ENTACT completed capping activities at this former industrial waste landfill. Scope of work included installation of a subsurface HDPE drainage system to depths up to 40 ft utilizing specialized one pass trenching equipment; construction of 2,830 lineal ft of slurry wall around perimeter of existing landfill to depths up to 40 ft; construction of a groundwater treatment system; construction of a 22 acre landfill cap; installation of new groundwater monitoring wells and abandonment of existing groundwater monitoring wells; site restoration including grading for water management; seeding, and installation of erosion control matting on the newly constructed cap; installation of gas vent system.
Additionally, ENTACT created approximately 6.48 acres of palustrine mitigation wetlands adjacent to the landfill cap and containment site. ENTACT completed the construction and grading of the wetlands footprint including a site access road, installation of erosion and sediment controls, clearing and grubbing, and staking of the mitigation wetlands footprint. A total of 78,000 bank cubic yards of overburden soils were removed during the construction phase. After overburden removal, ENTACT placed and graded 28,560 cubic yards of topsoil. The finish grading activities consisted of constructing the dry shelves and low flow trickle channels, installation of the water flow channels, placement and preparation of a one-foot topsoil layer, and installation of five 36-inch drainage pipes and associated rip rap aprons.
Following final grading and topsoil placement, 425 live plugs were installed within the flow channels (Duck Potato, Lizards Tail, Blue Flag, Soft Rush, Bur-Reed) and 600 sapling trees and shrubs were planted in the shelves (Primarily Poplar, Red-Osier Dogwood, Pussy/Black Willows, Tag Adler).
ENTACT completed remediation activities at this NPL site that included excavation, on-site treatment, and off-site disposal of over 110,000 tons of lead-impacted soils and sediments; excavation of impacted sediments from the Army Corps of Engineers drainage channel and the East and West Streams adjacent to the site; installation of storm water management controls around identified excavation areas; controlled sediment removal to minimize sediment re-suspension; conditioning of saturated soils in staging area to render suitable for transportation; and site restoration including seeding of affected stream banks and wetlands restoration.
Habitat Restoration Details:
Characterization samples were collected from the streambeds of the West Stream and Army Corps of Engineers drainage channel at a frequency of 1 sample every 100 linear ft to determine if lead concentrations exceeded the cleanup criteria. Those areas of the stream bed determined to exceed the cleanup standard were excavated using long-stick excavators to distances of 50-ft in the West Stream and 25-ft in the Army Corps of Engineers drainage channel on either side of the sample location. Excavation depths averaged approximately 6 inches.
The palustrine forested wetlands, palustrine scrub/shrub wetlands, palustrine emergent wetlands, and open water areas associated with the West Stream and the site were replanted per the requirements of the Wetlands Mitigation Plan developed by the Project Engineer. Emergent herbaceous species, such as Soft Rush and Rice Cutgrass, were planted within 10 ft of the stream bank. Scrub and shrub species, such as Arrowood, Silky Dogwood, and Highbush Blueberry, were planted within 10 to 25 ft of the stream bank. Forest and scrub/shrub species, such as Swamp White Oak, Red Maple and Pin Oak, were planted at distances greater than 25 ft from the stream bank.