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DuPont Newport Superfund Site, Newport, Delaware
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Woody debris was positioned along the bank at the Pike Property ecological restoration site. Debris will provide banks protection from boat wakes and roosting, nesting, refuge, and foraging opportunities for wildlife. Credit: DNREC |
The Problem
In 1902, pigment production began at
the Newport Site in Wilmington, New
Castle County, Delaware, and was
owned by Krebs and later DuPont,
who bought the facility in 1929.
DuPont continued to manufacture
pigment until 1984. Two portions
of the Site bordering the Christina
River were used for waste disposal.
The waste migrated through runoff
to the surrounding wetlands and the
River. Contaminants of Concern
(COCs) at the Site were primarily lead,
cadmium, and zinc. In 1987, the U.S.
Environmental Protection Agency
(EPA) added this Site to the National
Priorities List (NPL). The Site was
remediated between 1996 and 2001.
Restoring the Resources
In 2002, the National Oceanic
and Atmospheric Administration
(NOAA), the U.S. Fish and Wildlife
Service (USFWS), and the Delaware
Department of Natural Resources and
Environmental Control (DNREC)
(Trustees) pursued a cooperative
natural resources damage assessment
with DuPont (Responsible Party).
During negotiations 40 potential
restoration projects were considered
and a preferred alternative (“Pike
Property”) was selected. In 2006, a
settlement was reached. DuPont paid
over $2.2 million dollars for natural
resource damages, approximately
$608,933 was used to improve tidal
wetland habitat.
Accomplishments
The Pike Property is located along the Mispillion River between Kent and Sussex
Counties in Delaware. This privately owned 56 acre property included a degraded
oxbow overgrown by Phragmites, an invasive plant and eroding banks. This restoration resulted in significant habitat improvements in the Mispillion River ecosystem—home to many valuable natural resources, such as blue crab, Atlantic herring, spot, and striped bass.
Along the river, large diameter coarse woody debris (LWD) were used to provide immediate protection from boat wakes and trap organic and mineral sediment. Long-term protection will be provided by the re-establishment of vegetation. In addition to bank protection, the woody debris will enhance fish and wildlife habitat by providing roosting, nesting, refuge, and foraging opportunities
Removal of Invasive Species
Phragmites and dense stands of
cattails were removed by aerial
spraying with glyphosate for three
consecutive years. Standing dead
canes were removed by controlled
burns. A more diverse plant
community has recovered in 90% of
the marsh. Native plants, such as
pickerelweed (Pontederia cordata),
arrow arum (Peltandra virginica)
and salt marsh cordgrass (Spartina
alterniflora), now dominate the site.
Wild rice (Zizania aquatica) has
begun to colonize areas where soil is
thin layered. A combination of tree
seedlings and shrubs were planted
on the natural upland levees adjacent
to the oxbow channel in order to
enhance the song bird habitat.
Creation of Fish Rearing Areas
The oxbow channel has filled in over 50 years because tidal exchange has been diminished. A portion of the oxbow channel was dredged to a depth below Mean Lower Low Water. Selected mudflats were dredged to create fish rearing areas. Based on photo records from 1938, these mudflats were once tidal pools. Spoil from the dredging was broadcast over the marsh in a thin layer (≤ 3 inches).
Links:
Press Release -
Restored Mispillion Wetland Offsets Losses from Superfund Site (pdf)
Fact Sheet - Dupont Newport Superfund Site, Delaware
Damage Assessment and Restoration Plan/Environmental Assessment -
Word doc (2MB)
pdf file (2 MB)