Repeated Hurricanes Reveal Risks and Opportunities for Social-Ecological Resilience to Flooding and Water Quality Problems

Hurricanes
that damage lives and property can also impact pollutant
sources and trigger poor water quality. Yet, these water quality impacts
that affect both human and natural communities are difficult to quantify.
We developed an operational remote sensing-based hurricane flood extent
mapping method, examined potential water quality implications of two
“500-year” hurricanes in 2016 and 2018, and identified
options to increase social-ecological resilience in North Carolina.
Flooding detected with synthetic aperture radar (>91% accuracy)
extended
beyond state-mapped hazard zones. Furthermore, the legal floodplain
underestimated impacts for communities with higher proportions of
older adults, disabilities, unemployment, and mobile homes, as well
as for headwater streams with restricted elevation gradients. Pollution
sources were repeatedly affected, including ∼55% of wastewater
treatment plant capacity and swine operations that generate ∼500
M tons/y manure. We identified ∼4.8 million km2 for
possible forest and wetland conservation and ∼1.7 million km2 for restoration or altered management opportunities. The
results suggest that current hazard mapping is inadequate for resilience
planning; increased storm frequency and intensity necessitate modification
of design standards, land-use policies, and infrastructure operation.
Implementation of interventions can be guided by a greater understanding
of social-ecological vulnerabilities within hazard and exposure areas.