New Flood Study Reveals America’s Most Vulnerable Communities
06/21/2017

Thousands of homes were devastated by flooding in inland communities in Louisiana
in August 2016.Photo Credit: Nina Lam, LSU
BATON ROUGE – Floods are the natural disaster that kill the most people. They are
also the most common natural disaster. As the threat of flooding increases worldwide,
a group of scientists at LSU have gathered valuable information on flood hazard, exposure
and vulnerability in counties throughout the U.S. They studied development trends
from 2001 to 2011 and found that urban development has declined in coastal flood zones
in general across the U.S. However, development in flood zones in inland counties
has grown. These results and more have been published in the Annals of the American Association of Geographers.
"We found more urban development in the inland flood zones than the coastal areas
between 2000-2011, which is a worrisome trend. The implications are that people living
in the coastal zone want to migrate inland, but don’t realize they are still vulnerable
if they live in the flood zones in inland areas," said Nina Lam, LSU professor of
Environmental Sciences in College of the Coast & Environment and co-author of the
study.
This alarming trend may point to a need for more awareness, education and communication
about flood risk in inland counties, said the researchers. More affordable housing
in non-flood zones and strategies to mitigate floods are also needed inland.
“The results show that people in coastal areas are more aware of flood threats than
those living in inland flood zones, and that populations in inland areas are increasing.
This information could aid future flood-planning efforts in inland communities,” said
Judy Skog, a director of the National Science Foundation’s Coastal SEES, or NSF’s
sustainability program, which co-funded the research.

LSU Department of Environmental Sciences Professor Nina Lam and colleagues have published
a new study that shows while Americans in coastal communities have become more aware
of the risk of building in a flood zone, inland communities lag behind as construction
continues in inland flood zones. This research is funded by the U.S. National Science
Foundation.Photo Credit: Eddy Perez, LSU
The researchers compiled urban development, flood hazard and census data and overlaid
it on a map of the U.S. Although their analysis shows that Americans in general have
become more aware of the risk of floods over the 10-year study period, the researchers
identified several U.S. hot spots where urban development has grown in coastal flood
zones including New York City and Miami.
The three counties in the U.S. that have the largest concentration of people living
in a flood zone are located on the Gulf of Mexico. Cameron parish in Louisiana has
93.6 percent of its 6,401 population living in the flood zone, Monroe county in Florida
has 91.4 percent of its 66,804 population and Galveston county in Texas has 82.8 percent
of its 241,204 population living in a flood zone.
“This nationwide study of flood zones, human populations and urban development provides
a tool that could be used globally,” Skog said.
Climate change, land subsidence and new levees and dams will change long-term flood
exposure. Therefore, the accuracy of flood maps must be investigated.
“Flooding is the most common and widespread disaster we face nationally, and the one
that is the easiest to alleviate by effective planning,” said Richard Yuretich, a
director of NSF’s Dynamics of Coupled Natural and Human Systems, or CNH program, which
co-funded the research. “This study provides important data on flood hazards across
the country, and demonstrates that the research and education about floods that has
been done over the past decade has helped manage risk. Yet there are still places
where people are in harm’s way.”
This study was funded by the U.S. National Science Foundation grants CNH 121211 and Coastal SEES 1427389.
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Contact Alison Satake
LSU Media Relations
225-578-3870
asatake@lsu.edu