Orals: Wed, 30 Apr | Room 1.15/16
In Anthropocene, human activities have caused a lasting, substantial and often irreversible changes to the earth system. Coastal erosion and inundation are natural hazards that threaten the safety of humans’ properties and lives. Adaptive actions to combat coastal erosion generally rely on single method of Nature-based solutions (Nbs)—hard structures, soft engineering, or vegetation. However, instances of multiple Nbs being employed together are seldom studied, particularly in morphologically complex coasts. This paper briefly reviews the current governmental policy context in China (at national, provincial and urban levels) for climate adaptation in coastal zones and presents a local implementation process involving multiple Nbs applications at Chaoyang Port Coast in Weihai city. The analysis reveals that integrated policies and city orientation drive the coastline protection and necessitate the adoption of nature-based solutions. It also demonstrates that integrated management measures (including beach remediation, gabion seawalls, and coastal shelter belts) can create a relatively stronger ecological disaster risk reduction system in morphologically complex coastal regions. Furthermore, the paper discusses the impacts of strategic planning and policies on coastal environment, technical advancements for coastal protection, and future challenge for sustainable development. Recommendations for ensuring the success of long-term coastal environment recovery include sustained political support, active public participation in local economic growth, and the advancement of Nbs technologies. Through insights from coastal management policies and nature-based solutions, our study not only highlights China’s commitment to environment governance but also provides a practical paradigm for shoreline management applicableto coastal cities in China and other coastal nations worldwide.
How to cite: Liu, S., Cai, F., Wagreich, M., Rangel-Buitrago, N., Peng, Y., Zhang, T., and Wang, P.: Nature-based solutions for coastal ecological restoration during rapid urbanization process under strategic planing and policy support: Case study of Chaoyang Port Coast, Weihai City, China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1420, https://doi.org/10.5194/egusphere-egu25-1420, 2025.
Nature-Based Solutions (NbS) integrate natural processes to address societal challenges, such as climate change, disaster risk, and biodiversity loss. Mainstreaming NbS involves incorporating these approaches into policies, planning, and decision-making across sectors like urban development, agriculture, and infrastructure. Key elements include upscaling, cross-sectoral collaboration, capacity building, financing mechanisms, and robust monitoring. However, the mainstreaming process faces challenges, including limited awareness, fragmented governance, and a lack of comprehensive data on the effectiveness of NbS. Overcoming these barriers requires coordinated efforts across sectors and stakeholders to scale up NbS and ensure their integration into long-term sustainability frameworks. ResiRiver is a transnational project focused on resilience enhancement in river systems in North-West Europe through mainstreaming and upscaling NbS. By means of a range of project partners working on NbS in pilot sites, mainstreaming theory is tested in practice. This results in identification of diverse mainstreaming activities and objectives, creating opportunities to develop support for NbS mainstreaming tailored to pilots and organizational capacities to overcome mainstreaming challenges.
How to cite: Schielen, R., van der Meulen, G., Wilson, S., Bakker, B., and Snoek, Y.: Mainstreaming NbS: Experiences from the INTERREG ResiRiver initiative., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20690, https://doi.org/10.5194/egusphere-egu25-20690, 2025.
Nature-based Solutions (NbS) are widely known as effective strategies for enhancing coastal resilience to climate change. However, assessing their long-term efficiency remains challenging due to the complex interacting processes within coastal systems and the uncertainties associated with future climate scenarios.
Many existing frameworks for evaluating coastal NbS focus on single-domain systems, often simplifying key processes to reduce the complexity of modeling. However, coastal systems are inherently complex and include not only surface processes but also the subsurface groundwater domain. Therefore, to successfully integrate NbS into landscape planning and study their long-term efficiency, it is essential to understand the entire system, and to quantify the relevant interactions between surface and groundwater processes and their influence over the system’s resilience.
This research introduces a framework to evaluate the long-term efficiency of coastal NbS by identifying key surface and subsurface (groundwater) processes and trade-offs and synergies within the system. The framework is designed for application in coastal systems characterized by sandy beaches and sedimentary aquifers and its applicability is demonstrated through a case study on the island of Terschelling. For the case study, two NbS are evaluated: (1) a beach nourishment from 1993 and (2) the potential implementation of Managed Artificial Recharge (MAR). The long-term efficiency and resilience to climate change of these solutions are quantified using ecosystem, geomorphological, and hydrological indicators through numerical modelling (using Delft3D and Modflow) and scenario-based analysis.
Additionally, the study highlights the importance of understanding how NbS may require time to enhance the system’s resilience or lead to unexpected impacts under future climate conditions. Providing a better overview of trade-offs and synergies can reduce the uncertainty related to the long-term component, facilitating the uptake of NbS as a sustainable coastal management solution.
How to cite: Uribe Jaramillo, V., Luijendijk, A., and de Louw, P.: A Framework for Evaluating the Long-Term Efficiency of Coastal Nature-Based Solutions: Assessing Surface and Subsurface Processes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6733, https://doi.org/10.5194/egusphere-egu25-6733, 2025.
The increasing prevalence of impervious surfaces coupled with intense rainfall has exacerbated urban waterlogging, nonpoint source pollution, and ecosystem degradation. Nature-based solutions (NbS) have emerged as effective strategies for urban stormwater management. This study proposes a four-objective simulation-optimization framework, integrating the Stormwater Management Model (SWMM) with the NSGA-II algorithm, to optimize NBS layouts while accounting for ecosystem service value (ESV). Six NbS scenarios were evaluated in a case study in Beijing, China. Results indicated that rain garden scenarios outperformed others in maximizing ESV, particularly through enhanced net carbon sequestration. Sensitivity analysis revealed that pollution control rate exhibited greater variability than runoff reduction rate, and achieving simultaneous improvements in these metrics often incurred higher costs and reduced ESV. The optimal solution achieved a 51.95% runoff reduction rate, 87.35% pollution control rate, an ESV of 2.78 × 10⁵ CNY, and a cost of 40.14 × 10⁶ CNY. This framework provides a robust reference for harmonizing cost-efficiency, water quality and quantity control, and ecosystem service enhancement in urban stormwater management.
How to cite: Fang, D.: Multi-Objective Optimization of Nature-Based Solution Layouts for Enhanced Ecosystem Services, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-913, https://doi.org/10.5194/egusphere-egu25-913, 2025.
This study addresses the challenge of balancing ecosystem needs with rapid urban expansion by evaluating the relatively new phenomenon in Sweden of Stormwater Parks. These blue-green infrastructure parks are proposed as solutions for flooding and water pollution by enhancing ecosystem services and creating green recreational spaces. However, it is crucial to assess the potential and pitfalls of any new type of infrastructure, as well as to evaluate the effects from a multispecies justice perspective. This study presents a novel mixed methods approach to critically assess the multifunctionality of green infrastructure and nature-based solutions. The methods include data collection from implemented Stormwater Parks across Sweden, analysis of past and present aerial photos, field visits, and policy analysis. The study demonstrates the potential of using Carole Bacchi’s “What’s the problem represented to be?” approach to deconstruct nature-based solutions. The findings from the review highlight the importance of problematizing which issues and whose challenges a nature-based solution overlook or address.
How to cite: Hallerbäck, S., Persson Pavlovic, E., Alfredsson, C., and Johansson, M.: Evolution and evaluation of Stormwater Parks in Sweden, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9562, https://doi.org/10.5194/egusphere-egu25-9562, 2025.
Glacial retreat, accelerated by climate change, exposes rocks rich in metallic sulphides such as pyrite (FeS2) to geochemical weathering processes, resulting in Acid Rock Drainage (ARD) which releases H+, Fe, SO4-2 and trace metals that impact water bodies and ecosystems. This phenomenon has been evidenced in the Cordillera Blanca, where climatic seasonality is characterized by 2 periods, rainy and dry. In this context, Constructed Wetlands (CWs) emerge as Nature-Based Solutions (NbS) designed to mitigate effects of ARD. Although CWs have been extensively studied in acid mine drainages, their performance under seasonal and variable climatic conditions in glacial environments requires research.
In Recuay - Ancash, water quality of Negro river impacted by ARD which feeds a CW at ARD Pilot Treatment Plant was evaluated for 6 months every 2 weeks (rainy and dry periods) by taking in situ measurements and determining acidity, sulphates and heavy metals. In addition, modelling was carried out with different loads applied to size and determine average CW efficiencies.
Results of water quality in the river show higher concentrations in dry period compared to rainy period, where pH: 3.15±0.1 - 3.42±0.1, EC: 489.6±103.0 - 252.0±160.2 µS.cm-1, TDS: 275.5±63.4 - 121.0±78.4, SO4-2: 151.1±27.6 - 92.7±38.6, Fe: 16.8±2.3 - 8.5±3.6, Al: 3.5±0.3 - 2.2±0.7, Ni: 0.07±0.01 - 0.04 ± 0.02, Zn: 0.17±0.02 - 0.11±0.05, Mn: 0.79±0.09 - 0.48±0.20, Mg: 11.8±1.8 - 6.5±2.4, Ca: 17.8±2.2 - 11.5±4.5, Si: 4.3±0.4 - 3.5±0.5 and Na: 2.65±0.36 - 2.00±0.49 in mg.L-1. Cd, Fe, Mn, Al, Co, Zn, Mg, Si, Sr, Be, Ca and Na showed significant statistical differences (p<0.05) between periods.
Concentration in the CW effluent is: pH: 6.4±0.2 - 6.3±0.1, EC: 234.3±17.8 - 146.9±55.2 µS.cm-1, TDS: 130.2±33.5 - 70.1±26.7, SO4-2: 107.1±23.9 - 72.1±36.2, Fe: 1.3±0.3 - 1.1±0.6, Al: 0.05±0.01 - 0.06±0.01, Ni: 0.004±0.009 - 0.001±0.0, Zn: 0.005±0. 004 - 0.003±0.0, Mn: 1.12±0.11 - 0.83±0.38, Mg: 11.2±2.9 - 8.1±3.3, Ca: 32.7±5.5 - 19.6±11.2, Si: 6.5±0.6 - 5.7±0.8 and Na: 2.76±0.28 - 2.06±0.61 in mg.L-1 showing that there aren’t significant differences (p<0.05) between periods except for Si and Ca. Modelling results with 2 hydraulic operating loads (0.105 and 0.158 m.d-1) and residence times (0.079 and 0.118 d) at constant flow suggest that the CW is robust regardless of the hydraulic load. Maximum applied loads were 16.5, 26.9, 3.7, 0.7, 0.015 and 0.047 g.m-2.d-1 with average efficiencies of 50.4, 49.9, 90.6, 96.9, 97.9 and 98.9 % for acidity, SO4-2, Fe, Al, Ni and Zn, respectively. However, negative efficiencies were observed, primarily for Mn, Mg, Ca, Si and Na due to anaerobic processes and CW substrate and metal chemistry. In this context, CWs have proven to be a resilient and adaptable solution to climatic seasonality.
How to cite: León Menacho, V., Aguirre Falcón, K., Pacchioni Carranza, R., Loarte Rubina, M., Hernández Crespo, C., Asensi Dasi, E., and Martín Monerris, M.: Constructed Wetlands as Nature-Based Solutions: Resilience to Acid Rock Drainage and climatic seasonality in the Cordillera Blanca, Peru, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20000, https://doi.org/10.5194/egusphere-egu25-20000, 2025.
The identification of suitable and common methods and tools to evaluate the effectiveness of Nature-based Solutions (NbS) as adaptation measures for hydro-meteorological risks still remains an open challenge. NbS effectiveness is a complex concept whose evaluation needs to take into account also the reduction of the exploitation of both natural and economic resources, the achievement of the implementers’ and stakeholders’ intent at the design phase, and the provision of co-benefits. The following contribution aims to integrate the NBS concept in a novel hydro-meteorological risk framework reported by Brogno et al. (2024) 1. Starting from Crichton’s Risk Triangle, the framework allows the estimate of the risk as the sum of the economic losses and equivalent CO2 emissions resulting from hazardous events that may affect the healthcare system, social relationships, ecosystems, agro-food production, infrastructure safety, and cultural and natural heritage. The final output as a cost per day is a quantitative and pragmatic estimate to facilitate the decision-making process. In addition to presenting the framework, this contribution aims to show practical examples of how the proposed framework can be adopted as a tool for the assessment of NbS effectiveness in hydro-meteorological risk reduction. In particular, bio-geophysical quantities can be used to integrate the contribution of NBS intervention as a local modification of both the hazard characteristics and the predisposition of the exposed elements to be affected by the occurrence of hazardous events. These bio-geophysical quantities need to be directly influenced by NbS and affect in turn the targeted risk processes. The framework can also include the NbS life cycle into the risk assessment, accounting for the greenhouse gas emissions along with the implementation, maintenance, and restoration costs resulting from an NbS intervention. The comparison of the average framework outputs over several hazardous events before and after an NbS intervention can provide an assessment of the long-term NbS effectiveness.
1 Brogno, L., Barbano, F., Leo, L. S., Di Sabatino, S., (2024). A novel framework for the assessment of hydro-meteorological risks taking into account nature-based solutions. Environmental Research Letters, 19(7), DOI: 10.1088/1748-9326/ad53e6
How to cite: Brogno, L., Barbano, F., Leo, L. S., and Di Sabatino, S.: A Novel Framework for the Assessment of the Nature-based Solutions (NbS) Effectiveness in the Reduction of Hydro-Meteorological Risks, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12955, https://doi.org/10.5194/egusphere-egu25-12955, 2025.
Urban green spaces, an important component of nature-based solutions play a significant role in maintaining urban ecosystem sustainability by offering some ecosystem services. In this study, high-resolution satellite images were used to acquire the spatial distribution of urban green space, an advanced pre-stratified random sampling method was used to collect the vegetation information of Deer Park (urban green space) located in southern part of Delhi, India and i-TREE Eco vegetation model is used to assess the vegetation structure and ecosystem services like air quality improvement, rainfall interception, carbon storage and sequestration that can be use as an important sustainable tool to mitigate climate change and air pollution in Delhi. The modelling results showed that there were 250 trees with 2.072 acres of tree cover in this area. The most common tree species are Azadirachta indica, Erythrina lysistemon and Cassia fistula and there are 21% of trees which are having diameter less than 15.2 cm. In 2024, all trees in urban green space, Deer Park, could store about 73.96 tons of carbon, sequester about 3.196 tons of gross carbon, remove 30 tonnes of air pollutants/year and avoid 1.528 thousand gallon/year of runoff and oxygen production of 8.522 tons/year. This study outlines an innovative and sustainable method to observe the advantage of urban green space in Delhi by taking the Deer Park as one of the site with various ecosystem services to better understand their roles in regulating urban environment. This nature-based solution approach could help urban planners and policymakers to adopt this urban green space structure approach in Delhi which will further help in mitigating climate change mitigation, air pollution mitigation and maximize ecosystem services provision.
How to cite: Saxena, P., Sharma, R. R., Sonwani, S., and Srivastava, A.: Assessing the Ecosystem Services of Urban Green Space Based on Vegetation Model: Nature-Based Solution Approach in Delhi, India, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-833, https://doi.org/10.5194/egusphere-egu25-833, 2025.
Urban catchments include land, groundwater, sewer, river, and other water components. Together, these elements form a complex, integrated urban water system. Managing river water quality in such systems is particularly challenging due to built (grey) infrastructure, which increases pollutant impact through impervious surfaces and increases stormwater runoff, limiting natural filtration processes. In response, many cities have begun to adopt constructed wetlands (CWs) as natural (blue-green) infrastructure to improve river water quality at the catchment scale. Despite their growing use, several challenges persist, including how to quantify the impact of CWs on river water quality, optimise the design of multiple wetlands, and apply these insights to catchment[1]wide planning. This study addresses these challenges by introducing an integrated planning and design framework for CWs aimed at improving water quality across urban catchments. Specifically, the framework focuses on (1) assessing pollutant removal by CWs, (2) designing CWs locally, and (3) integrating CWs into larger catchment plans.
To develop and test this approach, we first created a CW module within the Water Systems Integrated Modelling (WSIMOD) framework, enabling the simulation of interactions between CWs and other water components in urban catchments. We then applied this module to the Pymmes and Salmon Brook catchments in the UK to evaluate river water quality before and after constructing CWs. Next, we used the model to explore various design variables (e.g., area, size, configuration) for placing new CWs within each sub-catchment, quantifying their effectiveness in improving river water quality. Finally, we propose a guiding principle for CW planning based on these findings, illustrating how different spatial layouts affect the achievement of nitrogen and phosphorus targets within sub-catchments.
How to cite: Mijic, A., Peng, F., Srivastava, S., Dobson, B., and Liu, L.: An Integrated Catchment-Scale Approach to Urban River WaterQuality Using Constructed Wetlands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4972, https://doi.org/10.5194/egusphere-egu25-4972, 2025.
Leaky dams, particularly those constructed from large woody material, are increasingly implemented in headwater streams to reduce runoff rates by enhancing channel roughness, slowing flow velocities, and creating temporary water storage during high-flow events to desynchronise flood peaks within catchments. Despite significant progress in modelling the hydraulic and hydrological effects of leaky dams through flume experiments and field studies, design guidance for the construction of leaky dams still needs to be improved. A key challenge in optimising designs is the limited availability of high-resolution pre- and post-intervention data in the field, particularly for extreme flood events, which constrains systematic evaluations of leaky dam performance. Enhanced observational studies are critical to validate the effectiveness of leaky dams and refine design strategies.
This study presents a controlled field experiment conducted at the Tees Barrage International White Water Centre, Stockton, UK, utilising a 300-meter white water rafting course to simulate flow events and evaluate the performance of three leaky dams under a range of flow conditions (up to 8.8 m³/s). Two dam designs were tested: (1) engineered dams constructed from pre-cut commercial timbers with consistent dimensions and (2) natural dams made from locally sourced pine timbers. The "leakiness" of the dams was systematically varied by adjusting timber spacings in increments of 10 mm to 100 mm.
Results demonstrate that both leaky dam designs effectively delayed flood peaks compared to the no-dam scenario. Engineered dams outperformed natural dams, delivering greater flood peak delays with better control of cross-sectional blockage. Smaller timber spacings further enhanced peak delays, with engineered dams achieving a 345-second delay and natural dams a 219-second delay relative to the no-dam scenario. Additionally, the study highlights the likely impact of debris accumulation over time on dam performance.
This research underscores the value of controlled artificial channels for generating precise, repeatable data on leaky dam performance under extreme flow conditions and provides a high-resolution dataset for in-channel hydrodynamic modelling. The findings advocate for further design-focused testing to optimise leaky dam configurations for improved flood mitigation, offering valuable insights for practitioners and researchers.
How to cite: Jones, A., Knapp, J., Reaney, S., and Pattison, I.: How “leaky” should a leaky dam be? Insights from physical modelling at a white-water rafting course, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-720, https://doi.org/10.5194/egusphere-egu25-720, 2025.
When transported in rivers, large wood interacts with one another and with flow, sediment, and river boundaries, leading to their physical degradation. This degradation, causing mass of loss and changing of the geometry of the wood, is relevant to various fluvial processes, including bed morphology evolution, aquatic habitat variation, changes to the local environment, and the carbon cycle. The physical degradation of large wood can be categorized into two main types processes, based on wood types and the characteristics of the wood physical motion: abrasion and debranching. Field observations suggest that abrasion primarily occurs through collision and shearing during transport, affecting large trunks as well as fragmented branches. In contrast, debranching results from the rotation of large woods and collisions with the riverbed, with the extent of this process closely tied to the wood's structural properties.
Previous studies have largely focused on large wood transport, the formation of logjams, and the bio-chemical degradation of smaller wood components (such as sticks and leaves) within aquatic habitats. While these studies have deepened our understanding of wood characteristics and their interactions with the environment, physical wood degradation during transport remains underexplored. This degradation affects wood transportation, logjam formation and failure, and aquatic habitats. Therefore, a more detailed understanding of the physical degradation process is crucial for advancing research on large woods in rivers.
Here we introduce a laboratory-based tumbling machine experiment to investigate the abrasion process of large woods during river transport. Preliminary tests examine the relationship between wood abrasion and the potential energy of water flow. Wood samples, with diameters of 10–15 cm and a diameter-to-length ratio of 0.5, were selected from various tree species. Experiments were conducted under different water depths and flow velocities. Our methodology includes measuring the basic physical properties of the wood samples, using motion sensors, and combining 3D printed sensors to monitor their movement characteristics. Additionally, Surface from Motion (SfM) is employed to capture changes in the wood samples' Digital Elevation Models (DEMs) before and after the experiments, enabling precise quantification of degradation volume and patterns.
Preliminary results will be discussed considering the level of observed wood abrasion, size alterations, and debarking of the wood surfaces. Specifically, the influence of water depth and relative flow velocity on wood abrasion will be discussed. Wood abrasion will be quantified using specific indicators, allowing us to define distinct degradation patterns and their mechanisms. The potential findings will highlight the connection between river flow energy and physical wood abrasion, offering preliminary insights into the mechanisms underlying wood abrasion in rivers.
Keywords: Large wood; wood abrasion; debarking process; experimental design; wood abrasion pattern
How to cite: Yang, J., Seidel, F., and Franca, M. J.: Experimental insights into the abrasion of large wood in rivers, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6721, https://doi.org/10.5194/egusphere-egu25-6721, 2025.
Wood is a key-component of river ecosystems, but it is also regarded as a detrimental element that may increase the hydraulic risk. For example, large accumulations of wood and fine vegetation at bridge piers can reduce the bridge span and generate afflux, potentially extending flooded areas. Such vegetation is generally transported during floods, originating from landslides, debris-flow and bank erosion. Additionally, river re-naturalization and nature-based solutions like large wood addition or the building of vegetation patches, may inadvertently contribute to wood transport. Therefore, both natural events and human interventions can increase the amount of transported wood, potentially increasing associated hydraulic risks.
While several studies have addressed the risks related to wood accumulation at bridge piers, significantly less attention has been given to wood accumulation processes at natural structures, like vegetated bars. Similarly to bridge piers, stable vegetated islands can trap wood, fostering its accumulation, reducing or delaying its mobility and protecting the downstream areas.
The present contribution analyses the influence of a mid-channel vegetated bar on large wood transport in the Adda River (Italy) employing the two-dimensional hydrodynamic numerical model ORSA2D_WT, which includes large wood transport dynamics. The vegetated island is located just upstream of a four-pier bridge. Its effect in terms of trajectory deviation, accumulation at the bar, and wood-pier interaction is analyzed by simulating different scenarios of flow, and large wood abundance and positioning.
The results highlight that the presence of stable non-erodible vegetation on a bar upstream of the bridge reduces the interaction between the wood and the piers, thus reducing the probability of accumulation. In addition, the ORSA2D_WT model aids in identifying which piers are most subject to impacts from transported wood, thus facilitating maintenance strategies. The proposed approach could be applied to other natural or human structures, to assess their efficacy in sheltering downstream critical sections from wood accumulation.
How to cite: Persi, E., Ennouini, W., Karimikordestani, D., Ravazzolo, D., Petaccia, G., and Sibilla, S.: Modelling the effect of a vegetated mid-channel bar on large wood accumulation at bridge piers, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5705, https://doi.org/10.5194/egusphere-egu25-5705, 2025.
Rewilding is a type of Nature-based Solution and has increased in popularity in recent years with rewilding projects rapidly increasing in number across Europe. Different definitions of rewilding have been proposed but it generally refers to large-scale, whole-ecosystem approaches to landscape restoration which can include the reintroduction of missing species. Rewilding has the potential to influence hydrological extremes (floods, droughts), which are expected to intensify with climate change, but the evidence base is limited. To address this gap, this project combines systematic literature review and meta-analysis of published data, an audit of existing publicly available hydrological data for rewilding projects and hydrological and hydrodynamic modelling of rewilding scenarios, calibrated using real-world data from two UK projects.
In this presentation we will share an analysis of published studies that indicates rewilding-driven landscape changes are likely to slow the flow of water through landscapes and attenuate flood peaks. In contrast, research on low flow outcomes is limited and outcomes are more complex. We will also illustrate that existing hydrological monitoring networks in the UK need to be expanded in order to effectively monitor the impact of rewilding projects on hydrological extremes. Preliminary results from modelling rewilding outcomes at UK rewilding projects will also be discussed.
How to cite: Hartley, A., Harvey, G., and Henshaw, A.: Quantifying the impacts of rewilding on hydrological extremes (floods and droughts), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11975, https://doi.org/10.5194/egusphere-egu25-11975, 2025.
Riparian zones are critical links between terrestrial and aquatic ecosystems, controlling the biogeochemical fluxes and thus the fate of carbon (C) in stream networks. However, long-standing anthropogenic modifications of waterways have resulted in significant losses of riparian connectivity. Following re-introduction of beavers across Europe, the resulting reconnection of riparian interfaces shows a high potential for improving water quality and C sequestration. Beaver dam construction gives rise to sequential shifts in lotic and lentic conditions that support high capacities for C deposition and increase the C produced by aquatic primary producers. However, due to inconsistent system boundaries and the overlooking of certain C pathways, our current understanding of C budget dynamics in beaver wetlands remains incomplete.
In this study, we quantified the annual C budget in an established beaver-impacted reach in Switzerland. Inputs and outputs of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) loads were modelled from biweekly water sampling and flow monitoring, in conjunction with measurements of gaseous C fluxes from soil, water and dead trees. Sediment storage of deposited C fractions was quantified in soil samples that were subsequently analysed with Rock-Eval pyrolysis. Biomass C storage was estimated at a plant species level by combining biomass surveys in field with multispectral imagery from drone remote sensing. Following hydrology and bathymetry measurements, the reach water balance was established by quantifying in- and outflow, wetland storage, subsurface storage and infiltration, and evapotranspiration.
We found large reductions in DIC loads along the reach, representing the main driver of the wetland's overall C sink response. The water balance partitioning further demonstrated that subsurface pathways were the primary sink of DIC, which was removed through transient and permanent storage, and deeper infiltration. Carbon dioxide (CO2) mineralisation in non-inundated soils was the dominant source of C emissions from the system. However, the limited release of CO2 from water surfaces showed that only a negligible fraction of DIC was released via this pathway. Instead, the annual accumulation of inorganic C in sediments suggests that DIC immobilisation in sediments, in conjunction with deeper infiltration, can be a significant C sink.
These results show that established, semi-confined beaver wetlands primarily regulate C dynamics via hydrological processes, overriding biogeochemistry and riparian feedbacks from primary productivity. It further stresses their high sensitivity to shifts in the C sink-source balance, and the importance of including inorganic C to elucidate their full impact on C sequestration in stream networks.
How to cite: Hallberg, L., Larsen, J., Larsen, A., d’Epagnier, R., Thurnheer, S., Ceperley, N., Schaefli, B., and Dennis, M.: Inorganic carbon unexpected driver of carbon sink response in an established beaver wetland, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11362, https://doi.org/10.5194/egusphere-egu25-11362, 2025.
Green infrastructures (GI) are key elements in urban areas for heat mitigation, carbon capture and providing of aesthetic reasons. However, there is currently limited knowledge about the effects of various plant compositions, arrangements and varying density of plant cover, because traditional measuring methods are expensive / labour-intensive, imprecise, and tall buildings pose accessibility challenges. The presented study proposes applying LiDAR measurements on GI to gain in-depth understanding of plant growth, inventory of vegetation cover and thereby providing a useful tool for sustainable urban hazard management.
The use of LiDAR (Light Detection and Ranging) technology has revolutionised forest monitoring by offering precise, efficient, and highly detailed spatial data for creating comprehensive 3D reconstructions of forest structures. The ability to capture fine details on both vegetation and structural surfaces is particularly advantageous for studying complex, vertical environments such as green façades. This study used static ground-based LiDAR (RIEGL VZ-600i) to capture the 3D structure of a vertical greenery with wooden support structures before and after harvesting. Defined squares of 1 m² were fully harvested, the biomass collected and dry weight was obtained. Reference measurements for vegetation height (distance from wall to the outermost part of the plant) were recorded on a grid for 40 measurement points. The reference measurements were related to LiDAR alpha-hull volumetric analysis and predictions of growing biomass could be derived.
By integrating point cloud analysis developed for forest monitoring into urban contexts, LiDAR facilitates a holistic analysis of natural and built environments. By analysis of LiDAR intensity and mapping further reference measurements for plant vitality and structural integrity, green wall health can be evaluated. Already established practices like alpha-hulling provide a successful tool to document green façades comprehensively. Combining LiDAR with traditional measures enhances our understanding of the interactions between vegetation and architectural surfaces, enabling improved design and maintenance of GI and NBS to enable better planning and maintaining of NBS to reduce the effect of urban heat islands.
How to cite: Briefer, A., Tockner, A., and Stangl, R.: LiDAR for Green Infrastructure: monitoring vertical greening with wooden support structures, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19479, https://doi.org/10.5194/egusphere-egu25-19479, 2025.
Traditional water management practices, largely based on hard engineered infrastructure and highly optimized systems, are proving insufficient for adapting to the complex interplay of future climatic, environmental and socio-economic conditions. The increased frequency and magnitude of hydrological hazards in Europe, such as the multi-year drought during the period 2018-2020 and the subsequent summer flood that hit Central Europe in July 2021, have underscored the need for integrated water management. Nature-based Solutions (NbS) offer a promising alternative or complement to grey infrastructure by leveraging natural processes and ecosystem services to simultaneously mitigate flood and drought risks. Unlike traditional water management, which has a well-developed knowledge base and specialized modelling tools to represent structural measures (e.g., dikes, dams) as well as guidelines to assess their performance, knowledge on NbS representation, functioning and their impacts on catchment hydrology over time is still limited. The simulation of NbS requires modellers to identify relevant hydrological processes involved in their functioning and find reliable ways to represent them based on the capabilities and limitations of selected physically-based models and available data. Agricultural catchments, while highly vulnerable to shifts in climate due to their dependence on natural climate-sensitive resources, offer significant opportunities for implementing nature-based strategies such as wetland restoration, tree planting and infiltration ponds. This study analyses the impact of NbS representation on the hydrological processes related to both floods and droughts in one middle-sized agricultural catchment under temperate climate: the Handzamevaart catchment (Belgium). Using MIKE SHE, a fully distributed hydrological model, coupled with MIKE 11, a 1D hydraulic river model, we explore a wide range of parameters to represent different types of NbS. Changes in the total water balance and in the individual hydrological processes and variables related to discharge, overland flow, evapotranspiration, infiltration, and groundwater fluxes obtained as a result of the different NbS representation will be assessed at catchment scale, but also locally - immediately upstream and downstream of the modelled measures. This study can serve to build the foundational knowledge required for the representation of NbS in physical models, anticipating process understanding for designing flood and drought mitigation strategies. Key outputs include an evaluation of model robustness to NbS representation, identification of the most influential parameters in the representation of different types of NbS, and thereby guidance for empirical data collection to improve NbS representation in future studies.
Research is supported by the Horizon Europe research and innovation programme: the “FUTURAL project” (Grant No. 101083958).
How to cite: Fragata dos Santos, C., Jonoski, A., Popescu, I., Chittrakul, K., and Samain, B.: The impact of Nature-based Solutions (NbS) on hydrological processes in an agricultural catchment through their representation in a physically-based model, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19299, https://doi.org/10.5194/egusphere-egu25-19299, 2025.
EGU NH1.7
A coupled mechanistic and in situ data approach to quantify the water retention potential of Nature-Based Solutions
The increasing frequency and intensity of droughts poses great challenges to water availability and the functioning of natural ecosystems. In response to this, nature-based solutions (NbS) have emerged as a promising alternative to traditional infrastructure. NbS offer multiple benefits, including water retention, improved water quality, biodiversity conservation, and carbon sequestration. However, despite the growing recognition of their potential, the hydrological benefits of NbS remain poorly understood. The hydrological effects of NbS, such as water retention and groundwater recharge, are complex and require an integrated understanding of surface and groundwater interactions. However, current models for assessing water retention benefits are either too complex or not specialized to capture the unique features of NbS interventions. As such, the hydrological benefits associated with NbS are not fully understood. Furthermore, long-term in situ data that provides evidence of the benefits of NbS is also lacking. Consequently, the adoption of NbS remains limited due to the lack of clear evidence regarding their effectiveness in mitigating water scarcity.
In our study, we address these gaps by developing a simplified hydrological model designed to quantify water retention benefits of reclaimed and rewetted areas in a nature conservation area. The model is based on physically-based hydrological properties, which allow it to represent the fundamental water retention mechanisms of NbS. The model captures the interaction between the catchment area, the water retention zone (the NbS intervention), and the exchange between surface and groundwater. To validate the model and provide robust evidence, we complement the modelling approach with in situ data collected from a network of low-cost soil moisture sensors and groundwater piezometers. The deployment of these sensors allows for extensive monitoring at a relatively low cost, which is crucial for obtaining long-term data on the performance of NbS.
Our study demonstrates that NbS have the potential to mitigate water scarcity by enhancing both surface and groundwater storage, and the findings provide evidence that NbS can contribute to drought adaptation, with the added benefit of providing other ecosystem services. We also conclude that this coupled approach could serve as a useful tool for promoting the wider adoption of NbS in water resource management strategies as a multi-benefit alternative or companion to traditional infrastructure-based solutions.
How to cite: Lekarkar, K. L., Dondeyne, S., and van Griensven, A.: A coupled mechanistic and in situ data approach to quantify the water retention potential of Nature-Based Solutions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17407, https://doi.org/10.5194/egusphere-egu25-17407, 2025.
Nature-based solutions (NbS) are known to be important measures that can help reduce climate change effects while providing environmental, social and economic benefits.
This study presents one of the evaluated examples of mitigation and adaptation in the wastewater management sector: the potential of willow (Salix spp.) plantations in different regions of Latvia. They are considered to be cost-effective and highly efficient solutions for recovering nutrients in wastewater and also provide biomass that can be used for energy production.
The particular study approximated the number of persons in households not connected to centralised wastewater treatment plants or using poor quality biological treatment plants in different regions of Latvia according to Latvia`s National Inventory Report under the UNFCCC Greenhouse Gas Emissions in Latvia from 1990 to 2022. Overall, 24% of private persons discharge inadequately treated domestic wastewater into the environment, accounting for 99.8% of methane emissions in municipal wastewater sector.
It is known that willow plantations are used for wastewater treatment in Denmark, Sweden and southern Finland (https://doi.org/10.1016/j.scitotenv.2020.138620), but their use in northern regions may be limited due to climatic conditions, as the efficiency of wastewater treatment decreases at low temperatures. Taking this into account, regions in Latvia where willow plantations would be more effective were initially assessed. Overall, trends in climate parameters gave reason to believe that the western regions of Latvia are already suitable for the establishment of willow systems.
The IPCC (2006) methodology for calculating GHG emission reduction was used. Main assumptions used in the evaluation of the implementation of the measures: assumption that all households without appropriate domestic wastewater treatment are connected to the system; assumption that biological treatment plants of adequate quality and efficiency are in place. The willow system is designed to accumulate as well reduce N & P and their efficiency depends on correct operation. It should be noted that the system requirements depend on the water consumption and pollution load.
The cost of installing such systems in the first year will be the highest, but as the indicative lifetime of the system is 20 years, the long-term average cost could be around €440/tCO2eq. Negative aspects or impacts as shown by studies are most related to the cost of planning directly for biomass collection (on average 15 minutes mowing per 100 m2) as they should not be overgrown, to the approximately 12 hours of regular annual maintenance and to extreme rainfall events during which water levels have to be monitored.
From an adaptation point of view, there are several known positive aspects of willow planting, such as reducing flood risk. Willow plantations increase evaporation and slow down the spread of water in the floodplain. They also provide several ecosystem services, for example, they attract pollinators, supporting biodiversity, as well as improve the aesthetic value of the territory.
How to cite: Briede, A., Steinberga, I., Putnina, K. K., Peneze, Z., and Vinogradovs, I.: The potential of nature-based adaptation solution in municipal wastewater sector: willow planting systems as GHG emission reductants in Latvian villages, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17771, https://doi.org/10.5194/egusphere-egu25-17771, 2025.
High levels of urbanisation, combined with the effects of climate change, are affecting meteorological phenomena, leading to an increase in global urban rainfall anomalies and more flooding. This phenomenon is exacerbated in urban areas by the increasing imperviousness. As a result, flooding is one of the most devastating and widespread natural disasters in the world, affecting regions on all continents. Sustainable Urban Drainage Systems (SUDS) have emerged as a practical solution to mimic natural drainage processes and mitigate the adverse effects of flooding while providing other co-benefits. This is the case, for example with stormwater trees, which contribute to the sustainable management of rainwater and surface water runoff by optimising the processes of infiltration, retention and transpiration. However, in the case of extreme rain events or a fast succession of rain events, the soil or substrate surrounding these trees can remain in saturated conditions for longer periods of time, undermining their capacity to provide the ecosystem services needed. In order to evaluate the resistance of urban trees and in particular to better assess/understand the physiological limits of the stormwater trees, soil saturation assays were carried out in 2023 and 2024 on maple trees (Acer platanoides Globosum), a common street tree in European cities. The assays consisted of evaluating the morphological and physiological responses of 3 young maple trees subjected to water saturation of the planting soil during 21 days and comparing them with 3 reference maple trees under normal drainage conditions. At the tree level, the transpiration changes and the trunk pulsations were continuously monitored with sap flow sensors (Implexx Sense) and dendrometers (Ecomatik), respectively. At the leaf leaves level, the physiological responses following prolonged soil saturation conditions were monitored by instantaneous fluorescence-based measurements of leaf pigments and the nitrogen balance index (DUALEX®, Force-A,) as potential stress biomarkers, and leaf stomatal conductance and transpiration (LI-COR). The soil compartment was monitored using continuous soil moisture measurements (Campbell Sci.) and punctual measurements of pore water oxygen level and redox potential (WTW).
The results showed a rapid fall in soil pore water oxygen level and redox potential, while the physiological effects of saturation were delayed and appeared only after 7 days of soil saturation. The most impacted tree measured parameter was the transpiration rate, followed by leaf ecophysiological traits such as phaeopigments. Remarkably, the prolonged soil saturation profoundly affected tree health, showing effects even after the winter dormant period during the following growing season This questions the extent to which stormwater trees could provide ecosystem services in the future. The presentation will focus on the impact of soil saturation on the various tree parameters measured and propose the definition of a “tolerance threshold” for stormwater trees in the context of runoff management.
How to cite: Zime Yerima, H., Techer, D., and Seidl, M.: Resilience of stormwater trees to temporary flooding: The case of Acer platanoides ‘Globosum’, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17941, https://doi.org/10.5194/egusphere-egu25-17941, 2025.
Posters on site: Thu, 1 May, 08:30–10:15 | Hall X3
A canopy-resistance based debris factor, CA (Follett et al., 2020), can be used to model the head-loss from flows passing through and over a leaky barrier. The advantage over a Mannings coefficient typically used in hydraulic modelling is the debris factor is a direct construct from physical factors characterising the bulk properties of the woody debris, including frontal area and bulk density. The debris factor has been established to be a robust predictor of head-loss across a range of flows. The aim here has been to quantify CA from remotely sensed data based on photogrammetric techniques estimating the required physical characteristics. To do this we have worked with a leading specialist UK surveyor, Storm Geomatics, who surveyed two small watercourses (Nethercote and Paddle brook) near Shipston-on-Stour, England.
A HEC-RAS 2D-only hydraulic model driven by design rainfall has been setup with 37 features in Nethercote Brook. The debris factor was first estimated based on photographic lookup and then refined to be based on analysis of photogrammetric data. For each unit a rating equation is generated given the estimate of CA which governs the head losses. The intention is that this process will become automated, such that a hydraulic unit for the leaky barrier can be generated automatically.
An equivalent reach-scale Mannings roughness (see Follett and Hankin, 2022) is also considered with a view to using in other catchments more easily based on the type of modelling typically undertaken. In a further UK case study, in the intensively monitored Eddleston Water catchment, the reach-scale roughness approach was also tested for leaky barriers in Middle Burn, applying a Mannings uplift based off photographs taken of the leaky barrier construction. Here CA is estimated and the equations to convert to a reach-scale equivalent Mannings is used.
As 3d point-cloud data from photogrammetry becomes more widely available, the intention is to make it easier to quantify CA and use the canopy resistance-based equations to generate a hydraulic unit for use in e.g. HEC-RAS 2D directly. This will help quantify the effectiveness of a range of nature-based solutions from large wood to woody debris barriers to slow the flow.
Follett, E., Schalko, I., & Nepf, H. 2020. Momentum and energy predict the backwater rise generated by a large wood jam. Geophysical Research Letters, 47, e2020GL089346. https://doi.org/ 10.1029/2020GL089346
Follett, E., Hankin, B., 2022. Investigation of effect of logjam series for varying channel and barrier physical properties using a sparse input data 1D network model. Environmental Modelling & Software, Volume 158, 2022, 105543, ISSN 1364-8152, https://doi.org/10.1016/j.envsoft.2022.105543
Hankin, B., Hewitt, I., Sander, G., Danieli, F., Formetta, G., Kamilova, A., Kretzschmar, A., Kiradjiev, K., Wong, C., Pegler, S., and Lamb, R. 2020: A risk-based, network analysis of distributed in-stream leaky barriers for flood risk management. Nat. Hazards Earth Syst. Sci., 20, 2567–2584, 2020 https://doi.org/10.5194/nhess-20-2567-2020 .
How to cite: Champion, H., Follett, E., Hankin, B., and Hopkins, M.: Using remote sensing to parameterise a leaky barrier hydraulic unit , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4245, https://doi.org/10.5194/egusphere-egu25-4245, 2025.
The changing climate creates challenges for green spaces everywhere. A special case is presented by the urban tree, which has several harsh environmental conditions to deal with, i.e. compacted soil, polluted rainwater, etc. Climate adaptation strategies for cities involve the urban tree as a nature-based solution due to its high potential for heat island mitigation and reducing surface runoff. Managing water resources efficiently is receiving more attention with measures including alternative resources for irrigation or incorporating more drought-resistant species, while the effects of changing macro- and micro-climatic conditions on urban trees are only now becoming subject of scientific scrutiny.
There are several important indicators for evaluating a tree’s living conditions and its water demand at a certain location. One such indicator is the start and end of the growing season. As temperatures rise, plants are seen to have shorter dormancy periods, resulting in earlier flowering and longer growing seasons, increasing both water demand and susceptibility to damage.
In this study, we compare the growing cycles of urban trees across varying locations in the city of Graz during a period of over 20 years. Tree specific information is taken from the city’s tree register which gives important information about species, age and location of urban trees. Growing cycles are evaluated using a remote sensing approach where NDVI-timeseries are then calculated for the selected areas using openly available satellite imagery to identify changes in dormancy and evaluate a possible trend. The influence of parameters such as location, micro-climate, species and date of planting are investigated using statistical analysis. The generated knowledge is expected to help in the prediction of future urban green irrigation demand and choice of tree species.
How to cite: Kudaya, F. S., König, A., and Fuchs-Hanusch, D.: Analyzing variability and possible trends in NDVI for urban water management: A remote-sensing approach for long term monitoring of green infrastructure, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15942, https://doi.org/10.5194/egusphere-egu25-15942, 2025.
Wetlands are critical nature-based solutions (NbS) for addressing environmental challenges, playing an important role in sediment and nutrient retention, agricultural runoff mitigation, and carbon storage, contributing to climate change adaptation. However, agricultural intensification and land conversion have drastically reduced wetland coverage globally, necessitating the precise selection of sites for restoration/creation. Depending on fieldwork and expert judgment, traditional methods often struggle to scale effectively, highlighting the need for advanced geospatial techniques.
This study compares two approaches for in-stream wetland site selection, the Analytic Hierarchy Process (AHP) and the machine learning Random Forest (RF) algorithm, within the diverse hydrological landscape of Estonia. Both methods utilized environmental variables, including slope, topographic wetness index (TWI), flow accumulation, soil organic carbon (SOC), and clay content, to evaluate their influence on hydrological and soil conditions critical for determining suitable sites for in-stream wetland creation and restoration. These variables were selected for their ability to capture the key factors that drive wetland formation and functionality. Geospatial datasets, including local and global environmental variables, were processed at 10- and 50-meter resolutions to analyze how spatial resolution influences model performance, providing high-detail insights for localized assessments and broader, regional-scale perspectives.
The AHP framework integrates expert knowledge to prioritize variables, while the RF algorithm provides a data-driven, scalable alternative. The RF model was trained using data from existing wetlands, which were identified based on geospatial datasets and intersected with stream networks, channels, ditches, and rivers to focus on areas directly connected to water flow. Training points were randomly sampled within these wetlands to represent suitable areas. In contrast, points from non-wetland areas, such as forests, shrublands, grasslands, and arable land, were sampled to represent unsuitable areas. This approach ensured that the training data captured the variability of environmental conditions influencing wetland suitability
Validation was conducted using a historical map to evaluate model accuracy and reliability across varying scales and data conditions. Results indicate that the RF algorithm outperformed AHP in predictive performance, achieving an accuracy of approximately 0.8 at broader resolutions and slightly lower accuracy at finer resolutions. This underscores the influence of spatial resolution on model performance. However, AHP underscored the importance of structured decision-making and stakeholder input, ensuring practical applicability. This research advances the integration of NbS into wetland planning, bridging traditional expertise-driven methods and machine learning innovations to enhance precision, scalability, and cost-effectiveness.
How to cite: Guamán Pintado, P. M., Muru, M., and Uuemaa, E.: Finding suitable locations for in-stream wetland creation/restoration: comparing suitability analysis with machine learning approach , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17250, https://doi.org/10.5194/egusphere-egu25-17250, 2025.
Due to human interventions such as river channelization, the diversity of the flow, sediment, and wood regimes in rivers has decreased. A common measure to locally reestablish flow heterogeneity are nature-based solutions such as logjams with the aim to create or increase habitats for aquatic organisms such as fish. To optimize the design of nature-based solutions and to leverage the habitat creation for fish, we need to create a better understanding of the underlying flow and turbulence characteristics due to nature-based solutions.
Laboratory experiments were conducted to investigate how different logjams affect the flow and turbulence properties. High-speed imaging was used to characterize the flow field at the surface and at a vertical plane at the channel centerline. The experiments investigated logjams differing in solid volume fraction, submergence level, as well as log alignment. All tested parameters altered the wake region. The results of the log alignment indicate that a random arrangement can lead to an evenly reduced velocity in the wake and lower turbulence levels. In contrast, a regular arrangement can lead to jets going through the structure and entering the wake unblocked, resulting in higher turbulence levels. The different turbulence levels may have implications for fish response.
As a next step, field measurements are planned to complement laboratory experiments. Selected engineered logjams will be investigated at a restored river reach at the Emme River in Switzerland. Specifically, flow measurements will be obtained through drone images and Acoustic Doppler Velocimetry and compared to results of fish abundance.
How to cite: Broß, F., Dorthe, C., Chang, K., Coletti, F., and Schalko, I.: Effect of engineered logjams on hydrodynamics and fish response, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10852, https://doi.org/10.5194/egusphere-egu25-10852, 2025.
Flooding is one of the great issues of our time and is the most damaging environmental hazard globally, costing over €40 billion a year in Europe alone. Solving the problem is a huge challenge. Climate change, resulting in wetter winters and more intense summer storms, is aggravating flooding. Meanwhile, demand for land to feed and house growing populations leads to increasing concentrations of people and assets in areas exposed to flooding, and ongoing land use change continues to increase the severity and frequency of flooding.
Traditionally flooding has been managed primarily through large, engineered structures, but these structures are costly to install and maintain, and often provide flood reduction benefits to the detriment of the environment, e.g., having a negative effect on wildlife and biodiversity. These consideration have, in recent years, driven a move away from such structures to multiple small-scale nature-based interventions distributed across the landscape, an example of which is the leaky barrier (LB). LBs can be used to mitigate flood risk and provide other benefits such as reducing diffuse pollution. Yet, LBs are poorly understood.
At present, there is no accepted way of representing LBs in models, although there have been attempts to put multiple LBs into hydraulic models of catchment systems. Modelling approaches include using high values of Manning’s n to represent LBs; modelling them as reductions in cross-sectional area; using combined weir/sluice gate equations; and using an equivalent ‘outlet pipe diameter’, defined by the amount of flow able to flow under, through or around the barrier as a parameter to represent leakiness. These models provide useful clues as to how combinations of features may behave in aggregate, but it is far from clear what sort of LBs they represent and there is high uncertainty associated with the results obtained.
The research discussed here combines physical and mathematical modelling to improve understanding of LB behaviour. Hydraulic flume experiments are conducted which model a range of naturally occurring and constructed LBs, including upright obstructions as a model of growing vegetation and horizontal obstructions as an analogue of log jams, woody debris barriers and beaver dams, all of which often form horizontal, or nearly horizontal, obstructions to the flow. Experiments show that barrier design has a big impact on the hydraulics. It is shown that some existing approaches, such as using an equivalent ‘outlet pipe diameter’ or a high Manning’s n were not able to capture the observed behaviour. This raises a series of questions about the sensitivity of hydraulic behaviour to various design parameters and what is required to model LBs adequately.
Data from the simplest design: the single horizontal barrier, was used to inform a finite volume model of the flume and LB. The combined weir/sluice gate equations are shown to provide a good model of a single horizontal barrier. However, the behaviour of the other LB designs is significantly different and cannot be represented adequately using this model.
How to cite: Hewett, C.: Unravelling the hydraulics of leaky barriers: physical and mathematical modelling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6152, https://doi.org/10.5194/egusphere-egu25-6152, 2025.
Due to increasing flood risks related to climate change and urbanization, solutions addressing environmental challenges must be more effectively integrated into urban environments. Green spaces and blue-green infrastructure, which combine water, vegetation, and recreational areas, can contribute to both flood risk mitigation while addressing the urban heat island effect, ultimately enhancing the quality of life in cities. These facilities also promote biodiversity and ecological resilience, supporting stable ecosystems while providing green and open recreational spaces even in the heart of bustling urban areas. The Gazelle Valley Urban Nature Park, located in the densely populated metropolitan area of Jerusalem, Israel’s capital, serves as a prime example of such efforts. The establishment of this park is considered a groundbreaking social and environmental achievement, made possible by the struggle of residents, local activists, social organizations, and the Society for the Protection of Nature in Israel. Built to the highest ecological design standards, the park has quickly become a popular destination for both residents and visitors, offering a model for integrating eco-hydrological solutions into urban landscapes. As part of an ongoing study, water inflow and its quality within the park’s water system are monitored. The park’s water system, which is fed by stormwater during the wet season (winter) and treated wastewater during the dry season (summer), is tracked through online monitoring using a low-cost open-hardware station. When combined with sampling and laboratory analyses, online measurement helps assess water composition and water quality dynamics in order to evaluate the impact of an urban nature-based solution on water quality. This study also tests the applicability of low-cost open-hardware technology for environmental monitoring in aquatic ecosystems, while examining the effectiveness of nature-based solutions in improving the water quality of stormwater and treated wastewater in urban settings.
How to cite: Ben Dor, Y., Sharabi, G., Alian, S., Nussbaum, R., Morin, E., Freiman, E., Lind, A., Shemesh, I., Balaban, A., Train, F., and Levintal, E.: Gazelle Valley Park – A case study of a dual urban nature-based solution for flood mitigation in a Mediterranean climate, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1422, https://doi.org/10.5194/egusphere-egu25-1422, 2025.
Deltaic coasts, with their fertile soils and diverse ecosystems, are critical for agriculture, trade, fisheries, energy supply, and manufacturing. However, these regions are highly susceptible to hydrometeorological hazards, including storms, flooding, and extreme temperature events. Anthropogenic climate change has exacerbated the frequency and intensity of such hazards, posing significant societal and environmental challenges. While traditional hard engineering structures (e.g., levees, dykes, sea walls) have been the primary approach to coastal protection, these solutions often increase hazard complexity and risks while requiring substantial financial investments. In contrast, nature-based solutions (NbS) have emerged as cost-effective and sustainable alternatives or complements to traditional engineering approaches, demonstrating their potential to mitigate and adapt to coastal hydrometeorological hazards.
Quantifying the effectiveness and potential of NbS in attenuating hydrometeorological hazards in coastal regions remains challenging due to the complexity in spatiotemporal dynamics of hazards and variations in assessment methods (e.g., qualitative, quantitative, or mixed). Despite numerous studies on NbS in coastal and deltaic contexts, there is a lack of comprehensive evaluations addressing the types of NbS, their geographical applications, methodological robustness, and confidence in their effectiveness in addressing hydrometeorological hazards. This study bridges these gaps by systematically reviewing 330 peer-reviewed English-language articles published between 2008 and 2024, identified using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. The review focuses on five key hydrometeorological hazards in coastal and deltaic regions globally: storms, floods, extreme temperatures, extreme precipitation, and droughts. NbS are evaluated as substitutes, complements, or safeguards to hard engineering structures, considering both real-world and hypothetical case studies. A comprehensive framework, adapted from the Intergovernmental Panel on Climate Change (IPCC), is employed to evaluate NbS based on three criteria: (1) robustness of evidence (e.g., mechanistic understanding, model validation), (2) the level of agreement (e.g., consistency of findings supporting NbS effectiveness), and (3) confidence (integrating robustness and agreement).
The findings provide key typologies of NbS applications across different hydrometeorological hazards, with a predominant focus on storms and floods, while extreme temperatures and droughts receive comparatively less attention. Most studies evaluate the effectiveness of NbS options such as mangroves, coastal wetlands, dunes, and coral reefs in safeguarding coastal areas from hydrometeorological threats, often drawing insights from real-world case studies. Studies on floods and storms frequently employ numerical or hydrodynamic modelling, using indicators such as flood depth, extent, velocity, wave height, and wave energy. These studies consistently demonstrate high confidence in the effectiveness of NbS in attenuating storm and flood hazards in coastal and deltaic regions, attributed to their robust methodologies and consistent findings.
The study highlights the effectiveness of NbS in mitigating coastal hydrometeorological hazards varies geographically, influenced by local factors such as geomorphology, hydrology, and human activities. Numerical or hydrodynamic modelling, supplemented by cost-benefit analyses and validated with observational data, is recommended for robust quantification of NbS benefits and trade-offs. These findings provide a foundation for future research and offer actionable insights for policymakers and practitioners, facilitating the integration of NbS into coastal hazard management as viable substitutes or complements to hard engineering measures.
How to cite: Adnan, M. S. G., Kebede, A. S., Addo, K. A., Dewan, A., Ghosh, T., White, C. J., and Ward, P. J.: Nature-based solutions for attenuating hydrometeorological hazards in coastal regions: Effectiveness and quantification approaches, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3855, https://doi.org/10.5194/egusphere-egu25-3855, 2025.
This study represents the feasibility study on landslide mitigation measures above the settlement of Koroška Bela in northwestern Slovenia. The settlement of Koroška Bela is very densely populated (about 2,100 inhabitants) and has a well-developed industry and infrastructure. The area above Koroška Bela has been recognized as one of the most active landslide-prone areas in Slovenia. It attracts attention due to historical evidence of past debris flows in recent geological history. The first recorded event occurred in the 18th century and caused the partial or complete destruction of more than 40 buildings and devastated cultivated areas in the village of Koroška Bela. In recent decades, two more events have occurred: In April 2017, part of the Čikla landslide turned into a debris flow, and in August 2023, the reactivation of the Urbas landslide led to the disruption of alarm systems and the triggering of emergency sirens. Each event was associated with prolonged and intense rainfall.
To reduce the landslide risk in Koroška Bela, a comprehensive engineering, geological and hydrogeological characterization of landslide-prone areas was required to prepare feasibility studies for mitigation and remediation strategies. So far, no specific remediation measures have been implemented, as the existing check dams do not have the necessary capacity to effectively manage sediment and debris flows.
Our findings highlight the need for holistic mitigation measures in order to protect residents and infrastructure. Key areas include stabilizing the Čikla and Urbas landslides and controlling sediment transport in the associated torrent systems. Given the complexity of these landslides, we propose a combination of traditional gray engineering (structural) measures alongside with hybrid solutions that integrate both gray and green elements. For debris- flow management, gray measures such as debris- flow barriers and flexible barriers are essential. To stabilize landslide-prone areas, hybrid solutions combining torrent channel works, drainage systems, and vegetative stabilization should be implemented.
As these landslides are situated in mountainous areas designated as Natura 2000 protected area, mitigation measures should incorporate green design principles that support both visual integration and ecological functions.
Acknowledgments: This research was funded by Slovenian Research And Innovation Agency through research project “J6-4628 - Evaluation of hazard-mitigating hybrid infrastructure under climate change scenarios” and research program “P1-0419 - Dynamic Earth”. Additional financial support was provided by the Ministry of Environment and Spatial Planning, and the Municipality of Jesenice.
How to cite: Jemec Auflič, M., Peternel, T., Oluwasegun Ogunfolaji , Y., and Bezak, N.: The feasibility studies of mitigation measures for landslides located above the Koroška Bela settlement in Northwest Slovenia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2521, https://doi.org/10.5194/egusphere-egu25-2521, 2025.
The increasing frequency and intensity of floods and droughts driven by climate change present significant challenges for water management. Small streams, which are crucial for maintaining ecosystem services, biodiversity, and local water management, are especially vulnerable to these changes. Nature-based solutions (NBS), including wetland creation and rewetting, stream meandering, and riparian zone restoration, have shown great potential for mitigating both floods and droughts by enhancing water retention and reducing hydrological connectivity. This case study focuses on Trelleborg, a coastal city in southern Sweden, where several community-driven NBS projects have been implemented to manage its small rivers and streams. By combining qualitative data from expert interviews with quantitative spatial data analysis, this study aims to evaluate the performance of various NBS in Trelleborg's unique environment. Focusing on Trelleborg’s small streams provides a valuable opportunity to understand how localized NBS initiatives can enhance resilience to climate change while delivering multiple co-benefits. The implemented interventions have not only reduced risks associated with hydrological extremes but also contributed to co-benefits such as improved biodiversity and the creation of new recreational areas. Additionally, the study highlights the importance of stakeholder involvement in understanding local socio-economic contexts and diverse perspectives, which is essential for assessing and designing effective NBS projects for future implementation. The findings can inform future NBS initiatives in similar contexts, offering actionable insights into their design, implementation, and performance.
How to cite: Kåresdotter, E., Rezvani, A., and Kalantari, Z.: Nature-Based Solutions for Reducing Floods and Droughts in Small Rivers, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12732, https://doi.org/10.5194/egusphere-egu25-12732, 2025.
Climate extremes like floods and droughts pose significant threats to both human communities and natural landscapes. The EU Horizon SpongeScapes and SpongeWorks projects aim to enhance landscape resilience against these hydrometeorological extremes by exploring "landscape sponge functions" – the natural ability of landscapes to absorb, store, and gradually release water. The SpongeScapes project investigates various nature-based solutions (NBS) across diverse European sites with varying climates, geographies, and soil conditions, to address three main questions: (i) what is the longer-term effectiveness of sponge measures (and what indicators/metrics are more adequate); (ii) what is the overall effect of all sponge measures in a catchment (i.e. sponge strategies); (iii) what are the main co-benefits and tradeoffs of sponge measures and strategies.
Here we will present a framework of context-specific 'Sponginess' indicators and metrics, in particular to assess the sponge function of water retention capacity in fluvial and agricultural sponge measures and strategies (catchment-wide combination of measures), with applications to SpongeScapes UK sites in the river Thames basin where work has been done since 2017 and is ongoing. These sites include the Littlestock brook, a headwater catchment in an agricultural landscape where a diversity of nature-based solutions (woody leaky dams, field corner bunds, wet woodland planting) have been implemented, as well as several farms where regenerative agricultural practices (RAPs) have been followed to improve soils, surface and ground water management.
How to cite: Dussaillant, A., Sah, N., Blake, J., Rameshwaran, P., and Old, G.: Sponge function: indicators and metrics to assess water retention in Nature-Based Solutions with application to UK fluvial and agricultural sites, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17085, https://doi.org/10.5194/egusphere-egu25-17085, 2025.
The increasing variability and extremes of hydrological cycles driven by climate change present critical challenges to water resource availability, raising the likelihood of floods and droughts. Understanding the potential impacts of changing climate patterns on future water resources is essential for developing effective adaptation strategies. Within the framework of the DISTENDER project (EU Horizon-ID 101056836), we focus on assessing the resilience of European watersheds to climate stressors by modeling future water scenarios and identifying sustainable water management practices.
This research comprehensively examines the impact of climate and future land use changes on extreme events in Ave Watershed in Northern Portugal using the MIKE SHE hydrological model. Future climate change projections (2021 to 2050) and Shared Socioeconomic Pathways (SSPs) were obtained from CMIP6 and were statistically downscaled. Annual 1-day and 3-day high runoff were used as a proxy for the extreme high runoff characteristics. We then evaluate three adaptive strategies for those impacts:
- Nature-based solutions: Restoring wetlands identified in the "Extended Wetland Ecosystem data," implementing sustainable agricultural practices, and adopting low-impact development methods like green and sponge cities.
- Technical solutions: Introducing new reservoirs in sub-watersheds lacking reservoirs to simulate cumulative effects of rainwater retention, check dams, or other storage infrastructures.
- Hybrid approach: Combining nature-based and technical solutions to maximize the benefits of water resources management.
The climate effects show an increase in the future 1-day and 3-day flood magnitudes across all gauges and return periods. The 100-year 1-day flood in Ave River is projected to range between 496 m³/s (33% increase in SSP 3-7.0) and 721 m³/s (94% in SSP 5-8.5), compared to 372 m³/s during the reference period (1980-2020). Future land use maps for 2020–2050 were generated using the CORINE land cover and the iCLUE model based on different SSPs. Incorporating these maps into the hydrological model shows further intensification of extreme events. For instance, using the 2050 land use map, the 100-year 1-day flood is expected to range 664 m³/s (77% in SSP 3-7.0) and 866 m³/s (133 % in SSP 5-8.5) compared to the reference period. Simulations of the adaptation strategies show that nature-based solutions can reduce flood peaks by 22–32%, while technical solutions achieve 20–46% reductions, depending on the SSP. The hybrid approach demonstrates the most efficient adaptation solution, reducing flood peaks by 37–67%. For SSPs 2-4.5 and SSP 3-7.0, the hybrid approach brings flood peaks close to those observed during the reference period.
By analyzing these strategies individually and collectively, the study identifies the hybrid approach as the most effective for enhancing resilience to extreme events and ensuring the sustainability of water resources. Efficacy analyses of adaptation options are essential to guide a stakeholder dialog and facilitate the necessary transformation. DISTENDER provides a methodological framework to identify and develop climate adaptation and mitigation strategies by integrating these results into a decision-support system.
Keywords: Adaptation strategies, Climate change, Land use, CMIP6 Climate Model, MIKE SHE, Ave catchment
How to cite: Zargar, M., Babker, Z., Reichenau, T. G., and Schneider, K.: Evaluating the Effects of Different Adaptation Strategies to Climate and Land Use Change upon Water Fluxes in the Ave Watershed, Portugal, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6088, https://doi.org/10.5194/egusphere-egu25-6088, 2025.
Nature-based solutions (NBS) are increasingly considered as components of strategies aiming to address climate-related challenges, since their impact expands across more than one aspect of the water, energy, food, and ecosystems (WEFE) nexus. Therefore, searching for tangible evidence on the impact of NBS requires addressing the complexities of the WEFE nexus, which is characterized by dynamic and highly nonlinear relationships. These complexities may challenge traditional modeling approaches, which would rely heavily on human intuition and the cumbersome integration of individual sub-models.
Driven by the continuous improvement of monitoring capabilities, the increase of computational power, and the emergence of efficient algorithms, data-oriented solutions gather momentum in the efforts to identify dynamic systems in a multitude of domains. Nonetheless, such solutions are rarely adopted by the nexus community.
In this work we aim to investigate the potential of data-driven approaches to identify the underlying dynamics of systems that exhibit properties commonly encountered in many WEFE nexus systems, such as nonlinearity, high dimensionality and non-stationarity (e.g., the exposure to extreme events).
To unravel these complexities, we employed a symbolic regression (SR) approach within a case study of a rainwater harvesting system operating in Mykonos, Greece. This system is designed to collect, treat, and store rainwater for agricultural reuse. A sub-surface collection system captures rainwater, diverting it into two storage tanks. The collected water irrigates an agricultural field using precision irrigation, optimizing water usage and minimizing waste. The system integrates components of the WEFE nexus, enhancing water security through rainwater collection and treatment, promoting energy security by reducing reliance on groundwater abstraction, improving soil quality, and enhancing food security through sustainable agricultural practices.
A one-year long dataset was generated from a set of individual process-based sub-models that simulate diverse components of the nexus, including (a) the system’s water balances (comprising infiltration, surface runoff and evapotranspiration), (b) water quality dynamics in the storage tanks, (c) energy consumption, and (d) plant growth dynamics, based on the estimated water stress and nutrient limitations that affect growth and yield. To mimic real-world conditions, we introduced random noise and incorporated missingness, simulating the variability and incompleteness of observational data. SR was applied to the dataset, aiming to inversely estimate the equations that describe the functional behavior of the NBS. SR employs a multi-population evolutionary algorithm, which navigates within the space of analytic expressions in search of accurate and parsimonious models.
The results unveiled parsimonious expressions that captured the dynamics of the system across different external hydrometeorological forcings with reasonable accuracy. These equations provided interpretable insights into the mechanisms underpinning this rainwater harvesting system, resonating, at the same time, with existing scientific understanding. This approach is an example of the potential of data-driven methodologies to enhance the understanding of NBS and their capacity to address multifaceted challenges. Even if a globally valid analytical expression for such systems is probably infeasible, this work managed to set-up a data-driven methodology for deciphering the WEFE nexus at a local scale, providing also a tool for optimizing NBS performance and informing decision-making.
How to cite: Kandris, K., Markatos, N., Nika, C. E., and Katsou, E.: A symbolic regression approach to illuminate the water-energy-food-ecosystem interlinkages in a rainwater harvesting system, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10713, https://doi.org/10.5194/egusphere-egu25-10713, 2025.
Nature-based solutions (NbS) draw researchers’ attention as they can offer numerous co-benefits to the society and environment, as opposed to the traditional grey infrastructure, while having a potential to offer the same level of protection against water-related hazards, such as floods. Therefore, NbS are deemed a viable option to climate change adaptation. However, proof of their effectiveness in mitigating water-related hazards, especially at a large-scale level (i.e., at a catchment level), are still lacking. Ex-ante assessments, which are needed for initiating NBS projects, heavily rely on the modelling, mainly hydrological and/or hydrodynamical. The effectiveness of NbS is quantified through modelling exercises, by comparing simulated hazard levels simulated with- and without an NbS implemented. However, these assessments of NbS effectiveness are fraught with uncertainties, which primarily stem from the way they are accommodated in the models. Specifically, there are no clear guidelines on inclusion of NbS in the models, and evaluation of their effectiveness.
To learn about modelling of the NbS effects on reducing water-related hazards, a survey was distributed among the RECONECT (http://www.reconect.eu/) participants. The survey contained questions about the NbS and water-related hazards considered, and on the details on the models employed to simulate NbS effects, as well as on the indicators used to gauge NbS effectiveness. In most cases, flood hazard was considered, while the respondents reported various NbS (e.g., retention ponds, flood plain restoration, afforestation and reforestation). The respondents indicated that the NbS were included in the models by (1) changing model parameters (e.g., to represent afforestation or reforestation), (2) by including additional computational elements in the model (e.g., storage-type elements that represent retention ponds), or (3) by changing simulation settings to represent hydraulic structure operation. The way in which NbS are modelled was also dictated by the features of the model used. In some instances, some NbS could not be modelled, since they act at rather small-scale, and their effects could not be captured by a model (e.g., check dams in the headwater parts of a catchment). The respondents reported various indicators, but those related to flood hazard was most frequently reported one. Generally, all respondents agreed that the NbS modelling remains a great challenge, and that specific guidelines are needed.
To facilitate bridging this gap, a new survey on modelling of NbS effectiveness in reducing water-related hazards is launched. The new survey focuses on the “water” aspect of the NbS effectiveness, and delves into specific details on the model development and application. The main goal of this research is to target a wider audience (such as audience at EGU), and facilitate sharing knowledge on modelling of the NbS effects. It is the authors’ firm belief that sharing knowledge on modelling of NbS effectiveness can promote their wider implementation, and aid sustainable mitigation of water-related hazards, and adaptation to climate change.
Acknowledgements
This research received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No. 776866 for the research RECONECT (Regenerating ECOsystems with Nature-based solutions for hydro-meteorological risk rEduCTion) project.
How to cite: Todorović, A., Plavšić, J., Manojlović, N., Tseng, K., and Vojinović, Z.: Ex-ante evaluation of NbS effectiveness in mitigating water-related hazards at a catchment level, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17756, https://doi.org/10.5194/egusphere-egu25-17756, 2025.
Posters virtual: Mon, 28 Apr, 14:00–15:45 | vPoster spot 3
EGU25-1523 | Posters virtual | VPS12
Assessing the Potential of Traditional Stone Weirs in Stormwater Management Through Integrated EO, In-situ and Crowdsourcing DataMon, 28 Apr, 14:00–15:45 (CEST) | vP3.21
Nature-based solutions (NBS) employ natural processes to mitigate climatic risks and evolving environmental challenges, offering sustainable, cost-effective alternatives to traditional grey infrastructure. Traditional stone weirs are considered multifunctional and environmental friendly structures contributing to sustain ecosystems and protect communities from water-related hazards. This type of NBS has shown potential to mitigate flood impacts through controlled water flow and sedimentation retention by reducing both water velocity and erosion during peak flows, with main objective to enhance community resilience to climate change. During CARDIMED project a network of 120 traditional stone weirs will be developed and applied in Sifnos island (Greece) strategically placed across two main streams aimed at mitigating flood risks, recharge aquifers, enhancing biodiversity, and supporting small-scale agricultural water use, tailored to the unique arid ecosystems of the Greek islands.
This study aims to monitor the efficiency of stone weir NBS in order to quantify climate adaptation benefits, particularly in relation to stormwater regulation, with application area Sifnos island (Aegean sea, Greece). The analysis utilises an integrated monitoring approach which couples remote sensing observations with in-situ data collected through monitoring stations, off-the-shelf sensors, and crowdsourcing participatory campaigns. Earth Observation techniques based on Sentinel-2 are employed to derive relevant vegetation and water indices (i.e. NDVI, NDWI), enabling to assess of vegetation health, soil water availability, and land surface dynamics. These are expected to be complemented by high-resolution datasets from Copernicus Contributing Missions, such as WorldView and Pleiades imagery, to enhance spatial and temporal resolution at locations of interest. EO techniques are validated by in-situ data derived from monitoring systems installed at strategic locations which provide localized, real-time measurements of hydrological, meteorological, and ecological parameters under different climatic conditions. The proposed methodology has the potential to provide key information about the quantified impacts from the application of stone weirs but also an understanding about their scalability as sustainable solutions for enhancing climate resilience at regional scale.
Acknowledgement:
This research has been funded by European Union’s Horizon Europe research and innovation programme under CARDIMED project (Grant Agreement No. 101112731) (Climate Adaptation and Resilience Demonstrated in the MEDiterranean region).
How to cite: Michalis, P., Kossieris, S., Papachristos, E., Petrakos, K., Sakellarakis, F.-N., Tsimiklis, G., and Amditis, A.: Assessing the Potential of Traditional Stone Weirs in Stormwater Management Through Integrated EO, In-situ and Crowdsourcing Data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1523, https://doi.org/10.5194/egusphere-egu25-1523, 2025.
EGU25-1168 | Posters virtual | VPS12
Assessing Nature-Based Solutions using the HEC-RAS modelling system: a reviewMon, 28 Apr, 14:00–15:45 (CEST) | vP3.32
Nature-based solutions (NBS) have gained increasing attention in flood management since the early 2000s as sustainable alternatives or complements to conventional flood defence strategies. Based on a systematic review of 1,080 published studies, we provide recommendations for implementing common NBS intervention types in flood management using the HEC-RAS modelling framework. The review considered published case studies ranging from small catchments of approximately 0.09 km² to large river basins exceeding 2,400 km².
The potential interventions explored include reforestation/afforestation, floodplain reconnection, wetland restoration, channel re-meandering, and the hybridization or removal of grey infrastructure. The recommendations detail how to adjust key parameters within HEC-RAS to effectively represent these interventions. For instance, increasing Manning's roughness coefficients can simulate the added vegetative roughness from reforestation. Likewise, modifying the digital elevation model allows for the representation of floodplain reconnection, benching, or channel modifications. By offering quantifiable methods and a clear linkage between interventions and hydraulic parameters, this work equips practitioners and researchers with the necessary tools to model flood mitigation strategies using NBS within HEC-RAS. To generalise the findings beyond HEC-RAS and make them applicable to other hydraulic modelling platforms, each intervention is linked to specific terms in the governing equations: conservation of mass and momentum equations, highlighting how parameters such as friction slope are affected.
How to cite: Sabeti, R., Rodding Kjeldsen, T., Chambers, M., Moftakhari, H., Stamataki, I., and Simmonds, S.: Assessing Nature-Based Solutions using the HEC-RAS modelling system: a review , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1168, https://doi.org/10.5194/egusphere-egu25-1168, 2025.
