Inequities in the distribution of flood risk under floodplain restoration and climate change scenarios

Abstract

The combined impacts of climate change and ecological degradation are expected to worsen inequality within society. These dynamics are exemplified by increases in flood risk globally. In general, low‐income and socially vulnerable populations disproportionately bear the cost of flood damages. Climate change is expected to increase the number of people exposed to fluvial flood risk and cause greater property damages. Floodplain restoration has the potential to mitigate these impacts, but the distribution of future risks among different types of property owners under these altered conditions is often unknown. Here, we develop a simple probabilistic approach for estimating flood risk to property owners under floodplain restoration and climate change scenarios for a range of flood recurrence intervals. We apply this approach in the Vermont, USA portion of the Lake Champlain Basin. Over a 100‐year time horizon, we estimate that the value of property damages caused by flood inundation is approximately $2.13 billion under the baseline scenario. Climate change is expected to increase damages to $5.29 billion, a 148% increase; however, floodplain restoration has the potential to reduce these impacts by approximately 20%. For all scenarios, a larger proportion of lower‐value properties, specifically mobile homes, face greater flood risk compared to higher‐value properties. Climate change is expected to cost higher‐value properties and commercial properties more than other types of properties, but these same groups are also expected to benefit most from floodplain restoration. In general, these results raise concern that those least able to prepare for and recover from flood damages are also the people who face the greatest threats. In response, public policy interventions must consider not only where flood risk is most severe, but also the vulnerability of people exposed to such risk. Read the free Plain Language Summary for this article on the Journal blog.

Terrain‐derived measures for basin conservation and restoration planning

“…These measures help to identify and rank the potential of improved function of stream reaches for conservation and restoration planning and represent a novel use of a new generation of low‐hydraulic‐complexity topographic‐based tools (Diehl et al, 2021; Zheng et al, 2018). Increasing availability of high‐resolution geospatial datasets has supported the development and implementation of these tools at broad scales, notably HAND‐based approaches for flood mapping and flood hazard assessment (Diehl et al, 2021; Gourevitch et al, 2020, 2022). We demonstrate the extended applicability of HAND‐based approaches, which may be broadly adopted to inform river condition and function.…”