Assessing the Co-Benefits of green-blue-grey infrastructure for sustainable urban flood risk management

Abstract

Green-blue infrastructures in urban spaces offer several co-benefits besides flood risk reduction, such as water savings, energy savings due to less cooling usage, air quality improvement and carbon sequestration. Traditionally, these co-benefits were not included in decision making processes for flood risk management. In this work we present a method to introduce the monetary analysis of these co-benefits into a cost-benefits analysis of flood risk mitigation measures. This approach was applied to a case study, comparing costs and benefits with and without co-benefits. Different intervention strategies were considered, using green, blue and grey measures and combinations of them. The results obtained illustrate the importance of assessing co-benefits when identifying best adaptation strategies to improve urban flood risk management. Otherwise green infrastructure is likely to appear inferior than more conventional grey infrastructure. Moreover, a mix of green, blue and grey infrastructures is likely to result in the best adaptation strategy as these three alternatives tend to complement each other. Grey infrastructure has good performance at reducing the risk of flooding, whilst green infrastructure brings in multiple additional benefits that grey infrastructure cannot offer.

Implementation of Nature-Based Solutions for Hydro-Meteorological Risk Reduction in Small Mediterranean Catchments: The Case of Portofino Natural Regional Park, Italy

“…The assessment of the impacts of hydro-meteorological events will address aspects such as society, built environment, park-generated ecosystem services, and biodiversity. For this purpose, the project team will apply a variety of methods-see, for example, [5,10,47,48]. The ecosystem services will be classified and quantified by applying a non-monetary donor-side approach based on emergy accounting (see, for example, [49,50]).…”

Nature-Based Solutions for hydro-meteorological risk reduction: A state-of-the-art review of the research area

“…However, it is important to note that very often a combination between natural and traditional engineering solutions (a.k.a. "hybrid" solutions) is likely to produce more effective results than any of these measures alone, especially when their co-benefits are taken into consideration (Alves et al, 2019).…”

“…Donnell et al, (2018) used BEST and the Blue-Green Cities toolbox to assess benefits, and Mills et al, (2016) assessed air pollution reduction based on tree canopy. Alves et al, (2019) presented a novel methodology for valuing co-benefit for NBS application in urban contexts. In order to evaluate benefits effectively , Fenner, (2017) recommended that their spatial distribution should be assessed through multifunctional design making possible to identify how this is valuable to stakeholders and where the overall aggregated benefits occur.…”

A Planning Support Tool for Layout Integral Optimization of Urban Blue–Green Infrastructure

“…Although the components of UBI and UGI are totally different, it has become evident that their services and spatial layouts may be correlated and that they can complement each other [6]. Consequently, recent research increasingly considers UBI and UGI as an integrated system and explores their combined environmental and public services [7,8].…”

“…For example, synergy in the layouts of UBI and UGI can take full advantage of the benefits of both green and blue technologies and services [6,9]. UBI and UGI can maintain natural water cycles and increase flood resilience by interacting with urban gray infrastructure [7,10,11]. As a nature-based renovated.…”