Waterways
Designing Stormwater
for Small Watersheds
Wetlands
Distributed in furtherance
of the Acts of Congress
of May 8 and June 30, 1914.
Employment and program
opportunities are offered to
all people regardless of
race, color, national origin,
sex, age, or disability.
North Carolina State University,
North Carolina A&T State
University, U.S. Department
of Agriculture, and local
governments cooperating.
North Carolina has become a very
desirable place to live and visit. The
state has a robust economy, mild
climate, and beautiful environmentally
diverse landscapes. Thriving environ¬
mental communities such as mountain
forests, piedmont streams, and coastal
estuarine waters are major reasons why
people choose to vacation or settle in
North Carolina.
Yet the influx of people has also put a
burden on environmentally sensitive
areas of the state. New shopping centers,
schools, offices, roads, and homes have
increased the amount of stormwater
runoff and have encroached upon or
eliminated many sensitive environmen¬
tal areas.
Perhaps the most documented impact
has been on the state's wetlands. Wet¬
lands are typically low-lying areas that
have water tables near or at the surface
for extended periods of the year. This
wet hydrologic condition creates unique
wetland soils (called hydric soils) and
supports wetland vegetation.
Development and agricultural uses
have converted roughly 50 percent of
the state's historical wetlands into
uplands, or drier land. This practice is
not new; even George Washington took
part in draining North Carolina's
wetlands. Once drained, wetland soils
are some of the most agriculturally
productive in the state. Wetlands are
often located adjacent to larger water
bodies such as streams, ponds, and
estuaries. By converting wetlands into
drier land, property can become avail¬
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able for lucrative waterfront develop¬
ment. Historically, new development
and wetland preservation have been
viewed as mutually exclusive goals.
New development does more than
affect the quality and amount of wet¬
lands. With development comes an
increase in pollutants such as sediment;
nutrients, such as phosphorus and
nitrogen; toxic chemicals and metals; oil
and grease; and litter. These pollutants
eventually enter North Carolina's
streams, rivers, ponds, reservoirs, and
sounds. The state of North Carolina
now requires much new development
to implement practices that reduce the
amounts of pollutants reaching our
water resources. These practices are
referred to as Best Management Prac¬
tices (BMPs). Some BMPs include
pollutant reduction strategies (or
practices) such as limiting fertilizer
spread on lawns or limiting the amount
of impervious surfaces in a watershed,
such as roads and parking lots. Other
BMPs are structural, meaning that they
are constructed. Detention ponds, sand
filters, and vegetative swales are
examples of structural BMPs. (For an
overview on structural BMPs, please
see Urban Stormwater Structural Best
Management Practices, AG-588-1,
another publication in this series.)
An almost ironic structural best
management practice is the stormwater
wetland. Stormwater wetlands are
designed to treat stormwater runoff
from developed areas. Instead of being
in conflict with development, wetlands
