- Workers are
beginning to transform a heavily eroded, silt-clogged stretch of Sandy
Creek near Duke University's West Campus into an eight-acre restored
wetland and flood plain designed to help protect the drinking water
supply and control stormwater runoff in central North Carolina.
- The
restoration, a project of the Duke University Wetland Center, received
the final permit from the City of Durham in June and is expected to take
about four to six months to complete. It is being funded by nearly $2
million in grants and in-kind gifts. Project sponsors include the Clean
Water Management Trust Fund, the North Carolina Ecosystem Enhancement
Program, Duke Forest, Duke's Facilities Management Department, the EPA
319 Program, and the Wetland Center.
-
Construction began after nearly five years of research and planning
aimed at restoring the degraded bottomland hardwood wetland around Sandy
Creek. "By restoring the natural flood plain that used to be here before
the onslaught of urban development, we'll recreate a healthy wetland
ecosystem that sops up pollutants and improves wildlife habitat," said
Curtis Richardson, Director of the Wetland Center and Professor of
Resource Ecology at the Nicholas School of the Environment and Earth
Sciences. Other faculty members from the Nicholas School and Duke's
Pratt School of Engineering are also collaborating on the project.
- The project
will include re-contouring and replanting more than 2,000 feet of
degraded stream as well as construction of an earthen dam and four-acre
stormwater reservoir. Duke Forest's Al Buehler Trail, located near the
Washington Duke Inn and Golf Course, will pass along the dam.
- The site
will serve as an outdoor classroom and field laboratory for students and
researchers from Duke and other area schools and universities. Signs
along the trail will inform the public about the project and the role of
wetlands in promoting water quality.
- Stormwater
from about 1,400 acres of Durham, including much of Duke's campus,
drains into Sandy Creek, carrying heavy concentrations of sediment and
urban pollutants. Sandy Creek is a tributary of New Hope Creek, which
meets all state pollution standards when it enters northern Durham
County but often is in violation by the time it leaves southern Durham
County bound for Jordan Lake, part of the region's drinking water
reservoir.
- A hike along Sandy Creek's current path where it flows under State Road
NC 751 east of the Duke University Road intersection reveals a
sediment-choked streambed with crumbling banks, downed trees, and
vegetation too sparse to retain soil during heavy downpours. During big
storms, nitrogen and phosphorus levels in the water can reach three to
five times the state limits.
-
Increasingly large amounts of land in Durham are covered by impervious
paving. Over the years, torrents of storm water diverted by this paving
have cut deeply into Sandy Creek's banks, eroding its natural bends and
creating "a straight chute for sediment and pollution," Richardson said.
"We've lost the bends and contours that allowed the water to overflow
into surrounding bottomlands, where wetland plants and soils could
absorb the majority of the pollutants."
-
Richardson's team will address that problem by engineering a new, more
naturally meandering streambed for Sandy Creek and filling in its old
channel. Creek banks and low-lying areas will be re-contoured and
planted as hardwood wetlands, which researchers believe will remove up
to 70 percent of the creek's sediment and nutrients.
-
The new dam and reservoir to regulate stormwater will replace a
deteriorating dam farther downstream. A short stretch of the Al Buehler
Trail will be re-routed across the dam to provide unobstructed views of
the reservoir, wetland, and wildlife. Trail closures during construction
will be brief, Richardson said, and advance notices will be posted at
the trailheads.
- A four-acre
wooded area to be flooded by the reservoir will be cleared in coming
weeks, and other trees that will not survive the raised groundwater
levels around the reservoir and new flood plain also will be removed.
Cleared trees will be used as "rootwads" to help stabilize the new
stream channel and to provide habitats for fish. New wetland trees will
be planted to replace any that are removed.
- "Our goal
is to recreate an ecosystem similar to what you would have found here 75
to 100 years ago," Richardson explained. He and his team have completed
a biological census of the area and collected three years worth of
pre-restoration data on its soil, water, plants and wildlife.
- Besides
being an example of a rare Piedmont wetland, the eight-acre ecosystem
will provide a site for research on biological diversity, hydrology,
mosquito control, invasive plant species and other environmental
concerns. "What we learn here will benefit many wetlands and watersheds
nationwide," Richardson said.
Tim Lucas
Nicholas School of the Environment and Earth Sciences
|
Nicholas School of the Environment and Earth Sciences
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