Quantification and transferability of decentralised Nature-based Solutions' effects for pluvial flood mitigation

Abstract

Decentralised Nature-based Solutions (NBS), such as swales and green roofs, contribute to flood mitigation during heavy rainfall events. The quantitative impact of these systems on flood mitigation can be determined using 1D/2D coupled models. However, developing such models requires comprehensive geospatial data and technical expertise. This article presents a methodology to transfer the detailed flood reduction effects of NBS from a 1D/2D simulation to other catchment areas using effect curves. For this the following information is required: the total catchment area, the total roof area and the potential for implementing NBS. This includes the green area available for infiltration systems (roof area is connected to the systems) and the roof area that can be converted to green roofs. Given these characteristics, the validation shows that the effect curves can be used for an initial estimation of NBS performance in reducing floods in the new catchment area. However, simulations are required for a detailed assessment of NBS performance due to the heterogeneity of catchment areas.