Nature-based solutions efficiency evaluation against natural hazards: Modelling methods, advantages and limitations

Abstract

Nature-based solutions (NBS) for hydro-meteorological risks (HMRs) reduction and management are becoming increasingly popular, but challenges such as the lack of well-recognised standard methodologies to evaluate their performance and upscale their implementation remain. We systematically evaluate the current state-of-the art on the models and tools that are utilised for the optimum allocation, design and efficiency evaluation of NBS for five HMRs (flooding, droughts, heatwaves, landslides, and storm surges and coastal erosion). We found that methods to assess the complex issue of NBS efficiency and cost-benefits analysis are still in the development stage and they have only been implemented through the methodologies developed for other purposes such as fluid dynamics models in micro and catchment scale contexts. Of the reviewed numerical models and tools MIKE-SHE, SWMM (for floods), ParFlow-TREES, ACRU, SIMGRO (for droughts), WRF, ENVI-met (for heatwaves), FUNWAVE-TVD, BROOK90 (for landslides), TELEMAC and ADCIRC (for storm surges) are more flexible to evaluate the performance and effectiveness of specific NBS such as wetlands, ponds, trees, parks, grass, green roof/walls, tree roots, vegetations, coral reefs, mangroves, sea grasses, oyster reefs, sea salt marshes, sandy beaches and dunes. We conclude that the models and tools that are capable of assessing the multiple benefits, particularly the performance and cost-effectiveness of NBS for HMR reduction and management are not readily available. Thus, our synthesis of modelling methods can facilitate their selection that can maximise opportunities and refute the current political hesitation of NBS deployment compared with grey solutions for HMR management but also for the provision of a wide range of social and economic co-benefits. However, there is still a need for bespoke modelling tools that can holistically assess the various components of NBS from an HMR reduction and management perspective. Such tools can facilitate impact assessment modelling under different NBS scenarios to build a solid evidence base for upscaling and replicating the implementation of NBS.

An integrated assessment of land use impact, riparian vegetation and lithologic variation on streambank stability in a peri-urban watershed (Nigeria)

“…Hence any alteration in their natural disturbance regimes could potentially trigger several geomorphological processes, such as irregular hydrologic regimes, cyclic sequence of erosion and deposition, and bankline migration. Riparian forest buffers provide essential ecosystem services, such as cycling of nutrients, stabilisation of streambanks, restoration of aquatic and terrestrial habitats, trapping of sediments, and reduction of flood hazards, among others 27 , 57 – 60 . Therefore, riparian forest buffers are one of the major nature-based solutions (NbS) used to stabilise streambanks and restore the riparian ecosystem.…”

Hydrological Modeling for Flood Adaptation under Climate Change: The Case of the Ancient Messene Archaeological Site in Greece

“…Hydrological models are useful tools used to assess climate change impacts and flood risks for the development of adaptation strategies [43]; they have been successfully used for the better understanding of nature, and to provide analytical tools to water managers and design engineers for risk assessment, and project planning and implementation [44]. In particular, in concerning NBSs, hydrological models are often used to quantify the hydrologic impacts of potential NBSs within watersheds [21,45]. The modeling tool used in the present study for the simulation of floods in Ancient Messene was MIKE SHE 2020, developed by the Danish Hydraulic Institute Water and Environment-DHI Water and Environment, a built-on coupled physics-based model for overland flow, unsaturated flow, ground water flow, and a fully dynamic channel flow, including all of the complex feedbacks and interactions [46,47].…”

“…The modeling tool used in the present study for the simulation of floods in Ancient Messene was MIKE SHE 2020, developed by the Danish Hydraulic Institute Water and Environment-DHI Water and Environment, a built-on coupled physics-based model for overland flow, unsaturated flow, ground water flow, and a fully dynamic channel flow, including all of the complex feedbacks and interactions [46,47]. MIKE SHE was successfully used in many studies to simulate the potential of NBSs for mitigating flood risks and climate change impacts (e.g., [45,48,49]).…”

Conceptual and Operational Integration of Governance, Financing, and Business Models for Urban Nature-Based Solutions

“…Nature-based solutions (NBS) are gaining traction as a novel umbrella concept that represents solutions inspired by and composed of nature, offering an alternative to traditional grey solutions. NBS are considered multifunctional and cost-effective solutions that are capable of addressing societal challenges [1][2][3], for example in providing strategies for the mitigation of natural hazards [4][5][6]. However, compared to traditional grey solutions, conceptual uncertainties (e.g., return of investment) still arise around NBS projects, hampering their acceptance among decision-makers and private stakeholders [7].…”