DuPont Newport Superfund Site, Newport, Delaware
Damage Assessment and Restoration Plan/Environmental Assessment

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.

woody debrisLarge peices of wood along the channel will reduce bank erosion caused by boat wakes. Credit: USFWS
Bank Protection
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.

Filled channel Oxbow channel before it was dredged to create to fish rearing areas. Credit: USFWS

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)

 

Last updated: February 13, 2013