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Marks the Spot Environmental group maps landslide
prone areas
By Scott Nicholson
An environmental group is combining landslide maps with
county deed records to show which areas might merit additional
engineering before development.
D.J. Durkin, senior attorney with the Southern Environmental Law
Center, said his organization put the project together at the
request of local residents, using North Carolina Geologic Survey
maps that marked historic slope movement, debris flow, and potential
rock slope instability. Those maps were presented at a public
workshop last year.
Durkin’s organization overlaid the maps with property records
to count the parcels that have had a geologic record of landslides.
“The Southern Environmental Law Center works directly with
other non-profits to provide them with resources they might not
have,” Durkin said. “What we have with these maps is
a series of information about how the county is growing. It’s
pretty timely with a comprehensive plan to make that vision a
reality in the future.”
Durkin said the maps show existing subdivisions in the county,
based on planning maps. Durkin said by comparing property-tax
maps with landslide data, the maps show where people are living
in relation to potential hazards.
Durkin said the combination of historical data and recent growth
shows “a fair amount of subdivided land that hasn’t
been built yet.” He said the lots may be for sale or eventually
built upon, with about 3,000 landslides indicated by geographic
data.
“Just because these landslide hazards are here doesn’t
mean people can’t build,” Durkin said. He said building
on such sites may require additional expertise in order to ensure
the site is safe.
Durkin said 990 houses in the county are sitting on lots where
landslides have been recorded, and another 321 sites are subdivided
and available for building sites or other development.
Durkin said because the numbers might be difficult to grasp, the
analysis becomes broad, but by zooming in to an area, “the
numbers become a story.” He said the Laurelmor development,
Heavenly Mountain and Powderhorn subdivision are located in areas
with some history of landslides.
“Currently, when you file a subdivision plat, you have to
denote a flood plain,” Durkin said. “In the same way,
you could require notification of a landslide area, so the developer
would know to take certain precautions.”
Durkin said there were costs attached for geotechnical engineering,
from $500 and up. “One thing about the numbers is it’s
very scaled to a specific area,” he said. “It wouldn’t
take much time for an engineer to come out and tell you you’re
building on a safe area.
“Most landslide areas are very steep, and houses there usually
cost a lot more money,” which made additional investment
make more sense. Durkin said the potential damage outweighs the
cost of engineering.
“The moral there is not that you can’t build on those
slope-hazard areas, but you need to do so carefully,” he
said.
In 2004, a Peak’s Creek flood in Macon County led to five
fatalities when a landslide occurred, and Durkin said it was a
margin of 50 feet between life and death.
Durkin said it was impossible to pinpoint exact locations of landslides
and the debris flow that results, in the same way flood levels
can be estimated but are unpredictable.
Durkin said there have been threats of litigation regarding landslide
hazards.
“That’s beside the point, though,’” Durkin
said. “These risks are real, but they may take 100 years
to come about. It’s much better for everybody if you plan
for a house to be there for 100 years.”
The Southern Environmental Law Center hopes to educate the public
by providing the maps,
“You’re one of only two counties that have these maps
with the very best science available,” Durkin said. “You
have the best picture available of where your risks are and the
ability to make responsible decisions and proportional decisions
in how to address that. That’s something the county can clearly
do with ordinances.”
Durkin said there were also potential liability questions but
it was an area of law that had been little explored. Haywood County
has crafted such an ordinance, though it wasn’t passed soon
enough to avert a slide. Durkin said a recent case in a Maggie
Valley landslide led to a house sliding downhill and destroying
another house.
“There’s a fair amount of misperception about addressing
the hazards,” Durkin said. “It doesn’t mean they
(houses) can’t build, it just means they need to get an expert
on the site to tell them what they need to do. These maps can
tell someone they need a site-specific look at their property,
and I think that’s the mitigation.”
The maps will be given to people in the county who request it,
as well as county officials.
“I think there are some great ideas out there without undermining
the development community, and I think it’s just a matter
of what the county wants to do with it,” Durkin said.
The county currently has no plans to review a landslide ordinance,
though the North Carolina Geologic Survey maps are available through
the county Web site at eww.geology.enr.state.nc.us/Landslide_Info/WataugaCounty.html.
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