We must be proactive to avoid another catastrophic flood
Oregon's story can't be told without talking about floods. The cataclysmic Missoula floods that flowed down the Columbia River Gorge formed the northern Willamette Valley's fertile landscape.
The tragic Vanport flood of 1948 inundated a slapdash public housing project where much of Portland's Black population lived, displacing 18,500 residents. The Heppner Flood of 1903, the Christmas Flood of 1964 — these and many other floods are part of our disaster lore.
Unfortunately, floods are becoming a more frequent part of our story because climate change is causing more rain to fall in the winter and spring and is melting snowpack in ways that increase flood risk. Sea-level rise adds to that risk along the coast. In four of the last five years, national disaster declarations for extreme storms, floods and landslides have been declared in Oregon.
Floods and other natural disasters do the greatest harm to socially vulnerable populations. A 2019 report by the National Academies of Sciences, Engineering and Medicine found that neighborhoods where residents are poor, where racial and ethnic minorities are concentrated, where the elderly and disabled live, are disproportionally affected by floods.
I am part of a Portland State University team that came to the same conclusion. Our spatial analysis found that the potential for flooding and extreme heat is most acute in East Portland's low-income neighborhoods. Factors contributing to these risks include too much impervious pavement and not enough parks, green spaces and trees. In the summer, paved areas create heat islands because they absorb heat; during the rainy season, they create excessive stormwater runoff because they do not absorb rain.
We must reduce flood risk and create communities that are more resilient in the face of natural disasters, starting with and centering those communities at greatest risk. This involves engaging these communities directly to determine their vulnerabilities and to learn directly from them what they need, building leadership and supporting community-based organizations while we're at it. By engaging communities in greening neighborhoods, we can also "multi-solve" for many other challenges, including extreme summer heat, leading to yearlong improvements in air quality and human health.
Proactive approaches include updating essential infrastructure (e.g., schools and hospitals), restoring wetlands and flood plains, and utilizing green infrastructure (e.g., trees, ecoroofs and vegetated bioswales that capture and treat stormwater runoff). We must also change public policies that put people in harm's way — doing away with incentives to develop in flood-prone areas. And we must move people out of harm's way — acquiring property vulnerable to flooding and helping families relocate.
At the federal level, a bipartisan bill, the Flood Resiliency and Taxpayer Savings Act (H.R. 8462), has been introduced. It requires federal agencies to plan for the future risk of floods — forecasting forward instead of relying on outdated historical models — before funding any new infrastructure or improving or repairing existing infrastructure. And the bill directs federally funded projects to build in a margin of safety, such as nature-based mitigation strategies or elevation, when flood risk does exist.
As we leave behind 2020 (which, in December, included stormwater and sewage overflow into the Willamette River), it's time to take flooding seriously. Smart policy and community-based action in 2021 will ensure that the story we tell about floods in the future is a story about how we worked with nature to create resilient communities that protect the most vulnerable among us.
Vivek Shandas is a professor at Portland State University and research director for PSU's Institute for Sustainable Solutions.
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