Green Infrastructure

A social equity approach to reduce flood risks due to extreme weather events

PRESENTED BY: Juliana Reu Junqueira

Green infrastructure is promoted as a suitable response to climate change and increased flood risk. With regard to urban retrofitting, one significant benefit associated with GI is their ability to perform multiple functions, including reducing flood risks on private land or property. Bio-retention cells, rain gardens and permeable pavements are solutions that can be easily retrofitted in the urban landscape as they require minimal space to be implemented and may not involve negotiations with private property owners. However, while the hydrological performance of GI has been acknowledged, there is still a lack of understanding about the varied efficiency of these alternatives at different scales and combinations, and how they could be used to increase access to greenspace within deprived areas. This study contributes to filling this gap for decision-makers by developing a method to assess the performance of different combinations and quantities of GI options in reducing flood risks under different extreme rainfall events (various intensities/durations) and then linking this to social equity issues. We tested this method in two case studies in Aotearoa-New Zealand: Auckland and Gore.

Our findings show that:

  1. the implementation of GI in targeted areas within a catchment can reduce flood risk;
  2. GI alternatives can play an important role in mitigating the effects of climate change, although this varies between highly urbanised cities and small regional towns, and the selected combinations; and,
  3. implementing GI with a clear social equity dimension can be a way of minimising green gentrification and reduce socioeconomic disparities in the access to environmental amenities