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Concentration of CO2 in the Atmosphere

Finding and Redressing Flood Risk Inequities

On July 29, 2021, rainfall and subsequent flooding caused a significant landslide dangerously close to a young family’s home. (Photo: Joseph Endris.)

Michael J. Daley

Even with a heroic effort to turn every bit of cropland, pasture, hay field, and barren ground into forest, a unique study of flooding in the Lake Champlain watershed by University of Vermont (UVM) scientists generated sobering news: such a massive change in use of the land would only prevent about 20% of the predicted damage climate change induced flooding will cause during the next 100 years.

Also, the benefits of such drastic intervention would mainly accrue to high value property owners leaving most mobile home dwellers, low-income people, and the disadvantaged, well, down the river without a paddle.

A paper describing the study titled, “Inequities in the distribution of flood risk under floodplain restoration and climate change scenarios,” appeared in the British Ecological Society journal People and Nature. A UVM press release announcing publication quotes lead author Jesse Gourevitch, “This research shows that the Vermonters least able to prepare and recover from flood damages disproportionally face the greatest threat.”

Fortunately, in a separate but relevant development last year, the Vermont Legislature established the Flood Resilient Communities Fund (FRCF) in an effort to correct some of these disparities. The FRCF focuses on buyouts of flood vulnerable properties, emphasizing projects that prevent repeated losses for low-income and marginalized Vermonters. Applications for the third round of grants are due by October 2022 with $4.6 million in funding available. While Gourevitch and team focused their first study on Lake Champlain, they say their new model can be of help to a wide-range of communities in determining what areas and citizens are most vulnerable to flooding.

Among all the increasingly frequent and severe disasters we face due to climate change, the paper notes research indicating that, “Flooding is the most widely experienced, deadliest and costliest natural hazard in the United States and globally. Already climate-change-induced increases in extreme precipitation events have contributed one-third of flood damages incurred in the U.S. between 1988 and 2017, with a cumulative impact of $73 billion.”

In hopes of providing policymakers with a tool to better target flood mitigation efforts, Gourevitch and four other colleagues associated with Gund Institute, developed a model to predict not only dollar damages, but to whom and where the damage might occur. Previous models rarely put these two elements together. For their pilot study, they chose five Vermont watersheds of Lake Champlain: the Lamoille, Mattawee, Missiquoi, Winooski and Otter Creek rivers.

First, they generated a baseline as if no climate change was happening. They then modeled expected climate-change impacts. Finally, they modeled a maximum imaginable flood mitigation effort. The authors state, “To simulate floodplain restoration, we converted cropland, pasture, hay and barren land cover classes to deciduous forest…this approach was designed to estimate the upper bound potential of floodplain restoration through reforestation”

The result?

“Over a 100-year time horizon [period – ed.], 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%.”

In email communication with this reporter, Gourevitch acknowledged that any real-world mitigation efforts would not reach the model’s ideal, thus damage reductions would be less than 20%.

In addition, modeling revealed that even this modest damage reduction mostly benefited high value properties. Simply put, a flood event that trashes a mobile home while also flooding the basement of a million-dollar home is not the same kind of catastrophe for each homeowner. Yet the more costly damage drives many flooding analysis and damage awards. The authors note, “This bias in monetary valuation is codified by FEMA’s hazard mitigation assessment methodologies, through their use of benefit–cost analysis. In the absence of equity weighting, these methodologies create perverse incentives in prioritizing flood mitigation interventions, whereby wealthier property owners often receive greatest protection.”

This shortcoming no doubt influenced Vermont legislators to create the FRCF. Experience with disaster recovery after Irene revealed many instances of inadequacy in FEMA reparations. Many of the first round FRCF grants awarded directly seek to help people who fell through the cracks, such as a young family in the Town of Rockingham whose home became dangerously unsafe due to a landslide. Of the nine municipalities awarded grants in the first round of submittals, five were to finance buyouts of flood prone properties.

Third round FRCF applications are due by October 2022 and are open not only to municipalities, but non-profits, and others. Vermont Emergency Management Director Erica Bornemann is encouraging eligible applicants to “think creatively about what types of projects could make a difference in their communities.”

Michael J. Daley is a life-long renewable energy educator and advocate, except for a brief time in high school when he thought nuclear power was cool. He lives in a tiny off-grid cabin in Westminster, VT with his wife, Jessie Haas.

Sources

The Paper: www.bit.ly/Flood_paper

Flood Resilient Communities Fund website: www.bit.ly/Vermont-frc-fund

Rockingham Home: www.bit.ly/frc-fund-projects

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