A modelling approach to assess Nature Based Solutions efficiency

The adoption of Nature Based Solutions (NBS) to mitigate several classes of natural hazards is becoming progressively frequent in the climate change perspective. Herein, we present an innovative modelling framework designed to allow an accurate assessment of the efficiency of NBSs under current and future climate conditions. This work leverages on NBSs designed, developed and implemented in the framework of the OPERANDUM project, to reduce hydro-meteorological risks in European territories. Specifically designed, multi-scale models-chains are described and applied to NBSs implemented in novel Open-Air Laboratories (OALs) where a range of hazards, from pluvial/fluvial flooding to landslides, from coastal erosion to desertification take place.

In the OAL-Ireland at Dublin site, where fluvial and pluvial flooding is considered to be the natural hazard, a modelling chain has been developed in order to investigate the effectiveness of two NBSs adopted. An inclusive model will be generated by linking the Regional Climate Model(RCM), Soil Water Assessment Tool (SWAT), and Greenroof models. This will allow the simulation of the total flood condition corresponding to different climate change scenarios and accounting for both fluvial and pluvial flooding at different temporal and spatial scales. Meanwhile, in the OAL-Greece at Spercheios Catchment river site, where several hazards related to flooding such as coastal discharge droughts and salt intrusion occur, a modelling chain for the assessment of the NBS concernings flood levels and groundwater resources has been used. For the flood levels and the flood mapping outputs TUFLOW model is being used. For the representation of terrestrial hydrologic processes and groundwater the analysis has been carried out by means of WRF-Hydro and MIKE model respectively.

The novel methodologies presented here can be instrumental to provide crucial science-based evidence of the efficiency of Nature-Based Solutions and to promote them as a mainstream approach.