holds unique opportunities to OAL-IE for potential retrospective interpretation of nature-based innovations. A detailed survey with the stakeholders is aimed to understand their perspective on flooding, to identify how and where nature-based innovations can assist the city council to develop an efficient sustainable flood management system. This information on how citizens perceived and attributed the delivery of nature-based innovation can provide guidelines for developing better flood management and mitigation policies in Dublin.

How to cite: Sarkar Basu, A., Basu, B., Sannigrahi, S., and Pilla, F.: A citizen-oriented understanding of nature-based innovations: A case study in Dublin, Ireland, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14404, https://doi.org/10.5194/egusphere-egu21-14404, 2021.

Carl C. Anderson, Fabrice G. Renaud, Stuart Hanscomb, Michael Loupis, Karen E. Munro, Alejandro Ollauri, Depy Panga, Eija Pouta, Katriina Soini, and Craig S. Thomson

Nature-based solutions (NbS) are increasingly recognized as sustainable approaches to address socio-environmental challenges. Disaster risk reduction (DRR) has benefited by increasingly moving away from purely ‘grey’ infrastructure measures towards NbS, which can better provide cultural, aesthetic, and recreational co-benefits that are highly valued among European citizens. Public acceptance is of particular importance for NbS since they often rely on collaborative implementation, management, and monitoring, as well as protection against competing land uses. Although public engagement is a common goal of NbS projects and found in the IUCN’s core principles of NbS, outreach efforts are rarely based on a sufficient understanding of the (de)motivating factors tied to public perceptions. As a first step, we conducted a systematic literature review to examine how unique NbS characteristics relate to public acceptance through a comparison with grey measures. We identified influential acceptance factors related to individuals, society, and DRR measures. Based on the review, we introduce the PA-NbS framework as a starting point for the systematic consideration, design, and testing of strategies for increasing public acceptance. The PA-NbS highlights the roles of trust, competing interests, and effectiveness of NbS, as well as public perceptions of risk, nature and place.

A lack of consideration of these factors may lead to misaligned public expectations and failed participatory initiatives, while jeopardizing the success of NbS projects. Therefore, as a second step, we conducted citizen surveys within three NbS host communities. Distinct NbS being implemented within the OPERANDUM project aim to reduce risk from (socio-)natural hazards in Scotland (landslides and coastal erosion), Finland (eutrophication and algal blooms) and Greece (river flooding). Associations of factors related to risk, nature, and place perceptions with pro-NbS attitudes and behavior were tested to determine how these may be leveraged to increase acceptance. We find that trust is a consistent factor for defining attitudes towards the NbS across the sites. Attitudes are strongly associated with respondents’ commitment to nature and concern for risk, while some skepticism of NbS effectiveness leads to high public demand for relevant evidence. Risk perception and particularly the potential for future impacts are associated with behavioural acceptance (i.e. willingness to engage), along with responsibility for nature and connectedness to place.

Current data collection efforts to demonstrate NbS effectiveness for risk reduction are well-positioned to increase public acceptance in Europe. However, recognizing the differences among segments of the public within each site along with distinct hazard types, proposed NbS, and historical, social, and cultural characteristics across the sites is crucial for designing strategies that increase acceptance. An overview of these dynamics leads to evidence-based recommendations for the case-study sites and for successful NbS in Europe.

How to cite: Anderson, C. C., Renaud, F. G., Hanscomb, S., Loupis, M., Munro, K. E., Ollauri, A., Panga, D., Pouta, E., Soini, K., and Thomson, C. S.: Public acceptance of nature-based solutions (NbS): a framework for successful NbS and its application in three European case studies, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4579, https://doi.org/10.5194/egusphere-egu21-4579, 2021.

Beatrice Pulvirenti, Paolo Ruggieri, Alessio Domeneghetti, Elena Toth, Silvia Maria Alfieri, Fatemeh Foroughnia, and Massimo Menenti

Po valley in the Emilia Romagna region, Northern Italy, is threatened by hydro-meteorological hazards, such as river flooding. In the last 50 years this area was interested by an intensive urbanization (with cities that span from the size of a village to metropolitan urban areas such as Bologna) with the realization of infrastructures, e.g. roads and residential settlements near rivers. In addition, the strengthening and expansion of the embankment system led to the development of the areas prone to floods located nearby the rivers. These modifications, in combination with the occurrence of high flood peaks recently experienced in this area have increased the impacts and thus, the attention, on riverine floods. The last event occurred in December 2020, where Panaro river, a tributary of the Po river, broke its banks near Modena causing large flooded area.

Co-design and co-deployment of nature based solutions (NBS) to reduce flooding risk in the Panaro river is one of the objective of the H2020 project OPEn-air laboRAtories for Nature baseD solUtions to Manage environmental risks (OPERANDUM). A portion of the Panaro river embankment is one of the Open Air Laboratories (OAL) where special deep rooted plants were implemented to evidence the mitigation of hydro-meteorological risks by NBS.

In this work, a combined approach between Earth Observation (EO) data and multi-scale modelling is shown, to support the co-design process of the NBS. Synthetic Aperture Radar (SAR) and optical EO data were used to identify areas at risk, i.e. the area most likely to be affected by severe flooding events.  A thresholding method was applied to the SAR and optical images available during past extreme events to identify size and location of the floods. The remote sensing analysis allowed the definition of specific portions of the Panaro river where NBS can be more effective for flood risk reduction. In a second step, a multi-scale modelling approach, based on the characterisation of deep-rooted plants by laboratory experiments and in-field measurements, is used to determine the response of the identified portions of Panaro river to flooding events and to evaluate the effectiveness of possible NBS.

Remote sensing analysis indicates that the area between Secchia and Panaro rivers, delimited to the north by the town of Bomporto and to the South by the town of Albareto has been most frequently inundated in the recent extreme events. The integrated analysis leads to the identification of potential sites, along the Panaro river, where NBS could be effective for river flooding risk reduction, contributing to the definition of the priority sites among the ones defined by the stakeholders and engineers.

How to cite: Pulvirenti, B., Ruggieri, P., Domeneghetti, A., Toth, E., Alfieri, S. M., Foroughnia, F., and Menenti, M.: Co-design and co-deployment of nature based solutions for river flooding mitigation in northern Italy river embankments, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15131, https://doi.org/10.5194/egusphere-egu21-15131, 2021.

Srikanta Sannigrahi, Bidroha Basu, Arunima Sarkar Basu, and Francesco Pilla

The concept of Ecosystem-Based Management (EBM) as part of Nature-Based Solutions (NBS) have frequently been adopted in different strategic planning as a cross-sectoral mechanism to manage environmental problems. The EBM combines all relevant approaches, methods, tools, and software that collectively provide key scientific and socioeconomic evidence and eventually address environmental issues more sustainably. The specific application of EBM in different environmental problems, including flooding, have been proven effective in many cases. This ensures the superiority of EBM approaches for designing collaborative programs for solving environmental problems. The EBM offers a variety of sustainable interventions such as reducing impervious surface through porous paving, green parking lots, brownfield restoration, and deployment of green-roofs, which collectively attenuates water runoff and peak discharge, and offers protection against extreme precipitation events by enhancing water infiltration. In addition to the targeted benefits and cost-effectiveness of EBM, the supply of potential ecosystem service co-benefits that usually comes with EBM can contribute substantially to generating environmental benefits and adds community well-being. In order to analyse the superior effects of green-roof as a part of a smart-EBM framework, which has been deployed in CHQ building in Dublin, Ireland, a conceptual upscaling scenario framework has been formulated for measuring the city scale impact of green-roofs in providing multiple-valued ecosystem services. The biophysical and economic benefits of smart green-roof EBM will be estimated using varied ecosystem service modelling and standard cost-benefit analysis. The proposed smart green-roof framework is expected to have a more significant impact in minimising the flooding problems in Dublin city and expected to provide multiple regulating, supporting provisioning, and cultural benefits that can collectively surpass the deployment cost of green-roofs in the long run.

How to cite: Sannigrahi, S., Basu, B., Basu, A. S., and Pilla, F.: The ecosystem service benefits of green-roof as a part of smart ecosystem-based management: A case study in Dublin, Ireland, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15504, https://doi.org/10.5194/egusphere-egu21-15504, 2021.

Lorina Schudel, Yvonne Walz, and Kokouvi Gbétey Akpamou

Floods in West Africa repeatedly cause devastating impacts on human life and livelihoods, infrastructure and the environment and they are expected to increase in frequency and severity under a changing climate. Ecosystem-based approaches can be a cost-effective, efficient way to reduce flood risk while at the same time providing co-benefits. However, qualitative and quantitative assessments of ecosystem-based approaches that are suitable for the climatic conditions and socio-ecological system of the region are scarse. This study therefore identifies and evaluates climate-sensitive ecosystem-based approaches for the transboundary Lower Mono River Basin in Benin and Togo. The identification of ecosystem-based approaches has been done based on a review of scientific literature and complemented by a participatory approach with experts from the catchment. During focus group discussions, national stakeholders and policy makers identified, prioritized and mapped existing measures and provided their perspectives on prospective measures to reduce flood risk in the transboundary catchment. They include measures to reduce flow velocity, increase soil infiltration and improve water management. In a next step, we used a multi-criteria analysis considering ecological, climatic and flood hazard data to create suitability maps for different clusters of identified ecosystem-based approaches. This study is part of the CLIMAFRI project, which aims at creating a river basin information system for the Lower Mono Basin as well as creating a flood risk management plan. Through the integration of the suitability maps into the flood risk assessment tool, which has been created in the scope of this project, the ecosystem-based approaches are evaluated quantitatively. In a second round of focus group discussions with representatives from the local communities, feasibility of selected ecosystem-based approaches, co-benefits and trade-offs of the measures are discussed. Through the combination of qualitative and quantitative data, a holistic evaluation of ecosystem-based approaches and their contribution to hazard mitigation, increase of coping capacity, ecosystem resilience and overall flood risk reduction can be achieved.

How to cite: Schudel, L., Walz, Y., and Akpamou, K. G.: Identification and Evaluation of Ecosystem-based Approaches for Flood Risk Reduction in the Transboundary Lower Mono River Catchment in Benin and Togo, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15937, https://doi.org/10.5194/egusphere-egu21-15937, 2021.